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Old December 7th 09, 02:52 PM posted to rec.radio.shortwave
Kevin Alfred Strom Kevin Alfred Strom is offline
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First recorded activity by RadioBanter: May 2009
Posts: 544
Default Selective Fading leaves KFI Unlistenable in North L. A. County

dave wrote:
[...]

I always used the sync detector or SSB ECSS to listen to it, so the
fading was much less an issue. Since you have to get both sidebands to
cancel out the IBOC, I can't use sync detection, because my SW2, just
like a Sony 2010, can only sync to one sideband at a time.

[...]


Yes, true. You need full DSB desired and undesired information in
order to cancel the IBOC junk.

When a sync detector uses phasing to cancel one sideband or the
other, it cancels only _interference_ in that sideband. It does
_not_ cancel that sideband of the desired signal -- since the Q
channel contains essentially no audio from the desired signal.

So you are _always_ listening to _both_ sidebands of the desired AM
or DSB signal, even when listening in the synchronous LSB or
synchronous USB mode.

But if the IBOC sidebands are transmitted in quadrature (meaning 90
degrees out of phase) with the AM carrier, and I seem to recall that
they are, then you're right -- you'd have to listen to the I channel
detector _without phasing_ in order to cancel them out. And the Sony
2010 unfortunately won't allow you to do that.


With all good wishes,


Kevin, WB4AIO.