[CW] 10mhz signals?

[repcomms+g3rep]

On 25.07.2013 16:58, Donald Chester wrote:
>>Covered (encrypted) 100wpm RTTY.
>
>>Probably military.
>
> I recall back about 1960 the short wave bands were filled with 
> signals that
> sounded kind of like the old Soviet jammers, but were outside the 
> SWBC
> bands. They were about 3 kHz wide, as I recall. Once, I was playing 
> around
> with the  old phasing type crystal filter and got the bandwidth down 
> to
> about 100 Hz. When I tuned through one of those signals, I could pick 
> out
> about two dozen individual signals that sounded like regular 
> narrow-shift
> RTTY. It was some kind of multiplexing that allowed a large number of
> signals to be transmitted simultaneously. I never operated RTTY, so 
> never
> tried to decode it. Don't know if each individual carrier was regular
> Baudot, or some  non-standard method of encoding.

Sounds like Piccolo which was the original MFSK mode, developed for 
British government communications by Harold Robins, Donald Bailey and 
Denis Ralphs of the Diplomatic Wireless Service (DWS), a branch of the 
Foreign and Commonwealth Office. It was first used in 1962 [2] and 
presented to the IEE in 1963. The current specification "Piccolo Mark 
IV" is still in limited use by the UK government, mainly for 
point-to-point military radio communications.[3]

http://encycl.opentopia.com/term/Piccolo




-- 
Bob Parkes
G3REP
(S21YP, 4S7RPG, A45XF, P29PR, VS5RP)
www.repcomms.co.uk