Friday, 17 June 2022

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!


Sunday, 12 June 2022

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







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 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 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 an working him off the back of the beam!





 

Saturday, 4 December 2021

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

Wednesday, 3 November 2021

Obtaining Accurate frequency spots from the RSP1a and skimmer server

 As my Anan-10 is often used as an HF multiband panadaptor (to see which bands are open) rather than a skimmer I needed to deploy another SDR as a cw skimmer. I had a spare RSP1a so decided to try that, even though it is in a plastic box!

Firstly the sdruno and api were installed from here, which made sure the rsp1a drivers were installed. Next the skimmer server was installed from here along with the needed SDRPLAYintf files to allow skimmer server to speak to RSP1a. The aggregator software was also installed from here to allow spots to be uploaded to the reverse beacon network.

The cw segment on 40m (outside contests) is narrow so only a 96kHz bandwidth (as is done on the anan-10) was chosen in the skimmer server settings and the system left running overnight

The following morning I examined the spots but found they had a random frequency error compared to other stations spotting the same station (eg ka9zap was -11.6 kHz, k3wjv was +2.1khz, k4ees was -0.3khz)

I wondered if the issue was band sensitive, so the following evening i skimmed 80m. The errors were similarily random.

I did a web search to see if anyone else had suffered the same issue, but found nothing. However I did find a page in Spanish by EA2NN showing he had succesfully used skimmer server with an RSP1a. I did however notice that he had set the skimmer server bandwidth to 192kHz so i thought it was worth a try.

After making this change all spots were within 100Hz of everyone elses spots on 160, 80 and 40m. The problem had been solved!

Note that in the skimmer server ini file you can define the frequency range that cw signals can be decoded (less than 192kHz!)

I also discovered that if you have the skimmer looking at 3 bands (the maximum it would appear from an RSP1a)  the default is that it skims 2 minutes on the 1st band then 2 minutes on the 2nd band then 2 minutes on the 3rd band before going back to band 1, so if you generate a local test signal locally it may take 6 minutes before it finds it!

Now to put the rsp1a in a metal box. I may even add an RF relay to the box so the input can be terminated on transmit!


Monday, 1 November 2021

47 GHz and 76 GHz DATV outing

 

Having failed to work 76km on 76GHz from the Blorenge G8GTZ and I decided to try some shorter paths

The first one was from Hackpen hill IO91CL to IO91GI Combe Gibet. I had never been to Hackpen, but I had previously worked it on 47 and 76GHz narrowband from Cleeve Common so I went there. When I arrived there was mist on the horizon towards Combe, but it slowly cleared and QSOs were had on DATV on both bands over the 26km path




I then travelled to Combe masts IO91GI61 and met with Noel and I worked G1EHF/P using fleapower on 47GHz. . With sunset being around 1615, and wanting to try another path of 35.6 km we forsook a pub lunch and had a sandwich before Noel went off to Cheesefoot IO91JB. I returned to the Combe masts. To save time we started on 76 GHz and a 250ks qso was had, even though there was a lot of mist on the path.




Tuesday, 28 September 2021

47and 76 GHz from Blorenge after the CQWW RTTY contest


 As I was off work for the week after the CQWW RTTY contest and was passing the Blorenge on the way back I wanted to try some more 47/76GHz TV. Noel G8GTZ was persuaded to come west to be the target

Arriving at the Blorenge at 1100 in high winds and rain squalls, we first tried the path to Birdlip, IO81WU at 67km  Two way qsos were had on 47GHz NB easily. I received Noels DATV signals easily but Noel was having trouble receiving me. After a lot of unsuccessful experiments, in desperation I reprogrammed the Lime to normal software and changed the Portsdown  setting from "Line DVB" to "Lime Mini" it all worked fine again. Two way 125ks DATV qsos were then successful. We then started on 76GHz but as s storm cloud had just come through and sat on the path no signals were received by Noel through the rain 

By the time Noel got to IO81XW81 the rain had cleared. Two way qsos were had on DATV at 125kS at 74km  76GHz was a bit more cooperative with a two way NB qso but not good enough for Noel to receive my high power DATV 




CQWW RTTY 2021


 

For a change this year Roger and I decided to try the MS section from MW2I. Having read the rules that MS doesnt really mean MS we set up the second K3S as the mult station. It didnt go quite to plan as the K3 went into "Hi sig" error mode and that was the end of that idea This is exacty the same issue as I had previously as recorded in my blog  where Q8 and Q9 had blown

So we ended up doing Multi op single radio 2 computers!

80m  dipole
40m rotary dipole
20/15/10 A3SDX 

The anan-10 rtty skimmer had a wellbrook loop for LF and a 12AVQ for the higher bands and proved its usefulness (it didnt capture G8S though)

Conditions were good. More  JA worked on 40m than we knew existed, along with KL7 for a new DXCC. 80m was very good into W sunday night and after many years of trying a new DXCC ....GJ!. Only gotaway was PZ5RA on 10m during the brief opening Sunday afternoon

 Band     QSOs     Pts  ZN   Cty  SP   Pt/Q

   3.5     333     700   11   52   14   2.1

     7     725    1697   23   75   40   2.3

    14     705    1713   25   70   50   2.4

    21     358     937   27   58   42   2.6

    28       5      11    4    4    1   2.2

 Total    2126    5058   90  259  147   2.4

Score: 2,508,768

As Roger said afterwards, "It is a long time since we did all 48 hours of a 48 hour contest" . Luckily I am on vacation this week so I can recover

After returning from the contest I replaced Q8 and Q9 in the K3S. I also changed the three resistors to the values Elecraft finally settled on see https://g4fre.blogspot.com/2018/08/k3s-hi-sig-warning.html.

Sunday, 8 August 2021

Plisch 432MHz amplifier module

 When I visited Frederichshavn in 2018 I purchased some small Plisch dual BLF861 device 28V 432 MHz amplifier modules  which had been used in TV trasnsmitters. I also got a larger two stage module with a single device driving  the same dual BLF861 devices.

When I returned I tried using the dual stage device but it saturated at 100W, even after doing the published modifications to the output stages at http://pa0ehg.com/70cmpa.htm and help from G4ERO. So the project was put to one side

I recently rediscoverd the modules and decided to try again, firstly with the dual device modules., With the same modifications I again got 100W output with 4W of drive. with each dual device set to 1A standing current.  I then reread the modifications and realised a PAIR of 5.6pf ATC capacitors were added across output capacitor, not a single one like I had been doing. Adding the capacitors and retweaking the input variable capacitor resulted in 190W output with 5W of drive, which is generally considered to be normal

A summary of my mods :-

Remove C62 and C63 (3pf)

Remove C7 and C27 (5.1pf)

Add TWO 5.6pf ATC capacitors across C9 AND C29

Add 22pf trimmer across C2 and C22

Add a 2N7000 FET at to turn the bias OFF on receive by earthing C19 V7 base junction (needs 5V on gate on receive)


The module after modification

Next task was to put it in a box. I did find the chassis from the defunct 6m 300W amp with coax relays and PIC controller so decided to repurpose it. 

The completed amplifier (with lid off module)


Saturday, 31 July 2021

PortsLang 4 Hardware Updates

 Having used the PortsLang 4 for a while I decided it needed 3 main improvements:-

1. The mouse for tuning works ok but is a bit clumsy and occasionally misses pulses

Fitting am Arduino Pro micro board emulating a USB mouse s described  at   https://wiki.microwavers.org.uk/Langstone_Project  with an Optically coupled encoder fixed this issue in my Langstone so the technique would be used again, There is not enough room for a turning knob on the Front panel. An external solution would have to be used.. The mouse simulator was built with 3 switches an an optical encoder in a small diecast box, allowing it to be plugged into the back panel of the PortsLang




2. The Adalm Pluto Oscillator drifts and has a frequency offset

This is not an issue in my Langstone as it has enough room to put a good oscillator and multiplier in the box.  There isnt enough room in the PortsLang to do that. Measuring the output frequency of the PortsLang showed the oscillator settled down 33kHz high at 437 MHz which was unacceptable. I had previously bought a couple of  the recommended replacement 49 MHz oscillators from Mouser, so decided to swap it out. The existing oscillator was carefully removed from the PCB with two soldering irons and the new oscillator soldered in place . Unfortunately when removing the original oscillator solder flicked onto the oscillator coutput capacitor and whilst removing this solder the capacitor vanished. A new 18pF 0402 capacitor , While I had the board out I also added the PTT output relay described at https://wiki.batc.org.uk/Custom_DATV_Firmware_for_the_Pluto#PTT_output

Measurements now showed the oscillator was now within 200 Hz at 437MHz without tweaking the Pluto calibration.

3. It has no speaker so a headset HAS to be used to listen

I had built a speaker into my Langstone so I could hear the signals when peaking a dish without tripping up on the headset lead. There was not enough room for a speaker in the PortsLang so an external box  was needed. Looking in my Junkbox I found a 12V 18W audio amp module, volume control,  a 2" speaker and a suitable plastic box, I built the amplified speaker with a DC connector to allow it to be powered from a 12V output from the PortsLang