Digital ATV live
----------------
At the start of HAM RADIO 2000 in Friedrichshafen all involved 
radio amateurs were nervous, while switching on their new DATV 
gear in hall 9 - but instantly the camera video from the stand of 
"DARC-Distrikte" appeared on the TV monitors at the AGAF stand! 
10 mW on 434 MHz in 2 MHz hf bandwidth were sufficient to deliver 
live pictures in colour with just a few motion artefacts in MPEG2 
fullframe quality over the given distance of 20 m.

The "father" of this development, Prof. Uwe Kraus, DJ8DW, from 
"Bergische Universitaet Wuppertal" was able to show a worldwide 
"first" to the group of authority representatives, DARC 
representatives and journalists coming around before lunch time: 
home made video transmission gear with up to date digital technology, 
developed by engaged hams with special knowledge for progressive 
radio amateurs.

Financial support from DARC as well as from AGAF and private sponsors 
was needed to reach practical maturity. A standard digital satellite 
settopbox is the only commercial modul used in order to replay the 
received camera video nearly without delay - but for this a 
"remodulator" had to be constructed just before the HAM RADIO 2000 
which transforms the MPEG signal received in GMSK modulation to QPSK 
as the Satellite-TV standard. So this official demonstration was the 
first real live test of the 2nd generation DATV gear after the 
laboratory phase. In fact some effects showed up during the exhibition: 
sometimes strong burst signals on the DATV channel urged the received 
video to freeze in, and only restarting the remodulator helped to make 
it live again. But DATV was the attraction of hall 9 and drew lots of 
spectators, some of them perhaps incited by the running text display 
at the railway station in Friedrichshafen "Digital Amateur Television 
Sensation".

Klaus, DL4KCK