The Scottish Microwave Round Table (GMRT) is now well established, and for the 9th year running was held on Saturday 2nd November at its usual venue, the Museum of Communication (MOC) in Burntisland. A record-breaking 53 amateurs attended.
Ten minutes before the official door opening time of 9:30 AM the organisers had everything set up and some attendees were already inside, enjoying welcoming cups of tea and coffee, eagerly looking at the piles of microwave equipment, modules and bits and pieces on the market stalls. The volume of voices steadily increased with more arrivals as old acquaintances were renewed and new faces were associated with names and call-signs.
Right from the start the participants also made good use of the test and measurement facilities provided by Brian Flynn GM8BJF and David Stockton GM4ZNX, and this continued throughout the day in the breaks between presentations.
The proceedings started at 10:30 AM with a welcome to the venue by Professor Tom Stevenson from the MOC. Martin Hall GM8IEM, the UK Microwave Group (UKuG) Scottish representative, then welcomed the participants and acted as chair for the morning session.
Mark Hughes GM4ISM started the presentations with his talk entitled “Microwave EME”, reminding us that Earth-Moon-Earth (“moonbounce”) is good for those who are surrounded by hills or living in remote locations and for whom terrestrial QSOs aren’t easy – for EME you just need to be able to see the sky. The concept of EME seems rather esoteric, yet many well-equipped terrestrial stations have the capability for working worldwide DX on the microwave bands. In a fascinating presentation, Mark guided us through the opportunities and challenges of microwave EME, describing the issues to be tackled and providing practical solutions, covering path loss, equipment requirements, polarisation, Faraday rotation, antenna feeds, Doppler shifts, and best operating times.
After a short break Sam Jewell G4DDK gave his eagerly anticipated talk on the “Icom IC9700: How does it measure up as a VHF DX Transceiver”. This was listened to attentively, since many participants either already own or were thinking of purchasing this transceiver, both for use to drive a transverter and directly on the 144, 432 and 1296 MHz bands. Sam gave a very clear and simple explanation of the architecture and characteristics of the transceiver that are not only important when chasing DX and contesting, but also the implications for other nearby stations. The characteristics described were supported by measurements carried out by Sam and other amateurs. Of particular note was that Sam recommends the injection of a 49.152 MHz signal from a low phase noise reference-locked source to over-ride the internal oscillator to address the radio’s frequency stability issues on 1296 MHz when used with weak signal digital modes. These are commercially available either as a kit or complete.
Whilst lunch was being set up in the conference room, attendees assembled in the museum where the entries for the GM4LBV Projects Trophy were displayed. We have come to expect a superb buffet lunch (included in the entrance fee) provided by the MOC volunteers and weren’t disappointed! Their efforts are very much appreciated by the attendees.
Andy Sinclair MM0FMF took over as chair for the afternoon session, which started with a talk by Martin Hall GM8IEM in which he described the architecture and system design aspects associated with “Constructing a 13cm (home) station around the Kuhne MKU23 G4 transverter”. Martin has made several attempts to build kit for operation on 13cm over the last 40 years, but these were never completed, since “life got in the way”. Prompted by talks given at recent GMRTs by John G4BAO, Andy MM0FMF and Jack GM4COX he decided to make a big push to get on the air as quickly as possible with a station based around the MKU23. Martin described his objectives, the architecture of the system, the practical issues addressed whilst designing and building the system (including the use of simple home-built test gear), and the future upgrade path now the system is operating. He also presented his QSOs to date on 13cm from his remote location in IO78HF and gave an update on his 23cm station count.
Another short break followed whilst the next presentation was being set up. The Hayling Project is named in memory of Mike Walters G3JVL and is intended to provide an advanced low cost SDR-based microwave transceiver in the same way that the very successful BATC Portsdown Project has delivered a low cost system for ATV, resulting in a doubling of the membership of the BATC. Heather Lomond M0HMO discussed various radio hardware, processor and software options for this project in her talk entitled “SDRs and Software for (Portable) Microwave Operation” and opened up a discussion in which she asked the audience for alternative ideas for achieving the project objectives. This provided a lively discussion and several useful suggestions for Heather to develop further.
During the afternoon break Roger Blackwell GM4PMK and David Stockton GM4ZNX judged the entries for the GM4LBV Projects Trophy, and the trophy was now presented to the winner Neil Smith G4DBN for his beautifully built 22db conical feed horn and wavgeguide flange to dish feed horn for 122GHz. The other entries were a microwave signal marker by Tom Melvin GM8MJV, an ADF5355 microwave signal generator covering 54 MHz to 13.6 GHz by Brian Flynn GM8BJF, and a second entry by Neil G4DBN of a QO-100 dish feed (2.4GHz circular patch and dielectric lens to 22mm ID copper waveguide feed to 10GHz LNB mount).
As in previous years the museum volunteers had kept us well supplied with tea, coffee, biscuits and scones throughout the day, as well as providing a splendid buffet lunch. Andy thanked them thanked for their efforts, and each was awarded a gift to a round of applause from the appreciative audience.
Finally, and looking forward to next year, Andy confirmed that the next GMRT would be held on Saturday 7 November 2020 - put the date in your diaries now! Anyone willing to make a presentation next year, please contact one of the organisers with details of your proposal.
During the course of the day those present provided updates to the Directory of Scottish Microwave Activity, which also includes stations in nearby areas that can reasonable worked from GM. This is intended as a reference for those considering who they might be able to work on the microwave bands (especially when upgrading their stations), and the latest issue will be made available via the UKuG, gm13 group, and GMDX Digest.
Time to chat is an important feature of the leisurely programme of the GMRTs, and as in previous years plenty of time was allocated for this purpose between presentations. However, as usual, it never seems enough, and some participants were still going strong when they had to be ushered out at 1700 so the doors could be closed.
Many attendees (and some YL/XYLs) moved on to the Kingswood Hotel in the evening for further chat and an excellent meal, followed by an auction of microwave related publications and hardware conducted by Roger GM4PMK which raised £165 for the MOC. Thanks go to those who donated the items for auction – Dubus UK, Dubus Verlag, David GM6BIG, Sam G4DDK, and Brian GM4BJF. Technical discussions and social chit-chat continued well into the evening.
Thanks go to the organising committee of Roger Blackwell GM4PMK, John Cooke GM8OTI, Brian Flynn GM8BJF, David Stockton GM4ZNX, Colin Wright GM4HWO, Ian White GM3SEK, Peter Dick GM4DTH, Andy Sinclair MM0FMF and Alan Masson GM3PSP.
Prepared by Martin Hall GM8IEM 08-Nov-19, reviewed by the organising committee.