[Boatanchors] Feb 1964 CQ?
lmpicard at allstream.net
Fri Feb 18 10:31:03 EST 2011
VOA used to run shortwave feeds to remote transmitters using ISB. Each
sideband would carry program material in different languages. This
disappeared with satellite and other distribution technologies.
George Babits wrote:
> 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
>> 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
>> 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
>> Okay, same situation but you're aware of the offset so listen 3.2 KC
>> 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
>> That's not only bad manners but it might be illegal dependent on how
>> 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
>> Hiki Nô!
>> Boatanchors mailing list
>> Boatanchors at puck.nether.net
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