VHF COMMUNICATIONS 3f96

Wo(fgang Schneider, DJ 8 ES

VHF, UHF and SHF MeasuringMethods Using a PC

Part 1: Essentials of ControlUsing the PC's Centronics Port

Developing VHF, UHF and SHFml'3suring methods is an ambitiousgoal. Rad io amateurs can s i lll p l ~" notdo without mea suring methods non,in connection with build ing th eir ownequipment o r CHn opera ting theirown radio systems. Ohtainin g thea ppa rat us requ ired for this is nota lways simple, and is certainly nota lways inexpensive.

1.ll'iTRODliCTlON

There are particularly interesting possi­bilities for DIY work in the area ofmeasuring methods. Numerous differentpublications in the relevant amateurradio literature support this opinion.Wh ether it' s a test transmitter, a milli­watt metre or even a spectrum analyser ­as Robert Lentz, DL3WR, once wrote inVIIF Communications - "state of the art

technology comes to DIY assembly" ,

All these devices have one thing incommon, they should he usable over aswide a range as possible. But it is notsufficient for the milliwatt metre tofunction well at 23cm alone, It mustgive readings which an: j ust as precisein the short-wave range, at 2m or "Ocm.

And it's precisely here, when »c cometo deal with wide-hand linear operat ion,that the problems really begin. Thecomputer can help us here to a reallymiraculous extent. Linear isation of tun­ing characteristics in the test transmitter,automatic calibration of the \....aumcrer,zero offset compensation, etc" The listof possibilities is virtually endless.

Specifically, this series or articles willdeal with the themes of input and outputunits lor Centronics interfaces, mWmeters, frequency synthcsisers, and acomputer-controlled measuring position,with additional options for a wobblerand a spectrum analyser.

165

2."OSSIII LE LI:'/KS TO A PC

VHF CO MMUNICATIONS 3/96

If the computer is to take over co ntro lfunctions, it must be able to communi­ca te with the outside world. fhar s whatinterfaces are for.

Now y Oll can find virtually everything inthe PC line which is nvailahlc Oil themarket.

However . before this universa l measur ­ing pos itio n comes intu being, theprinciples must be s.cl nut fi rst. Th isapp li..-s. in part icular. to the d igita lwor ld of the personal coenpcter . Corn­putcrs can now he: found in the shackso f the major ity of rad io amateurs . Tostart with. we used the C6·1 or I.X RI forapplic ations which were still " relatively

limited".

OTAOlIE

00

••D2

os....DO.,AC ......

..,OY

PEBLeTFF

, .

•••~•

RESET

ERROR

GROUND

erer IN

DJ 8 ES

2. 1. Pli rdUd Interfaces

Any commercia lly availabl ... !"C has atleast ooe pamllcl imcrfacc as per theCentronics norm as It standard feature,10 which rhc primer is connectcd . bUIthis interface can do much more!

The data traffic between the PC and theprinte r is carried O1l through a minimumof 8 data circuit s and 4 cont rol circ uits .

When data arc transmitted, the transmit­ter sends the data ucm on circuits nil tuD7 and chec k.. whether the subscriber isready tn recei ve data (HUSY) ,

As soo n 3., I~ BUSY circuit accepts alogic O. the transmitter generates aSTROBE signal (br iefly, a logic I) andenters the informat ion into ihe pcriph­eraL

The printe r ackrllm kdy;e, u..ill~ theACKNLG signal (ACK NOWI.I .lXiE).

The PE circu it WAI' U( Er.. W I'Y) s ig~

nels thai the printer has run 0111 of

paper.

These four con trol circ uits are all that isneeded for data transmission.

Many printe rs have addilional ' contro loptions. I shall not be gning illhl theseadditional options in grea ter dctai l hereand now, But they arc included in Fig. l,for the sake of completeness.

FiU,I : P in· Assiunmt'n t for a36- llin-Cl'nlrollie Co nnec to r

166

'-"'-==="-==-"=-------------(~

Fig.2: Driver Circuit for DrivingSwitc hing Stages

2.2. Co ntro l using the CentronicsInterrace

The circuits referred to above can beused as follows in control tech nology:

DO to 0 7 as exi t

ST ROB E as haudovcr signal

ACKNLG, BUSY, 1'1-: as entry

All circuits on the Centronic s interfaceope rate at trans istor transis tor logiclevel. Switching stages, transducers. etc.can he connected up directly here. Dueto the fact that the switchabte power is

on ly "low", drivers (c.g. 74 LS244 Of

LS245) sho uld he looped in. Theypro vide multiple amplification for theswitching current .

To wire up lamps. motors, etc.. relay'smust sometimes be inserted into thecircuits . O ptoelectronic couplers areused here too, for de-coupling, and soarc elect ronic load relays.

De-coupling an he reco mmended, espe­

cially for appli cations using supp lyvol tage (or at higher volta ges). Fig.::?:shows simple driver cir cuits tor driving

switching stages .

2.3. Adapter Ca rds for Experiments

A simple and eas ily monitorahle adapterca rd is useful tor the first pract ical te sts.

lh c circu it is shown in Fig.3 . It includ esthe bus driver for the output circuits DOto 1)7 and, as an updated sta tus d isp layfor a ll circuits , LED's o r various co l­ours .

With th is adapter card, we can "sec"whaf s going on in fro nt of us (FigA).Fig.5 shows th e com ponent s plan to r thedouble-sided printed circuit board .

Fig.3:The Ce nt ron icsAdapter CardFully Asse mbled

167

VHF COMMUNICATIONS 3196\~ - - - - - - --- ----'-""-== = ""-'==

""'SY ..ACKNLG ='0sreoee ~

~0 , •O. ~•O.

~0,~

O. C0, ••n C

•• ~

i

~~~-0 ,

D, ~O.

OJ 8 ES

.~ ====E=~======~ ACKNLG ---=jC

~e~

Fi~A : Centronics Ada ptt'r Card Circuit: sctminstette -: In terface

gelb grCm '".., ~ ...,. , ~,

+5V · · ... · """ :", " ', ~', '.. ' , ¥" '." " '> ' ."_.... .. , ... .... - - ' ... .... - :.:: ':

Fi~.5 :

Components Plan ofAdapter Card

Gelb == Yellow;(,',,111 = Green;Rill = Red:.,tllschlujJ = Connectio n

168

VHF COM MUNICATIONS 3/96

Cidddddc:idAusgabe~ 378h

W0

~QW e,

" •~

w"" 0 "

I~z w

~Q

< • "0 < w e< • • W

Input [111 10 [iiE3ElJ]] 379h

"c

", ~e, Q, W

D..J 8 ES " W IW0 ~ " QW Q Q

" • ~ i~w w• "Output CIJJ:=::36 ,31E4EJ 37Ah

Fig.6: Allocation of Cont rol Signalsto cor responding Register

3.ACT lIATI:'IG THE Il"TER·FACE

The PC must be appropr iately pro­grammed so that it can comm unicatewith the outside world.

The logic addressees) of the built-inCentronics interface in the computeris/are important in this context. Thisis/these arc dependent on the hardwareconfiguration :

278h - 27ah

378h - 37Ah or

3BCh - 3BEh

In each case, the first address - 27Sh.378h or 3BCh (vh' signifies "option" inhexadecimal) - actuates the data registerof the parallel interface. Data can beentered into this B-bir register by thecomputer , to be output to the externalequi pment.

DO - Pin-2

D! - Pin-3

up to

D7 • Pin-e

The second address in each case - 279h,379h or 3BDh - actuates the so-calledstatus register of the interface. Specialreplies from the printer arc depos ited inthis register, \,...hen ACKNOWLEDGE is

•

0 ,0 ,0 ,0 ,0 ,0,0 ,0 ,

~E

AIm> FErn-.ilLE---eT'i"--

I ' I I I I~ I I ! I I I ; ! : II ' I I ,JHI II,;~~ lS 374 ~4 lS 374 ~174lS 374 : 74 lS 374

j I ! , ! , ,II i IIj •

~ -

h 'I~.

I D.J a ES

1

Fig.7: Register as O utput for 4 Data Items, each 8 Bits long

169

VHF COMMUNICATIONS 3/96

o 1 2 3

~cn I i1'-....1 •

. i b . ,i I ,

,,

~~ ~1574 74 "1LS173 LS173 ... LS173

'-rnI rrI,

I I II

D.D.D,D.

DJ 8 ES

...·il!.R: Output Unit o rga niwd as 16 \. 4 ni b

there on hit 6 (pin- Hl]. BUSY 011 bit 7(pin-Il ) and PA PLR END Oil bit 5(pin-l 2). The thi rd address in each case- 27Ah. 37Ah or 3HEh - actuates thecontrol register of the interface . Here wefind the ST R.O HE signal on bit ()(pin- ! ).

N. B.: The STROBE signal is output III

invert ed form For example, if it isdesired to output a " I" 011 the STROBEcircu it, a "0" must be entered ill hit O!Various other circuits arc a lso inverted!The s ignals are correspondingly idcnti­fled.

Fig.6 shows the allocat ion of all controlsignals to the various registers. Forexample. here we have the con tents forthe addre sses 378h. 37% and 37Ah. lheboxes show the rele vant pins of theJ(j.p i n ~Cen trollics connector

3. 1. Tesl I'rugram in IJ,t,SIC

A simple Hnsic program checks thefunct ioning of the adapter card . As aFirst step, a running light is programmedfor the output circuits. so that theSTROBl : Fl ashes. The three input cir-

1 2 3 ••• .. 17 1e" ...

11U~

~74150 , 741501

~rr1I ~J I

• I~

• I I•

enwco

d

o,

••••••••Fig.9: Circuit Proposal for 32-bit Input into Time 'I ult iplex

170

VHF COMMUNICATIONS 3/96

+o 0 0o 91 PI

,.~ O 2'11' 0~ O

:t o :::Ie," 0 'Ct..

c:tD"'mt.:IcnN

I:D 0_. N... 0)

0 .1'1

Fi~.IO : 32·hil Input l;nil3.2. Output functions

Merely observing: flashing LEn·s is ab onor satisfac tory in the long run.

_._.~-~--

I

Fi~.ll:

Exper imenta lSetup for 32·bitInput Unit

171

VHF COMMUNICATIONS 3/96(~ ---------------'=.>"""'=""-"~~It cert ainly looks nice. but my PC issupposed to be controlling something:For the PC to be able 10 tak e over thiscontro l function, it has to "talk" to theworld beyond itself. This leads usdirectly to one of the most importantaspects of the interface, namely theinputt ing and outputt ing o f data.

The simplest case (x-bit output) call beco vered by the Centronics inter faceimmed iately and without any expansionof any kind. If applicable. ST ROBE canbe used, in addition to the 8 bits ])0 to0 7, as an intercha nge signa l tor periph­era ls.

100 REM output[ 10 REM data120 OUT 888. I)ATA130 REM STROBE signa l140 OUT 890,0150 OUT 890. 1

A further interesting output option canbe implemented in an easily monitorab leway using. 4 x 8 bits. In addition toSTROBE. the circ uit shown in Fig.7a lso uses the other outpu t signals RE­S ET, SELECT-INPUT and AU1'O­FEED (H) as interchanges. with thedata bei ng entered in output latches inR-bit blocks.

3.3. Data output in ti me mutnprcx

It is also possib le to output data bymeans of the time multiplex process.This method considerably increases thenumber o f ports which can be d ifferenti­ated. Il ere Fig.8 shows a path for amaximum of 16 x 4 bits. The individualdata items for eac h " b its are transmittedsequentially in this system.

100 REM out put time multiplex110 RE\ 1 data + address120 FOR ADDR ESS = 0 TO 15130 OUT SIlS. DATA - ADDRESS*16140 REM STROBE signal150 OU T lNO,O160 OUT S90. 1170 NEXT ADDRESS

3..1. In put fu nct ion

At tirst glance . it looks as if even moreeffort is required for input, And yetthere are only 5 input bits there in all.As a rule. th is is too le w. Only a time

multiplex process can be cons idered forinputting entire datil items (1 byte ormore).

rig.9 proposes a circuit for inputt ing 32hits. The ind ividual bits are sequentia llyscanned and read in through the PA PERE\1 PlY (PE ) circuit. For this purpose .the data circuits DO to 0 4 se lect theind ividual input channels . The desireddata formats (c.g. 4 x S bits) are then setup internally through software.

100 RE,\;l input time multiplex11 0 FOR ADDRESS :::: 0 TO 3 1120 OUT SSS. ADDRESS130 INPUT - I!'JP ( S8~) A\D n1·10 I!'JPUT "'" I ~ PUT!32

150 PRINT A DDRESS, INPUT160 r\ EXT A ODRESS

Fig.1O shows one side of the printedcircuit board for the 32·hit input unit,wh ich is coated on both side s. Theprototype for this expe rimenta l printedcircuit board can be seen in Fig. I I.

And now all the best for your firstexperiment s.

To he continued

172

VHF COMMUNICATIONS 4196(fo ---------- - --'-"'--==="'-"'==

Wol}'i:;ang Schneider, DJ8ES

VHF, UHF and SHF MeasuringMethods Using a PC

Part-2: Milliwatt Meter FromShort Wave To SHF

A wattmeter is definitely a necessityfor th e active r ad io amateur, andthere' s probably one in every shack.Hut what about low-power measure­men ts '!

Is the vro s till supp lying the correctoutput level, or wha t' s the controlpower level for the tra nsvcr tcr? O r,or, or... A simple mw mete r can helpill many such cases.

I.GENERAL

Many descriptions have been written inthe relevant amateur radio literature inthe past on the assem bly of milliwatt

meters - and 1 hope this will contin ue inthe future. Two main measuring meth­ods could be distinguished:

1. Thermal power measureme nt (bo lom­eter). and

2. Measurement using high-freque ncyrect ifier diodes

This arti cle will neither be dea ling withthe theoretical princ iple s of the twooptions nor contrast ing the ir advantagesand disad vantages.

Whethe r a bo lometer or a diode detectoris used . they have one problem incommon - the linearity over a frequencyrange as large as possible. It is j ust notgood enough if the mill iwatt metermere ly works well at 23cm - it mustgive read ings just as accurate for shor t­wave . from 2m to 70cm.

Fig. I :Diode Detector withHigh-Frequency RectifierDiode

206

VHF COMMUNICATIONS 4196

U' j." ,l.4 i,, ',' 1....

••

Detektor 15599("d. Nr. 501)

Erequenzkorrektu.t;

28 MHz 1.025tI MHz 1.00

U4 MHz 1.00432 MHz 1.00

1296 MHz 1.112320 MHz 1,.18

144 MHz

Fig. 2:O ul put Volla ge, dt'pcnd{"nl o n r owe ra nd Frequen cyn etctaor = Detecto r: l jil. Nr. = Scr. 11 0 . ;

t-reqoemkorresmr = Freque ncyco r rectio n factor

OJ 8 ES

"•rc• .\.-..,-,~e=:;,::' ~ . - r,-~~,~ p

~ - ,

••

....

..

Many authors offer interesting analoguesolutio ns to this prob lem in their publi­cat ions. But there arc others too !

The ratios arc shown in graph form inFig.2 and arc listed systematically in thetable.

l.inc arisution of characteristics, auto­matic calibration of the power meter,zero point correction. etc. - you canconfidently entrust these jobs to theco mputer!

What is described be low, then, is anIlIW meter which enjoys the advantagesor ,I Pc. A simpler and faster way tomeasure power is the afo rementionedmethod using high-frequency rectifierdiodes. Fig.1 shows the standard circu it.

The output vo ltage. LJ" , which is de­pendent on the input power, PtN' and thefrequen cy response are important valuesfor the description of the circu it. Thecharacteristics can be plotted simply,using adjustable o utput power and avoltmeter as accurate as possible, e.g. ad ig ital gauging instrument.

Another simple circuit (Fig.3) operateswith simultaneous voltage doubling .Two gennan ium diodes (type AA 119)supply an output voltage proport ional \(l

the input vo ltage.

2.TH E CIRCIJITS

2. 1. The Detector

/\ measurem ent detector should fullilvarious crite ria:

The wide dynamic range is provided bya type ISS99 Schottky d iode. Moreover.the wide frequency range goes fro m the

207

VHF COMMUNICATIONS 4196(~------------"-''-===''-'-'''==

p. i 1hQIl I1n 2x _50 _ M119]n 10k

u. f ig, 3:High-freq uencyRectification with Volta geDoubler

2.2. t he A I n converter rill' them\V meier

short wave right into the GH z range.Apart from the components selected, themain factor determ ining the frequency isan assembly appropriate for high fre­quency! FigA shows the circuit of theme asurement detector for frequencies ofup to 2.5 onz,

The detector supplies an output voltagepropo rtional 10 the input voltage (Fig.2).T he high-Ohm input de-couples themeasurem ent detec tor from the rest ofthe circuit. This is brought abo ut via ano perat ional amplifier (y, LM324) withV "" 1. The subsequent comparatorcompares the reading with a comparisonvol tage generated by the Pc. In accord­ance with the up-to-da te condition, thereis 0 V or • 5 V at the PE connection("paper empty" ).

The PC controls the entire measurementproc edure through the Centronics inter­face.

The comparison vo ltage just referred tois generated by a D ! A converter(ZN42fiE·8) from an x-bit data word .

Fig, 4:The completed Circu itwith li n 15599 asDet ector

The validity range runs from 0 to

2 55d~1 '

The procedure uses the success iveapprox imation principle.

Rapid 0 / A con version is accomplishedwith the help of this method. An attemptis made to guess the voltage read ing.Naturally. this sequential proces s is notcurried o ut randomly, but is done inaccordance with a balancing process, inaccordance with which one feel s OJH: ' sway towards the desired value in a lewsteps . Natura lly, this happens very la st i fa PC is used .

When the measurement begins. the valueis fed into the D / A convener whichcorr esponds to exactly half the max i­mum voltage. A comparato r reportswhethe r the comparison voltage ishigher or lower.

If the voltage to be measured lies in thebottom half of the range, this is div idedagain into two halves. If the uppersegment is involved, the procedure isexactly the same.

Thus each new experiment narro ....s thevoltage range dO\\I1 more and more. Forg-bit accuracy, the successive approxi-

27

-oo-

P~

:ro0 '-

208

>.-t-~~-.--% u....eQ10k

VHF COMMUNICATIONS 4/96

'OnH ..

0 , CO 6.00, Q ,0, W 4u7O. Q ._ - -" Cll JH0 , , ~ CIJ

l lj ... 00, • 1+0, _' a, Z 1k *'n0, N o .

•w -,2k7

• LM324

..

+12V6 , u-.-

DJ 8 ES

u..1k'Ok

J.

Fig. 5: The complete A / 0 Converter with Centronics Interface

merton procedure requires only eightsteps to yield a result.

The comparison voltage (LlDAd of theA / 0 converter is fed out as a check.Anyone who wan ts to may connect asimple direct reading instrument to pointUMe'll to obtain a relative display.

3.SOFTWARE

The flow chart on the following page­(Fig.7) shows the steps of the processvery clearly.

The screen is set up as a first step. Thismust be done before the actual measure­ment ro utine begins.

The prevailing reading is continuouslytransmitted in an endless loop, andconverted into the proportional powerwith the help of the detector characteris­tic line from Fig.2.

Last of all, it only remains fill' acorrection factor to be brought intoaction, corresponding to the measuredfrequency. The frequency range can beadjusted for this purpose at any time viainput through the keyboard .

The measured poe....er is displayed on thescreen in mW and dBm. The readingscan be displayed as a graph withoutfurther ado. There are 110 limits to whatthe interested programmer can do here.

209

(~----------~~~"""'-"""=

Detektor

+9·15V

DJ 8 ES!=cxx:oc:cc>e U",

AID­Wandler

:xx=oocc.....=o U,

Centronics

4.ASSEMBLY INSTRUCTIONS

Special attention should be paid whenassembling the measurement detector.A suitab le assembly for high frequencyis an absolute must for the desiredbroadness of band! That means shortconnecting wires , tidy ea rth connectionsand a mechanically stab le structure.

The carr ier material can he, for exam­ple, the hexagon nut from a HNC plug,sawn off in advance. Don' t forget tode-burr it!

Set up screen ]

Pre-set frequ encyrange

r-r--r-r-:!Determ ine upda tedn'ading (socccsstve

apprO;l:lma tinn)

IReading mlllt~licd. Iby freque ncy actor l,

_~__ --.J

Display reading

IL-._

Changefrequenc y y"

No DJ 8 ES

Fig. 7: Flow cha rt

210

Fig. 6: Hooking lip t he Detecto r, theA I 0 Converter and the PCDetek tor = Detector:A / D Wandler = A I I) converte r

fi~. R:IntJh id u,lIl1clcclorCHm pu nt'n h

lhc .~ l1lall number or -nucurral r Ul1Ip'"

ucm-, i-, -otdvrcd cuuo or' into 11K'I ~' , idlldl threaded ,,'Cl i' lil and Ih~' 11

111"0\ i J~' J II i th -horr 1\ i re ':11 ..1,

l eU ;\ >!, dianl,'!':1 lmm r tor plug. ;md" .,-I.", t ' IIt.' detector prep ared ill thi..

\I; l~ i-, 11l '\\ , n cl' cd imp the plllg .mdnlup l i ll >! hl1tl , ing. \\ lim 1iln c l i llil a l il ~

ha-, hecn ,ul:c ,' ~, tl1 l l ~ tc-acd, ,I dr op ofr,lpid -ill'li llg adhesive Ih es all ( Oll1pO­ncnt-, ol the completed mca-urcmcnr

de tector.

I ig.x ..ho\ ' " add itiona l dct.ul-, r (.' ~a rd ing

the lnvuut and incorp oration " I' Ihl"r ,.nlp,11I(.'111'> ,

H~, ca :mW Meter t .ayoutU.J8[ S 027

211

VHF COMMUNICATIONS 4/96

also be operated by a simple compactbattery.

5.CALIBRATION ANnPRE-SETTINGS

(~ ---------_-"-".':-""'''''''''"'''-'''''''~

The board for the A I 0 converter isdouble-sided coated epoxy mater ia l1.57mm thick. The board measures75mm x 75mm..

Marching bores are to be provided forthe IC' s and the trimming po tentiometer.The same applies to the Cent ron ics plug

and the UUAC' UDat- U~lcl\ and + 12 Vconnections.

Righi up to the Centronics plug, all theco mponents arc mounted on the foi lside! This also applies to the Ie's andthe trimming potent iometer (F ig.9) .

1\11 earth connec tions are soldered onboth sides. The earth surface may not hemilled down in advance here!

Finally, the entire circu it can he incor­permed into a housing. as selected. Ahigh-quality plug connection should betaken into account for the measurementdetector lFig.IO).

Th e low current consumption for thecircuit - app. 12mA at 9V - means it can

Th e complete ca libration of the mWmeter assembly can be divided into 4steps:

- Characteristi cs of Diode Detector

For the diode detector, the outpu tvoltage shou ld be meas ured in relationto the input power. All exped ient way todo this is to use a d igjtnl voltmeter anda 144 MHz standard signal generator. Atransceiver with an adiusrablc transmis­sion powe r will also lit the hill, o rcourse. Fig.2 shows the levels and somepossible step sizes.

BC848B r-,C\. -0 "~-en ":;WJ .co ~-.., -c -

Fig.9b:Component Plan of A I 0Conver ter Assembly

212

VHF COMMUNICATIONS 4196

r

Fi~, 10: The Pr in ted Ci rc uit Huard alo ne lind as Full)' Com ptet ed Ilnit

Rated valin: at 144 Mllz

Measured value

- Co r rec tion factor liU

Tight tolerances in the component s, oreven in the D I A conv erter ZN426 E-8,lead to d iscre pancies in the measuredvo ltage . The factor d U acts as a thee­rerica l correc tion factor . It has a valueof app. 0 .0 I. The reference voltage ,URcf' can be precisely measured at pin5ifi of the D I A converter with a digitalmeas uring instrument.

An apprupl'"i,"'ne measurement J:!rdph isusually provided with ready-made mens­uring beads.

If we increase the number of measure­ment po ints, the accuracy of the equ ip­ment COin be furthe r increased . Theprogram is designed for a minimum stepwidth of IdB. The corresponding ..-aluesfihou ld he entered in a table.

- Correction factor Sf

Part icularly at high frequen cies, theact ual in put impedance devia tes fromthe expected value by 500 . A correctionfactor , 81: theoret ically balances this out.

The factor should be measured fur thefrequen cy ranges 28, 50 . 144, 432,1.296 and 2.320 MHz, with a contro lpower o f, for example. l mW (OdUm):

aU =U Ref

256

213

VHF COMMUN ICATION S 4/96(~ ----'-""-'~"""'''''_'2''''''_'''_''''

10k Potentiometer for relative dis­play of measured power

If no diode detector is connected up,maximum power is displayed. Themeas uring instrument should now be setto end-scale defle ction using the potenti­ometer.

The detector readings and the correctionfactors for frequency and voltage arelisted in the table MWTABLE.TXl,Any standard text editor makes it possi­ble to correct th is table using theupdated values lor the d iode detectorused.

This also applies to the Centronicsinterface des ired. Ll'fl, LPT1. or LPlJcan he used, depending on the configu­rat ion of YOllr own PC.

and in surface-mo unte d format :

I x BCR4RB transistor or the like1 x 1'A 78LOSF voltage regulator1 x l. 0llF i 35V tanta lumI x 4.71lF i 25 V tanta lumI x 10,uF i 20V tanta lum

all resistors and capacitors surface­mounted (1206/0R05 format)

I x 2702 x loon1 x Mw n4 x Id2I x 2.71.:£14 x 101(0I x lMDI .\ 120nl-'1. x InF3 x 10nl-'

6.COMI'ONF.NT LIST

7.L1T F:RAT lIRF: RI·:FI<:IU:NCI<:S

I x l SS99 Schottky diodeI x ZN426E-8 0 i A converter1 x LM31.4 operations ampli fier1. x (J(j RR AiU BNC plugsI x UGS9 AiU BNC cable jackI x 36-pin Centron ics ja ck

(print ing installation)l O x 1.3 mm. diameter termina l pins

I x 10 k trimming, potentiometer (hori­zontal, IOmm bas ic grid)

[1 1 Carsten Vic land. DJ4GC: UHF andSHY Broadband Mixers,VHF Communications 1/19S 9,pp. 39-45

L2] Det lef Burcha rd: Linear SignalRectificat ion (Pa rt I)VlI F Communications 3/1994.pp.168 - 179

214

VHF COMMUNICATIONS 1/97=~~~~~"------------(~

wolfgang Schneider, DJ8ES

VHF, UHF and SHF MeasuringMethods Using a PC

Part-3: 0.9 - 1.5 GHz SynthesizerT he frequency sytuhecizer can hethought of as one of tile corners ton esin the str uct ure of an amateur radioenthu siast ' s mea surin g eq uip ment.Even just a 23e m signa l to balancethe pre-amplifier, an oscillator for thenew 2m mi xer module. All the fre ­qu encies which arc of interest toamat eur rad io enthusiasts should becovered, a t t he lowe st pos sible cost.

It is obvlc us t hat all th ese wishe s ca nnot be granted right aw ay with justnne piece of eq uipm en t. Ai least, 1I0t

at a re asun a hlc cost and wi th th emeasurement options no rmally av ail­ahle!

I,

GEl'iERAL

The following article , "0 .9 - 1.5 Gf lzSynthesizer" , describes the core of sucha unit, the tuna ble osci llator (VeO) withthe phase control circuit (PLL). Inaddition to the Vr'O, the synthesizermodu le and its prog ramming arc of vitalimportance in this context (Fig. l :1,

Othe r module s req uired, such as mixerassemblies for additional frequencyranges and PIN diode co ntrollers toadjust the output power. will be the

,,~

Fig. l :Exper imental R igfor 0.9 - 1.5 GHzSyntheslser

13

VHF COMMUNICATIONS 1197(~----- ---------'-'-"--"'=="'-""'-"'-"-'-'-

+5V}f

--:J'" r---~,'" L" I~

III " "

DJ 8 ES

_ SOA 3302 ' [-+- - - -y f.:. ,- II". 11

+1 2V~~i; i t n ~A J,

s1-'.,;, : 'J'ZT;;,~~I.i~J-l. ~~'II-;~ V i - --- - -0 -Out

I ~ B~ l 22 r:-l O +} V I-fl ' y' +30V

'1-1 ;i! "L:J w- n~tn , - . ""J ,- .". 'II .. • -1"""""--- ,............

SDA3302 '~I-II ,. "1n ' 'r-J

~ _ IlCS49C

"SDA SCl

. ~~~--.-- J

Fig.2: Ci rcu it Diagram for 0.9 - 1.5 GilL Frequency Syuthesiser

subject o f art icles to he published infuture editions of VIJr Communications,

2.CIRCUIT

The 0.9 - 1.5 GHz synth esizer wascreated on the basis of the FM·A TVtransmitter for the 23cm band [I],deta ils of which were publish ed at thatlime. The only new feature is theSDA3302 pr ogra mmable synthesizermodule in the circuit (Ptg.z),

The tunable oscillator (VeO) covers theent ire frequency range, with a tuningvoltage of +30V, in one sweep. Thearticle referred lo above contains anydetails required in connection with theassembly and operation of the circuit.

The frequency information is transfer redto the integrated circuit through a spe­cial log on a z-ccncucror bus (P C bus).The lines distinguish between CLOC Kand DATA.

GUnter Satt ler (DJ4LB), among others,has made the functioning of such syn­thesizer modules clearer for us. asamateur radio enthus iasts. in [2] and [3].Fig.J merely shows once again the

14

VHF COMMUNICATIONS 1/97

It. AcIrn<JWlodge (log . 0)

N Fr equen cy I)i\'id el(2_8 . 1296 MH2: No,. No• • M. .. 1)

:r:'A. -jCAU (Pin Ill!o 0 '"c 1 offon

0N,,: N,,[~~ ~~,~,... ... ... '" .. .. '....

~~'i~

[0] 0GEl':::::o:r:o:lili

Chipad..........

('muml 2

Divider I

,\dd re~s

COlltrol I

Dlvlder 2

structure o f the data elements for theprogramm ing of the SDA3302 as asynthe sizer.

There is also an addition 10 the completec ircuit here, in the shape of an\lSA 11 04 broad- hand ampl ifier. Fheoutput power is thus app. 50mV·/ overthe entire luning range (FigA). More­over , the amplifier acts as a buffe r stagefor varying loads at the output.

A fur ther SDA33 02 Ie is wired up 1Il

the experimental rig for my own experi­ments, th is time as a frequ ency divider.The [2(: bus controls both circu its!

,·t,·t(I 0 - Pu.- -1 0 mvrdcr

F igA:Output Power andFrequency plott edagainst the 'runtngVoltage

•

Funktiofl

Fig.3:nata For mats fur Pru~ralllmin ~ thesnA 3302 as a Frcq Synthesi'ier

f1J4I,B describe s the details and, inparticul ar. the temporal sequences forthe data transfer very graphically in [2Jand [3 [.

Another program is available which is

I I18 .. 20••••

.:o 0 0 f_o ....__..---- 7G

~,-

1000 / 30

={ OJ 8 ES :"

The entire data log is transferred to theSDA3302 PLL Ie for each frequencysett ing , The Pc hus fonn s the link. Inthis way, the chip address and allfrequency and control parameters aretrans ferred to the module integratedwithin specia l start / stop condi tions.

3.SO FTWARE

,-

15

VHF COMMUNICATlONS 1/97(f'-----------~"""'!"'!!!'~-""""--""-'

Fig5:Th e AssembledVCO, showng rea tly Magnified

55.5 x 74 x 30mm. The ho les arc to hemilled on the earth side using a 2 .5mmdrill. Only the earth contacts remain inexis tence.

T he assembly of the veo (Fig.5) andthe subsequent bro ad-band am plifier isdescribed in de tai l in [ l]. As always inhigher frequency ranges , spec ial auc u­lion must he paid to creating a structuresuitable for high frequencies. Shortconnecting wires arc an absolute must!

Further details can he found in theequ ipment diagrams for the roil side(fig.6) and the eart h side (Fig,?) More ­ove r. the rig can be copied without anyspecia l pro blems for the person assem­bling it.

4.1. Compo nents list

suitable for O ,l) - 1.5 Gilz frequency'synrhesisers, and is written in Turbo­Pascal 7.0. It contains all the com po­nents for the frequ ency synth csiscr. butnot for the frequency divider! Addit ionalinformation required for operat ing theprogram is contained in the READ.t.,l Efile on the associa ted diskette .

Once started , the program sets thefrequency of l ,2WdlO()O MHz as thedefault value. Other frequencies can beset through direct entr y by mean s of thekeyb oard, or else using the cursorcon tro l keys. The minim um step width is62.5 kHz , determined by the system.

4.ASSEM BLY INSTRUCTIONS

The entire circuit is constructed on anepoxy printed circuit board, coated onboth sides, with the dimens ions 54 x72mm. It therefore fits into a standardt inplate hous ing with the d imensions

lCIIC2IC3D I, D2TlT24

SDA3302 (Siemens)SDA3J 02 (Siemens), opt iona l!'.ISAI I04 (Avantek}Var icap diodes BB405(;BFR96 (Valvo)BC549C (Va lvo)4 MH z crystals(HC I8 U or HC25 U)

16

VHF COMMUNICATIONS 1/97

,• •

..,I

ri~ .6 :

O nly 11 few Components IJII

th e Foil Side

Fil::.7:La yout of Elements onComponent Side

aaaa

VCOO,9-1,5 CD

Fig.8 :n.un:s nzs Pr inted CircuitHoard. Reverse Side passill~

Ihrou~h Ea rth17

VHF COMMUNICATIONS 1197

The READ.ME tile on the di skette hasaddit iona l informatio n, especially withregard to installation. It shou ld he read

before the equipment is put into opera­tion .

The standard address for the Centronicsinterface is I.PT I. For other ports. thedata can be adapted in the SYN­

T II r:S I.CH ' tile.

+ 5V (PU . ). + 12V (VeO with ampli­ficr stage ) and - 30V {tun ing voltage )

arc appl ied. A poI\er leve l of apr.50m\\ ' (cf Fig..!) and a frequencysomewhere between 0 .9 and 1.5 G Hz

can now be mea sured at the output jack.

Tile PC is n,}II' connected up. The

Centronics adapter ca rd described inPart 1 ad s as interface. In this connec­tion. d7 is the lima line (SDA) and

ST RO Bl: is the cloc k (SeL).

. If til" SYNT II LSI.EXE program is nowsta rted, the frequency J.296.00()O :\l H,m ust be set at the outpu t of theassembly. l-Ine balancing can be carriedOUI using the 22 pF trimmer at pin 2 ofle i (SDA 3302). A " Help" function isavailable through funct ion key F1 , as forthe m W meter.

IJ4 choke. 5 turns on 3mmdia m rod. O.lmm Cu lacquered

wire22pF foi l tr immerValvo. gree n~lKT capac itor 47nF,7.5 mm bas ic gridMK T cap acitor O.I~IF .

7.5mm basic gr idMKT capacitor O.22 ~IF,

7.5 mm basic gridcarbon Film 120!l 1 1Vt',12.5 rnm basic gridTe flon bushingsBNe jack lJG290 A I Utinplate housing55 x 74 x 30mm.PCA DJ8ES 02&

Ce ramic disc capacitors. 2.51lUll basicgrid

I IOOpF ce ramic disc7 1nf ceramic disc

And in SMD format(1206 ! U805 construction)

711

1/&Walt. 10111m basic grid resistors

220nl kn2 .71dl

3 IUkU3 lo"n2 22"!l

(~------------""''-'''''==-'=~

D,

2

3

470

Jnl-' S.LITERATURE REFERE1\TES

4.2. Putting, into operation

The assembly group forming tbc 0.9 ­1.5 GHz frequency synthesiser mustoperate as soon as the operating volt­ages:

[ I] wolfgang Schneider DJ 8 ES (ex.DD2F.K): FM-ATV Transmitter for

the 2Jcm HandVHF Communications. no . 1'89 ,pp. 25·)0

18

VHF COMMUNICATIONS 1/97

[2) G unter Sattl er 11J4LR: SDi\ 3202 ­:\cw PLL-Ie up to 1.5 GHzVHF Communications 1,.'86,1'1' ,18-22

1'1 <C"",,, Sattler Il J4L H, Crystal­Stab le VCO Freq uenci es for ATVPrece ssingVH F Congress We inhe im 1991Congress Proceedings. pp. 173

Sole /11/ Sates ofArticles:

lh e aim of the series of articles onVIIF . LII F and Sil l ' 11l1:asur ing met hodsusing a PC is to enable us amateur rad iocnthnviasts to gain entry into this newand intere sting area o f discussion.

Arter the initial preparations and practi­«I I re-sts (c f. Centro nics interface, rnWmeter and synmes tscn, the next step isthe deve lopment of a universal mcasur­ing apparatus tor the amateur radioenthusias t.

lhis Pc -conrrolted measur ing apparatusfor the 10 - 1,400 Mill. frequency rangecom bines tile following functions :

Synth esiscr

wo bbler

- mW meter and

- Spectrum ana lyser

lssues J and 3./')7 of VHF Communica­tions will contain a complete descriptionof the assembly of all the clem ents.

In add ition, the experimental mw mete rand cynthesiser set-lips already pre­sented are being revised and turned intoa more efficient version of what is aconstituent part o f the measurementequ ipment.

Thus, for example, the reso lution in the!11),.! ra nge for the !IIW meter has beenincreased by two powers of ten, whilethe output power in the synthesiser hasbee n largely kept con stant, and thefrequency range has been extended tocover the necessary minimum of 700 ­1,400 I\Hl /..

Wo lfgang Schucidcr, DJ8hS

VHF Communications Magazineon the World Wide Web

Please note that effective April 1st 1997 the VHFComms WWW site will no longer be available at Eolas

The VHF Comms WWW site is now:

http://www.c1earlight.com/-vhfcomm

19

VHF COMMUNICATIONS 3/97((' ---------------'"'-"-''''''''= ''''''-'-'''''=

Woljganx Schne ider, DJ8ES

VHF, UHF and SHF MeasuringMethods Using a PCPart- 4: High-Frequency Test Rig forup to 1.4 GHz

Following t he intmduction to thesubject of VHF, l JHF a nd SHF mcas­urinl2; using a PC. we now come to thereal foca l point of this series ofarticles - the development of a hig h.frequency test rig for up to 1.4 GH7,.

Specifically, th is means a frequencysynt hesiscr, au mW meter, a wobblerand a spectrum ana lyser, comhinedinto a measuring apparatus.

The result of all this is no miraclema chine, but with minimal usc ofhardware a high-freq uency test rig

for up to 1.4 GUt: can be createdwhich makes interesting additionalmeasuring options available for usradio amateurs.

I.COI"CEI'T

The PC takes over contro l of theindividual assemblies (Fig.l ) and ofplotting the test results on the screen. 1\

"486", such as is common nowadays, or

Imw~·~'1

DJ8ES

Fig.I:The PC Controls allFunctional UnitsSteurung = Control, Kabel= Cable, Messung =

Measurement152

VHF COMMUNICATIONS 3/91

---" .

. _ ----1.. --_-1rvro--~ I j - - --, i r:=:: _

Synthes,-zer I ~DO - ' ''oo .• .;- ---l PlH Regler ----ql 0 -700undtill J_ .-•.,. 1 r00 - 1000

.. .. - I0 ~~r::;) Olio ·

E_-t--=L- ",i """-'"'..-..... I I .. un

~"""" II

ITiefpalls _ .. _ - ..! -_~,5 MHZ ..

· ~l ~-]-. -~f--I~ DJ8ES

mW-Meter @& Wobbler 1

Spektrumanalyser5--1o • 100 und (0)- Mlscher100 • 14(1(1 I __ ell- 1-

- ,."'jg.2: Auto mated Lo~ic Diagram or High-Frequ ency Test Rig up 10 1.4 G ill

Und - And, Df'teltJ"r " - Detector, Mi'S{:her = Miur. Tic/pa ss = "Ba ndpass, Regler = Co nlm ller, 1.111:. Detektor = Loga rilhmic detecto r.A UJgang = Outpul

even a "386" with a hard disk and acolour monitor, can meet the require­mcnts.

The interface berween the PC and thehardware is provided by a Centronicsprinter interface (e.g. LPT I), wh ichmany people will have already.

The automated logic diagram (Fig.2)shows the individual assemblies andtheir inter-connections.

The complete hardware consists of thefollowing units:

- veo with PLL (700 • 1,400 MHz)

- Mixer with LO (10 - 700 MHz)

- PIN diode controller

- Diode detector

- Analogue I digital convener

- Mixer with logarithmic intermediate-frequency amplifier

The measuring apparatus referred to atthe start can be created through asuitable combination of these assem­blies:

- mW meter; Diode detector and A I Dconverter

- Synthesiser: veo and PLL, mixerand LO, PIN diode controller

- Wobbler: veo and PLL, mixer andLO. PIN diode controller. diodedetector and A I D converter

153

VHF COMMUNICATIONS 3/97(~ - - - ----- - - ---='-===""-'= =

Fi~.3:

Th e High­Fre quency Te..tRig in Evpcrl ­menta l For m

- Spectrum analyse r: veo and I'Ll..mixer and LO, PIN diode controller,mixer and logarithmic intermediate­frequency amplifier and A I 0 con­verter

The only additional information to begiven at this point is the pin occupancylayouts (not completely identical) of the25-pin and 36-pin plug connections onthe lines which are relevant for U~ .

These relationships and rho circuits willhe dealt with more specifically in theappropriate section. Thus, for example.the inter-action of the diode detector andthe A / [) converter in the mW Old erwill be described separately.

2.PC INTERFACE

The standard equipment for the Centron­ics printer interface includes an 8-bitdata output, a 5-b it input capacity andalso 4 output lines. A comprehensivedescription expla ining the functioningand, abo ve all. the contro l of thisinterface can be found in Part I of thisseries of articles [I ].

Con nectio n Pin (2-1) Pin(J6)

Data I 2 2Data 2 3 3Data 3 4 4Data -I 5 5Data 6 5 5Data 7 8 8Data R 9 9

Strobe 1 1Auro Feed (FF) 14 14Reset 31 16Sel in 36 17PE 12 12

2.1. Circuit Descr iptio n

Controlling all the test rig hardwarerequires more lines than are avai lable inthe Centronics interface . This appl iesboth to the control of the individual

154

VHF COMMUNICATIONS 3/97

DJ8ES""

I,;~:,," J-~I

mW-_

'I'_ L_,74 HCT!i:j-

f t-==i=-'J

~~u"..~o

In- J ---v'w ------ -- -----c•nt,o smoB"En AUTo F£EOi SEi.i:CT~IN

o ~=

•Fig.4: Interface Card for Connection to Centronics Interface

natenbus = nata bus, Regter = Controller, Steurung = Control

assembl ies, e.g. the A I D converter, andto the lines connecting the units 10 eachother.

onto the individual JC pins on theunde rside of the board.

4 type 74HC573 data latches distributethe daLa ( Fig.a} The control data fromthe I'C arc deposited in the associatedlatch by means of a tra nsfer pulse. Anadditional Ie 74HC573 acts as a busdr ive. The b locking -off capacitors (100IIF) for the 5-V ope rating voltage arc inSMD form at and arc soldered directly

2.2. Assembly Instructions

TIle double -sided interface card hoards(DJSES 029) have only a Centron icssocket, 5 74IIC573 data latches and theassociated rod str ips for the internalwiring or the rig (Fig.S). The data bus isthrough-hole plated with short pieces ofwire.

'''_!''''i1i!1,,"='''.+:i!-+iilU'0%.'1:~#t$Y'''''''''.'''''''!8~Fig.5: Component Overlay for Interface Card; Buchse = Socket, Pol = Pin

155

VHF COMMUNICATIONS 3/97(+ ---------_--'!:!!'-""''''''''=-''''''~

of stab ility and secondly to guarantee agood earth connection.

Fig.6: Prototy pe Inter face Card

It is also important that the Centronicssocket is connected to the board by M3x 10 screws (Fig.6), firstly for reasons

2.3. Parts List

5 x 7411C573 5 x 100 nF (SMD,model 1206) 1 x Centronics socket(print model) 4 x rod strips (8-pin) 2 x\1 3 screws (10 mm. long) with nuts 3x solder posts (1.3 mm.) c/w plug I xDJSES-029 board

3.FREQUEl'iCY SYl'iTIlES ISER

As has already been seen in the auto­mated logic diagram (Fig .2), the COlD­

plc tc frequency synthcsiscr consists ofthree assemblies ; yeO with PLL, mixerand PIN diode controller. When theseare inter-connected. the combinationcovers the frequency range From 10MHz to 1,400 YlHz. The output levelhere can be adjusted between 10 mw ( +

10 dBm) and 10 W (-20 dBm).

-r='n ='n

+ 12V o>- · - - ---~ •

._...., 1

11 ! [lj - - -tCl Out lUI

~a~ : _ T Mischef

{}• I - ----i:li}-I -'" " ,~..F I H~ ' .~--1pn-~ Ow

- ... -1 - --J1.J I _

~-I ._ , 1 I

... u ... I ... '":I: -, :t ir 1" ::= T '" 0------- - -00 + 5Vl k 2211 :l I " " ,-;-,

-- - ~III =:J-~ "cr-CJ-.-II- I' PLL .- - ~ SCli~· "l ". 220<1 SOA.3302... " l:l _ \ _ ----:' - --- - " ' !----------;0 SDA

' 3<lV'>- - --I~ -e '[¥.--,"= - C.:;;;. 22DJ8ES

Fig.7:Wi ri ng Diagram of700 MHz · 1,400MHzVCOFOr Mis ener = Formixer

156

VHF COMMUNICATIONS 3/97

Fig.S: VCO Prototype with PLL

3.1. VCO with PLL

3.1.1. Circuit Description

The veo, with a MSA 088 5. spans thefrequency range from 700 Mllz to 1,400MHz. Th e combinatio n o f threeBB621 ' s and the inducti ve resistor, L, isused for tuning. The signal then passesthrou gh the ampl ifier stage (equippedwith an MSA 048 5) and achieves agood 20 mW of output power (Fig.7).

The veo has a special output of app. •10 dBm, which avo ids saturating themixer and th us creat ing unnecess aryinter-modulation products.

The SDA 3302 comp onent, fam iliartrum TV engineering, acts as a cont rolcircuit (I'LL). Th is makes tun ing stepsof 62.5 kHz po ssible in the above­mentioned frequency range.

The frequency data requ ired arc seriallytrans ferred to the PLL modu le from thePC through an 12C bus (SDA = data,SCL = clock ).

Fig.9: Magllilicd View

3.1.2. Assembly Instru ctions

lh e complete circuit is assembled on atwo-sided coated epoxy board, withdimensions of 54 mm. x 72 mm.. It thusfits into a standard tinplate housing,dimensions 55.5 mm. x 74 nm. x 30mm. (rig.S).

Drill-holes should be cut out on theearth side with a 2.5 mm. drill. On ly theearth contacts are to rema in!

The assemb ly of the VCO and thesubsequent broad-band amplifier hasbeen descr ibed in deta il by DF 9 IC inL2J. The frequency is essentially deter­mined by the length of the inductiveresistor. L, and fine calibration is als opossible, through a slight bending of thewire strap .

The BB 621 tuning diodes are flushwith the surface of the board (Fig.9) !All additi onal details can be taken fromthe components diagrams (Fig's. I0, 11).

As always with relatively high frequen ­cies, spec ial attention should be paid toan assembly suitable for high frequency- short connectio n wires arc an absolutemust! Th is can not be said too often.

157

VHF COMMUNICATIONS 3/97(t< 2!:!~~~~~

Fig.! 0: Components un Foil S ide of veo

Fig. l1 : Co mponents on Ea rt h Side of veo158

VHF COMMUNICATIONS 3/97

Fig.12:Prototype Mixer I LOAssembly

3.1.3. Parts List

I x S[)A 33 0:2 (Siemens)I x MSA Ot;t;5 (Avantek}1 x MSA 04X'i {Avantek}3 x HB 62 1 capacitance diodesJ x HC 549C (Va lvo)1 x 4 M Hz crystal HC IX U/HC25 lJI x 22~p F foil trimmer

(Va lvo , green)

1 x

1 x

I x

I x

I x

47-IlF MKT capacitor7.5 mm. basic gr idO.I -flF MKT capacitor7.5 mrn. basic gridO.22-,LlF MKT capac itor10 mm. basic grid120D. ! 1 W, carbon filmresistor in 12.5 mm . basic gri d1500 ! I W, car bon filmresis tor in 12.5 mill. basic grid

T _ T I<, nn -U310 r1I \.l ="' - " r>_ . I II II ":' la BfR9Oa -I

I J -.-T- II . --1 ' TB.FR9Oa'''= Op'01 1 ,_ \ ".l __

I " I: '"I ~ I 1- I ''" ." .111 ':;; ,, - ' - ',§ 10 1 1'1 I ~ ,

, "-'" I~ 1 - -b1 -~-r.;;;j- , "'": '''' I''''''' I'" 1 10 I '" _ '0 l" r T

f" L - jav

'co '.E-~c '" {T t '" [- s,o - --I I ,,>-_n-"!~ 1 -':' _ .:. - 1 11 / - U -c) Out;lj / _ I""· I'P2 _10 _1lP' r~P9 / _ l

MSA0104 - - MSAl104lAGHz DJ8ES

Fig.13: Circuit Diag ra m of 10 MHz - 700 MHz Mixer

159

VHF COMMUNICATIONS 3/97(~ ------------'""'-""'==~~

~ ..

"'ig.l 4: Mixer Components Diagram

yi~..

Fig.15: Components on Foil Side Mixer

510hmI pFI nF

x tinplate housing55 x 74 x 30 mill.wire strap, 15 mm. longCuAg e I mm. (sec text)SMA flanged bushes (4-hole)Teflon bushings018ES-030 board

Ceramic Capac itors 2.5mm Grid6 x l nf

and in SMD format (model 0805 or1206)

2 xI x3 x

1/8 Watt resistors, 10 nun. basic grid2 x 1 k2 x 22 k

160

VHF COMMUNICATIONS 3/97

3.1.4. Putting into Action

The YCO needs an operating voltage of+ 12V i 115mA and + 5V / 35mA,together with a tuning voltage of +30Y.

First the tuning range of the VCOshould he tested. For this purpose, thecontrol circu it is disconnected (collectorBe 549C). With a tuning voltage be­tween 0 Y and 30 Y. the osc illator mustcover the frequency range 700 t>.1Hz to1,400 Mllz and more. The output poweris an almost cons tant 20 m \V over theentire frequency range.

3.2. ,\1 h:er / 1.0

So that the lower frequency range canalso be used, a mixer / LO modu le iswired up subsequent to the VCO(Fig.12 l. This prov ides function al accessto the range between 10 Ml lz and 700MilL.

3.2.1. Circ uit Descr ipt ion

The local oscillator requ ired (117 Mllz)is created with the oscillator circuitwh ich is normal in amateur radio circ les,using a lJ3 10. The subsequent twelve­fold circuit with 3 x HFR 90 A (Fig.13)gives an output power of app . 20 mW at1,404 MHz.

An S\1D-C3 serves as a mixer module,fo llowed by an MM IC MSA 0 104, the9-pin deep-pass filter, and an MSA 1104as an addit ional amplifier. A level ofmax. 50 mW can be expected at theoutp ut to contro l the PIN diode contro l­ler over the range from 10 MHz to 700MHz.

3.2.2. Asse mbly Instruct ion s

The mixer with the LO is also createdon a double-sided coated epoxy board ­the dimensions arc 54 mm. x 108 mm..The circu it thus fits into a standa rdtinp late housi ng with the dimensions55.5 nIDI . x 111 mrn. x 30 mrn..

The thro ugh-p latings on the ring mixer(SMD C3) are of 1.5 mm. CuAg wire,while 3 mm. long hollow rivets havebeen used fo r the other plat ings.

Otherwise, the type and manner ofassembly are the same as those for theYCO assemb ly. The position of th eassembly elements can be taken fromthe components d iagrams (Fig.l 4 andF ig.l 5) ro r the foil side of the DJ8ES03 1 board .

l'hc SMD-C3 mixer shou ld bc solderedon only followin g the complete cali bra­tion of the frequency multiplier stage s.The assemb ly can thus be put intooperation faster and more easi ly.

3.2.3. Pa r ts List

I x MSA 0 104 {Avantc k)I x MSA 0304 (Avantek)I x 78L09, voltage contro ller1 x U310 (Siliccn ix}3 x BFR 90A (Valvo)I x SMD C3, mixerI x 117 MHz crystal, series

resonance. HC l 3-D or HC25-U1 x nv 5061, Neosid, O.IIJ.H

blue / brown3 x 5 p F Sky-Trimmers (green)2 x 6 pF foil trimmers (grey)2 x 22 pF foil trimmers (green)7 x 1 nF trapezoid capacitors

161

VHF COMMUNICATIONS 3/97(f' - - - - ----- ---="-""="""''''''''''''=

-r­: ....: +12V

,~~- Out1

--.- -

i:-1, [IIc-- . ."1'- ' '" I} 1 " I •, .-I =..-

DJ8ES -

~)

C' +5V

I ii !-· ----..,3 + 12V

: [f.:~:>.)' '-'._f-~[';' .jI -...-I;, ••• LW324;'-

"' - 11I f" ! / ' ·

+ 12V ;L : •• r-C-'j r"' 11-.Fi J;!;.16: I"in ninde Controller

r ig.17:Pin Iliode ControllerPrototype

162

VHF COMMUNICATIONS 3/97

I x I!1F / 20 Vtantalum electrolytic capacito r

Ix 10 )lF ! 20Vtantalum electrolytic capacitor

1 x tinplate housing55 x 111 x 30 mm.

2 x SM A flanged bushes (4- ho1c)16 x hollow rivets, length 3 mm.I x Teflon bushing1 x DJSES-031 board

liS Watt resistors , 10 mm. basis grid4 x 47 Ohm2 x 68 OhmI x 100 Ohm2 x 120 OhmI x 220 Ohm2 x UkI x 10 k2 x 15 k

Ceramic cap acitors, 2.5 nun. basic gridI x 10 pFI x 82pF7 x 1 nFl x JOOnF

All SMD capa citors (model 0805)l x 2.7 pl-2 x 3.9 pl-2 x 8.2 pF1 x 10 pF3 x I nF

3.2 .4. Putting into Operation

With an ope rating voltage of t 12 V.the assembly pick s up about 160 rnA ofcurrent. Only 50% of this is alloca ted tothe two amplifiers MSA 0 101 and MSAJ 104.

Fig.I8: Pin Diode C ont roller Components DiagramRelais = Relay

163

VHF COMMUNICATIONS 3197(~ - - ----- - - - ----'-'-"--"'==""'-'=""'"

Fig.19: Foil Side Co mponents

Arter the oscillator (l J31O with aHV506 ] coil) has been made to oscillateat 117 MHz, the frequency multiplier iscalibrated step by step. With the veoconnected up. the mixer achieves anoutput power of max. 50 mW in therange between 10 MHz and 700 Mllz.

3.3. Pin Diode Co ntro ller

3.3.1. Circ uit Descr iption

A circuit which was previously standardin televis ion eng ineering is used as thepin diode controller (Fig.16). ThreeSMD diodes (SA 595) thus control theoutput power of the synthesiser at thedesired value.

The contro l circuit is voltage-controlledand is controlled by the PC by means ofa 0 I A converter (ZN 426E). Th us with

IS bits, about 256 steps are generated inall in the 0 to 2.5 V range for every 10mY.

Because of the circuit, a control value of"0 dez" corresponds to maximum outputpower. The maximum possible dampingis obtained with "225 dez" . Dependingon the frequency, it is at max. 70 dB inthe short-wave range and is still 30 d uat the upper frequency limit of 1,400MHz (Fig.17).

3.3.2. Assembly Inst ru ct ions

The pin diode controller is created on adouble-s ided coated epoxy board. Thed imensions are 54 x 72 mm.. The ci rcuitthus fits into a standard tinplate ho usingwhich has dimensions of 55.5 mm. x74 nun. x 74 nun . x 30 mm..

164

VHF COMMUNICATIONS 3/97

The posit ion of the assembly elementscan be seen in Fig.LS for the compo­nents side, and in Fig.19 for the fo ilside, of the DJ8ES 032 board . In otherrespects . the same assembly instruct ionsapply here as !(jr the assembl ies alreadydescribed.

3.3.3, Pa rts List

I x ZN 426E-8, D / A converter1 x \1SA 1104 (Avantek)J x LM 324J x 781.09, vo ltage controllerI x BC549CI x BC848 C (S.'\'1O)1 x 1;-':4 148 (SMD)3 x BA595 (SMD)

1 x 2 kn , trimmer(vert ical, 2.5 rnm. basic grid)

Ix 120 Q/ I W12.5 mm. basic grid

I x I IlF / 35 VtantalumI x 10 IlF / 20 Vtantalum1 x RK 1-l2V, relay (Matsushita )3 x srviA flanged bushes (4-hole)I x post strip (8-pin)3 x Tetlan bushings5 x hollow rivets (3 mm. long)I x tinplate housing

55 x 74 x 30 mm.1 x DJSES-032 board

l i S Watt resistors, 10 mm. basic grid2 x I kI x 4.7 k2 x 10 k

Ceramic capacitors, 2 .5 mm. basic gr id1 x I nF3 x 4.7 nF2 x 10 nF

and in SMD format:

3 x 10 !1H chok es1 x 4.7 IlF / 25 V tantalum

SMD resistors and capacitors(model 1206 or 0805)I x 680 Ohm

I x 1.5 k4 x 10 k7 x 4.7 nF

3.3.4. Pu tting into Operation

The PIN diode controller needs twooperating voltages: + 12 V I 65 rnA forthe ana logue section and + 5 V I lO rnAto operate the ZN426E 0 / A converter.

For calibrat ion, the spindle trimmermust merely be set in such a way that ahigh-frequenc y signa l can be fed in andgiven maximum amplificat ion. For thispurpose, the data connections DO to 0 7must be connected to earth, whichcorresponds to a D / A convener o utputvoltage 01'0 V.

The entire assembly has a transit ampli­fic ation of app. + 3 dB.

The output level can later be reduced tothe desired value using the program.

4.LITERATURE REFERENCES

llJ Wolfgang Schneider, DISES:VHF, UHF and SHF MeasuringMethods using a PC,Part I : Essentials of Control usingPC' s Centronics InterfaceVHF Communications 3/96,pp.165- 172

165

VHF COMMUNICATIONS 3/97

rSl Giinter Sattler, DJ-lLB: Crysta l­Stable veo Frequencies for ATVPre parationsVl lF Congrcs....., Weinheim, 199 1,Congress Proceeding.'

(4) Gunter Sattler. DJ4LB: SDA 3202- New PLL Ie up to 1.5 GHzVHF Commun ications 1/86,pp.18-22

[S] Carst en Vieland, DJ-1GC : DiodeDetec tors in 50.0. Broad-BandTec hnologyVIIF Communlcarionsno . 2/88,pp. I I I· 125

(~ - - - - - --- - - --'''"''--''-== = = =l2 ] Wolf-Henning Reeh, DF9IC:

Simple Measuring and Ca librat ingAids for the UlI F RangePart 5: A Simple 5... 1,500 MHzSpectrum AnalyserVHF Con gress, Dcrsren, 1990Congress Proceedings, pp.42 • 70

EH. H.AT UM: 10 GHz Super-Regenerative Receiver, Issue 1/1997

Please accept our apo logies for an error which appeared in Fig.3 (page 3). Thesupplies ar the bottom right-hand side of the d iagram were incorrect. The correctedd iagram is reprodu ced be low.

,., "

IOOn F

lo. J n" T,.." n F

1__-,

10 nFOf l ...o"

' n F

TBA

8 20M

U u f'

n o n F

166

VHF COMMUNICATIONS 4/97(~------ - - - - ---'-""-''''''''''''''''''''"'''''''=

Woljgang Schneider, DJ8ES

VHF, UHF and SHF MeasuringMethods Using a PC

Part 5: mW Meters, Wobblers and

Spectrum Analysers

5.mW ~mn:RS

5.1. Diode Detector

The diode detector has a dynamic rangeof over 5UdD with 11 ISS99. This high

F i~,2 1 : O utp ut vor tegc to InputPower Rati o:

n etetaor » Detector, LId. vr: = Seria lno., Frequenzkorrektur = Frequencycor rection

144 MHL

DJ8ES

Detektor 18599(lId. Nr. S51)

fJJlQUftlUllor fCkll.IG2 8 MHz 1,0050 M Hz 1,00

144 MHz 1,004 32 MHz 0.9 7

1296 "1Hz 0,8 2

· ' 0 0

D.4 Iu ~.~' -....",~:.

0 .• -

,.

..-

U' l••..The mW meter can be used to measurepow er le ve ls be tw een 100m \\'(f 20dBm) and IOIlW (-20dBm). Forthis purpose, two functional units arcused from the hardware range ava ilable.

The power level - or a voltage corre­sponding to the power level - is meas­urcd using the diode detector ( ISS(}9)with an integrated 5W moving load.

This voltage must be suitably preparedfor the PC - say, be digitised. The AiDconverter is used as the secondassembly here .

Fig.20: Diode Detector Ci rcuit

194

VHF COMMUNICATIONS 4/97

Fig.22 : T he B:\C Detectorver ston

value naturally requires the circuit to beassem bled to be suitable for radiofreq uencies! Sf\..ID components and shortconnecting wires where wired compo­nents are used arc an absolute must.

F ig.20 sh ows the detector ci rcuit; Fig.21show s its output voltage, plotted agains tthe mea su red input power in the rangebetween IOrnW (- 20dil rn) and 100mW(--- 20dHIll).

F ig.2J: The N-l'<:o rm Detector

5.1.1. Assembly Instructions

The detecto r is inserted in the standa rdway, in the BNC version. As an airassembly, directly incorporated in a plugi jack. it obtains the bes t perfo rmance.

All the details for assem bly have alreadybeen described - in Part 2 of this seriesof articles ("'m W meters for short-waveto SI IF"). Assembly in an N-plug isnaturally also possible,

Fig.24: A ID Converter Circuit with DctectorSteurung = Control

195

VHF COMMUNI CATIONS 4/97

5.2. Anal ogu e I Digital Conver ter

5.2.1. Circuit Description

A reference voltage between 0 and 2. V

is generated in the analogue I digitalintegrated circuit from a pre-set x-bitdata word with a ZN416E (Fi g.24).

The comparator compares this with thevo ltage to he measured. 11 gives rhcdec is ion a:. to whcther the reading ishigher or 100\e r than the referen ce

voltage at the I>E con nection. in theform of a high or low level signal to the

PC.

5. 1.2. Component Li, t

I x I SSl)lJ diode

I x lIG 8S/U B NC plug(All ernative : 1 x N-plug (A ircomj)

I x lJG 89/lJ Bf\iC ca ble j ack(Alternative: I x micro-jack P-r in»

Im. RG5SU coa x cable with suitablepin-and-socket connectors

(to --- - ----- ---""''-''''= = ''-'''''-==Th e photographs in Fig.22 and Fig.23each show all the indiv idua l componentsand the associated. fully assembleddetector head.

Fi~.25 : IU SES 033 PCB;A J lJ Con ve r te r

jhe method used to determine themeasured vo ltage is that of successiveapproximation. In this way. the sco rin g.log ic in the program approaches themeasurement result throu gh a series of

Jumps.

So that usable measuring results ca nalso he obtained in the 100\-er. tlatsect ion o f the det ector diode characteris­tic curve. an operational amp lifier is

connected in series to the convener.This ca n be adj usted in stages. \\ ithrega rd to it:. amplification (x 0. 1 I :\: I Ix 10 I x 1( 0). Depending on the

Fig.26: Componen ts Side uf Prototype

LWU:S OJJ

and capacitors in 1206SM D resistors

for mat:

I x 270.2 x IOOUI x IOku1 x InF1 .\ IOnF

l o~====~B...

DD

196

VHF CO MMUNICATIONS 4/97

j _1l.!: .

";~."J t·J..,- I· "•"' : "01

. rvt

.n 1" /,-'· II~ ,

"~ • •

--•

.."." ....".. " ,

• •

Fig.27 : ICs and ConnccttonElements a rc mounted fromthe Earth Side; Retats = Relay

Fig.29: Tracks Side has only SMDComponents

switching condition orthe CD 4066, theinput signal is thus a lways in theoptimum range.

individual tracks in accordance withFig's.2 Xand 29.

5.2.3. Component List5.2.2. Assembly Instructions

The anal ogue I digital converter circuitIs assembled on an epoxy board, copper­coated on both sides, with the dimen­sions 60 mm x XO mm (Fig.25). Ie's,relays and all the connection jacks andpins arc mounted on the componentsside (Fig·s.26 and 27). All earth counce­rions are soldered onto this fully lami­nated side as well. The SMD compo­nents arc soldered directly onto the

I xI x

I ,

2\I xI ,

Sxz ,I \I ,

LM 324 operational amp lifierZN 4261->8 digita l ! ana logueconverter4066 analogue switchACS4S C, SMD transistorsLlA 148. Mini Molf diodcReed relay (I x Ur n}l.Jmm terminal pinsIu-pin socket terminal strips4.711 1-" SMD electrolyticDJ8ES 033 peR

SMD resistors and capacitors an: 0805or 1206 format:

I)J ~ ' s.l "He 0 ~,~"V

Fig.28: View of SMD Componen ts onTracks Side

I x4 ,I xfi x2,I xI xI xI xI x

6800.l kn2.7ld lJOkO9LkO9 10kD1MD.120pFInFIOnF

197

5.2.-1. PUlling Into O peratio n

The data lines dO to d7 for the A ! Dconversion are to be connected througha ribbon cable with the correspon dingpins of the Selln-Latch on the interfacecard.

The PE pin is to be used 10 repon backto the PCon the A I \) conversion.

Lines dO to d3 on the Formj-eed-Latcharc reserved to r setting the ampl ifica­tion. Bit d7 of this pori switches theanalogue Input over (A or B).

Th e diode detector is connected toinput B.

The circuit should now be ready foroperation, so its funct ioning can betested using Hf M.ESS soil ware.

With a voltage of +5V, the currentconsumption of the analogue / digitalconvert er assembly amounts to about15 rnA.

The final step is to measure. the refer­ence voltage of the A I D converter. Thevalue should be 2.52V at pins 5 I 6, tothe earth of the ZN426 E. Any discrep­ancies have an influence on the correc ­tion factor, AU (cf Section 10.13.).

fig.30: A Filter fo r ATV Applicationsat 23 em as Test O bject

198

VHF COMMUNICATIONS 4/97

6.WOB BLER

No additional circu it need be added forthe functioning of the wobbler. Thecombination of frequency synthcslser,d iode detector and A ! 0 converterallows for wobble measurements overthe full range between 10 and 14000MHz.

The dynamic range of the wobblcr thusresults. on the one hand, from the outputpower of the synthesiscr, and on theother hand, natura lly. from the limitingsensitivity of the detector: in the givencircuit. there fore. just 40dB .

The test object i.. merely looped inbetween the synthesiscr and the d iodedetector for the measurcrneut. The son ­ware docs everything else.

Fig.30 shows the result of a wobblemeasurement in the range from 1000 101400 MHz. For this purpose. the entirerange is traversed step by step. and foreach frequency step the current level atthe out put of the test object is deter­mined and plotted .

7.SPECTRCM AI':ALYSER

The only new assembly which comes upunder the heading "Spectrum analyser"is a mixer with a logarithmic detectoramplifier.

Only in combination with the frequencysynthesiscr does the complete spectrum

VHF COMMUNICATIONS 4/97

. ~ ;

- I "':'" 2 _I J: aS y nlh .... iz..',,--OO- =",7n "1" ' '''' =..,7n ;r r a"l" 'j,'- " i 5V._.+-__---L.. ,;;1 "~ •

tl I ..... ..... - I ' r ' O. - ,'- "----t-lI 0 _ __<~ .. II - , ..

r-t- _' " _.... -- , ." .. ,~_---:: i · -r -r .'" N E614 ="'"

HF-Inpul .'?~ r -~~... I ....• I on .1.:',.. .:-t ...Be,eich .0---l '~l----T- t l _ I _ I ,-

11/10 ......" ) - '-- --1 ~_'40 I Il.JetOS r-~' U.,-

,), '"'1 ~

Fig.31: wlrlng Diagram of Mixer with Logarithmic Display Amplifie r;Bereich = Range

ana lyser emerge, for the frequency rangefrom 10 to 1400 MHz.

7.1. Ci r cuit Descript ion

The mi xer assembly with logari thmicdetector amplifier operates on the directmixing principle. The frequency rangeto be represented is traversed step bystep and mixed down (Fig.3I).

The two dee p pass filters make two

band widt hs possible: DC to 0.5 MHz,or broad-band DC to 5 MHz.

The logarithmic detector amplifier iscreated usi ng an le from FM techno logy(N E 6 14). Depending on the input level,

Spektrumanalys e rOJ 8 ES 034

the vo ltage meter output supplies avoltage between IV and 4V; the dy­namic range amo unts to j ust 70dB.

The PC takes liver this level inform ationusing the ADC assembly.

The voltage divider (39k / 47k) isprovided at the output of the IC, tomatch the voltage range to the measur­ing range of' thc converter (O...2.5V).

7.2. Assembly Instructions

The mixer assembly with the logar ithmicdetector amplifier is also assembled onan epoxy board, copper-coa led on bothsides, with the d imensions 54 nu n

Fig.32: DJ8ES 034 Printed Circuit Board; Direct Mh er with LogartthmicLevel Oispla)i; Spdtrumana/yser = Spectrum Ana lyser

199

VHF COMMUNICATIONS 4/97(t ----- - - ---- --""--== = "-""""'-=7.3. Co mponen t List

Ceramic capacitors, 2.5 mill grid:

2 x S20pF1 x 1.2nF2 x 4.7nF3 x JUnF

1/& W resistors . 10 mm grid:

I x 51 nI x 1.5krlI x 2.2kUI x IUkUI x ] 9kUI x 47K!1

NE6 14BC549C trans istorl N4 148 diodeSMD C-2 mixerrelay (2 x Urn)BV5 138 (2.61J11) Ncosid

I x

4 ,6 x1 x1 x

I xI xI ,

I xI,2xready­made filterI x BV53 13 (22IJH) Neosid ready

made f ilterl nl ' DF. solderable(} . I ~tF. HM 10. MKIIIO ~I F / 35V tantalumtinplate housing.55 x II I x 30 millI)J8ES 034 PCB

Operating voltages, the switch voltagefor the finer convers ion and Ihe log.voltage output arc connected by meansof InF fccdtbrough capacitors . Therad io-frequency connect ions are carriedour using SMA connectors.

Fi~.JJ ; View of Prototyp e i\li X('r

The earth feedthro ughs are manufac­tured using. silver-plated copper wire,with a diameter of 1.5 111m.

x lOll 111m (Fig.32) . The circuit thus titsin a standard tinplate hous ing (55.5 millx III mill oX 30 mru) (l' i~ .33)

T he coupling capac itors and the mixerare soldered on the fo il side. all othercomponents 0 11 the components side(Fig.34).

••

•

Fi~.34 :

Components 1'lan ;SMn Mixer an dCo upling COs aremounted on TracksSide;He/ais = Rela y

200

- - ------:0 + 12V~a = e5- ,-

Fig.35 :Exa mple of Ci rcuitfor Power Suppl)

DJBES

1_ . ~ ----;.:a + 5Vr 1~ 6 = .5

, - -- -- - ~ 33.}--+-~ - -0 -+ 3rN

_ , j;\ ~ _tO

-~ Ia 't' -~- -

7.... I'llllin~ Into O perati on

The assembly requires two operatingvoltages: 15V / 3mi\ and, for the bandwidth selection. "'2V I I ~ mA .

The measurement output. URI. is COIl­

uecte d to input A of the analogue /d igita l convener. lh c filter switching. Ito 10 Mllz. is determined by pin __hi 0 11

the Formf eed-latch of the interfacecard.

'1he oscillator input of the mixer (1.0 )must no t be saturated. The '-0 outputca n be held constant at - 7dBm onlyfro m software version 3.0 onwards.Earlier versions requ ire a IOdB atrenua­tor between the synthcsiscr and the LOinput.

Sinn: the compression on the S~tD C-2mixer sets ill as early as app. IOO~lW(- IOdHm), a WdU ancnuator shou ld alsobe con nected in series to the radio­frequency input. The maximum usableinput level thus rises 10 l mW (OdBm).

The value \ faxVoltSA for OdBm for thesoftw are is set at z.uv. The default

value lo r :\linVolt SA (-70dBm) isO...lV.

l.rurics are to he matched in the file11r;\ l ESS.(T(J if necessary (sec Section[( ),I 2,),

H.I' OWER SUI' PLY

Three ope rating voltages arc needed forthe powt:r supply (Fig.35):

=:,V for d igital sect ion, PLL and A I nor ]) I A converter

± 12V for switching relays. OP·s. ampli­tier and transistor stages

i 30V as tuning voltage for veoIn the specimen un it. this ptlwer supplyis assembled on a standard breadboard.Because the total current consumption is[ow, no heal sinks are required fur the7llxx family of regulators.

201

9.INTER-CONNECTINGINIIIVIIIlJAL ASSEMBLI ES

The individual assemblies arc to becombined with one another dependingon the app lication (mW meter, synthe­slscr, wobbler O[ spectrum analyser).E.g., simple switching relays arc usedhere, as well as a coax relay. fur theradio -frequency branch - users can de­cide the details for themselves.

For the prototype assembly, Nccormec­tors were used for the external radio­frequency connections. and SMA con ­nectors for the internal ones.

Oth er connections inside the equipmentare carried out using single-row pin­and-socket connec tors. Connections tothe exterior arc made using feedtbrougbcapacitors ( I nl'] .

10.SOn WARE

" is frequently necessary to spend a lotOil electron ic components fo r opera tionand display in con nection with measure­mcnt and test procedures. The math­emat ical preparation of the signals canalso he vel)' complicated .

The expense increases still funher ifinterfaces also have to be providc'd withother equipment such as, for example. aprinter.

Ideally, the computer can take over awhole series of task.. from a measuring

202

VHF COMMUNICATIONS 4/97

in..trumcnt. It can be ope rated throu ghthe keyb oard , and readings can bcdisplayed numerically or even graphi­call y on its screen.

Other equipment can be influencedthrough its interfaces - printers can becontrolled, and in add ition readings canbe logged and put on paper.

Its capabilities for convert ing readingsmathematically leave scarcely anyth ingto be desired .

The various assemblies essentially usecompon ents which arc highly compat iblewith a PC. Here. tor exam ple, there arcr c bus circuits and up-comparfblc AD IDA conveners. The HFMESS softwa rewas devel ope d SO thai th is techno logyco uld he used as a whole.

The program contro ls the assembliesthrough the printer interface , which canbe freely selected (l. PTI , LPT2 O[

I.PTJ ).

I0.1. Operatt na Softwa re

The program diskette contains the fol­lowing files :

HFI\H:SS.EXF, is the mum progra mitse lf. It can run on MS-DOS andIBM-DOS.

HFI\1 E.SS.H tP conta ins help texts to

guid e the operato r. They can he calledup at almost all points d uring therunnin g of the program, using the F Ifunction key.

Il FI\1 F.SS.c r G is used to pre-set neces­sary param eters (e.g . inter face ad­dresses). The data can be entered orchanged using a standard text editor , 0 1'

with EDIl .COM. supplied with MS-

VHF COM MUNICAT IONS 4/97

DOS. The contents are indi viduallylisted in Section 10. 12..

II f M ESS.1\I NU is the list of the menuitems a va ilable.

CALlBHI. H1N contain s level settingstr am - lOdH to tlOdB, over the ent irefrequency range. Th is fllc is generatedthrough the "Calibrate" routine (seemai n menu).

FF.HL EH.TXT shows the measured

values per frequency in Ml lz for leveld iscrepancies . This file is generatedthrough the "Calibrate" rou tine (seemain men u).

J\1WTA IU'£'TXT contains all the ta­bles for the output ca lculation andca librat ion of the diode detector. '111istile is d iscussed again, in greater detail,in Secti on 10.13..

READ.I\n~ contains curre nt informat ionon the s oftware. and should be readbefore installation.

111.2. Hardware Requirements

Th e p rogram requires a PC with a 1 86processor . a (dO-l.. b)1e main memoryand a VGA graphics card. However, a386, or be tter mill a 486, is preferab lefor the wubblcr and spectrum analyser.

If a hard disc is available as well, if thecomputer is faster, and jf mo re ma inmem ory is available, plus RAMDRIVEand a co lour monitor, then naturallyeverything is even more sp lend id.Above all , everything can he done muchfaster!

10.3, Inst allation

To be able 10 usc the H Fl\I ESS.program, it is more advisable to copy itinto a sub-directory (If its 0\\'11 on thehard d isc.

MD C:\HF MESS

CO PY A:*:C:\!I FMESS

111.4. rrognam Sta r t

In order to sta rt the pro gram, go into thed irectory on the hard disc and ca ll theprogram up by its name. II FJ\n:SS. orstart it through a batch file .

Aller a short load ing time, the programbriefly introduces itself: and then dis­plays a menu with its functions:

Synthesis erWobb lcrMilliwatt meterSpectrum ana lyser

Calibrat ionError list

End

The red bar above the indi vidual menuitems can be moved up and down usingthe cursor key. Press the "Ente r' key togo to the se lected fu nction.

10.5. Synt hcsiser

lh e sub-program ,S'ynthe,\i \w dis playstwo window s on the operator screen.The la p window displays the name"Synthesiscr", the current frequency andthe output level.

203

VHF COMM UNICATIONS 4/97(/'--------------'''''-'''''''''''''''''''''''''''=The frequency can be varied between 10MHz and 1400 MHz. 'lhe output levellies in the range -10JBm to + IOdBm.

The messas c "UNCAL" may be dis­played in the output level field, due 10tolerances in the hardware (PLL oscilla­to r, mixer and level regula tor ). Theinter-relationships arc d iscus...ed in Sec­l ion 10.\),. "Calibration" .

The bottom window 011 the screenindicates [he significance of individualkeys and (heir functions.

The frequency can be changed. step bystep, by moving the cursor key len orright, and the leve l can be changed . stepby step, by mov ing the cursor key lip ordow n.

Use the " Return" ("'I::n"..r"] l ey 10 go 10an entry window, into which the desiredfreq uency can be enter ed d irect ly via thekeyboard,

This entry proc edure is terminated ucing··Enter" .

Use F I 10 view tbe "Help text", whic hdepends Oil the cont ext. Press " Enter" or"Esc" 10 leave this text.

Use F lO \0 leave the "Synthcs iscr"function and go hack to the main menu.

10.6. Wobhl n

When the ,,"ohMer function is selected,the screen is set up in graphics mod e.This preparation is dire ctly de pendenton the pmecssor output and the VGAcard speed.

A large. wide window in the top half ofthe screen shows the wobble curve,while the bottom len-hand windowshows the current va lues for the mean

frequency and the span in MHz. Thebottom right-hand window, on the otherhand, shows the con trol optio ns throughthe keyboard.

The mean frequency cun be changedstep by step hy mov ing the cursor keyleft or right (half span ) and the span[wobble width) ca n be changed step byste p by moving the cursor key up ordo wn, from t 10 MH/ to ±500 MilL

Usc the "E nter" key to go into an entrywindow where the mean frequency canhe set thro ugh direct entry. l'his entryprocedure is to be ter minated using"l-ntcr".

The program mon itors the technicaloptions and prevents the frequency lim­it:'. from be ing exceeded.

Usc 1'10 to leave tbe "Wobhlcr' func­tion and return tu the main menu.

H1.7. Till' I\li lliwa ll Mell'r

Three windows are displayed in theMilliwatt meter funct ion. At till: topright, you ca n see the measured output

in milliwalls in part icular ly large chamc­tcrs, whic h can Mill he seen eas ily, evenfrom some di stance away. Below this isa hor izontal yellow bar, whic h changesin line with the output Jill' tuningpurposes.

At the bottom lctl. the current readingsare shown. such as mitliwa u s, out put indBm, volta ge in Volts, and uuturally , thefrequency runge set.

The bottom right window show s theope rating options.

The frequency band can 11 ..:: selected bymoving the cursor key up or down. Here

204

VHF COMMUN ICATIONS 4/97

the program takes account of frequency­dependent non-lineeritics o r the diodede tec tor and converts the readi ngs ac­cord ingly .

Use 1'1 to call up the con text-dependenthelp tex t, and "Enter" or " Esc" to leaveit again ,

Usc FlO to leave the " Milliwatt meter"funct ion and return to the main menu.

10,8. Th e Spect rum Ana lyser

When th e Spectrum Analyser funct ionis selected, the scree n is sd up ingraphics mode. Thi s preparation is d i­rectly dep endent on the proc essor outputand t he speed of the V ( jA card.

A large , wide window in the top half ofthe screen shows tile measured fre­quency spectrum. The bottom Icfl win­dow sho ws the current values for themean frequency and span in MHz.

Th e bottom rigiJl window , on the otherhand, shows the contro l opti ons throu ghthe keyboard .

Mov ing the cursor key to the left orright ch anges the mean frequency stepby step (half span) and mov ing thecursor key up or down changes the spanstep by step from ± 10 MIlz to ±500MHz (wobble width).

Use the "Enter" key to ente r an entrywindow, where you can enter the meanfrequency direct ly. Press "Enter" toterminate this entry procedure.

You can now use F2 to select theintermediate-frequency band width ­band widths of 500kHz and 5MHz arepossible .

The pro gram monito rs the technicalopt ions and prevents the frequency lim­its f rom being excee ded.

Use F l O to leave the "Spectrum Ana­lyser" function and return to the mainmenu.

10,9, Calib rat ion

The Catihmtinn funct ion runs throughthe entire available frequency spec trum.step hy step . The maximum outputpower of the frequency synthesiscr ismeasured every 1 M l L~, and the levelsett ings in the range frum + IOdBrn to- IOd Bm are de termined as well.

The test readi ng is graphically repre­sented in the top half of the scree n.

Carrying our a successful calibration is apre-requi site for the functioning of the"Synthesiscr" and "Wobblcr" appli ca­tions.

Possible tuning problems • c.g . maxi­mum output level sma ller than + 10 dltm• an: outpulled in the form of an errorlist (cf Section 10.10. "E rror list').When the calibration is complete . thistab le is d isplayed for the user in awindow on the lower left-hand side.

The " Calib rat ion" program item is time­intensive ! In unfavourab le ci rcum­stances, c.g, with slow computers or ifthe param eters have not been set opt i­mally, the complete running time mayamount to 10 - 15 minutes.

While the reading is heing dete rmined,the func tion can be interrupted at anytime, just by press ing a key . In thateven t, the calibrated values are notupdat ed (file CALIBRJ.BfN) on thehard disc.

205

VHF COMMUNICATIONS 4/97(~ - - - - - - ------'-"'-==="-""""'-'=

SPAN '" 2Frequency span (I , 1...6)

\'lOBBI.E STEP "" 4Step width for wobble measurement(l..I6)

MAXVOLTSA = 1.0Max. output spec trum of spectrumanalyser

10.10. Error list

Wh en the Ermr List menu item j ~ ca lledup, it is set up for graphical display.Implausible measurement values arcshown in table form as frequencies,theoretical levels and actual val ues.

Ir this table takes up more than onescreen page, the display can be changedthrough the cursor key s.

Use FJ ((I view the context-dependenthelp text and "Enter' or "Esc" to leaveit again.

"ES(;" terminates the error list displayand returns yo u to the main menu.

PRNP O RT = LPTICentronics interface (LI'"I" I..3)

FREQUENCY - 1200frequency target (0 ..1400)

MENU "" HF MESSDescription of option screen

Mean

HUt. End

With this selec tion , the II Fr\.u:SS pro­gram is completed, and the screenreturns 10 what it was before the call-upprocedure.

After a brief farewell, you return to theDOS operating system level.

M IN VOLTSA -" 0.4Min , out put voltage (no ise)

MAXo u r SYN "'" 17Max. output level (d Um) o f synrhesiser

PR INT ERDRI VER = ...

li ard copy funct ion (carried out late r)

PRTNl ERCIIFCK - ONPrinter test (carried out later )

10.12. The Con r tg u rauon File

In the JlFMESS.CFG Jill'. various pa­

mmctcrs, esse ntially con ditioned by thehardware, arc added to the lUMES~

S.EXE program.

T he individual values are brie fly out­l ined below:

READI NGS = MWTAB LECon version table for diode detector

AD·DELA Y = 200Time delay AID converter ( 1..1000)

[Q-DELAY " 20Transmission pulse time de lay (1 .. 1000)

TEMPDRIVE '" C:Description of RAM disc, if applicable

10.13. The Read tngs Ta ble

!\1WTAHLE.TXT

The elec trical behaviour of the diodede tec tor (F ig.20) is summarised in theMWTABLLTXT tab le. including nec­ess ary correction factors for frequencyand voltage. Any standard text ed itora llows the correction of this tab le andthus the capture of the current values forthe detector in usc.

206

VHF COMMUNICATIONS 4/97

- Diode detector characteristic line

For the diode detector, the outputvoltage should he measured in relationto the input pl l\\ er. This call be done ina sat isfactory way with a digital vo ltme­ter and a test transmitter for, e.g. , 144~Hz . A transceiver with adju stabletran sm ission power can be used as well.of course .

The pro g.ram is designed for a precision(minim um step width) amounting to IdB, lhe voltage values measured are tobe en tered in the table MWTAB­LE.TXT in data fields MESSWERn A­BELLE [ ,,31.

- Frequency correction

At high frequencies in particular, theinpu t impedance diverges. in reality,from the desired 50f.!. A correct ionfactor in the data lieIds FREQQUEN7.­TAHE LLE [ • , 21 balances this outthrou gh a computer.

Fh.... factor should be measured for thefrequency mnge 28, 50, 144, 432, 1296and 2320 MHz, with a con trol power of• for example - Imw (OdDm).

Frequency correction '"lhecrctical value at I·U Mjlz I Reading

- Correctionfactor. I\V

Small to lerances for the components, oreven for the 0 ! A converter Z;-.s426E-8 , result in divergences in themeasurin g voltage. The eU factor acts asa computer correction. Its value is app.0.0099. The reference voltage can beprecise ly measured at pin 5 ! 6 of the [)! A con verter. using a digita l gauge.

AU '" lJKef 1 256

10, 14. HFrt'l ESS,:\ll"U

The Hr\1 ESS.:vt~U file conta ins theindividua l items of the main menu. witha descri ption and a screen number (e.g.synthes lser; 110).

The description can be changed. but not

the screen number allocated. This datumis coded in the program and is thusa lways pre-determined.

I I.Conclusion

As already stated at the start the test rigjust described represents a welco me andcosr-cffccrivc gauging aid.

Naturally. with this relatively low ex­pcnduurc. it is not poss ible to create ahigh-end apparatus, and so practica lwork with the radio- frequency rig dcm­onstrates the limits o f this techno logysooner or later.

Certa inly improvements could be madehere. as with any circuit. It is importan there that individual hard ware changesdo not also make a change in thesoftware imperative.

Circuit modifications by users can possi­bly be published in this magazine.

207

12.Lite rature

I I) Carsten Vicland, OJ 4 (I e ; DiodeDetectors in 50 W Broa d-HandTechnologyVIIF Communications 4/87,pp. 223 ..237

121 Ganter Sattler, DJ 4- LO; SDA1202 • New I'LL-IS lip to 1.5 GJlzVIIF Communications 4/85.pp. 205 .. 209

fJ1 Gunter Sattler, D1 4 LH;Crystal-Stable VC<l Frequenciesfor AT V Set-UpsVHF Congress Wctnhelrn 199 1;Congress Proceedings,pp. 173 - 184

208

VHF COMMUNICATIONS 4/97

[4] Wolf-Iknning Rech. DF Q lC;Simple Gauging and SmoothingAids fur the UHF RangePart 5: 1\ Simple SpectrumAnalyser, 5..1500 Mil l.VIIF Congress Dorstcn 1990;Congress Proceedings. Pp. 42 .. 70

[5] Designing with the NE6021N E604;Robert J.Za"TCI Jr.Valvo Application Note.February 11)87

[6] The New Professional's Book;Mart in AlthausSybc x Verlag Gmh H

[7] Borland Pascal with ObjectsProgrammi ng and ReferenceManualBorland <,mbH