Given that there may be a short break in LORAN transmission this coming
Tuesday I thought that I would post an e-mail requesting measurement of the
background noise floor, whilst the Rugby transmitter is off, and a further
measurement when the Rugby LORAN signal re-appears. It would be helpful if
this could be done in a number of locations around the UK, especially where
the interference is significant, so that we can get a better picture as to
the extent of the problem. Unfortunately, I will be travelling on Tuesday
so won't be able to participate from my QTH in Newport Pagnell.
I would like to be able to compare results from a number of sources, so it
may be best to calculate the difference between the noise level in say a
500Hz bandwidth with and without the Rugby LORAN transmission and thus
compare S/N. The other measurement that is probably worth doing is to
measure the S/N of one of the lines. Any other suggestions?
On the complaint front the RSGB made an official approach last year and had
a reply from Trinity House. However, at the time it looked as if the NELS
might close many of its LORAN transmitters at the end of 2005. Given that
this didn't happen, and the continuing nature of the problem from the Rugby
transmitter, I feel that we now need to follow-up our initial approach, and
perhaps widen our concerns, given that a proposal for an Amateur Secondary
allocation at 136kHz is on the agenda for WRC07.
73 John, G3WKL
RSGB HF Manager