OPEN UNIVERSITY AMATEUR RADIO CLUB
NEWS LETTER no:15
G0OUR Affiliated to the OU Club and the Radio Society of Great Britain
Firstly please make a note in your diary of the forthcoming AGM. As usual, it will be held in the Green Room above the Lecture Theatre at Walton Hall. This area has been refurbished following adjacent building works. Access is via the door at the end of the Airport Bar, up the stairs and first right. The AGM is on Tuesday 14th January at 12.30pm. All subscriptions are due on the 1st of January, and remain at £6 per annum. Your continued support for the club would be much appreciated.
I am pleased to report that we purchased a ladder back in July. We managed to obtain it second hand from a local plant hire firm that was recommended by our Chairman, Ted G0CGC. The ladder is a 2 x 5.5m heavy duty aluminium type, and is ideal for our purposes, i.e. reaching the top of the tower when it’s telescoped down. We also bought a hefty padlock and chain, so hopefully it won’t suffer the same fate as the last one. Our thanks go to the O.U. Club for providing funding to buy the ladder (£150).
The aerial repair and maintenance work has now been completed, just in time before the winter weather. The most difficult job was repairing the break at the feed point of the top doublet. This entailed loosening off the boom support clamps and stub mast coupler, and dropping down the fifteen foot extension pole above the beam. This in itself doesn’t sound too tricky, but manipulating a fifteen foot pole above you while being twenty five feet up a ladder makes it a hairy experience, despite wearing a safety harness. Getting the extension pole back in position after the repair job was no picnic either, but all was completed safely and without incident.
A new balun was fitted to the cross bar just below the rotator, which feeds a pair of parallel dipoles for 80 and 40m. The 40m dipole being suspended about 5 inches below the 80m one. Tuning the 40m dipole was surprisingly tricky and time consuming, not only altering the lengths, but the distance between the dipole ends and the 80m wires proved to extremely critical. Each adjustment meant lowering and raising the tower and retensioning the dipoles, and four or five iterations were needed before the 40m resonance fell nicely in the middle of the band. A good match was obtained on 40m, but not so on 80m, where the swr at resonance is about 2.5:1, presumably due to the 40m dipole positioning, so some further work is needed. The big topband doublet works very well on 80m anyway, so it’s not a major problem. The old 80 dipole has not been re errected since it too caused severe detuning of the 40m aerial! The balun and feeder remain in place, so it can be reused in the future, perhaps for a WARC band dipole.
While the tower was down we also took the opportunity to replace the old 2m groundplane, and this has been returned to Tom G3LMX, and is now being used at Bletchley Park. Thanks for the long term loan Tom! Also, congratulations to Tom on being appointed MKDARS station manager at Bletchley Park. Our new aerial is a dual band colinear mounted on a wooden crossbar at the top of the tower, giving 4.5dB gain on 2m, and 7.5dB on 70cm. This is fed with W103 low loss coax, and then via a diplexer into the two radios. Very good results have been obtained on both bands, with excellent coverage on FM of the immediate area and beyond. Some good contacts have also been had on 2m SSB despite being vertically polarised. We have still not managed to obtain a 70cm linear. We have chased after a few, but have always been too late. However another one has now been located second hand, which we hope to purchase in the near future.
Congratulations to Adrian G1NIQ who recently obtained his class A callsign M0ANS (which he had pre booked by the way!). He becomes our first member with an M series callsign. Adrian took his Morse test locally at Bletchley Park, having attended Morse classes there run by the MKDARS. He had his first HF contact from the club shack on 20m CW, and is now quite active from home on 40m CW and has made many contacts throughout Europe using a long wire aerial.
Welcome to new member Matthew Walden from Hampshire (R0197702). Matthew holds the callsigns G4XWV and AE4PH, and can be contacted via packet @ GB7VES, or Email 101732,3044 @ Compuserve.com. He is about to embark on T102. Matthew becomes member number fifty in the all time membership list.
Not much has changed on the packet front, the node continues to provide good service, touch wood! The TCP/IP port has been taken off air, and the 2m radio put back on 144.675 on the AX25 node. Unfortunately there is some problem whereby packets are being lost somehow between the TNC and the PC serial port, so the 2m port is currently transmit only, not very useful! Hopefully we’ll sort it out in the near future. We have hosted a number of further MKPAC meetings in the Cellar Bar at the O.U., the next one being due on Monday 16th December at 8pm. OUARC members are of course very welcome to attend. There seems to be some progress towards siting a node at Bletchley Park, at least to aid DXCluster access to DXI or DXH, and a meeting has been proposed for Friday 10th January at MKDARS for all interested parties.
The club station was active for the last hour of the Club Calls Contest on topband in November and we submitted an entry for the first time, so look out for the callsign when the results are published. A total of 66 SSB contacts were made, 25 of them being with other UK club stations, so the event certainly ‘put us on the map’ alongside other clubs. Perhaps next year we can put in a more serious entry and get closer to the top of the list. The club station was also activated during the CQ WW CW contest, making many world wide contacts, and more recently in the ARRL 160m contest where we worked a dozen or so stations ‘across the pond’ with good signals.
Unfortunately we did not make the MKDARS boot sale this September as the members who normally organise and man the stand were unavailable for various reasons (holidays etc.). Arrangements were made to sell some of our ‘junk’ on another stand, but in the event we were let down and no money was made. We have continued to collect for future sales, and in particular thank Jim G7HUE who has been having a clear out, and has also donated some useful amateur radio books to the club. Hopefully next year we will be more organised and be able to make a few bob for club funds.
The last lunch time video was ‘Aerial Circus’ by the late Dud Charman G6CJ, back in November. This video shows practical demonstrations of different aerial configurations scaled for 3GHz operation. Although a bit dated, this black and white video gave a very interesting insight into the way aerials work. If you haven’t seen it and you get a chance to, it is thoroughly recommended.
The next lunch time video will be ‘Amateur Television’ on Tuesday 21st January, as usual in room N2028 Venables Building at 12.30pm. This is a sixty minute video comprising a series of short programs on amateur television, both in the UK and in Australia. Guests are very welcome.
We have had a number of enquiries about the club from students who are starting with the O.U. in the new year, so hopefully we will get some new members as a result. Members are reminded of the Thursday lunch time meetings in the shack from around 12.30, it would be nice if more members made use of the excellent facilities we now have in the shack for HF, VHF and UHF. Finally a reminder of the Pavilion Bar meetings on the first Wednesday lunch time of each month. That’s about it for now, have a good Christmas, and please try not to forget the AGM! 73...
Contact: Adrian Rawlings adrianrawlings@googlemail.com