[Boatanchors] Feb 1964 CQ?
wh7hg.hi at gmail.com
Fri Feb 18 04:18:56 EST 2011
From: boatanchors-bounces at puck.nether.net
[mailto:boatanchors-bounces at puck.nether.net] On Behalf Of doc at kd4e.com
> I am wondering if the same descriptive label was applied to two
> somewhat different modulation schemes and thus the confusion.
Well, no. Let me kind of explain. IDSB is kind of like DSB except what
others will receive as the upper sideband is below the original carrier (or
lack thereof) and the lower sideband is above it. Let's say you're on 40m
and you call CQ. Someone 3.2 KC above you hears an LSB signal and happily
replies. In the meantime, someone 3.2 KC below you hears a USB signal and
is replying either to chew you out for being so crass as to use the "wrong"
sideband or is a military surplus user who's delighted to find someone else
using USB there. Which do you hear or are they QRMing each other so you
can't understand what's happening? They can't hear each other, of course.
Okay, same situation but you're aware of the offset so listen 3.2 KC above
and hear the gentleperson replying to the effective LSB signal while the
other one is mumbling bad words because you've got a sideband hanging out in
space that you can't use and may well be QRMing a QSO already in progress.
That's not only bad manners but it might be illegal dependent on how that
other sideband is perceived.
Would I use IDSB? Not a chance in a very hot place.
By the way, band conditions have changed significantly since 1964 when that
article was written. So has Part 97.
Michael, WH7HG BL01xh
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