[A-DX] Fwd: Shortwave Radiogram, 29-31 March 2019

Sa Mär 30 10:09:35 CET 2019

Am 29.03.2019 um 15:46 schrieb Mike Terry via Groups.Io:
> "..........Hello friends,
> Slow Scan Radio has been transmitting two streams of text 
> simultaneously. We have tried this a few times on VOA/Shortwave 
> Radiogram, and will try it again this weekend.
> Near the end the half hour will be a simultaneous transmission of a 
> news item from swissinfo.ch in two languages, both in MFSK32, with the 
> English version centered on 1500 Hz and the Spanish version centered 
> on 2200 Hz.
> Why 2200Hz? The "primary" MFSK32 occupies audio spectrum approximately 
> from 1250 to 1750 Hz. This sometimes results in an audio harmonic from 
> 2500 to 3500 Hz. MFSK32 at a 2200 Hz center frequency occupies 1950 to 
> 2450 Hz, placing it above the primary MFSK32 but below the 
> harmonic......."          [Kim Andrew Elliott, KD9XB]

SWRG#93 - Easily to detect: The increased noise level caused by 
higher-order intermodulation products [the double track test]
  "...one more track..."  =  stronger intermodulation