Amateur Television (ATV)
A primitive 23 cms
(1300MHz) ATV system has been set up which comprises a Comtech
23cms transmitter and receiver for analogue transmissions and a
satellite TV Comag SL55 for digital transmissions. The Comtech
transmitter power is raised to 1 watt in a Comtech amplifier and
that in turn drives an aged solid state 15watt PA comprising a
Mitsibishi module. The antenna is a 32 element quad loop yagi
with a mast head preamp. It is cut for 1296Mhz and is not optimum
for the ATV band so there is room from improvement here.
With this set up I can
work throught the analogue repeater GB3IV
TV repeater on the Isle of Wight with reasonable results (See picture
below). The repeater output frequency is 1316Mhz.
A 3cms (10GHz) analgoue input is now proposed for this repeater so a 13cms Tx module has been purchased with a view to using a X4 multiplier shown here to get to 10GHz with suitably reduced deviation.
Excellent digital signals from the site of the proposed GB3SQ repeater in Bournemouth have also been received at a distance of ~24km (See below). Frequency is 1311 Mhz, Symbol rate: 4000 and FEC 1/2.
This was received using a cheap Comag SL55 digital receiver (shown below) of the type sold for caravan and camping installations.
