LF: RFI from 136kHz transmissions

["John W Gould" <jwgould@iee.org.uk>]

In the discussion that I am currently having with Ofcom over the RFI assessment for 501-504kHz applications, the question has been raised as to whether interference has been noted with nearby neighbours, etc, from the transmissions at 136kHz. The licence allows operation on 136kHz without any RFI assessment. It would be helpful to have honest feedback on this if anyone has examples to offer. In such cases I would like to know details of the aerial, distance to the neighbour concerned, power into the aerial and approx ERP, and likely cause (if it's other than straight V/m) and cure.

It would also be worthwhile knowing those who have done significant operating using up to the 1W erp from aerials that are in close proximity to the neighbours, e.g. 5 to 10m or so, and not had any RFI problems.

Not sure the best way of doing this, but rather than clog up the reflector with replies it might be best for people to e-mail me directly.

I will of course collate the data anonymously; it could make life a bit easier if I could convince Ofcom that from a practical perspective -10dBW at 500kHz isn't going to cause much problem as far as RFI is concerned. Of course that may be pre-judging the facts!

73 John, G3WKL 
 RSGB HF Manager

g3wkl@btinternet.com