Thanks to Chris, G0FDZ for giving a fascinating talk to the club this Wednesday on the microwave bands. Chris is one of the few amateurs in the UK that is operational on the bands up to 241GHz, what he calls the other ‘Top Band’. On display were three of his homebuilt transverters, some of which are dual band capable, covering in total 24GHz, 47GHz, 76GHz, 134GHz and 241GHz. All using an FT-817 as an IF.
One answer is to to learn a low powered digital mode, CW fits the bill but things have moved on in the last 100 years and computers have provided an even better, more robust form of digital communication.
What am I talking about? No not the internet, but low power digital modes like JT65, JT9, Olivia, PSK to name a few… In this article we was going to concentrate on JT65 and JT9, like many modes its hard to know where to start, what software and what frequency should you listen to.
So what is JT65
Its a low power digital mode invented by Joe Taylor K1JT in his original paper and I quote “It is easy to show, however, that neither the encoding nor the modulation of CW is optimum. When every dB of signal-to-noise ratio counts, as it does in amateur meteor-scatter and EME contacts, there are very good reasons to explore other options. Personal computers equipped with sound cards provide a golden opportunity for experimenting with the wide range of possibilities.”
The JT65 protocol uses 65-tone frequency shift keying with constant-amplitude waveforms and no phase discontinuities. The original mode was optimised for EME QSO, but later versions JT65A, B and C had a more HF focus. The mode used in the programs we will look at is JT65A although its usually described as just JT65.
This weekend sees activation of GB0SNB for the Havering & District Amateur Radio Society’s Work the World Weekend. A chance for club members to operate outside of a contest and to experiment with equipment and to have a less intensive style field day.
Taken just as the sun was setting, the two large antennas can be seen with the club caravan and members vehicles. The black dot suspended above the caravan is part of the 40 metre dipole configured as an inverted-V.
In total, we made just shy of 1000 QSOs during the weekend. The total was 973. Not bad going at all, and I think the RSGB Bureau will be busy! The breakdown goes something like this:
It is worth noting here that all of the CW QSOs were made by Fred G3SVK!
During the weekend we managed to work 68 separate DXCC entities, 16 on 40 metres, 47 on on 20 metres, and 41 on 17 metres.
The weekend saw a few firsts for GB0SNB. First QSO with Anguilla (VP2E), Bahrain (A9), India (VU2), China (BY), Mongolia (JT) and Puerto Rico (KP4) to name a few.
Some more images and further reading can be seen on the GB0SNB.com site.
Members of the Havering & District Amateur Radio Club took to the air this weekend operating as G4HRC/P for the 2014 VHF national field day. Members activated 4 bands, 6 metres, 4 metres, 2 metres and 70 centimetres.
|50 MHz||Icom IC-7400||6-element Yagi|
|70 MHz||Icom IC-7100||8-element Yagi|
|144 MHz||Icom IC-7000||16-element Tonna|
|432 MHz||Yaesu FT-847||27-element Tonna|
Two masts were used. Pictured left are the 6 metre and 2 metre antennas on the SCAM 12 metre mast.
During the 24 hours of activity, starting 2pm UTC on Saturday, we managed to rack up 20 QSOs on 50 MHz, 53 QSOs on 70 MHz, 76 QSOs on 144 MHz and 24 QSOs on 432 MHz (173 QSOs total). Maps of the QSOs made are shown below for the 4 bands.
Members of the Havering & District Amateur Radio Club took to the air operating as G4HRC/P for the 2014 50MHz Trophy Cup. Equipment was an Icom IC-7700 transceiver, 6-element 6 metre beam and 12 metre SCAM pneumatic mast.
During the 24 hours of activity, starting 2pm UTC on Saturday, we managed to rack up around 150 QSOs in conditions which where a little above average. Best DX was a tie between EA8 and IZ1 both very close to 3000 km. Splashes of sporadic-E were noticed, but these patches where few and far between (hence sporadic!).
A map of QSO’s can be seen here.
On this occasion we chose Holyhead Mountain, this is SOTA ref GW/NW-069 and at just 220 meters is a real little summit with an interesting walk. Its on the Isle of Anglesey, over looking the Irish sea with good view North into Scotland, Ireland, Isle of Man and South into England. The antenna was a new portable design 6 element from John M0UKD, using a light weight aluminium boom and a quick release element system never before seen in the UK.
John had designed the antenna to be easy to assemble, having learnt on the activations to date that its often cold and hard work to tighten screws and secure elements. The new revised (mark 3) design makes use of textile secure spring loaded gripping devices, some will know these better as clothes pegs. The pegs are secured to the boom on a wooden plate, so the elements simply need to be clipped in place making the entire assembly around 60 seconds. On this occasion we used the Yaesu FT 897 and internal battery at 20w on 144 MHz SSB.
Despite our best planning the SSB part of the band was almost all filled with s9 of harsh electrical noise, in some directions we could null out the noise but it soon became apparent that SSB would not be possible from this summit. The back up plan was to move the beam into the vertical polarisation and operate on FM. This proved much more successful, with the noise reduced and we had soon worked 10 stations, including 3 summit to summit which are listed below:
GM7PKT/P (Robin) GM/SS-060 Meall Buidhe 719m (SSB) – a distance of 348 Km
M0NJW/P (Nigel) G/NP-004 Whernside 736m (FM) – a distance of 184 Km
MW6GWR/P (Ricky) GW/NW-048 Mynydd Nodol (FM)- a distance of 78 Km