[GreenKeys] 20 M RTTY

[John Vendely]

No, it's nothing so sinister as "The Woodpecker".  It's just an older 
synchronous binary FSK teleprinter system still in widespread use by the 
Russian Navy. Irritating though it is when it appears in the ham bands, 
it doesn't cause anywhere near the kind of mayhem the ultra high power 
wideband "Woodpecker" radar system did...

On 9/19/2015 10:40 PM, Dave Horsfall wrote:
> On Sat, 19 Sep 2015, John Vendely wrote:
>
>> This is the Russian Navy 7-bit synchronous system known colloquially as
>> "36-50".  It has a 36 baud phasing sequence (sometimes mistaken for RYs)
>> followed by a preamble, then encrypted synchronous data.  50 baud with
>> 250 or 500 shift seems the most common, though others are occasionally
>> heard.  They sometimes send operator chat or ID's using FSK morse for
>> short periods.  These transmissions are all over the HF bands, and the
>> Russians seem to place them more or less wherever they please.  I have a
>> decoder for this mode, but have never observed any traffic in the clear.
> Is (was) this the dreaded woodpecker?  The damned thing used to wander all
> over 20m; somewhere, I've got photographs of the thing, with its massive
> curtain arrays.
>
> Oh, and Australia has its own woodpecker (i.e. OTHR) in Jindalee.
>