This Month’s Meeting

Test Gear and Rig Programming.

Members are invited bring along a piece of two of test gear to show and hopefully to demonstrate to fellow club members.  It would be interesting to see examples of nano-NVAs, modern digital oscilloscopes, small spectrum analysers, RF power measuring devices etc along with demonstrations of their uses especially to radio amateurs. 

Members are also invited to bring along kit to program channel info into rigs, such as handhelds, belonging to other members.

The meeting will take place on Thursday 16th May at 7.30 for 8pm in the Premier Suite, Cheltenham Town Football Club, Whaddon, Road GL52 5NA.  The bar will be open as usual for the sale of tea and coffee as well as alcoholic and non-alcoholic drinks.

Visitors and prospective members are invited to attend and will be made welcome.

April’s Meeting

Annual Constructors’ Exhibition

Here are the rules.

  • Entries must have some relevance to amateur radio.
  • Entries must not have been shown at a previous CARA Exhibition.
  • Entries must have been constructed within the previous couple of years or so.
  • Entries must have been built or heavily modified by the exhibitor who must be a member of CARA.
  • Kits built by the exhibitor are permitted.

The following awards will be available for presentation:

  • The Bill Brown G5BK Cup for  “The Best in Show”.
  • The Pat Moore G3IKR Memorial Cup for “Innovative Construction”.
  • The Roger Kendall G0UPU Memorial Cup for “Best Software or Computer Related Project”

An exhibitor winning the same award for two consecutive years will not be eligible for that award the following year but, if rewarded by the judges, will receive a certificate instead.

Thursday 18th April.  7.30pm for 8pm in the Premier Suite, Cheltenham Town Football Club, Whaddon Road, GL52 5NA. Visitors and prospective members will be made welcome.

The G6CJ Aerial Circus – A demonstration by Peter G4ENA

Report by Tony G3PJQ

The demonstration and talk by Peter at the March club meeting was very interesting and well delivered. I had not seen the original talk given by G6CJ in the 1940’s to an audience of the IEE and subsequently by others, but it was a novel way of demonstrating the performance of various antenna types.

The demonstration used a microwave source of 3000MHz (3 cm) and model antennas were tested on this scale over a copper ground plane using a sense antenna and oscilloscope. Antennas ranging from a simple quarter wave vertical, through dipoles, yagis, quads and a rhombic were tested and their radiation patterns demonstrated. It was very clear how the spacing of parasitic elements could be introduced and surprisingly even the effect of the ionosphere on fading.

It proves that a practical demonstration is worth its weight in gold compared to sitting through hours of theory. Well done Peter.

March Meeting

The G6CJ Aerial Circus – A demonstration by Peter G4ENA

Peter writes: how about playing with some aerials to see what they can do and discover things you’d may not realise.  It was back in the late 1940’s that Dud Charman G6CJ created his “Aerial Circus”.  A lecture he first gave to the IEE in London.  In brief, it was a field test site in which various aerial configurations could be tested, but being in the microwave domain, it could be done on the kitchen table.

This re-creation relives Dud’s experiments.  The weather is sure to be dry and beer will be on tap.

  Thursday 21st March  7.30pm for 8pm at the Premier Suite, Cheltenham Town Football Club, Whaddon Road, GL52 5NA. Visitors and prospective members will be made welcome, as a;ways.

February Meeting

Table Top Sale for Members – Thursday 15th February 2024.

This is an occasion when members bring along their unwanted radio kit and sell to fellow members.  No domestic stuff though!

Sellers – On arrival members grab a table, or part of one, set out their stall and enjoy an evening of haggling over prices! 

Buyers – Please come with well-loaded and well-oiled wallets.  Most transactions will be in cash but a few members may take cards.

Venue – as usual, the Premier Suite, Cheltenham Town Football Club, Whaddon Road, Cheltenham GL52 5NA.  Doors open at 7.30pm for a nominal 8pm start.  The bar should be open as usual selling tea and coffee and well as alcoholic drinks.

Visitors and prospective members will be made welcome as usual.

January Meeting

This month’s meeting will be held on Thursday 18th January 2024 at the usual venue, the Premier Suite at the Cheltenham Town Football Club, Whaddon Road GL52 5NA.  Doors will be open by 7.30 pm for an 8pm start. 

Members are invited to bring something along from their shack/radio-room to display to other members.  Perhaps a new rig, or a classic rig.  Perhaps a special or unusual piece of equipment.  Perhaps an item or two of historical note.  Perhaps a few photos or video display of a club meeting or a field day. 

Visitors and prospective members will be made welcome, as always.

November Meeting. An HF Receiving Loop – A Suggested Club Project

In RadCom for September 2021, CARA member John G8CQX wrote about a wide band HF loop antenna with a high-performance amplifier which he had designed and built.  As described in September’s CARA News, he has recently developed a simpler version of the amplifier (easier to build), but still with a good performance.  At our November meeting he will tell us how it all works and answer any questions we may have. 

Towards the end of the meeting John will ask for firm expressions of interest from members who wish to build their own amplifier.  He will then procure all the necessary components and assemble them into kits.  The cost should be in the range £30-£40.  He is NOT offering to supply the PEX barrier pipe which forms the actual loop, nor the T to support the loop, nor the coax cable to go between the loop assembly and the shack.  Cash payments will be preferred at the time to guarantee delivery of the kits.

Thursday 16th November at the Premier Suite, Cheltenham Town Football Club, Whaddon Road GL52 5NA.  Doors will open by 7.30pm for an 8pm start.  The bar should be open as usual.

Prospective members and visitors will be made welcome, as always.

October Meeting

Thursday 19th October.  7.30 for 8pm at the Premier Suite, Cheltenham Football Club, Whaddon Road GL52 5NA.

A talk by Roger G4BVY on HF Propagation.  The talk will cover the fundamentals of HF propagation, explain some of the terms/numbers used, explore how to predict propagation, describe means of real time monitoring of propagation and look at the causes and effects of sudden disturbances.

Given that we are at around the maximum of the current sunspot cycle, when HF conditions should be at their best – at least for some of the time! – this talk promised to be of great interest to club members and especially to those who operate on the HF bands.  It should appeal to newcomers and “old timers” alike.

Roger is travelling some distance to give this talk so do please come along and make his trip worthwhile.

September’s Meeting

Aerials, Transmission Lines (Coax), Transmission Line Transformers and Transformers.

Thursday 21st September at the Premier Suite, Cheltenham Football Club.  7.30 for 8pm

The stimulus for this talk was my lack of understanding of how to determine the voltage at the end of an aerial, needed for the new regulations, and the operation of the 49:1 baluns so often used to feed wire aerials. The answer, it turns out, to these and other problems is to be found in determining and analysing the equivalent circuit of the aerial, transmission line, transmission line transformer and  transformer.

In the talk we will look at the early contributions to radio of Faraday, Maxwell and a little known maverick Heavyside, and see how a telegraphy operator sorted out a load by identifying the correct equivalent circuit for a transmission line. We will then look at the equivalent circuits of the afore mentioned RF components and see how wonderful computers are at doing sums to give us an insight in to the operation of these RF components. Don’t worry I will keep the maths to a minimum and give you a warning before showing any equation! While there will be a few equations in the talk, it is my intention to provide a clear practical view of how these devices work rather than produce a maths induced coma in the audience.

At the end of the talk I hope we will all be able to go away having a better understanding of how aerials, transmission lines and transformers work.

Mike G4GHL

August Meeting

Auction of SK and Other Items

Thursday 17th August in the Premier Suite at the Cheltenham Town Football Club, Whaddon Road GL52 5NA.

The doors will open by 7.30pm for viewing and the auction proper will commence at 8pm. If you are likely to bid, on arrival you should sign-in and collect a bidding card. Bids will accepted only from those with cards. Lots will be sold as seen. Please note that some of the equipment may use high, dangerous, voltages – proper care must be taken when using such equipment.

Payments must be made at the end of the auction and may be made by cheque (if presenter is known) or cash. No lots may leave the room until paid for.