G3JVL

I was sorry to receive the news that Mike, G3JVL, has passed away.

I first met Mike back in the 1970s at the Crawley Court, Winchester, Microwave Round tables.

Subsequently, I joined the RSGB Microwave Committe back in the 1980s and Mike was afellow member.

We had a lot of dialogue during those years, Mike made me a 2.3GHz quad loop yagi that I used for many years and then in the 1990s I visited with him and saw his home station. From that I was loaned a small (2.5W) TWTA that I used in my home 3cm station. I had never seen a TWTA with only three (or was it 4?) connections previously. Mike showed me how to use it and I had many long distance QSOs on 3cm,  not only with Mike, but also with many of the other 10GHz narrowband home and portable stations that were around during the 1990s.

I later met Mike, again, when we were both attending the Plano, Texas, Microwave update. I think that was around 2000. Mike was visiting with his daughter who, I recall, lived local in the Plano area of Texas. 

I don’t think I ever saw Mike again. I am sure he continued active to be active on the bands,  but our paths never crossed again. Ioften wondered what he was up to.

I guess I will never know,  now.

Vale Mike.

23cm on the IC9700

I have been busy bringing my IC9700 on-line in place of my 23cm transverter based system.

It is not that straightforward. One of the problems is that the radio is on my operating desk whilst the linear is in the rack. They are either side of a door, so the cable route between them  is about 3m, at shortest. I do have coax and control cables running between the desk and rack. But, it is impractical to run large, low loss cables, so with Ecoflex cable the 10W from the IC9700 is not enough to drive my 200W SSPA to anywhere near full output. In fact just to 80W output. My answer?

I have a now rather elderly twin brick M57763 amplifier with about  30W output, when driven at 400mW. I have turned down the IC9700 to about 5 to 6W output, drive the cable to the twin brick, situated in the rack next to the 200W SSPA and then use a 12V coax relay to separate transmit and receive path. I have a 6dB/10W SMA attenuator in the twin brick input to bring the input down to about 250mW (don’t forget the cable loss). With this arrangement I can drive the main amplifier to around  150-180W output and I have some power control by turning down the IC9700 when required.

I’ve still got to tidy up the cabling, reset power levels and then connect to the dish antenna.

BTW, there’s a lovely bright, near full, moon out there this evening, but it is low in the sky.

Sam

IC9700 progress

I have been conducting more tests on the radio and talking to a number of more experienced RF engineers to get a better ‘handle’ on the transceiver’s performance. I’ve also been using it extensively on air on the three bands during contests, using satellite mode, D Star and FM on repeaters and giving FT8 a good airing on 2m.

My user review for PW is nearly complete and I’m awaiting feedback on the draft from the editor.

I will comment further on some other measurements done on the transceiver a bit later.

Regard this as a place holder!

Sam

RSGB PSC meeting

Just back from an RSGB PSC (propagation studies committee) meeting in Leicester. Just a corresponding memeber, but try to get to one meeting a year. Very enjoyable. Great committee. Serious discussions.