Low cost skimmer

Occasionally intersting projects do get shown on the BATC QO100 net which runs on Thursday evenings.

One such occasion was when GI4DOH mentioned he was using a cheap A to D board in front of a commercial FPGA board to do cw skimming and rtty skimming instead of the expensive Red pittaya board

I had been using my ANAN 10 to do my skimming which is overkill . It is limited to 4 receivers. His system could do 8 so time to Investigate!

Full information was available at https://pavel-demin.github.io/qmtech-xc7z020-notes/ who was the designer of the  A to D board. All the necessary files were available to get the boards assembled in China. Luckily i found someone who was getting a batch made so i ordered one from him. The cost (shipped) was £58

The FPGA board QMTECH ZYNQ7000 XC7Z020 Development Board was available from Aliexpress  for around £80. It came with a 5 Volt Power supply

The only other items needed were a 2x25 pin header and socket to mate the boards,  a heatsink to keep the FPGA from overheating and an edge mount SMA socket

The A/D pcb has a reminder to remove R14 and R15 on the FPGA board before mating the two boards and to connect 3.3V wires between the 2 boards, It didnt take long to put together

 Software was easy. Format an SDHC card then copy the contents of qmtech-adc-20240614.zip to it. I also copy the start.sh from  sdr_receiver_hpsdr_77_76 directory to the root directory so that on power up the receiver can be accessed by HPSDR

After power up I found the ip address assigned by the router and pointed HPSDR running on my PC . It connected and I could see signals

Overnight i compared the 600m WSPR decodes on the new receiver with the 600m WSPR decodes on the ANAN-10. They were within 1dB of each other , the new receiver has good sensitivity

Next task is to get it skimming! 

IARU TV Contest 2024 Day 2

 An early start was made from Membury services after coffee and pastries. I then drove to Combe Gibbet, IO91GI61 from where I could see Gareth G4XAT/P on top of Walbury. 

He was worked on 5GHz, 10GHz and 24 GHz easily, it didnt really matter which way the antenna was pointed

Noel, having driven from Devon appeared from Stockbridge and was worked from IO91GC on 5GHz, 10GHz 24 GHz 47 GHz and 76GHz 

Dave G8GKQ/p appeared from Lane end, IO91JA and was worked on 5GHz, 10GHz and 24 GHz

Noel then moved to Morestead Road, IO91IB and was worked on 5GHz, 10GHz 24 GHz 47 GHz and 76GHz

While Noel moved to Butser Hill IO90 MX. I moved to Combe Masts which had a good takeoff in that direction.  On the way past I visited Gareth

G8GTZ/P was worked on 5GHz, 10GHz 24 GHz 47 GHz and 76GHz. 76GHz was fairly easy and set a new UK distance record of 53km. 

76 GHz

47GHz was harder, taking 30 minutes, mainly due to Noels synthesised LO not locking up

47 GHz

Having worked all I could on the TV contest I had a quick tune around 144MHz and found a 2m QRP contest was happening and was surprised to work GW1YBB/P using the IC705 and vertical whip on the car roof. I think he was equally surprised by the locator of G4FRE/P!!

IARU TV Contest 2024 Day 1

 Noel G8GTZ decided he would be starting the contest at Dunkery beacon IO81FD so the obvious place to start the contest was Cleeve Common IO81XW, at the roadside position which always completes the path. The normal road to the car park was closed for 6 weeks for repairs so a convoluted route was taken, which was full of sponsored walkers. However Noel was worked on 5GHz, 10GHz and 24 GHz easily as usual

10GHz towards Dunkery

Gareth G4XAT had meanwhile installed himself at Walbury hill IO91GI. I packed the gear into the man portable fishing trolley and moved to the trig point and worked him on 5 GHz 10 GHz and 24 GHz

5GHz man portable towards Walbury

Next I drove to Notgrove IO91BV and again worked Gareth G4XAT/P on 5GHz, 10GHz and 24 GHz easily

IO91BV 5 GHz

I then drove to Membury services on the M4 and stayed the night there at the Premier Inn hotel, which would be convenient for the day 2 activities. 

A visit to Dunkery Beacon IO81FD

 Having booked a 7 night walking holiday at the HF Holidays location at Selworthy, Devon I realised it was just down the road from the famous Dunkery beacon IO81FD which I had worked many times from Cleeve Common IO81XW. It was decided to take some narrowband microwave equipment to see how the site really was.

I parked at the layby previously used by Noel G8GTZ on the North side of the Beacon. First QSO was on 24 GHz SSB with G4UVZ IO80KX near Taunton.

G8CUB/P had been persuaded to go to Cleeve Common IO81XW and was a huge signal on 24 GHz NBFM, He was loud enough to work on 47GHz SSB for my best ever DX on the band at 136km. No signals were hear either way on 76 GHz.

The takeoff over the  Bristol Channel

24GHz towards IO81XW from the layby

47GHz (a dish was needed for the QSO)

Meanwhile G4LDR, G8GKQ and G8GTZ had gone to Bullbarrow Hill, IO80UU (96km)  I worked G8GKQ and G8GTZ on 24 GHz NB and DATV and G4LDR/P on 24 Ghz SSB and 47GHz CW

The setup to G4LDR/P on 47GHz CW

I also tried working G8IKP/P IO80RQ near Hardy monument and M0GHZ/P at Cold Ashton IO81KP (obstructed path the plots later showed) but no success was to be had

After packing away the gear I did walk to the Top of Dunkery Beacon to see if it was worth the extra effort of going man portable. I was not convinced!

The summit of Dunkery Beacon

The takeoff towards IO81XW from the summit

IARU TV Contest 2023 Day 1

 This year I decided to go somewhere closer to home. Titterstone Clee seemed a good choice  but the usual spot would be a bad choice as the path North was blocked and G8GTZ was threatening to be QRV on Meryton Low. There were a couple of spots on Hoar edge that looked useable. Mid morning I was on my way with 23cm 13cm 9cm 6cm 3cm and 24GHz,

Arriving on site after an easy journey I had a look and found a site in IO82

I worked G3VKV two way over a 65km on 13cm 9cm and 3cm On  6cm band Graham could receive me but I had no chance of receiving him through the local widehand WIFI QRM.

I had been monitoring the skies all afternoon as the forecast had been for storms. They were seen approaching from the South from the Hereford Direction, but they seemed to go either side of the location without dumping rain!

Noel then appeared from IO83AD On 13cm and 9cm I could receive him over the 92km path with a MER of 20dB. However he could not receive me. Turned out he had a receive issue. We tried narrowband on 10GHz which just about worked. I called Noel on 2m Talkback with no response, so after a 2m qso with a station who took pity on me calling G8GTZ for so long I packed up and headed home.

The homeward trip was challenging as there was localised flooding and tree branches on the road, Glad it missed the hill

Takeoff towards Titterstone Clee

9cm towards G3VKV

View South

View towards G8GTZ/P

The journey

DATV-Easy

Having listened to the presentation by PA3FBX during the BATC Convention 2022 Part 2 about the F1EJP DATV-Easy 2.08 software, I thought I would give it a try.

The installation procedure is well described in "DATV-Easy-2.08-En.pdf"

First I needed to install OBS. This would be a learning experience having never used it before! I installed OBS 2.8 which meant I would need to install Droidcam for OBS as the virtual camera. 

I launched OBS and was met with complaints that Virtualcam for OBS could not be opened which was a mystery as I had installed Droidcam for OBS, After a lot of experimentation i discovered the solution was to delete Droidcam!

Next I installed DATV-Easy 2.08 which was easy. I then installed the Pluto driver. My Pluto (with F5OEO software was found. The callsign etc settings were changed. On starting to transmit, the left LED in the software lit, but the right one did not nor did the transport rate box change from zero. I eventually found out that DATV-Easy Encoder defaults to NVIDIA (which i didnt have)  so it needed to be changed to Soft(ware) With this change the second LED lit up, the transport rate got close to the expected value and a DVB-S2 signal was decoded

I confirmed that the maximum rate that could be supported by the software encoder is 333kHz. Next I need to investigate hardware encoders

This system is going to be fine for fixed station useage, but forget it when going portable, as it is very complicated and needs much hardware

Portable on Rosedale Moor IO94MJ

Before returning South I wanted to try another path with Rob M0DTS/P The slightly obstructed path was 115km between IO85XF20 (Winters Gibbett) and IO94MJ97 (Rosedale Moor) 

 Two way QSOs were had on all bands 2GHz and 24GHz on 333ks DATV with MER ranging from 24dB on 9cm to 5dB on 24GHz(rob forgot to pack the 23cm antennas!) 

 A Two way QSO was also had on 6cm FMTV, the previous intermittent issue with carrier and no video on transmit being traced to a poor quality Chinese BNC plug 

My FMTV signal was also received by G1LPS in IO94EQ at 55km after he did some careful arranging of components through the shack window

9cm equipment

24 GHz equipment

6cm FMTV equipment

24GHz signal received

13cm signal received (Note Gibbett at Robs site!)

The following day I went to Pickering and caught the NYMR train to Whitby, which was much busier than the visit the previous Monday. I was staying at the White horse farm in at Rosedale abbey. 

On Sunday I intended to get up to see the sunrise but my GPS was on GMT so i missed it by an hour, so contented myself with a walk on the moors, getting back for breakfast at 0930

It took 4.5 hours to get from Rosedale Abbey to Malvern. 

In total, 560 miles were driven in the 10 days!

IARU contest 2022 Day 2 Wharram le street IO94PB

 On the second day of the contest both Rob and I moved locations. I went to Wharram le Street IO94PB88 (just down the road from the deserted medial village at Wharram Percy) and Rob went to Sutton Bank IO94JF55,  a path length of 38km

2 way QSOs were had on all bands 432MHz (despite the local radar qrm and me using the 24GHz transverter 436.5MHz output of 250mW into a dual band co-linear) through 24GHz. Signals were not as loud as the previous day, but the path was slightly obstructed

Only equipment issue was the 6cm FMTV only producing vido output when it so desired, but by wiggling cables Rob saw the numbers

Takeoff towards Rob

9cm

24GHz

I also easily worked G4EEV 2 way on 23cm for my longest contact of the day at 61km 

IARU contest 2022 Day 1 Garrowby IO93XO

After the boredom of last years IARU TV contest I decided to do something different in 2022. Being on a walking holiday in Ravenscar the week after the contest I decided to try some paths  up there with the only other station likely to be active Rob, M0DTS and also try for a UK first on 122 GHz

I travelled up on the Friday which went so smoothly I even had time to visit the Yorks air museum which was very interesting

Saturday morning I travelled out to Garrowby IO93OX. It was very breezy. While setting up the Red Arrows flew low overhead on their way to the Teeside air display, Nice of Rob to arrange the welcome

122GHz was setup first as it was going to take most time. G4NXO/P was at IO93PW49 5.6km away. Output was around 12uW using DB6NT HSCH-9401 diode mixers with 100mw of 40GHz local oscillator and 146.5MHz IF at both ends. Antennas were pasolink dishes fed with VK3CV horns via a machined adaptor.

47GHz QSOs were also completed with G4NXO/P over the 6,  16 and 37km paths at IO93PW, IO93PU and IO93RQ respectively. I used my old DB6NT mixer with a DB6NT 47GHz amplifier used as a preamp and power amp and pasolink dish. G4NXO/P used my complete DB6NT transverter with W1GHZ horns

Rob, M0DTS/P. I went to IO94DF, a 66km line of sight path. 2 way QSOS were had on my intended bands 2GHz to 24GHz. I also had 2 way QSOS on 2 unplanned bands. 23cm using my DEMI narrowband transverter and half a 23cm Tonna antenna, (thrown in the car at the last moment) and held on the tripod with Wilco large croc clips. The other band was 432MHz using the 1W IF drive for my 24GHz transverter into the dual band mag mount on the car. This QSO was made even more challenging by Fylingdales Radar QRM

13cm equipment. Note manner of affixing yagi to tripod!

24GHz and 6cm FMTV setup

122GHz 

I also worked G4EEV two way on 23cm. Loud signals both ways, even with my miscalculation of which way west was, and working him off the back of the beam!

 

47 and 76 GHz man portable on the Malverns

 

As G8GTZ and G8GKQ were going to the Midlamds Convention at Eaton Manor, it seemed the ideal opportunity to try to extend the 76 GHz record distance record. They would go to Titterstone Clee amd i would go man portable on the Malvern Hills. The hereford beacon would be ideal, but it has steps to the top, not ideal for towing a fishing trolley. Eventually a location on Black hill was found which was just an uphill slope approach from the North Hill car park

Having done my stint on the 160m ARRL contest from Florida i set out at 1200. The weather was ok and the RH was only 61%. However when i got to British camp it was very windy (gusting 35mph!) and was very cold. I set off up the path. Very shortly afterwards the bottom of the plastic container fell out and one battery landed on the floor. I proceeded with just one battery. Going to the summit of pinnacle hill was impossible due to the wind so i found a lower location IO82TB96 which still had LOS to Titterstone Clee IO82QJ85. 

First we tried 47GHz and i received the loudest narrowband signals from Noel I had ever received from any loaction. A 47GHz DATV qso was easily had. We tried 76GHz but due to the wind it was impossible to keey the dish pointing corrrectly so the attempt was abandoned

Talkback was an issue. My ic706 was too heavy and my only ht did 2/4m, previously we had used 70cm. We tried to use the phone., I had coverage but Noel had flakey coverage which made coordinating an issue system. Time to look for a new HT for these occasions