TX ATV 23cm 0.5W - Assembly Sequence

In this page you can find a short description accompanied by pictures of the ATV transmitter assembly sequence. This is not a complete description of the assembly procedure, but simply an help for beginners. The complete description can be found in the assembly manual downloadable here.

You can start assembling all resistors (except those in the RF part), IC sockets and diodes.

Than the capacitors (except those in the RF part).

A this point, the most difficult part, you have to mount the 1.2 GHz oscillator and the first amplifier.

Pay attention to the inductors to be wind-up using one of the 10Ohm resistor terminal using a 3mm drill bit da 3mm and to the Varicap BB833 (it is very small!!!).

We suggest to stop here and to test the power supply, to check whether everything is OK.

On the back side of the board you have to set-up the two wire jumpers (the picture is taken on the first prototype not yet modified, therefore it is visible only one wire).

Done this, we suggest to mount a 47Ohm resistor as a load of the BFR96 and to do a first test without integrated circuits to check that no components fail and that on the IC pins there are 5V on the PIC and 8V on the TL081.

If everything is OK, you can mount the IC, program the PIC, set-up the audio and video input connections and, closing the first JUMPER for channel selection, you should receive the video signal at 1240MHz with a SAT receiver.
We suggest to clean the board with a toothbrush and a solvent (like trichloroethylene) to remove soldering debris that at 1.2 GHz can create problems.
A useful check consist of measuring the error voltage of the PLL on the 10k resistor. It must be about 4V.

Now you can complete the assemblying mounting the 2 final transistors.

Finally you can build the box made of copper sheet, make the 3mm holes for the feedthrough capacitors and solder them. You need a sufficiently powerful soldering iron since the copper takes some time to reach the temperature....


Advanced search...