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Chelmsford Amateur Radio Society

CARS Meetings January - March 2017

Award for All

29th Mar 2017

Added Classic Computing talk

January Meeting
Tue 3-Jan-2017, 7.30-10pm
Oaklands Museum, Moulsham Street
"Riding the Radio Waves"
By Jane Humphreys OBE

For our first meeting of the new year we welcomed Jane Humphreys OBE. Jane will talk about the part radio spectrum played in her career as a Civil Servant, and some of the challenges we face today for making the best use of the radio spectrum.

Jane was former head of Spectrum Policy at the Department of Culture, Media and Sport, during the period that included the multi-billion pound 3G Auction in 2000 and 2012 Digital TV switchover.

Janes background includes being the daughter of a Marconi Engineer and a member of Friends of Chelmsford Museum. You can see more in a video interview at the time of the 2016 Hall Street exhibition

Jane introduced radio spectrum from LF to UHF and beyond indicating typical ranges and applications. Whilst her early career had been completely different, her time in government coincided with being in the key place at the time of the 3G Phone auction, and then later for the Digital TV switchover which released 800 MHz (UHF Channels 60-69) for 4G LTE. Most of the demand in the main UHF bands is from mobile broadband as smartphones etc have grown in numbers and data traffic.


In 2000, the 3G Auction raised £22bn and vividly demonstrated that spectum was worth money, although the crazy sums it raised were not to be repeated. The more recent 4G auction in 2013 for ex 800 MHz ex-TV frequencies and 2.6GHz raised a more modest £2.4bn.

3G Auction - at the end of Round-150
A TIW        £4,384,700,000
B VODAFONE   £5,964,000,000
C BT3G       £4,030,100,000
D ONE2ONE    £4,003,600,000
E ORANGE     £4,095,000,000

Total       £22,477,400,000
4G Auction
EE         800+2.6   £588,876,000
3UK        800       £225,000,000
Niche Spectrum 2.6   £201,537,179
Telefonica O2  800   £550,000,000
Vodafone   800+2.6   £802,860,143

Total receipts     £2,368,273,322

The implementation of DSO to free up the 800 MHz channels for phones and also upgrade the power of the Digital TV multiplexes was the topic of a lot of detailed planning. This eventually saw BBC2 going digital early to flag up swithover in a given area (as the BBC would not be worried about a dip in advertsing revenue) followed a few weeks later by the other channels. In total 80 main TV transmitters and ~1100 relays were converted. The 800 MHz frequencies that were released are the basis of long range 4G-LTE (complementing some of the higher frequency bands)

An imminent prospect is a second Digital Switchover as the 700 MHz TV band (used at Winter Hill, BlueBell Hill and a few other regions) is cleared ready for sale in 2020 for 5G. This will require further modification to all the TV tranmitters and a few areas will need new aerials.

Jane also had slides on DAB toolout and the improvements to battery life that DAB chipsets had made (and over 2 million cars were sold in the UK last in 2016 with DAB Radios).

It was clear that spectrum was a finite and valued rsource with much of the demand crammed in the UHF/microwave range below 6GHz. At the end of a very well presented and insightful talk, Jane was presented with the traditional speakers prize of a CARS mug...

The famous CARS Raffle also had a good selection of prizes - as Dorothy M0LMR was pleased to find..


Some older tech was also on display - wartime BC-611 walkie talkies - from well before 1G-5G!


February Meeting
Tue 7-Feb-2017, 7.30-10pm
Oaklands Museum, Moulsham Street
"Diplomatic Wireless Service"
By Peter Scrimshaw M0HSG

For the February meeting CARS were pleased to have Peter Scrimshaw visit us from Verulam (St Albans) ARC to give a talk on the former Diplomatic Wireless Service (DWS) of the Foreign & Commonwealth Office (FCO). An audience of around 40 including several visitors heard a wonderful and little known tale of this 'Secret' wireless service, whose work covered FCO-Embasssy Communciations, Broadcasting and Wireless Security (inc cypher machines and sweeping for bugs).

Photos of the audience by Colin G0TRM and speaker by John G8DET

The DWS evolved from its WW2 origins to set up at Hanslope Park as a semi-autonomous part of the Foreign Office, and was quite distinct from its bretheren such as GCHQ and MI6. Led by Richard Gambier-Parry it built its staff up from wireless operators and a number of Philco staff.

During WW2 the MI6 radio network included a receiving station at Whaddon Hall, and a transmitting site to its south. Afterwards, the FCO took over, Whaddon was closed, and some staff retained relocated to Hanslope Park (which was a former WW2 Radio Security Service base) which also acted as a receiving station). Whilst the DWS name has gone, the park is now home to HMGCC.

Richard Gambier-Parry who was a sales manager at Philco in the 1930s (and an amateur) worked for MI6 during WW2 at Whaddon Hall. He became the first director of Communciations at DWS until 1955. (He retired to run a Casino in Malta and died in 1965). At DWS he was joined by another Philco man Harold Robin who was Chief Engineer until 1971.

Part of DWS was a production unit (formerly at Borehamwood until 1965) for cypher machines (such as Rockex) and radio bugs. The diplomatic radio network served embassies in communist countries (whereas US and Western Europe could use Telex etc). Morse and teletype were used but by 1975 CW had declined and the circuits were being converted to Piccolo. DWS developed Piccolo which uses 32 Murray code digits each 10 Hz wide (and a sync tone) and was transmitted as SSB in an audio range of 320-660 Hz and sent at 100wpm. As such, Piccolo was a pioneer of modern multitone data modes (MGM) that are superior to CW.


Eventually satellite communciations and other technological changes came along as did the end of the Cold War in Europe. Consequently HF usage and much of the foreign broadcasting declined. The last HF communciation was on 4th July 1993 to the Tehran embassy.

Peter also included some detail on MI6 comms (inc the Gawcott-Tx and Poundon-Rx sites) which were separate from DWS, though there was some cooperation. This used 5 digit codes to agents in the field and other overseas centres. The famous 'Lincolnshire Poacher' numbers station from the MI6 site Cyprus continued until 2008. MI6 abandoned HF and other sites when it moved to its new Vauxhall Cross HQ in London 1994.

Another item was the little known story of William Marshall, a 24 year old DWS radio operator at the British Embassy in Moscow. He was passing info to the KGB until spotted by MI5 (see article below).

At rather higher power was the Broadcast section of DWS based at Crowborough East Sussex. They operated large MW and SW transmitters in the UK and overseas in liaison with the BBC World Service. The Crowborough Tx was replaced in 1982 by one at the Orford Ness site. The latter ran BBC-WS on 648 kHz until 27-Mar-2011. Other sites included Cyprus (MW+SW), Francistown in Africa and Masirah in Oman. The remaining sites were taken over by BBC Engineering in 1986, which subsequently was privatised and became Babcock in 1997.

After the talk, the break had some homemade goodies to eat by Ann Salmon, followed by the raffle. Chris then presented a CARS speakers mug to Peter.


Useful Links:-

  • Hanslope Park is now HMGCC, Map
  • William Marshall - Article, Text
  • Book: 'The Secret Wireless War'

    March Meeting
    Tue 7-Mar-2017, 7.30-10pm
    Oaklands Museum, Moulsham Street
    "Classic British Computers"
    By Andy Chapman G7TKK

    Andy Chapman G7TKK, famed for his innovative antennas, returned to give a talk on another of his specialties - Classic British Computers.

    In the 1970s and early 80s pioneering work led to a wide variety of kits and models and a whole hobbyist movement.

    Andy has an unprecedented collection including some of the original prototypes...

    The Chapmans - Chris & Andy - with Andy G7TKK starting his talk

    Ferrite core memory board and a prototype of the Sinclair Mk14

    Nascom-2 and a collection of Sinclairs (ZX81, QL & Spectrum)

    Amstrads - PPC640 Portable and a NC100 Notepad

    Microsoft Windows 2.1 - the early days...

    Our thanks to Andy (and Chris) for the unprecedented collection coming out for public view

    PS - Do you have an Apple-1 - it is worth a fortune!)

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