Re: VLF: W4DEX trans-Atlantic at 8971 Hz

[Paul Nicholson <vlf0403@abelian.org>]

Wolf wrote:
> do you have an estimation about how many percent of the
> transmission time were actually 'blanked' due to sferics ?

Yes, blanking factor is about 25%.  Varies from hour to
hour in the range 20% to 35% and not necessarily more at
night.

I combine E and H signals and steer the pattern, then
apply blanking to the combined signal (as opposed to
independent blanking of the three components before mixing).

Blanking threshold is 1.2 times the moving mean amplitude.
I think the default threshold in Spectrum Lab is a bit higher
but the effect of that difference is very small.

I band limit to 8970 +/- 1500 Hz before blanking. Much
narrower and the sferics become stretched and blanking
less effective.
--
Paul Nicholson
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