The 10th Scottish Microwave Round Table (GMRT) was held on Saturday 22nd October in its usual venue of the Museum of Communication (MOC) in Burntisland. Despite issues with public transport, road diversions, the increasing age of the attendees and lingering fears of Covid, there was a good turn-out, with 36 attendees.

On arrival, after a friendly reception at the door by Peter Dick GM4DTH, the sound of voices from within indicated that everyone was already renewing old acquaintances, having much to discuss since the previous GMRT 3 years earlier. New faces were also being made to feel at home as they were associated with names and call-signs.

Attendees were spread amongst two areas, those in the conference room where refreshments were available right from the start, and those who had migrated downstairs to the area where bits and pieces of microwave equipment and components were piled up on tables for sale or swap, and where the test and measurement facilities provided by Brian Flynn GM8BJF, David Stockton GM4ZNX, and David Nugent were already in operation. These activities continued throughout the day in the breaks between presentations.

Formal proceedings started at 10:30 AM when Colin Wright GM4HWO opened the event on behalf of the organisers, with a welcome to the venue by Professor Tom Stevenson from the MOC who gave the customary safety announcements. Martin Hall GM8IEM, the UK Microwave Group (UKuG) Scottish representative, then welcomed the participants and acted as chair for the morning session.

Roger Blackwell GM4PMK started the presentations with his talk entitled “EME from the Hebrides – an update 10 years on” – on the 10th anniversary of the talk he gave to the GMRT in 2012. Roger is based on Mull, in an exposed location, where high winds, driving rain and salt spray have to be combatted to keep his station operational. He described improvements to weather proofing for the 23cm preamplifier at the feed, as well as the successful installation of a weatherproof metal Asgard shelter close to the dish to house the Power Amplifiers. Tracking has also been improved. Since his last talk Roger has installed a 9cm system based on an SG Labs transverter and Ionica PA boards, which he described. Unlike the permanent feed for 23cm the feed for the 9cm system is only installed when operational. Roger presented his results to date on 23cm and 9cm EME.

After a short break Brian Howie GM4DIJ gave a talk on “OpenEMS for Microwaves”, which is a free and open electromagnetic field solver using the FDTD method. He described how it can be used with a Matlab or Octave scripting interface for modelling various antenna structures, running the software on his laptop to carry out a demonstration analysis of simple antennas such as a dipole, and presenting the results of more complex antenna structures, which would have taken too long to analyse during a live presentation.

As usual we were asked to vacate the conference room while lunch was being set out and re-assembled in the museum where the entries for the GM4LBV Projects Trophy were displayed, and where Ian White GM3SEK and David Stockton GM4ZNX judged the entries. Once judging was finished, we returned to the conference room for a superb buffet lunch provided by the MOC volunteers which was greatly enjoyed by the attendees.

John Cooke GM8OTI, took over as chair for the afternoon session. Speaking in the after-lunch slot isn’t easy, but Malcolm Hamilton GM3TAL was up to the task in his light-hearted but nevertheless informative talk on “Microwaves – theory and practice or five different ways to cook eggs”. In this amusing and entertaining talk Malcolm covered everything the radio amateur might want to know about microwave ovens. His demonstrations using a microwave oven certainly kept everyone awake!

Another short break followed whilst the next presentation was being set up by Peter Bates, GM4BYF, for his talk on “122GHz Operations and Experiences. Pete was one of 5 amateurs based in Scotland who ordered 122GHz kits from VK2XAX (the others are Mark GM4ISM, Brian GM8BJF, Andy MM0FMF, and Chris GM4YLN). This kit uses the TRA120 chip incorporated in a board developed by VK3CV in conjunction with VK3ZBJ. Pete described the background to the project, the equipment itself, improvements he made and the tests that he had been involved with, which included the first GM to GM and GM to G QSOs on this band. The finale to his talk was a live demonstration and the opportunity for a member of the audience to conduct a first 122 GHz 2-way QSO. Norman Stewart GM1CNH jumped at the chance and worked the speaker Pete along the length of the room.

Immediately following Pete’s talk we had the conclusion of the construction competition and award of the coveted GM4LBV Projects Trophy. Ian White GM3SEK and David Stockton GM4ZNX gave a review of each of the diverse selection of entries, all of which had great merit making it difficult to select the winner. However, Mark Hughes GM4ISM’s entry of a user-friendly display and control panel for the VK3CV/VK3ZBJ/VK2XAX 122GHz kit was judged to most closely meet the award criteria. The interface on the kit itself is not very easy to use, and Mark’s solution is likely to encourage more amateurs to experiment with this system. The other entries were a 3.4GHz filter submitted by Jon Joyce GM4JTJ constructed using simple hand tools (and no pipe caps); the 2.3GHz entry by Jack Hood GM4COX was a complete masthead transmitter, PA and control unit (not a complete station).

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 the splendid buffet lunch. John thanked them for their contribution to what was viewed as a very successful event, and the volunteers were given gifts in appreciation to a round of applause from the audience.

During the day those present provided updates to the Directory of Scottish Microwave Activity, which also includes stations in nearby areas that can be reasonably 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.

The leisurely programme of talks at the GMRT gives plenty of time to chat, though it never seems enough, and once again 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 spouses and partners) moved on to the Kingswood Hotel in the evening for further chat and an excellent meal, followed by a delightful musical performance by the Microwave Band comprising Nadine White MM0WNW, Ian White GM3SEK and John Cooke GM8OTI. After the musical interlude an auction of items was undertaken, and thanks go to those who made the donations. The proceeds from the auction, other donations, and a small surplus from the door takings raised £193 which has been donated to the MOC to support their activities. 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, with contributions from the organising team.

06-Nov-22