"AM" vs. DSB

Brian Carling bry at MNSINC.COM
Mon Nov 17 21:44:15 EST 1997

On 17 Nov 97 at 12:16, Joel wrote:

> I never did monitor my own signal, (and the rig operated fine,) but now I
> wonder - was the rig only generating the sidebands (both); i.e. was there
> no carrier generated in that case (true DSB)?  Or would there have actually
> been a carrier, perhaps reduced, compared to a "normal" AM  transmitter -
> signal.

Your PWR or SWR meter at the station would have told you the answer.

OR you could have looked at plate current during xmit, between words.
What I mean is - if you had ZERO plate current through the finals (or
nearly zero), and NO power out, then you were truly running DSB.

Most likely you were running AM in some efficiency modulation scheme.
A few people made DSB reduced carrier rigs, or even SSB, with a
reduced carrier, but these were few and far between.

What was more commonly built EXPERIMENTALLY was the
"super-modulation" scheme of Don Hoisington, W4CJL fame in the early
1950s, in which one could get like 400% positive modulation, or even

> Perhaps the DSB was merely a feature to allow for AM compatibility on the
> air(?) -- but I never asked -- would the other stations have had to use a
> BFO to copy me?

Probably not, but I know VERY few guys ever used their HT-32 or HT-37
rigs to run anything voice-wise but SSB!
*** 73 from Radio AF4K/G3XLQ Gaithersburg, MD USA  *
**  E-mail to:  bry at mnsinc.com                     *
*** ICQ: 3910641  ***
**  http://www.mnsinc.com/bry/                     *
AM International #1024, TENTEN #13582. GRID FM19. Using a SWAN 250 on 6m,
Other rigs: Valiant, DX-60/HG-10, FT-840, TM-261, Ameco TX-62, Gonset Communicator III
HTX-202...TEN-TEN #13582, DXCC #17,763 Bicentennial WAS

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