Notes on LF Round Table at Wimborne, Dorset, 20 May 2001
The meeting was attended by:
G3XDV, M0BMU, G4JNT, G3YGF, G3AQC, G3LDO, G3YSX, G3GRO, G3HEJ
and G3OLB. In addition, G0API represented our hosts the Flight Refuelling
Amateur Radio Society, and GW3JBH called in as he happened to be holidaying in
his caravan next door. Several attendees were unable to stay until the end at 1700.
The morning saw a demonstration of a Tesla coil. The coil was about 1.5m high and
it generated very spectacular sparks half a metre long. Other morning activities
included a car boot sale of Litz wire, variometers etc.
After a splendid pub lunch, the formal session started with M0BMU describing the
latest data mode, WOLF, and how to keep its transmit bandwidth down. This was
followed by G4JNT showing off his innovative 600W transmitter, and describing
the various stages in its development.
The final half hour was given over to a discussion. Two topics were raised: how to
make the most of the 73kHz band before it is taken away, and how to encourage
others onto 136kHz.
It was felt that there should be a concerted effort to cross the Atlantic on 73kHz,
although there may be up to 10dB more losses to overcome. To this end, stations in
the US and Canada would be asked to monitor the HBG time signal on 75.0kHz to
get experience with this part of the spectrum, and to report on propagation
variations. Perhaps there should be a 73kHz activity period (month?) next winter to
concentrate effort in the UK, mainland Europe and America.
Several suggestions were made as to how to encourage newcomers onto 136kHz. It
was felt that once active, stations were reasonably well looked after by other band
The problem was identified as many people trying to listen on the band with poor
receive systems, then hearing nothing and giving up. Some way was needed to
ensure that casual listeners would have a fair chance of hearing one of the stronger
stations. Suggestions were:
* Run a contest, or series of cumulative contests, perhaps as part of the RSGB's
"LF Cumulatives" which run on 160, 80 and 40m. Scoring could be similar to a VHF
event. Include a receiving category.
* Encourage crossband activity between 136kHz and 3.5 or 7MHz. This could be
helped by a RadCom article on LF receiving techniques, followed by a crossband
contest which could be entered either as an LF or MF station. Crossband preferred
frequencies should be published.
* Informal CW beacons, perhaps using the transatlantic slot below 136kHz,
G3XDV said he would raise these issues with the RSGB HF Contests Committee
and the RadCom Editor.
Our thanks to Flight Refuelling for the use of their club house.
Mike, G3XDV (IO91VT)