Chelmsford Amateur Radio Society

CARS Meetings   July - September 2017

Award for All

July Meeting
Tue 7-Jul-2017, 7.30-10pm
Oaklands Museum, Moulsham Street
"Three Short Talks"
By CARS Members

After a very successful debut last November, the three-talks format returned with some more enlightening topics:-

The first two ran before the break and raffle with the third one after the break. A little more about the speakers and the topics:-

Bryan and part of the Type-52b (No 237) Airborne Spark Transmitter

Tony started by telling us about wave transmission using an illustration of ripples (waves) in a pond showing how they could be related to the terms we use in Radio and how they were related to the parameters and terms we are familiar with Wavelength, Frequency, Modulation, CW, AM, FM and the speed of transmission in liquid, sound and light (Radio Waves).

Following the refreshments and raffle break, Murray gave the final talk in which he eventually revealed the answer to the teasing talk title - which was that one of the great hidden gems is the “Museum of the Story of Communications “ in the Eur governmental district of Rome. A statue of Marconi is in the telecoms ministry entrance next to the museum. The latter was founded in 1982, with a collection covering 2000 years of history starting with the Roman Postal system, followed later by Swiss Post, Pirelli telecoms cables, their Marconi collection and Olivetti equipment. Despite his trip to England, the Italians realised how important he was and have maintained their history of it all (unlike their English equivalents in Chelmsford and Ofcom!).


Useful Links:

  • Murray's slides: Marconi Museum Talk slides (2MB pdf)
  • Museum info is online at (Use Google translate in Chrome)

    August Meeting
    Tue 1-Aug-2017, 7.30-10pm
    Oaklands Museum, Moulsham Street
    "Constructors Competition"
    By CARS Members

    The August meeting iwas the annual time to show what had been constructed.- CARS accept all sorts of entries (and have done so in the past) from still photographs to video clips. The only real Rule is that it must be electrically SAFE.

    1) John G8DET: John presented three items to illustrate how NOT to do things which might seem alright at the time.

    • Dummy load in an aerosol can with sealed in carcinogenic transformer oil - Would explode when hot and/or give you risk of Cancer
    • Surge limiting set of electical components enabling an in-series filament lamp which could be switched out after the initial surge. (it had an illegal 13 amp plug which did not have shrouded live pins )
    • Homemade small aerial with reflector and diamond shape elements to improve mobile phone range. (did not work)

    2) Andy G0IBN: Presented a small memorial to the RAF including a "bathtub" morse key from a Shackleton maritime patrol aircraft, sounder and a model Lancaster.

    3) Peter Bridgeman G3SUY: Peter had built an 80 /160m tranceiver in a green metal case with a cream front panel completed some 6 months ago his design and construction.


    4) Dave Bolwell Entered a 6L6 valve amplifier for PA which he constructed some 50 years ago (with the help of Marconi's he said )

    5) Colin Page G0TRM: Colin demonstrated some Variometers which are a coil with some of its turns on a smaller former placed inside so that it could be made to increase or decrease the total induction by turning it on a spindle. He added an aerial and a detector diode to produce a tunable crystal set which he demonstrated with the use of a guitar audio amp

    During the tea break Tony G4YTG collated the audience votes. The result of the voting was :-

    1. First: A clear winner for Peters 80/160m tranceiver
    2. Second: went to Colin G0TRM's Variometer sets
    3. Third: to Andy's Memorial key base and oscillator

    Peter G3SUY (right) collecting his prize from Tony G4YTG

    The money prizes were presented on the night and the certificates will be presented at the AGM.

    September Meeting
    Tue 5-Sep-2017, 7.30-10pm
    Oaklands Museum, Moulsham Street
    "Radio Caroline"
    By Martello Tower Group

    The September meeting began on a sad note with a minute silence held to remember CARS member David Davis G3SVI who passed away recently. - A true radio ham gentleman. See his SK page

    The subject of the September meeting was 'Radio Caroline' and the recent GB5RC special event celebrating it. We were treated to an interesting talk by members of the Martello Tower Group following their recent return visit to the Ross Revenge, the 5th vessel used by Radio Caroline in her 53 year history!

    Following a successful activation in 2016 of this historic vessel, Keith G6NHU & Richard G7HJK together with other members of their group revisited the Ross from Thursday 3rd to Monday 7th August. The tender trip journey should have been somewhat easier than when the ship was in the South Falls Head outside the UK territorial limit (the Ross Revenge is now anchored in the River Blackwater) but the weather decided to produce a Force-8 gale so the short journey out proved a reminder of what many have encountered in the past!

    Various stations were set up on board with three vertical aerials attached to the ship's railings and dipoles running from the bow to the stern. Operating was below deck from the comfort of the mess room and a good number of contacts were made on various bands including 15, 40, & 20 metres. FT8 data signals were also used with good results, although Keith pointed out that in general the bands were noisy and whilst many hams were hearing the GB5RC station's calls, unfortunately it was difficult at times for the group to hear people returning to the station during the many 'pile-ups'. That said, an impressive response was received together with many requests for the special QSL card produced, both from hams and SWL's.

    The GB5RC team on board

    From the informative photos it is apparent that the team on board fed well and thankfully the Force-8 abated. Whilst the River Blackwater is a relatively calm location compared to previous anchorages, some of the team found the vessel's movement unsettling especially when the tide turned. It is evident that an incredible amount of work has been carried out on board by the volunteer restoration crew, and the GB5RC team also showed us further views of the ship taken with their drone.

    A lively question & answer session followed, with topics ranging from the amateur radio special event transmissions to more general discussion around the whole topic of offshore broadcasting. Newly licensed Mark Willis recalled his trips out to see the 'pirate' ships from Walton in the 1960's, and more in depth information was supplied by our past President & 1960's Radio Caroline transmitter engineer Carl Thompson on many aspects of the transmitter equipment and conditions on board the Mi Amigo. (The RCA 50 kW Tx is pictured right)

    Carl also recalled the time when he was rescued from the Mi Amigo by 'breeches buoy' in January 1966. He pointed out that at the time of the 1960's offshore stations, no-one ever thought this whole subject would still be of such interest 50+ years later.

    Our grateful thanks to the Keith G6NHU and the rest of Martello Tower Group for their work in activating the Ross Revenge and for giving us a fascinating talk, enjoyed by all, and adding to the wide variety of interesting topics covered by CARS meetings.

    Thanks also to the two lovely ladies who provided the teas and cakes to the many members & visitors attending.

    L-R: Colin G0TRM, Keith G6NHU, Keith G3WRO (RSGB Region-12 Mgr) and more of the GB5RC team

    The GB5RC QSL Card

    Useful Link:-

  • QRZ: GB5RC

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