Wednesday, August 18, 2010

Crawley Microwave Round Table Program Sunday 12th September 2010

This venue has a reputation of having a very friendly atmosphere - come along and support the construction contest and hear the talks.

10:00 Venue Opens
The pre-lunch program will open with the usual table-top sale of useful bits and pieces plus general natter session giving a chance to meet up with old friends.

In parallel we will be as usual running the UK Microwave Group annual construction contest for the G3VVB trophy. Participants are invited to bring along items of home constructed equipment and enter the contest. Entries do not necessarily need to have been constructed during the past year. Last year's winner was Mike G3LYP – this year it could be you that carries away the trophy!

12:00 Construction contest judging commences.

13:00 Lunch. (rolls, sandwiches etc. and tea/coffee will be available at the tea bar)

14:00 Opening address by Derek G3GRO and the results of the construction contest

14:15 What to do with a big dish ? Mike Willis G0MJW

15:00 Getting the most from your G3DDK LNA – Sam Jewell G4DDK

15:45 Break. (tea and coffee available)

16:00 Applications for weak signal modes – Brian Coleman G4NNS

16:30 End of meeting

Tuesday, August 17, 2010

The Mystery of the Phantom Whistling Kettle - an Unusual Case of RFI!

One night during recent testing of the revised earthing arrangement of my HF Windom antenna I became aware that I had signs of RF feedback on 7Mhz SSB when running QRO especially with the audio processing switched on in my FT1000MP – a sure sign that all is not well with the earth routing in my newly relocated shack downstairs in the conservatory . I had also heard a few occasional thuds from the loudspeakers of the hi-fi system.

I then became aware that I could hear the electric kettle whistling in the kitchen which has a rather unusual mournful sound as the whistling dies away after the appliance switches off after reaching boiling point. This puzzled me because that apart from myself, I thought that the house was empty.

So I went into the kitchen to investigate thinking perhaps I had an un-announced visitor but the kitchen was empty and what is more,the water in the kettle was cold so it could not have boiled to create the whistle! It was only at this point that I realised that the whistle on this new Morphy-Richards kettle was not in fact driven by steam but was electronic in origin and had a switch underneath to turn the noise on or off! A couple of bursts of QRO on 7Mhz again produced the same mournful wailing again confirming that I had clearly got quite a bit of stray RF getting into the house wiring since the kettle 13A plug in the kitchen was at least 35ft away from the earthing point of the HF rig and Expert 1K-FA linear amp.

Helped by Peter G4FYY, some general re-routing and shortening of the various earth leads ensued and separation of the earth route from the ground point of the in-line choke balun in the feeder to the Windom antenna to the copper ground stake. This seems to have cured the earth problem and now when I hear the kettle whistle I know that a cup of tea is really on its way !

73, de Derek G3GRO

Friday, August 13, 2010

Intermediate Course being Planned

Subject to sufficient take up, there are plans to run a 10 week Intermediate Course commencing Thursday September 30th, 19.00 to 21.00 each week. The contact address to register for the course is training@carc.org.uk.

Foundation Course 25th and 26th September

Malcolm, G3NZP has now confirmed that CARC have sufficient interest to run a Foundation Course on 25th/26th September and there will probably be room for a couple more candidates. The closing date is Friday September 10th, so if you, or anyone that you know are interested in taking the foundation course/exam, please contact CARC using the club training email address (training@carc.org.uk).