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Real world distance test of the VK5REX B 70cm D-Star repeater

On Thursday 13th October 2011, I was able to really test out the performance of the modified 70cm duplexer recently installed at the VK5REX B D-Star repeater. The blog post previous to this one details what I did to the duplexer.

The family and I were on a road trip, travelling from Port Lincoln to Adelaide the capital city of South Australia. We were heading off on a much needed break from work and to catch up with family. This rather long drive necessitates driving North East following the East Coast of Eyre Peninsula, rounding Spencer Gulf at Port Augusta and then heading South toward Adelaide.

I was able to follow my D-Star transmissions via APRS. When I keyed up on D-Star, I was able to see my position pop up on APRS via my dash mounted HamHUD II display. I had VK5REX B connected to REF001 C, this ensured a lot of RF traffic and no shortage of people to talk to.

My mobile radio is an Icom IC-2820H radio and I had two antennas connected and diversity mode enabled. I kept the radio on low power for as long as I could, and only switched to higher power settings when my transmissions degraded info R2D2.

This is a screen capture from the aprs.fi website showing my trip as recorded via the APRS network. At highway speeds, my HamHUD beacons at 90 second intervals.


Below is my track via D-Star.  The track up the coast of Eyre Peninsula shows the coverage of the VK5REX 70cm D-Star repeater.  The last two-way QSO via VK5REX B was around 182km away from the repeater and the last GPS "ping" transmission received by VK5REX B was 202km away at Moonabie Hill.  The terrain from then on did not permit any further contact with VK5REX B. However, this is not the end of the story...

Pleae note that the D-Star GPS track/positions that appear near Port Wakefield and head South are via the Adelaide VK5RWN C D-Star repeater.



 One final surprise was being able to hear VK5REX B for a short time after we left Port Augusta and were heading South.  I had a very quick QSO with John N3SBP as we drove past Port Germein. This was most unexpected and was around 270km away from the repeater!! I was able to hear VK5REX B until we were near Crystal Brook and then a range of hills to the West prevented any further reception.  Below is a "close up" aprs.fi screen capture of where the QSO took place.


I uploaded a short YouTube video that was recorded 274km away from VK5REX B.  We were crossing the main railway line as the camera was "rolling" and this was just prior to my QSO with John N3SBP.



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Reader Comments (1)

Well Michael, we will be expecting a full review of the ID-31 by the end of January I expect??? :-)

December 20, 2011 | Unregistered CommenterNik VK3BA

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