THE DIGITAL GEAR
Composite analogue input from the 23cms receiver into a JVC Timebase Corrector into 19" rackmount Snell & Wilcox ADC to give component video into Tandberg Evolution 5000 MPEG2 encoder into Tandberg modulator giving 175Mhz +3dBm into homebrew upconverter to 1311Mhz into PA driver into a dual RA18H Linear PA. Simple as that !
We are currently testing with a symbol rate of 4000 and FEC of 1/2
A DATE FOR THE HISTORY BOOKS!
SUCCESSFUL TESTS (4th JAN 07) OF THE REPEATER CONTROL BOARD ALLOWED NORMAN (G3UXR) Nr CHRISTCHURCH TO TRANSMIT ANALOGUE TV INTO THE REPEATER ON 1255 AND GET DIGITAL OUTPUT ON 1311 at 10W--- RECEIVED 'P5' IN WIMBORNE (>11km) BY JOHN (M1BAI)
G8AJN location: SZ 12500 92800 IO90CR16CH 24mtr/80ft ASL
LOOKING AHEAD
The BATG Committee has moved the repeater to G8AJN QTH whilst new equipment is installed and tested. Then to decide if the nearby Pokesdown site gives satisfactory coverage. The Pokesdown site is 40mtr/130ft ASL.
It may be necessary to use Digital output only on 1311 due to the proximity of GB3IV on 1316. Analog input would either be on 1280 if permission is granted or remain on 1250.
Following discussions with the SCART group in Southampton we will be incorporating a digital 10Ghz relay of the GB3IV signal when IV is in use and when SQ is 'idling'.
It is also intended to enable SQ users to access the IV repeater through SQ when available on 10Ghz in the future.
The smd analog rx front end stages.Left to right we have the baseband input from the Comtech rx into a video amp into the de-emphasis then via a level-set pot into the video agc chip AN302 followed by a buffer transistor giving 2v pk into 75 ohms.
GB3SQ proposed location: SZ 12300 92600
WITHOUT WHOM....
Thanks to all the club members and others who have helped either with info or equipment. Special thanks to G0DQH G0GMK G3NZL G8CKN G8GTZ G8LES G3PYB.
