OPEN UNIVERSITY AMATEUR RADIO CLUB
NEWS LETTER no:38
G0OUR Affiliated to the OU Club and the Radio Society of Great Britain
Please make a note of our forthcoming 2011 AGM on Tuesday 18th January at 12.30pm. We are in the same room as last year, Central Meeting Room 6, on the ground floor. This is accessed from outside via the West Central Meeting Rooms entrance, near the shop. Alternatively you can get there through the back of the Hub Lecture Theatre. An email reminder will be sent nearer the time, and local members are urged to attend if they can.
Back in the summer we changed the club/shack meeting day from Thursday to Tuesday of each week for a trial period. This has worked out well so we are sticking with it for now, hence the AGM also being on a Tuesday.
A reminder that subscriptions are due on 1st January, and remain at £5 per year. Subs can be paid at the AGM, or a cheque made payable to OUARC can be sent to the Treasurer, Fraser Robertson, S1021 Venables Building, Open University, Walton Hall, Milton Keynes, MK7 6AA. Your continued support of the club is appreciated. Copies of the 2010 minutes can be obtained from the Secretary, Adrian. Please note that Adrian has changed his email address to: adrianrawlings@googlemail.com
There is still no further news regarding the proposed car park extension and possible relocation of the Field Research Site (where our club station is located). So we hope that no news is good news. The area in front of the shack is still being used extensively by building contractors, and has become a bit of a storage area. This has occasionally caused access problems for us. Other news is that there are plans to erect a 3m diameter radio telescope on the Field Research Site, close to the existing optical telescope. This will be remotely controlled by students as part of the new S288 Practical Science course. The telescope will be looking at the 21cm hydrogen line, using a specialised receiver system that measures the Doppler shift of noise around 1420MHz. If there are local noise issues the system will be relocated elsewhere, but it will be mounted here for initial testing at least.
Back in May we had our traditional stall at the DDRC sale at Stockwood Park, Luton, and cleared £227.20 for club funds. Following that we attended the MKDARS sale in August, which we have missed in recent years due to it being on a Bank Holiday weekend and clashing with holidays etc. This sale has returned to its old venue in Bletchley Park. It is a smaller event than the DDRC one; even so we cleared £175.70, so making a total of just over £400. As always, we still have a large stock of junk in the shed next to the shack, and it keeps on coming in dribs and drabs.
Purchases since the last newsletter have included the general coverage module for the K3, along with the matching fist mic. and a pair of 8 pole SSB filters for the main and second receivers. We are very grateful to the OU Club for their grant towards the cost of these.
We are hoping to branch into the world of SDR (software Defined Radio) next year. After looking at various options, mostly in the form of single band receiver or transceiver kits, we decided that the commercial Flex-1500 SDR would be a much more useful option long term. This has internal 48kHz sampling A/D and D/A convertors so unlike many other SDRs it does not need a high quality sound card, and simply connects to the PC via a USB port. It covers all bands, 160m to 6m with a 5W output transmitter and has general coverage receive capability. We are also hoping to add the internal ATU for the K3 next year. We are currently waiting to hear if our bid for OU Club grant money towards purchasing these items has been successful.
We have had some minor problems with the K3, in the form of burnt out resistors associated with the rear panel accessory port. These are tiny surface mount devices, and have been replaced with more manageable 1206 size surface mount resistors. After talking to Elecraft we’re still not sure of the cause of these failures. We use the ACC port for band data to switch the antennas, but the current drawn on these lines is very small. Also, the digital I/O resistors have also burnt out, and we’re not using those lines at all. We suspected RF getting back into the rig via the RX ant socket and/or second RX ant socket. The power on these ports was measured worst case at 100mW, which is way below the limit specified by Elecraft. We’ve temporarily reduced this by 10dB. We also measured up to 100mA common mode RF current on the screen of the band data cable, and this has since been reduced to 15mA with a common mode choke. So hopefully, one way or another, this problem has been solved. The Omni6+ still has a problem that is proving a bit more involved to fix than at first thought.
Unfortunately the PC that was donated to the shack by Steve M0BPQ has given up the ghost. Either the PSU or the motherboard are suspected, as the power light comes on but it won’t start up at all. Fortunately we were able to retrieve data from the hard drive. The older shack PC that was on loan from the OU MCT Faculty has been upgraded. This is now is now installed and working well after fixing some initial RFI issues. We are still using Steve’s Wi-Fi USB dongle for internet access. This gives a marginal connection, and we’re looking into improving the antenna.
The OU packet node is still running in a reduced capacity, and awaits decommission.
We were busy again during the summer months clearing vegetation from around the shack, guys etc. This has become an annual chore, but is good exercise and gets us out in the sunshine at least. We haven’t had to do any major antenna maintenance this year. Replacing the guys and general maintenance on the M100 mast remains on the “to do” list.
As usual we were active during the November RSGB Club Calls contest on Topband SSB, putting the G0OUR callsign on the map alongside other UK club stations. G0OUR was also active during the CQ WW Topband contest. Paul M0OOM remains quite active in the shack on digital modes using the IC7400.
That’s about it for now; hope to see some of you at the AGM.
Season's Greetings…
Contact: Adrian Rawlings adrianrawlings@googlemail.com