[Boatanchors] Feb 1964 CQ?

George Babits gbabits at custertel.net
Fri Feb 18 11:04:59 EST 2011

At the risk of being a square peg in a round hole, I'm going to put in my 2 
cents worth on IDSB; which I think is more properly referred to as ISB.

 My take on that, having played with the TMC SSB-2 exciter, is that you run 
the two sidebands completely independent of each other.  Maybe voice on LSB 
and RTTY on USB.  No carrier.  The SSB-2  (and probably other 
commercial/military gear of the time) could be run as LSB, USB, or ISB; 
using voice, CW, or RTTY (data) on either or both sidebands.  You could run 
AM by using both sidebands with the same audio feed and insert as little, or 
as much, carrier as you wanted.


----- Original Message ----- 
From: "Kludge" <wh7hg.hi at gmail.com>
To: "'BoatAnchors'" <boatanchors at puck.nether.net>
Sent: Friday, February 18, 2011 1:18 AM
Subject: Re: [Boatanchors] Feb 1964 CQ?

> -----Original Message-----
> 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.
> Best regards,
> Michael, WH7HG BL01xh
> http://www.nationalmssociety.org/chapters/NTH/index.aspx
> http://wh7hg.blogspot.com/
> http://kludges-other-blog.blogspot.com
> Hiki Nô!
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