Saturday, September 20, 2014
Many years ago I built a 1296Mhz transverter using the DF8QK design from VHF/UHF Communications magazine. It took me quite a while to build and setting up and aligning was very tricky. After lots of patience, I managed to get the main part of the transverter working with an output of only about 100mw. Later, I built a three stage receive pre-amp with three BFR34 transistors and also added a single transistor BFQ34 power amplifier to increase the output to around 1watt.
The whole of the transverter was enclosed in fibre glass copper clad boards and as they were all built in separate modules, I assembled them all together, with the pre-amp and P.A. mounted separately inside a box.
I built a 10 over 10 slot fed yagi as per Radio Communication handbook (P13.25) using plumbing pipe and brass rods. This together with the transverter worked well. Unfortunately, back in the early 1980's there was little activity on 1296Mhz, so I hardly heard anything! When I took my shack apart and kind of 'gave up' amateur radio the transverter has stayed in the attic. The antenna gradually fell apart.
Since I have returned to amateur radio again I have taken part in the Tuesday evening activity contests. In fact, I have operated on all the contest bands, except 1296Mhz and above. I felt a bit left out with 23cms, surely there must be activity on these nights? Several times I have brought down my old transverter and connected it to my Yaesu FT101E, but heard nothing and have not even been sure whether the transverter even works any more. It got to the stage where I was about to throw it out because it I really couldn't be bothered trying to fix and align it all again after all the problems that I had initially.
Then earlier this year I got a SDR receiver which works happily on 1296Mhz. So on the contest nights I tried it out to see if I could hear anything on 1296Mhz. I was quite amazed to find that I could hear several stations with just my 70cm antenna connected!
On Tuesday this week I decided to try just once more to see if I could hear anything on my old transverter. I put in all the plugs and checked all the connections then switched on - nothing! I stood staring at the little beast scatching my head. Then suddenly I had a thought...I wonder if the oscillator crystal is working? I flicked the crystal a few times then with my fingers turned the core of the coil a turn.
OMG! It burst into life! I tuned and heard several stations in the contest...I was amazed! I listened for a while and wondered if the transmit part works. I found a strong station and called him...I works!!
The station I called was G4NTY/P and he came back with a 5-3 report although he was 5-9 with me.
I was so pleased that after all these years the transverter still works! I carried on working some more stations with the transverter connected to the 70cm antenna (No antenna for 1296Mhz)
My log now shows:
G4NTY/P, G8XUJ/P, G4HGI, G3TDH, G4CFP.
Not bad for a home made transverter built back in 1980!
Now I need an antenna...do I build another 10 over 10 or should I splash out and buy myself a 1296Mhz Tonna? Watch this space!
Monday, August 25, 2014
The other night I watched a programme on TV about the taking of the Arnhem Bridge during the war. It was interesting to watch and also why the mission became a bridge too far. It seems that one of the problems was the radio equipment which failed to function correctly. That meant that there was a breakdown in communication between the different troops. In the film showed one of the radio operators at Arnhem using an R109 receiver. I took some photos from my screen.
I was amazed to see this because I had one for years when I first got my Radio Amateur licence. It cost me £1.50p from a surplus shop on Folds Road in Bolton. It worked perfectly and ran from two 6 volt motorcycle batteries that I had permanently charging. The R109 had a vibrator pack to increase the voltage and also had a spare set of valves held inside the case of the receiver. The first thing that I did was to the metal guard on the front, it must have been hard for the radio operator to use this receiver with the guard fitted. I also removed some of the other things like the antenna terminals and big knob on the left that didn't seem to do anything. I fitted a coax socket for the antenna.
Here I am operating the receiver when I was 17 years old, note the two 6v batteries under the bench and old WWII headphones.
As I watched the programme I could remember what all the switches and knobs did on the R109, it was a fine receiver and I modified it inside to make it better. I added a BFO so that I could listen to SSB signals and also an S-Meter connected to the AGC line, it worked well! You can see the BFO adjustment knob just above the microphone.
I would love to play around with some of these old receivers again!
I'm not sure what the transmitter is on the right of the R109, I don't recognise it at all.
Wednesday, August 13, 2014
For the first time ever I managed to work a DX station outside of the UK on 70Mhz!
I have always liked to use 4m, back in the 70's I operated the 70Mhz contest station during VHF NFDs. A great band, but not much activity. On Sunday I listened to 4m out of curiosity because there was a contest sometime during the day. When I switched on my FT101E and home built transverter I heard a couple of local stations calling CQ. Then I tuned down a little and nearly fell off my chair when I heard CT1HZE in Portugal calling CQ!
This was obviously Sporadic E and his signal was fading in and out from S3 up to S7. I gave him several calls, but to no avail. After tuning up and down the band there he was again S9+ this time. I called again and he heard me! Amazing...we exchanged reports he got me at 5-7 and he is located at IM57NH.
My home built transverter from the 1980's still works perfectly...running about 4w into a 70Mhz HB9CV...I was so pleased with the contact!
Shortly after I went onto 50Mhz and worked another station with Sporadic E from Spain EA1AR in IN17PP.
Friday, August 08, 2014
The other night I set up my old disco equipment that I have had now for over 20 years! Until now, the equipment was stored in a cupboard at school gathering dust. It consists of a 100 watt MOSFET Amplifier that I built from a kit supplied my Maplin. It is mounted in the original aluminium case that I built back in 1970 that housed my stereo 'PW Partygram' amplifier.
The speakers also came from Maplin and the boxes I built myself from a design for the speakers that I used. The quality of these speakers are superb, even now after over 20 years of use.
The mixer was again supplied by Maplin and I built it into a case with jack sockets on the back for easy connection.
When my disco was in it's haydays the mixer was housed along with two Gerrard SP25 belt driven decks. Later, when CD's came along I stopped using the decks and just used two CD players.
Gosh...it seems so strange after all these years to think that I was once a DJ! I remember doing discos in all kinds of places. It started at school before I became a teacher, but then did discos for all kinds of events. I think the biggest was at the Pack Horse in Bolton with a huge number of people on a charity event. I also used it as a sound system for school plays.
Now I have a JVC LA-100 deck connected so that I can listen to my vinyl LPs and singles! The equipment works perfectly and the quality is brilliant....now that i'm a bit older, I don't whack up the volume like I used to!
Next job is to give the disco another coat of mattblack paint!
Wednesday, July 30, 2014
Here I am now, 60 years old and wiser. Still an analogue native at heart but having embraced the digital technology. My 60th birthday was spent at St Annes-on-Sea on holiday. The hot weather was just the same as it was when I was 18 at Camber Sands. In fact, it occured to me how much the same it felt in the hot hotel at St Annes and the hot challet at Pontins. On my birthday I got text messages from my family and friends and many greetings on Facebook. How times of changed. Now I have semi-retired from teaching and look forward to some time on the air and maybe building some equipment again.
Friday, July 25, 2014
Every picture tells a story...this desk could tell lots of stories!