Chelmsford Amateur Radio Society

Past Club Meetings: July to September 2007

September Meeting. The History of Radar by Andrew Tyler, G1GKN

Andrew is a member of BAE Systems so is well up on Radar. BAE Systems Great Baddow Chain Home Tower

Using his laptop he projected beautifully produced slides onto the Marconi screen to a large audience.

He started by reminding everyone that a Chain Home Radar mast dominates Chelmsford. It was originally at Canewdon during WWII and was moved to Baddow in thw mid-1950s

Murray, G6JYB took this photo of the Mast recently - a similar one used to be at Bawdsey Manor (near Felixstowe) where much of the Radar development took place.

Andrew said he would trace the history of Radar and lead to how we rely on it in our everyday lives.

Andrew G1GKN

Andrew presenting his Lecture.

Andrew G1GKN
Photos by John, G8DET.
CARS President, Harry, G5HF is sitting to the left.

Andrew G1GKN
Slide showing the number of German Airship raids
over England during the middle of the 1914 - 1918 War.

Zeppelin journeys over the UK -- 37
Flights by defending aircraft -- 81
Number of times enemy seen -- 3
Number shot down -- Zero.

This was mainly due to not having bullets with incendiary capabilty to ignite the Hydrogen and low fighter ceilings.

Andrew G1GKN
German Radar - Freya

Long range surveillance - Frequency of 125MHz.
TX Power: 8kWatts - Range of 130km.
Seven were in operation in 1939.

Kinetic Avionic ADS-B Receiver
ADS-B Receive Unit & Aerial tuned to 1030MHz.

ADS-B Receiver Display
ADS-B display using a home built aerial support outside on a mast provided by Martyn, G1EFL.

The receiver was remarkably sensitive and displayed aircraft well beyond Gatwick & above 1700 feet.
To reduce the clutter, Andrew reduced the range to be more local.

ACARS - Aircraft Communication & Reporting System.

HF or VHF Receiver & good Aerial
PC with a good Sound Card
Free Software - PC+FDL for HF

After the break and raffle, Andrew showed a Video of Mr Watson Watt telling of the first official UK trial of Radar at Daventry on 26th Feb 1935.

Thank you Andrew & your Wife for spending the evening with us and presenting such a terrific evening of interesting information.

August Meeting:-
Constructor's Competition
Organised by Carl, G3PEM

The Constructors Competition is not everyone's cup of teabut it is put on by CARS Committee to encourage the Constructional Aspect of Amateur Radio.   Past years have seen a variation in the number of entries such that had this year had been poor, the Committee would have considered replacing it next year.
However a surprising number of entries were displayed on the front desks to be examined briefly by those present before the Competition really began.

Carl, G3PEM introduced the evening and stated that the Club Members were each given a Voting Form & it was them alone which determined who got the money.   He said he was pleased to see so many entries.

Carl G3PEM

Carl, G3PEM starting the Competition
Photos by John G8DET

Carl G3PEM

Carl, G3PEM starting the Competition with his 250mWatt TX

Carl then described the entry by M3YLB, Richard Beck, a beautiful Morse Key on a black Granite Base.

Morse Key

Morse Key

Tony, G4YTG was soon on the stand describing Fred, G2HNF's 80 Metre Vertical Aerial which he had just erected in the rain.   A schedule had been requested with Doreen, G8ONM, one of the Scouts running GB100J at 8 pm BST on 3.716MHz. Brian, G3CVI had brought the Club's new IC756 into the Meeting and had tried to find the contact but to no avail.   We now know they were without power in Hylands Park!
Fred had constructed everthing to a very high standard and the Aerial had been used for years when Fred went camping.

Tony, G4YTG alias Fred, G2HNF

Tony, G4YTG alias Fred, G2HNF. In the background can be seen Brian trying to contact GB100J.

Colin next described a Wein Bridge Oscillator he stated to make in the mid 1970s using a "then modern chip". It also use a Thermistor R53 to stabilise the output.

Colin G0TRM & Wein Oscillator Colin G0TRM & Wien Oscillator

Colin G0TRM & Wien Oscillator. This was demonstrated on an oscilloscope

Gwyn, G4FKH next took the mike to describe his WinKey CW Keyer. This was made from a kit from America and enabled one to put a message into the unit which it memorised and then played back under your command.   Very useful for contest working.

Gwyn, G4FKH Gwyn, G4FKH

Gwyn, G4FKH and his WinKey

Geoff, G7KLV next told the audience (in the middle of a rain storm) that he liked a slice of toast from time to time in his shack.   The problem was that he did not like it crusty on the outside and pappy inside - he liked it crunchie all through.

He decided to find out if he could modify a Toaster to do this so he took one to pieces and was suprised to find it worked on a simple timer - no function of temperature.

Using a Designers approach he 1/4 the heater power with a diode and then modified the timer to run 4 times longer

Geoff, G7KLV Geoff, G7KLV

Geoff, G7KLV and his Toaster - first problem was getting it out of his transporting basket

Geoff, G7KLV

Geoff, G7KLV and his Toaster

Tony, G4YTG next described how he had designed and built the 5/8th over 5/8 Dipole used at Sandford Mill during Sunday Open Afternoons for the 2 metre Station.   He felt his approach of having a non-radiating matching stub was unique.

Tony, G4YTG

Tony, G4YTG pointing to his Aerial ontop of Sandford Mill.

Break-time was called for the Members to have a look at the exhibits & mark their papers accordingly.

Carl, G3PEM

Carl, G3PEM looking pensive while collating the marks for each exhibit.

After the refreshment break the room reassembled and the many Raffle Prozes won.

CARS President, Harry, G5HF

CARS President, Harry, G5HF sitting next to Gwyn (red shirt)
with Ken Dews holding his Raffle Prize (behind).
Murray, G6JYB is sitting by his laptop computer for the next part of the evening.

CARS President, Harry, G5HF gave out the prizes.

First Gwyn, G4FKH was called to collect the "First Time Winners Prize" for his WinKey.

CARS President, Harry, G5HF  & Gwyn

CARS President, Harry, G5HF presenting Gwyn with his Prize.

CARS President, Harry, G5HF & Geoff, G7KLV

CARS President, Harry, G5HF presenting Geoff, G7KLV 3rd Prize for his Toaster.

CARS President, Harry, G5HF & Brian, 2E1RMD

CARS President, Harry, G5HF presenting Brian, 2E1RMD, 2nd Prize for his Regenerative Receiver.

CARS President, Harry, G5HF & Richard Beck, M3YLB

CARS President, Harry, G5HF presenting Richard Beck, M3YLB, First Prize for his Morse Key.
Brian said he nearly did not enter it but was persuaded to get it from his car at the last moment!

Trevor, M5AKA

Trevor, M5AKA telling the audience about the Scouts using GB4FUN to contact the ISS on 4th August at 22.10 BST.


Off air photograph of the Scouts reading their questions to the ISS.
Carlos is seen nearest the camera from the RSGB.
Thanks to Murray for projecting the images from his laptop.

Once again, the evening, both constructively & socially was deemed a success.   Thanks to all who contributed to the evening.

Report from details supplied by Carl, G3PEM

We will run the Constructors Competition again next year - look out for it in our 2008 Programme.

July Meeting - Livery Companies by Robin Butcher

John, G8DET welcomed the many visitors to the Social Meeting in the CARS calendar. He explained that Harry, G5HF celebrated his 90th Birthday this year & his Family had organised an event at which CARS were requested to provide a station to contact members of the Secret VI Group.

To commorate this event John presented CARS President, Harry, G5HF with a Birthday Card signed by all who attended tonight and a Gift in the form of a Theatre Token for the Cliffs Pavilion or Palace Theatre at Southend on Sea.

Harry & John

Harry, G5HF being presented with a 90 years old Birthday Card &
a theatre Gift Card for the Palace & Cliffs Pavilion, Southend on Sea from CARS.
Photos by John Yates, G1UZD

Tony, G4YTG playing his squeeze box to sing Happy Birthday to Harry

Tony, G4YTG playing his squeeze box to sing Happy Birthday to Harry

Sandford Mill Open Sunday Afternoons was promoted and volunteers requested to operate, log, host or even turn-up between 2 pm & 5 pm.   A number came forward - thanks.

Robin Butcher was introduced and the meeting reminded that he last presented a Talk about the RNLI. Doug came last time & set up an RNLI table and did the same this time - doing brisk business for this worth while charity.

Robin said his talk tonight was the Livery Companies of the City of London. These were formed in the 11th Century and were mentioned in the Magna Carta of 1215 when there were 44 of them.

Robin Butcher

Robin Butcher introducing his Talk.
Photos by John G8DET

The Livery Companies were formed in London to oversee the work of the City. They were formed before the Health & Safety Executive & Trade Unions and were essential to control the vast amount of trade which passed through London in the years past.

Trade and craft associations have flourished all over Europe for many centuries, but the City of London Companies, now collectively known as the Livery, are unique in their survival, number and diversity. The social and economic conditions which gave birth to the original guilds have long since been overtaken by the development of industry and commerce, but the livery companies still flourish today as living institutions. Their survival has been achieved by doing what they have always done: fostering their trade in a wide context, serving the community, and embracing modern skills and professions.

Today there are 144 livery companies in the City of London.

Mercer Company Crest

Mercer Company Crest

Mercer Company Hall

The entrance to being a Member of the Livery Company is by:-

  • Parentage, your Father was a Member,
  • You passed an Apprenticeship
  • Bought your way in.

    The Companies have an order of precidence with the Mercer Company being number 1.
    Two Companies vie for 6th & 7th place - on alternate years they reverse hence the Old English Phrase "Being at Sixes & Sevens".

    The highlight of the Livery Companies year being the Lord Mayor's Show.

    Lord Mayor's Coach
    The Lord Mayor's Coach

    Answering a question, Robin said he was a Member of the Shipwrights Company, paid for by his Company.

    Robin was thanked for a very interesting talk, nicely presented and finished in time for the refreshment break after which the 20 Raffle Prices were drawn.   Ela, G6HKM & Jill (M0BQC) staffing the Raffle Table with Martyn G1EFL & Geoff, G7KLV selling tickets.

    John then showed photos of Harry's June Event to round off the evening.

    Another pleasent evening at MASC with the Lifeboat Charity gaining as well.

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    ęCopyright CARS 2007
    Last revised:- 6th Oct 2007 to update the Sept Meeting.