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Date: Fri, 26 May 2000 22:15:37 +0100
To: rsgb_lf_group@blacksheep.org
From: "Walter Blanchard" <blanch@pncl.co.uk>
Subject: Re: LF: LORAN sidebands
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At 04:18 25/05/00 +0100, you wrote:
>Can anyone provide a formula or graph showing the relative strength of
>sidebands down to 80 kHz, please?
>
>73 de
>John Rabson G3PAI

John,
Official US Loran-C spec. states :
"Specification for energy distribution outside the 90-110 kHz band will be 
achieved
if the spectral density of the radiated signal at 90 kHz and 110 kHz is 
down at least
20 dB relative to its value at 100 kHz"
"Total spectral energy below and above the 90-110 kHz band shall be less 
than 0.5%
each".
It is specified this way because the designers are only interested in 
shaping the rising
edge of the pulse properly and  don't much care how it decays.  So the 
spectrum
differs between transmitters and is not necessarily a smooth exponential decay.
That's why we have trouble at 136 kHz.
Walter G3JKV.