Duplexer losses

[K2OWK]

I have purchased a 2m/70cm ground plane antenna. I have a yaesu (old type) 2m/70cm transceiver with dual antenna output cables (one on 2m and one on 70cm). The instructions say to operate a single dual band antenna with this radio a duplexer is required. My first question is will there be a 3db loss at each output of the duplexer? My next question is would it be beneficial to simply switch the antenna manually to each frequency as required? This would save me the price of the duplexer and the possible insertion loss. This transceiver can not receive two bands at the same time. Thank you for your replies.

73s

K2OWK

[K2DC]

Duplexer insertion losses are pretty low - typically 0.1-0.2 dB on 2M and 0.2-0.3 dB on 70cm.  And they're not tremendously expensive, I've seen Comet and Diamond models for around $60.  There is one distinct advantage to a duplexer compared to a switching arrangement.  With a duplexer, you won't run the risk of keying up with the switch in the wrong position and somking the finals.

73,

Don, K2DC

[K5LXP]

will there be a 3db loss at each output of the duplexer?

You're thinking of a 0⁰ splitter.  As K2DC points out, the losses through inexpensive and commonly available diplexers is quite low.  I've tested a bunch of them and the $30 MFJ V/U model is just as good as the more expensive Comet and Diamond models.


Mark K5LXP
Albuquerque, NM

[K2OWK]

Thanks Mark and Don, I was thinking of a splitter (as a TV type). I was looking at and thinking of buying the MFJ-916B. It sounds like a good investment. Again thank you for the information.

73s

K2OWK