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Date: Fri, 18 Jun 1999 19:38:44 +1200
From: "vernall" <vernall@xtra.co.nz>
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Antennas, bandwidth, etc
References: <199906180116_MC2-79DE-E0E9@compuserve.com>
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Dave Sergeant wrote:
> 
> >From Dave G3YMC
> 
> Bob ZL2CA says:
> 
> <It has been noted in ZL that noise blankers do not work so well on
> <narrowband loop receiving antennas
> 
> I have never found a noise blanker on any amateur receiver which has the
> slightest effect on the sort of noise we encounter on 136 or any of the LF
> bands, and they only really seem to work on ignition type of noise such as
> you might expect on VHF.  Some recent rigs may perform better, but in
> reality the noise blanker on most rigs is wasted space and it is no great
> loss if it works even less well with a narrow band antenna!
> 
> 73s Dave G3YMC

I can say that at least 3 ZL LowFers find the noise blankers on Icom
IC-751, Icom IC-735 and Kenwood TS 520 to be effective on LF, equivalent
to 6 dB or so of signal improvement.  This is mostly for "spike" type of
noise.  All the noise blankers are in the IF, using the "Lamb" type of
noise blanking with a diode ring type of noise gate, before the main IF
filter.

Bob ZL2CA