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Date: Thu, 02 Mar 2006 19:15:46 +0000
From: Wolf DL4YHF <dl4yhf@freenet.de>
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Subject: Re: LF: LORAN spurious emission levels
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Status: O

Hi Peter and group,

Peter wrote:

> 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 energy 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 130kHz, measuring the levels in a narrow 
> bandwidth (<2kHz?) from an antenna-current monitoring point.

I think Dave's "extrapolated" chart will give more reliable data than 
this "relative" measurement described in my previous message:
I live 230 km away from Burg, and 300 km from Sylt. Now I found this: 
Turning the receiver's AGC off (to get a meaningful result from the 
audio amplitude), and setting the gain manually so DCF39 just doesn't 
overload it, I can hardly see the Loran signals on 137.x kHz /  QRSS3 
mode. The dynamic range is not sufficient for this test. I guess a 
transmission from an amateur station with well-known radiated power 
(possibly close to a Loran site) would be better suited.

73,
  Wolf .