Does anyone have a 23cm duplexer available? Or maybe instructions for converting a 70cm?Sinclair Q3220E to 23cm, I have several to use? I have this ICOM ID-PI1200VD sitting here that I'd like to get on the air for a few of us who have ID-1's.

I've seen the info at??I might be able to work along those lines, only for a duplexer, don't need the additional port for the DD radio.

Thanks,
August KG7BZ
Sweet Home, OR.

I once retuned a 800 MHz TX/RX duplexer to 23cm by removing the tuning plunger and cutting off the outer fingers.
Then I used a fine hacksaw to cut new fingers and reinstalling the inner plunger.

Finally I recut all the interconnecting cables to the correct frequency.

I did not modify the loop on the small tuning device but there are places to learn about that.

Using a Rigol spectrum analyzer the pass and notch bands tuned perfectly.
The loss was 3 db or half the power.

Note: I have no real technical knowledge about this, just like to experiment and wasn’t afraid to ruin a cheap duplexer I brought off eBay if it didn’t work out.

Rex, AJ4GC

Have you considered just running dual antennas? Vertical separation at 23cm is not much.?

My experimenting is showing that it's not going to be too difficult to make a combination of notch and bandpass cavities from the 70cm?Sinclair Q3220E. Not going to try to make the combined notch/pass cavities, that gets too much into "magic". If necessary I can go with 2 antennas with the duplexer if I need additional isolation. Luckily I have a Tek 794P analyzer with companion tracking generator. First tried a NanoVNA-F but since it's working on harmonics at 23cm, it kept tuning on the 70cm resonances.

August KG7BZ

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