PORTABLE 23cms ATV.

To keep things simple (otherwise they don't get built!) I decided to base the receiver on an existing satellite tuner. The smallest one, that I knew about at the time, was the Tatung tuner that Bob Platts uses in his Dove receiver, and is known to work ok. The rest of the circuits are conventional and realised in surface mount components where possible. Exceptions are things like large value electrolytics, too expensive for their space savings, integrated circuits and tunable coils.

Below are some pictures of it to prove it really exists.

Complete receiver with colour viewfinder monitor. Sockets on right hand side: 2x phono = A & V. 3.5mm Jack = ext LS. SMB = prescaler o/p Sockets on left hand side: sub min 3-pin = Viewfinder(5v & V). 2.5mm = 12v in. 3.5 Jack = 'S' meter. F = Antenna. Front Panel: 10T dial = Tune. LED = On/Off. Switch = tune range. Knob = On/Off + vol.

The mess inside.	A received signal.
This shows the type of construction and components used.	The Hastings repeater as seen on my 14ins monitor, plugged into the mini RX, during good ducting conditions.

Here's a block diagram of the receiver, drawn in MS Word:

Future additions, modifications and new versions.

1. RX: The most needed addition is a low noise preamp. Perhaps if I found a smaller satellite tuner I could put it (the preamp) in the receiver case.
2. RX: Make this or another 'S' meter circuit work.
3. G4WIM TX: Add a manual frequency setting circuit. E.g. Thumbwheel switches, EPROM or better still PIC controlled.