Peter have you looked at the "megapulse" web site for power levels. ERPs may
be calculatable if we know the mast heights....these may be available
Lessay and Sylt are quoted as 250kW, there are even powers for the western
Chayka system ! Exact locations are also given.
Also at a lot of locations you will receive signals from more than one
station maybe from different chains....will this affect you calculations? or
the sensitivity idea. I suppose there will generally be one main site, the
nearest, which will predominate ?
----- Original Message -----
From: Peter Martinez <[email protected]>
To: <[email protected]>
Sent: 02 March 2006 17:57
Subject: Re: LF: LORAN spurious emission levels
> That would be another way to get a calibration, so long as we also knew
> emrp of DCF39. If you are close enough to receive surface wave from DCF39
> and surface wave from Sylt, then a ratio of the DCF39 carrier level to the
> level of a typical Sylt LORAN line (at midday) could be used to give the
> emrp of the LORAN line. WE can estimate the path loss from the distance
> within a few dB so long as the both paths are over similar type of ground.
> But Dave G0MRF also sent me a nice spreadsheet of some measurements which
> were made at Rugby when the LORAN transmitter was installed. This is a
> record of the classic USCG measurement to confirm that only 1% of the
> is outside 90-110kHz. This spreadsheet seems to be a chart of the readings
> of a spectrum analyser which is changed in 2kHz steps between 70 and
> measuring the levels in a narrow bandwidth (<2kHz?) from an
> monitoring point. From this I can apply an F-squared factor to calculate
> power spectral density. I have to guess the shape of the curve from 130kHz
> to 136kHz.
> This tells me (if I did it right) that the spectral density at 136kHz is
> about 47.5dB down on the spectral density at 100kHz. The problem now is
> I don't know how to convert this to the mean level of a single spectral
> line - I need to know the relationship between the published power of the
> transmitter (presumably the peak pulse emrp) and the spectral density
> power/kHz) at 100kHz.
> Anyone have any ideas? Maybe this can be measured off-air, or we can
> it out from published info.
> Peter G3PLX