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Date: Sun, 09 Apr 2006 19:42:11 +0100
From: Stewart Bryant <stewart@g3ysx.org.uk>
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Subject: Re: LF: Rugby LORAN measurement?
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Status: O

If you are doing measurements....

I went to a conference on time and frequency measurement last year
and one comment I got from someone at NPL was that they were unsure
whether the LORAN TX was impacting the precision frequency reference
at 60KHz. They say that they do not have the resources to do the
measurements.

It would be interesting if we could determine whether the LORAN
TX was having any impact the ability to MSF and Drotwich as
precision frequency references.

If we could demonstrate an effect we would probably get support
from NPL in making a case against the LORAN TX.

- Stewart G3YSX


Peter Martinez wrote:

>> From Peter G3PLX:
>
>
> No, I didn't see it go off either.  The first Tuesday in the month is 
> documented as the Rugby maintenance period, but perhaps the grass 
> didn't need cutting this month because the weather has been so cold.
>
> I have written a little program which will measure the SNR of the 
> LORAN signal on 137kHz, by comparing the amplitude of the 
> signal-plus-noise to the amplitude of the filtered and smoothed LORAN 
> pulse alone.It can be done at any time and doesn't need to wait for 
> them to turn it off and on.   The program requires that the soundcard 
> and the receiver frequency should be accurately calibrated, but the 
> tools for doing this are contained within the program, using the LORAN 
> signal itself as a timing and frequency standard. I need to do some 
> beta tests first, then I will be asking for volunteers to use it to 
> measure the LORAN SNR at various places around the UK and NW Europe. 
> The results can be passed to John G3WKL and will be useful in any 
> campaign to get something done about the LORAN interference on 137kHz.
>
> 73
> Peter
>
>
>
>