Filter hacking for 2395 ISS TV

[G3GJA]

Yes it will change the tuning Gareth.

I used PTFE tubing placed over the tuning pistons to lower the operating frequency of a 10-cavity duplexer originally intended for use at 1496MHz and 1354MHz so that I could tune it to 1308MHz and 1275MHz for use in a repeater.

Although the the 33MHz separation was much less than the original 142MHz, it still gave useful isolation between the TX and RX ports. However, it didn't cope with the power level needed and was prone to flashing over, but it now has use as a look-through filter at home so I can monitor the repeater whilst transmitting.

Clive