Hearing the ATV Buzz

ampr.bbs.atvZur Gruppenliste
Betreff: Hearing the ATV Buzz
Von: g8mny@gb7cip
Gruppen: ampr.bbs.atv
Datum: 04. Feb 2016, 08:04:00
To  : ATV@WW

By G8MNY                                (New Jan 09)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

Originally taken from my UK BATC's CQTV 163 "Tuning 70" of 8/93...

Trying to beam up on weak fast scan ATV signals with tight beams on a TV mon is
not that easy. Here is a way that greatly helps when you don't quiet know the
beam heading (e.g. /P). It is of no use for digital TV modes!

Take the recovered video and feed it to the TV audio stages (decent size LS or
HiFi headphones!) after some CR filtering to remove the line timebase & treble

FM SOUND >컴컴컴컴컴컴컴컴컴컴o  FM
                        SWITCH \o컴컴컴컴>AF AMP
  VIDEO  >컴6k8컴쩡6k8컴컫컴훟  BUZZ     Volume?
                               BEAM UP
                === u1   === u1

This works by listening to the 50Hz buzz, as your ear/brain is a few dB better
than the TV sync stages. It also works on 10GHz/1255MHz FM TV just as well as
AM mode.

The extra 6k8 load on the 75ohm video line has no effect.
Tx _picture         Rx 같같같같같같같같     As        /~\
___ Info   |_ _        같같굅같같같굅같     AF _     /   '._._./\_
 斌같같같같같 斌같      굅굇굇굇굇굇굇갚         \   /              \   /
                        갚같같같같같같굅          ~-~   50Hz BUZZ    ~-~
 <--- 20mS -->          같같같같같같같같캮oise

This can work on any band including 70cms, although on AM a narrow band SSB/FM
phone Rx may even better if the exact carrier frequency is known!

Why don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP

Datum Thema#  Autor
04.02. o Hearing the ATV Buzz1g8mny

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