Hey J34...I have had a good chat with my tels guys this morning....it appears the Craigowlhill TX/RX site operates on the spot frequency of 119.875mhz, Lowther hill operates on an offset of -7.5khz and Windy head on an offset of + 7.5khz. This is done so that when I transmit from all 3 sites I dont just get a load of mush!!! Apparantley all aircraft recievers should have sufficient bandwidth to cope with recieving offset transmissions...that said I remember in my military days we could not talk to USAF F111 swing wing bombers if using multi channel TX/RX we had to select a single channel before their radios would recieve our transmissions. It apppears there are some certain types of radios on the market that have a poor band width capability..it would be interesting to know what radio you use and see if it is on the known list of offending radios. Another problem could be is the aspect your aircraft shows to the aerial site. Sometimes on certain tracks to and from the TX site your own aerial may be shielded from the TX site....altering your heading may indeed improve reception but of course not always practicle.
As for auto triang coverage over the north Irish sea/Solway as I said before the auto triang is a little old hat so dont worry too much there....providing you have a transponder and can squack in event of an emergency your 7700 code will be picked up very quickly and accurately from one of our many radar heads....Coverage over the Solway area is good as one of our main radars sits on high ground not too far away...that said at the moment it is off for long term maintainance as it has mode"s" equipment fitted.
