Ham Radio Forum

Balarabay1 · Guest

antenna tuning so you can safely tune an antenna with a diplexer? I had the unfortunate experience of adjusting the diplexer for the swr of my TX antenna and blowing my Rf Module! Can anyone suggest a safe method? I do not want to blow the new one. I hooked up a 50 ohm dummy load to my SWR meter & transceiver, and calibrated my meter for the power output of the transceiver and set the swr at 1.5(Which the Dummy is at). After that is done, I will disconnect the dummy load and connect my antenna again. The next step is to adjust my diplexer trimmers until I get the same 1.5 swr as the dummy, or close to it. Is there anything I should be especially careful of? Thanks All!

Cuc Tu · Guest

You can put an attenuator right on the output of your transceiver. You can easily make a switchable attenuator--up to 40 dB or more in 3 dB and 10 dB steps is nice to have (or you can buy them). Then any type of load on the output (short or open) will not harm your RF PA.

When you adjust your Diplexer, you should put a dummy load on the input port, then attach the transceiver to one of the output ports with an SWR meter inline. Tune that band's filter for 1:1, and then repeat the process for the other band.

I would also suggest tuning the antennas one at a time and independantly from the diplexer (i.e. remove the diplexer from the circuit).

Radio_Girl · Joined: 26 Feb 2007 Posts: 10

Usually, just tuning out the antennas works fine for me.

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