Chelmsford Amateur Radio Society
G0MWT, GX0MWT, GB5HF, GB100MWT & GB100-2MT

CARS Meetings: April - June 2024


April Meeting
Tue 2-Apr-2024, 7.30-9:30pm
Danbury Village Hall		 "Constructors Competition"
CARS Members

The April meeting was our annual constructors competition – complete with generous cash prizes. The only entry rule is that it must be safe. Electronics metalwork or software are all valid entries.

This year’s entries are below and covered a wide variety from Raspberry-Pi SDR, to four pieces of wood!

Each entrant presented their creation, followed by preference voting that was collated by Paul G4PVM during the refreshment break – see next page for the results.

Fancy a prize? – get building now for next year! We also have a newcomers prize – to give you a chance.

Cash prizes were on offer for 1st 2nd and 3rd and newcomers. Murray totted up the voting preferences from the audience and in the event we had five entries so the latter was split evenly for fourth place as there wasn’t a newcomer entry. The Prizes and certificates were thus:-

May Meeting
Tue 7-May-2024, 7.30-9:30pm
Danbury Village Hall		 "Multimode Digital Voice"
Oscar Wood 2E1HWE

Our May meeting had a nicely illustrated presentation by Oscar Wood 2E1HWE on multi-mode VHF/UHF Digital Voice and how it has been greatly enabled by MMDVM - Multimode Digital Voice Modems. These were pioneered in 2015 by Jonathan Naylor G4KLX. Low power MMDVM kits and modules are now widely available and often associated with Raspberry Pi controllers.

There are an increasing number of Digital Voice modes. Many use AMBE or FreeDV codecs, but also utilise quite different RF modulation schemes. MMDVM kit addresses the compatibility issues as it can be configured to auto-detect the various modes and handle the complexities of internet routing and reflectors.

MMDVM (search on Amazon!) is quite popular for domestic low power hotspots and the basis many simplex gateways. Their use in repeaters is somewhat rarer. However we heard how Oscar had one of the first new permits from Ofcom/RSGB-ETCC for GB7IX in Southend which is in the new Ofcom category of 5W erp repeater systems, ideally suited to local coverage and experimentation.

Using the club VHF/UHF antenna, Oscar gave a demonstration as well as some useful DV operating tips - where latency and multiple remotely linked users are a factor:-

GB7IX covers Southend and the Thames Estuary well on: 430.9375 / 438.5375 MHz (7.6 MHz split, 110.9Hz CTCSS for FM) - initially using Yaesu C4FM with other modes to follow

Useful Links: www.qrz.com/db/GB7IX - and try the QR Codes above!

June Meeting
4-June-2024, 7.30-9:30pm
Danbury Village Hall		 "IMD & Quiz Social"
By CARS Members

The June meeting had a mix of socialising, radio, IMD update by Paul G4PVM and a quiz by John M0JOC

Overall it made for a varied and enjoyable evening with some of the quiz questions prompting some comments and memories

Before things became too formal the CARS VHF station was connected up to our refreshed Diamond X30 antenna at Danbury. As the tea and biscuits started to settle down, Paul then presented slides on this years IMD efforts.

HF Conditions had been poor due to a solar flare, but we still managed to work quite a number of European stations – assisted by the CARS HF bandpass filters that enabled dual HF rigs.

International Marconi Day

So our 2024 Marconi Day Summary was:

A good time was had by all but alas not enough stations for the Award - so do help us do that next year.

Paul also had the summary of our GB9MWT Special Event Station call, which had run from April 19th to 20th May. marking the 150th Birthday anniversary of Marconi (1874 - 2024). Overall this clocked up 350 QSOs including lots of Italian '150' stations.

After a short break we then switched to the quiz. John had used a mixture of history and a few training questions to create a very entertaining mix.

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