Download - Transverters for 24 GHz CW & SSB
Transverters for Transverters for 24 GHz CW & SSB24 GHz CW & SSB
Steve Kavanagh, VE3SMASteve Kavanagh, VE3SMA&&
Bob Golden, VE3OIKBob Golden, VE3OIK
OVHFA Annual Meeting, Toronto, Oct. 11, 2003OVHFA Annual Meeting, Toronto, Oct. 11, 2003
ContentsContents
• Background
• VE3SMA Transverter Description
• VE3OIK Transverter Description
• Results So Far
• Demonstration
BackgroundBackground
• 24 GHz local activity on Wide Band FM:– VE3SMA (2 rigs)– VE3VXO– VE3OIK (2 rigs)– VE3FHM– W2EV (2 rigs) – no other nearby US stations– Others using borrowed rigs: VE3MNA, VE3EZP,
VE3NPB, WB2VUO, etc.– VE3EZP is building, VE3VZ has most parts needed– Best DX so far: VE3OIK-VE3VXO 74 km
BackgroundBackground
• Narrowband (CW/SSB) on 10 GHz– Active in Southern Ontario:
• VE3OIK, VE3SMA, VE3FHM
– Best DX so far in Southern Ontario: • 308 km - VE3SMA (EN92fn)-K2AXX(FN12cs) under poor-to-
average conditions• VE3OIK has had several 280-290 km QSOs with W8’s• VE3SMA heard K2UYH in NJ (about 550 km) in August• Compare with best of about 175 km on wideband FM under
very good conditions (VE3EZP – N2JH)
– Much easier to work >100km on narrowband
BackgroundBackground
• Nearby Activity on 24 GHz Narrowband– Rochester Area
• K2DH, K2AXX, K2EHF, K2LDU/K2LDT, WO2P, N2EZS, WB2BYP, W2DYY
• They have already worked paths up to about 200 km• K2LDU/VE3 broke Canadian 24 GHz DX record, working
K2EHF at 134 km from FN14 (near Colborne)– Detroit Area
• WW8M, NE8I, WA8HGX– Eastern Ohio
• KB8VAO
• So why not give 24 GHz CW/SSB a try and see if we can work more/better DX ?
BackgroundBackground
• Commercial or Homebrew ?– Only one source of commercially built transverter:
Kuhne Electronic (DB6NT)• Most Rochester & Detroit ops are using these• Approx. CDN$675 for basic transverter with 2m IF (200
microwatts output)• Add approx. CDN$740 for preamp + power amp to 100 mW
(not including antenna relay, 24 GHz bandpass filter and interconnects, not available from Kuhne Electronic)
– Bob and I both prefer to spend little and homebrew a lot so the obvious choice was to design & build our own rigs….what little we knew then !
VE3SMA TransverterVE3SMA Transverter
• Many design options were considered
• Choice driven by availability of two parts– W5LUA LO-doubler/mixer board kit obtained
from K2DH (described in Microwave Update ’97)
• 10944 MHz LO input, 2304 MHz nominal IF for 24192 MHz RF (calling frequency is 24192.1 MHz)
– Qualcomm Q0410 PLL synthesizer board thrown out by my former employer
VE3SMA TransverterVE3SMA Transverter
• Block Diagram
ImageFilter
W5LUADoublerMixer
2304MHzXvtr
FT-290R2m Xcvr
Antenna
Doublerx4Qualcomm
Q0410Synth.
10944 MHz
5472MHz
1368MHz
145.9MHz
2304.1MHz
24192.1MHz
VE3SMA TransverterVE3SMA Transverter
• Qualcomm Synthesizer– Q0410 is demonstration board using (now obsolete) Q3036
synthesizer chip– Specified for 1-7 mW output at 900-1600 MHz (mine works over
about 750-1700 MHz)– Requires +/-5V and +12V so had to provide some power
supplies to run from +12V only– On-board 10 MHz frequency reference oscillator is not very pure
or stable – I used an external 12 MHz TCXO module removed from a surplus UHF radio board
– Added switches to control PLL divider ratios – makes a good multi-purpose UHF signal generator
– Thanks to N6IZW for providing a copy of the manual
VE3SMA TransverterVE3SMA Transverter
• LO Quadrupler (1368-5472 MHz)– Own design using amplifier MMICs– Quite broadband, covers about 5.4-6.1 GHz– Lessons learned:
• Normally well behaved ERA-3 can oscillate when driven non-linear
• Input and output impedance of 50-ohm MMIC is not 50 ohms when driven non-linear
MAR-8Doubler
MicrostripBandpass
Filter
MAR-3Amplifier
ERA-3Doubler
MicrostripBandpass
Filter
MGA-64135Amplifier
VE3SMA TransverterVE3SMA Transverter
• LO Doubler (5472 -10944 MHz)– Own design using microstrip circuit with
MGF1902B GaAsFET– Short section of WR-75 waveguide after this
doubler to eliminate any 5.472 GHz output– Using 13 GHz spectrum analyzer (tnx to
VE3TCK) could not detect any spurious outputs after this doubler/waveguide
VE3SMA TransverterVE3SMA Transverter
• 2304 MHz Intermediate Transverter– Single connector for Tx & Rx from/to FT-290R
• 100 mW Tx from FT-290R on low power• FT-290R provides DC on coax on transmit for T/R control
– Single connector for Tx & Rx to/from 24 GHz mixer• 1 mW output at 2304 MHz in transmit
– Unusual features• High side LO at 2450 MHz (allowed the use of an available
crystal and tiny surplus 2450 MHz ceramic filters in the LO chain)
• Use of GaAs FET RF switch ICs for T/R switching (thanks to AD6A for providing them !)
– Modified Down-East transverter a good alternative
VE3SMA TransverterVE3SMA Transverter
• 2304 MHz Transverter Block Diagram
GaAsSPDT Switch(AS169)
9dBpad
9dBpad
(MSA-0786)
MicrostripBandpass
Filter
GaAsSPDT Switch(AS169)
GaAsSPDT Switch(AS169)
GaAsSPDT Switch(AS169)
(MSA-0786)
(MGA-86576)To 24 GHzMixer
ToFT-290R
T/R Control
Control voltagesto switches andamplifiers
40.833 MHz Osc./tripler(2x2N5770)
122.5 MHzAmplifier(2N5179)
245 MHzDoubler
(2N5179)
450 MHzDoubler
(2N5179)
Diode Quintupler
(2x”VE3EZP”)
2450 MHzAmplifier
ERA-3+ERA-1
RF
DC
(WJ MY84-1)
VE3SMA TransverterVE3SMA Transverter• W5LUA LO Doubler/Mixer
– Uses ATF-36077 PHEMT doubler and HSMS-8202 dual Schottky diode in rat-race mixer
– About 13 dB conversion loss, in prototype• In this transverter this implies Rx noise figure of about 15 dB
and Tx output of about 50 microwatts.– Al says he has some boards left but hasn’t given me a
price. DEMI no longer stocks the HSMS-8202.• Coax-to-Waveguide Transition
– To get from microstrip mixer to waveguide filter– Uses .085” semirigid coax soldered to mixer board
and to 3/8”x3/16” hobby brass tubing waveguide.– Performance unknown as no way to measure !
VE3SMA TransverterVE3SMA Transverter
• 24 GHz Bandpass Filter– To remove 19.584 GHz image signal & 21.888 GHz LO leakage– 2-cavity post filter in 3/8”x3/16” hobby brass tubing waveguide– Designed using WGFIL program by WA4LPR (described in
Microwave Update ’89)– 4-40 tuning screws though broad wall of waveguide at midpoint
of each cavity
~.33” (inside)
.335” .335”End posts .032” dia.Centre post .078” dia.
VE3SMA TransverterVE3SMA Transverter
• Antennas– 1st QSO with 17 dBi horn made from hobby
tinplate sheet– 1 foot surplus dish with “Penny Feed” in
3/8”x3/16” hobby brass tubing• Feed dimensions (thanks to VK3ZQB)
– Slots 6.2 x 0.6 mm– Disk 12.5 mm dia. x .032” brass sheet
• Got reasonable SWR without any tuning
VE3OIK TransverterVE3OIK Transverter
• Some design options were considered• To use 23 GHz P-Com surplus modules
acquired in Dayton, would have to build a 3456 MHz transverter for the IF.
• The design chosen was to use a lower IF frequency based on the availability of parts.
• Took advantage of using 12 GHz Microwave L.O. bricks that I acquired.
VE3OIK Transverter
Flex w/g
+24vdc In
TX gndto TS-700A
1st RX IF in220 MHz
2nd TX IF out
2nd TX IF in 2 Ft Dish
2 * 1pf silvermica capsin series
1st RX IF out220 MHz
Coax Mixer
Coax Mixer
W/G BPF 4 pole24192 MHz
W/G BPF 4 pole24192 MHz
12/24 GHz DoublerNE32584 Fet
12/24 GHz DoublerNE32584 Fet
DB6NT LNA Board3 * NE32584 Fet's
24 dB gain
DB6NT LNA Board3 * NE32584 Fet's
24 dB gain
SMA Relay
SMA Relay12 GHz
Brick L.O.Ref. Osc.
96.874 MHz
Coax to W/G feed
IF in/out144 MHz
to TS-700A
TX/RXSwitching
dB
dB dB
20 dB padMAR-6 MMIC
20 dB gain @ 144 MHz
12 * 680 ohm 2 wattresistors, 24w, 56 ohm load
3 dB pad
DPDT RF relay SPDT RF relay
Coax Mixer
2nd L.O.364.388 MHz
TX IF relays +12v
TX RF relay +24v
TX L.O relay +24v
TX/RX 24 ghz Modules +12v
12206.124 MHz24 GHz Transverter - VE3OIK
W/GHPF
W/GHPF
BPF 220 MHz
MAV 11MMIC -20 VDC IN
Toshiba Amplifier0.5 watt, 36 dB gain
220 MHz Amplifier20 dB gain
VE3OIK TransverterVE3OIK Transverter
• 144/220 MHz IF Section– DPDT RF relay to switch 144 MHz path for
the IF rig either in transmit or receive.– The receive path contains a 20 dB pad and a
MAR-6 MMIC to protect the IF mixer– The transmit path contains a resistive dummy
load to terminate the transmit power from the IF rig and provide 1mw of transmit power.
VE3OIK TransverterVE3OIK Transverter
• 144/220 MHz IF Section, cont’d– The coax mixer is used for transmit and receive.– The Local Oscillator frequency is 364.388 MHz – When mixed with 144 MHz it produces a 220 MHz
signal for transmit.– On receive it allows a 220 MHz signal to be
downconverted to 144 MHz. – SPDT RF relay selects either the transmit or receive
path from the 24 GHz modules. – The transmit output is about 200W.
VE3OIK TransverterVE3OIK Transverter
• 24192/220 MHz Downconverter– The 24 GHz coax mixer is used to convert
24192 MHz signal to 220 MHz RX IF.– The L.O. is fed from a 12/24 GHz doubler
which takes a 12 GHz signal from a Megamicrowave Brick L.O.
– It is then doubled to 24 GHz using a NE32584 FET.
– The HPF after the doubler filters out any products below 24 GHz.
VE3OIK TransverterVE3OIK Transverter• 24192/220 MHz Downconverter, cont’d
– The 4 pole waveguide filter filters out the image frequency.
– Ahead of the waveguide filter is a DB6NT LNA board• bought as a kit containing an etched PCB, 3 *NE32584 FETs, and
some brass foil for making the z-wires during construction. • This amplifier has about 25 dB gain and 2 dB noise figure.
– An SMA relay rated for 18 GHz is used as an antenna relay• The loss is slightly higher at 24 GHz but very useable for amateur
radio purposes. – A small piece of 0.085 semi-rigid cable is used to connect the
downconverter module to the RX port on the SMA relay.
End posts .062” dia.
Centre post .125” dia.Intermediate posts .125” dia.
.42” (inside)
.331” .331”.373” .373”
VE3OIK TransverterVE3OIK Transverter
• 24192/220 MHz Upconverter– The IF input to the 24 GHz coax mixer is 220 MHz, which is
filtered by a 220 MHz BPF and amplified by a MAV 11 MMIC. – The filter chooses the desired IF frequency of 220 MHz from via
the first TX mixer in the IF section then amplifies it drive the IF port on the 24 GHz coax mixer.
– The coax mixer is used to convert 220 MHz Tx signal to 24192 MHz Tx signal.
– The L.O. is fed from a 12/24 GHz doubler which takes a 12 GHz signal from a Megamicrowave Brick L.O.
– It is then doubled to 24GHz using a NE32584 FET. – The HPF after the doubler filters out any products below 24
GHz.
VE3OIK TransverterVE3OIK Transverter
• 24192/220 MHz Upconverter, cont’d– The 4 pole waveguide filter filters out the image
frequency.– After the waveguide filter is another DB6NT LNA
board. – This amplifier has about 25 dB gain.– The DB6NT amplifier also drives a 0.5 watt Toshiba
commercial amplifier.– A small piece of 0.085 semi-rigid cable is used to
connect the power amplifier to the TX port on the SMA antenna relay.
VE3OIK TransverterVE3OIK Transverter
• 24 GHz Power Amplifier– The Toshiba power amplifier was purchased from EBAY for $85
USD.– The output power is rated at 0.5 watt.– The frequency range of this commercial amplifier is 23 – 26
GHz. Ideal for 24192 MHz.– The output from the upconverter module is fed to the amplifier
input via coax to waveguide transitions.– The amplifier output is equipped with a waveguide to coax
transition.– This is connected to the TX port of the SMA switch with a short
piece of 0.085” semi rigid cable.
VE3OIK TransverterVE3OIK Transverter
• Coax to Waveguide Feed– The SMA TX/RX relay is attached via a SMA barrel connector to
a coax to waveguide transition.– A length of WR-42 waveguide is used to cut down the losses of
the transmission line to feed the dish. – A fish hook feed is constructed using a flex piece of waveguide
and a small pyramidal horn to feed the 2 FT antenna with an F/D of 0.45.
• Parabolic Antenna– The antenna is a 2 ft. (60 cm) diameter dish with an F/D of 0.45.– Antenna was purchased from Down East Microwave.– The waveguide protrudes through the dish via a cut out.
VE3OIK TransverterVE3OIK Transverter
• 12 GHz L.O Brick– The 12 GHz L.O. brick is a made by
MEGAMICROWAVE. – These bricks can be found surplus at Ham flea
markets. Other names such as California Microwave, Frequency West, Collins work very well.
– This particular brick has an external reference oscillator connection.
– Most of the PLL bricks have internal crystals and don’t need external crystal reference.
– The reference oscillator frequency is 96.874 MHz.
VE3OIK TransverterVE3OIK Transverter
• 12 GHz L.O Brick, cont’d– This reference frequency locks the brick to 12206.124
MHz. – The reference frequency was chosen using trial and
error to come up with a usable choice for the right up/downconversion IF frequencies.
– The multiplication factor is shown below: 96.874MHz * 14 * 9 = 12206.124 MHz– This means the total multiplication factor is 126. – This signal is then fed into a 12/24 GHz doubler to
achieve a fundamental L.O. at 24412.248 MHz.
Results So FarResults So Far
• Lots of time spent by both of us on design, parts scrounging, construction, debugging, etc. !
• We have concluded that, compared to the time spent on the homebrew rigs, DB6NT transverters are well worth the money ! But not as educational, or satisfying.
Results So FarResults So Far
• Initial QSOs– July 29/03 VE3SMA-K2LDU 0.6 km & 4 km paths
across Niagara River • Frequency calibration was only 15 kHz different from
Charlie’s. Minimal drift (by 24 GHz standards!) and good CW note were noted.
– Sept. 9/03 VE3OIK-VE3SMA 3 & 10 km paths in Cambridge/Kitchener area
• VE3OIK at 2.5 mW output (without power amp)• Very loud signals• Drift stabilized after about 15 minutes warm up
Results So FarResults So Far
• 2003 10 GHz & Up Contest (24 GHz NB)– VE3OIK (FN14ba) – W2DYY (FN12ev) 127 km– VE3OIK (FN14ba) – N2EZS (FN02xu) 130 km– VE3OIK (FN14ba) – KB8VAO (FN02xu) 130 km– VE3OIK (FN14ba) – W2DYY (FN02xu) 130 km– VE3SMA (FN14ba) – W2DYY (FN02xu) 130 km– VE3OIK (EN92ci) – KB8VAO (EN91kt) 85 km– VE3SMA (EN92lp) – KB8VAO (EN91kt) 94 km– VE3OIK (EN92fn) – KB8VAO (EN91kt) 89 km– VE3OIK (EN92fn) – VE3SMA (EN92lp) 44 km
What’s Next ?What’s Next ?
• VE3SMA needs preamp, power amp and antenna switching between them
• Graham, VE3FHM, is collecting parts and starting to build a transverter !
• An attempt on the VE-to-VE dx record
• An attempt on the VE-to-W dx record