The kit chosen for the Buildathon was the Walford Electronics Brendon 80m DSB transceiver and very popular it proved too. Everyone commented on how well the kit went together and all were extremely pleased when they received their first signals. Not everyone finished the transmit side before the event closed but those that did enjoyed QSOs across the room with Tim Walford, G3PCJ, the kit designer. Tim very kindly donated a prize to Brian Jones, G1ZEZ, who was the first to complete the kit on the day.

Feedback from the builders was extremely positive and most are ready to do it again soon. Steve Hartley, G0FUW, who arranged the event said that it had been a huge success and that he would encourage other tutors and clubs to have a go with their own Buildathon. Steve was assisted by Mike Coombs,G3VTO, and Lewis Thomas, G4YTN, and all agreed that team work was the key to success.

If anyone would like more information on how to organise a Buildathon of their own Steve can be contacted at g0fuw@tiscali.co.uk or at the address in the RSGB Yearbook.

Photographs taken at the Bath Buildathon by Jacob Howarth, M3MOB

To cut a long and boring story short, I decided the best option (for now) was a rotary dipole for 80m – and it needed to be discrete if it was to avoid complaints.

And withstand ‘very’ high winds on a regular basis.

The ingredients:

3 sections of 5 foot swaged alloy pole
1 tee-piece from Sandpiper
2 80m mobile whips bought on ebay
black silk spray-paint
lots of cable as the ’shack’ is now upstairs.

All in all quite a decent result – barely visible from all but one angle, until you get right up close – given the much higher contrast of the stairwell it would be a very unreasonable person indeed to whine about that aerial

The balun is simply about 18-20 feet or so of the coax close wound on a slice of cola-bottle and secured with gaffa-tape, then tied to the mast with cable-ties.

How well does it work?

On 80 it’s got a bandwidth of about 40khz without using the atu, and can still reach the USA at a readable strength despite being only 16 feet wide. The high-angle radiation that was missing from it’s predecessor makes inter-G contacts much easier.

It loads up quite happily for both 40 and 20 – I haven’t tried it anyplace else yet – and performs a lot better than I expected it to given the loading-coils.

I’m happy to call this experiment a success.

Sources:

Tee-piece from http://www.sandpiperaerials.co.uk/ (£5 plus postage)

80m whips from eBay seller chalesantennaman (about £11 each)

Sectional mast from http://www.haydon.info/
(I bought some rejects – 3 20 foot sets of 2″ mast for £49 plus carriage)