Extreme Grids PF98 – about 100 km North of Yunta

By Rex VK7MO and David VK3HZ

This was one of the best locations for microwaves I have visited but definitely 4WD only. Glad I got the

Prado – could not have got this grid with my X3.

Again a successful aircraft scatter QSO with VK3HZ (793 km) and also tropo-scatter with VK5KK (343 km).

VK5AKM also copied me on SSB but nothing the other way. Tests with VK5DK over 633 km gave nothing

on aircraft scatter or tropo-scatter.

LOCATION OF PF98

Initially I tried to find a location on the closer part of this grid but there were either no roads or the path

was blocked by hills towards VK3HZ. However, by moving to the West these hills were cleared and a hill

with a reasonable take-off identified (30.90295 S 141.787333 E) – the problem was could I get to the top

of this hill which was about 200 metres off the road.

My GPS told me to go some 468 km but from Google Earth there seemed to be a shorter way by going

North from Yunta. Immediately after turning North I was greeted by the sign at Fig 1. But at least they

had plenty of signs to the Grid (Fig 2).

Fig 1: And this was the sign on a good road and I had to divert off to on a minor track

Fig 2: Lots of Signs directing me to the Grid

On the way I passed the town of Waukaringa. Google told me it had a population of 474 in 1889 when

they mined gold. But today all that is left is ruins and a very large chimney (Fig 3).

Fig 3: Ruins of Waukaringa – the large chimney is on the distance hill

Fig 4: The track to the top of the Hill. Doesn’t look too bad in the picuture but it felt like is was much

steeper

Fig 5: Near the top but not quite. The gear would have to be operated remotely as the car was on the

wrong side of this rock to the direction I needed to beam.

Fig 6: The take-off

Fig 7: The remote dish and 10 GHz Head and the ADSB antenna to the right

Coverage Diagram

Fig 8: The Orange line is the path of propagation. Blue lines are aircraft paths and red shows where

aircraft traversed during the period we were working. The common coverage area is defined by the

overlap between the two brown sets of lines.

It is noted in Fig 8 from the Red paths that aircraft were being received on ADSB slightly beyond the

coverage limits.

LIASION

No mobile telephone coverage in the area so we used 7.160 MHz. Thanks to Barry VK3BJM for

coordinating liaison and to Keith VK5AKM who liaised with David VK5KK. And to Andy VK3ES who set up

a long wire for 7 MHz and for providing his home location for David. One problem was that when I ran

my Honda Generator to power the 10 GHz system it completely wiped out 7 MHz.

RESULTS

ALL.TXT File Rxed by VK3HZ

Good data is highlighted in Green and DF in Yellow. The DF shows the Doppler changing from around

+200 Hz to -200 Hz on each aircraft crossing.

UTC Date: 2014 Aug 08---------------------232945 Transmitting: ISCAT- VK7MO VK3HZ....235930 0 -20 4.8 194 0 VK3HZ VK7MO 12 2 6 2.2235946 Transmitting: ISCAT- VK7MO VK3HZ -8000000 0 -20 7.0 -172 0 VK3HZ VK7MO 12 5 10 2.2.... Second aircraft000400 0 -20 13.7 108 0 VK3HZ IK7MO 12 1 6 2.2000430 0 -20 9.3 -108 0 VK3HZ VK7MO 12 10 10 1.1.... Third aircraft000900 0 -20 14.3 65 0 VK3HZ VK7MO 12 10 10 1.1.... Fourth aircraft001730 1 -8 13.7 172 0 * VK3HZ VK7MO 12 8 10 4.5001800 0 -20 11.5 -43 0 R-20 5 10 10 2.2001819 Transmitting: ISCAT- RRR001830 0 -20 3.7 -215 0 R-20 5 7 10 2.2001900 0 -20 5.4 -43 0 G 2 0 1 1.1001930 0 -20 14.8 -151 0 QPSXBT6Z7WLXR 8HWG 19 0 3 1.1002000 0 -20 9.3 -301 0 W30JK44X2M74Y-U9 16 0 5 1.1002030 0 -20 0.0 0 0 0 0 0 0.0

.... From Doppler below appears to be a fifth aircraft002100 0 -20 13.2 86 0 R-20 5 9 10 4.5002130 2 -3 3.7 -86 0 * R-20 5 10 10 1.1

.... Again Doppler suggests a sixth aircraft002152 Transmitting: ISCAT- RRR002200 0 -20 9.8 108 0 73 3 10 10 1.1002216 Transmitting: ISCAT- 73002230 1 -9 12.0 -43 0 * 73 3 8 10 4.5

ALL.TXT File Rxed by VK7MOUTC Date: 2014 Aug 08---------------------224400 Transmitting: ISCAT- VK3HZ VK7MO..... Fourth aircraft before anything received001745 0 -20 7.0 108 0 VK7MO VK3HZ -8 15 5 10 2.2001806 Transmitting: ISCAT- R-20...... Fifth aircraft RRR with one R missing002115 0 -20 14.3 -43 0 RRW 4 1 5 1.1002133 Transmitting: ISCAT- 73002145 0 -20 8.7 -280 0 73 3 3 4 4.5002215 0 -20 3.7 0 0 WHZF3H 6 1 3 1.1..... sixth aircraft002245 0 -20 7.0 -86 0 73 3 10 10 4.5

Comparing the two sets of ALL.TXT files it is again seen that the power difference shows up as manymore decodes when David is receiving.

ALL.TXT File RXed by VK7MO when receiving VK5KK on JT4f

UTC Date: 2014 Aug 09---------------------021300 6 -14 -0.3 -24 28 * VK3ZQB VK5KK PF94 1 0 DDavid called VK3ZQB after his computer restarted021400 Transmitting: JT4F VK5KK VK7MO -14021500 1 -19 -0.4 70 13 #021600 Transmitting: JT4F TRY VK7MO021500 1 -19 -0.4 70 13 #021700 9 -12 -0.3 -77 33 # VK7MO VK5KK -14 1 28 DSignal increased dramatically as David peaked is dish on me021800 Transmitting: JT4F VK5KK VK7MO R-12021900 7 -13 -0.1 -103 33 # VK7MO VK5KK R-12 1 18 D022002 Transmitting: JT4F @1500

CONCLUSIONS

Again the use of the Heywhatsthat 2D coverage diagram gives a good indication of where it is possible towork aircraft.