It was a gloriously sunny Sunday and I escaped for a couple of hours of GHz fun to one of my favourite sites Britwell Hill (229m ASL, IO91LO98FM). I'd hoped to be up on the Chiltern Ridge at mid-day for the 4M AFS contest but other stuff got in the way. I arrived just after 3pm local time (the UKuG 24GHz contest is from 10am to 6pm local time).
Britwell Hill is 30 minutes drive from my home, and is a reasonably clear site with an amazing take-off to the West. In the recent July 1.3GHz UKAC I worked EI2FG 478km easily using 10W into the 44Y WiMo under flat conditions. With 24GHz, attenuation due to water vapour is a strong function of temperature and humidity. This means that generally cold (winter or autumn) dry days are much better than hot humid (summer or spring) days.
It was also first time out using the Pluto SDR as a 70cm IF plus a UHF Chinese 1W Amp. SDR Console is used to sequence a USB Relay which powers on TX the SMA Relay and RF Amp. Transverter is a modified 0.25W masthead Nortel ODU unit with 30cm PF Dish, kindly on long-term loan from Mike G0MJW.
For 2M talkback I took the FT-847 providing 50W into an HB9CV. On set-up I quickly found Barry G4SJH/P on Walbury Hill (IO91GI44) 44km to the South West on 144.390MHz. After some tuning around on SDR Console (I've still got my SDR "L" plates!), I heard Barry's dots. This was after accounting for the Nortel unit's offset of around +434KHz (!) due to it's aged LO xtal. We exchanged reports and 8-digit locator's. The Britwell to Walbury path had gone before on 24GHz in October 2018.
I then tried with Roger G8CUB/P who was 50km distant near Hackpen (IO91DL68). The path that way is always difficult and I could just make out a weak trace on the SDR. Roger could not hear anything from me unfortunately.
Some while after I heard Noel G8GTZ/P on 2m talkback who was at Sparsholt Down (IO91FN86) a site near Wantage that I visited for the March SHF UKAC. I could hear Noel on the SDR working Barry. Sparsholt Down is further round The Ridgeway path and is actually LOS at 36km. It's visible on the horizon just inline with the remaining chimney at Didcot. When Noel swung his dish towards me he was a truly massive signal turning the SDR plot yellow! It was great to work Noel for the first time on 24GHz.
Another very pleasant couple of hours up on the hill messing about on 1.2cm! I'm still yet to work anyone outside of IO91 square, my 24GHz PB ODX is 67km Hackpen to Cheesefoot Hill with John G8ACE/P. It would be great to work 100km or more and into IO92, IO82, IO81 or IO90. My best bet to increase my ODX is to visit Hackpen (IO91CL) again to try the 94km path to Blorenge (IO81LS) and the 123km path to Brown Clee (IO82QL).
I'm enjoying getting more acquainted with the Pluto SDR. I now have a working 1-2W SDR IF system that I can use in the SHF UKAC's on 144MHz to drive 13cm and/or 3cm, and on 70cm to drive 9cm. I'll probably rotate its use with various 2M and 70cm radio's - it will be too chaotic to use it on more than one band in an evening contest!
After my recent 6cm SSB QSO with the Pluto, the plan is to use that as the prime mover with a 2W Amp to compliment my WBFM capability.
Britwell Hill is 30 minutes drive from my home, and is a reasonably clear site with an amazing take-off to the West. In the recent July 1.3GHz UKAC I worked EI2FG 478km easily using 10W into the 44Y WiMo under flat conditions. With 24GHz, attenuation due to water vapour is a strong function of temperature and humidity. This means that generally cold (winter or autumn) dry days are much better than hot humid (summer or spring) days.
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| 24GHz at Britwell Hill |
It was also first time out using the Pluto SDR as a 70cm IF plus a UHF Chinese 1W Amp. SDR Console is used to sequence a USB Relay which powers on TX the SMA Relay and RF Amp. Transverter is a modified 0.25W masthead Nortel ODU unit with 30cm PF Dish, kindly on long-term loan from Mike G0MJW.
For 2M talkback I took the FT-847 providing 50W into an HB9CV. On set-up I quickly found Barry G4SJH/P on Walbury Hill (IO91GI44) 44km to the South West on 144.390MHz. After some tuning around on SDR Console (I've still got my SDR "L" plates!), I heard Barry's dots. This was after accounting for the Nortel unit's offset of around +434KHz (!) due to it's aged LO xtal. We exchanged reports and 8-digit locator's. The Britwell to Walbury path had gone before on 24GHz in October 2018.
I then tried with Roger G8CUB/P who was 50km distant near Hackpen (IO91DL68). The path that way is always difficult and I could just make out a weak trace on the SDR. Roger could not hear anything from me unfortunately.
Some while after I heard Noel G8GTZ/P on 2m talkback who was at Sparsholt Down (IO91FN86) a site near Wantage that I visited for the March SHF UKAC. I could hear Noel on the SDR working Barry. Sparsholt Down is further round The Ridgeway path and is actually LOS at 36km. It's visible on the horizon just inline with the remaining chimney at Didcot. When Noel swung his dish towards me he was a truly massive signal turning the SDR plot yellow! It was great to work Noel for the first time on 24GHz.
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| Local 24GHz SSB QSO's within IO91 |
Another very pleasant couple of hours up on the hill messing about on 1.2cm! I'm still yet to work anyone outside of IO91 square, my 24GHz PB ODX is 67km Hackpen to Cheesefoot Hill with John G8ACE/P. It would be great to work 100km or more and into IO92, IO82, IO81 or IO90. My best bet to increase my ODX is to visit Hackpen (IO91CL) again to try the 94km path to Blorenge (IO81LS) and the 123km path to Brown Clee (IO82QL).
I'm enjoying getting more acquainted with the Pluto SDR. I now have a working 1-2W SDR IF system that I can use in the SHF UKAC's on 144MHz to drive 13cm and/or 3cm, and on 70cm to drive 9cm. I'll probably rotate its use with various 2M and 70cm radio's - it will be too chaotic to use it on more than one band in an evening contest!
After my recent 6cm SSB QSO with the Pluto, the plan is to use that as the prime mover with a 2W Amp to compliment my WBFM capability.