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From: "Dave Sergeant" <dave@davesergeant.com>
To: rsgb_lf_group@blacksheep.org
Date: Mon, 02 Jul 2007 18:51:21 +0100
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Subject: Re: LF: 500 - Signal on 504 KHz
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Status: O

The second harmonic of RTE has always been present on 504kHz here, 
though normally only copyable by ear after dark. I am surprised you 
didn't know this, it has been occasionally mentioned on here and is 
no secret. Convenient frequency calibration mark!

The RTE transmitter is due to change to DRM sometime soon. Maybe they 
are doing some changes in preparation for this. I am not sure what 
the implications for us are when they do the DRM change, presumably 
then we won't have the carrier but instead have harmonics of the DRM 
noise which would spread right over our allocation.

73 Dave G3YMC

On 2 Jul 2007 at 18:19, Gary - G4WGT wrote:

> Hi All,
> 
> During my monitoring of 500 KHz I have almost always seen a line on
> SpecLab at 504.0 KHz. Whilst attempting to improve a shielded loop for
> 500 KHz I have been receiving the signal on 504.0 KHz stronger &
> stronger with accompanying hetrodyne. After todays changes to my loop
> the signal has become so strong that I now hear garbled audio &
> SpecLab is showing audio sidebands (see capture attached). I notice
> that there is a line at the same frequency on the Bimingham Grabber
> some of the time. I first thought it was some product of mixing strong
> signals in the MF range. I decided to try to work it out & realised
> that in fact it is the second harmonic of RTE Radio 1 on 252 KHz. I
> have studied the uninteligable audio pattern & it does relate to  that
> signal.
> 
> I must admit that I don't know if it due to improvements or some other
> quirk of my loop or just the fact that the filtering at RTE Radio 1 is
> poor. Although this signal has got stronger with changes to my loop
> there doesn't appear to be the same improvement with normal 500 KHz
> signals.
> 
> Perhaps someone can shed some light on this for me.
> 
> 73
> 
> Gary - G4WGT - IO83qp
> 
> 


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