Using A Diplexer For 2 Simplex Transcievers

[mrtor]

A question for the more experienced than I !

Scenario: 2 simplex GM300's. One running at 470 Mhz TX/RX, the other at 475.200 Mhz TX/RX (ie: 5.2 mhz spacing)

In a crossband situation, ie: One receiving and the other re-transmitting and vice versa

Would I be able to use a Notch Diplexer with one set at the 470 mhz and the other 475.200 as you would for a normal talk through repeater and therefore only need 1 stick ?

Thanks in advance
Mike

[kcbooboo]

In theory, it should work, but you might encounter some amount of receiver degradation on one radio when you transmit on the other. Notch-only duplexers usually only give you 60-70 dB of notching; on UHF if you have 100 or more dB of rejection, you'd be good enough to use the setup as a repeater and would have no interaction between the two signals. But such base-station duplexers are quite a bit more expensive than the notch type, which are most often used in mobile applications.

Bob M.

[mrtor]

In theory, it should work, but you might encounter some amount of receiver degradation on one radio when you transmit on the other. Notch-only duplexers usually only give you 60-70 dB of notching; on UHF if you have 100 or more dB of rejection, you'd be good enough to use the setup as a repeater and would have no interaction between the two signals. But such base-station duplexers are quite a bit more expensive than the notch type, which are most often used in mobile applications.

Bob M.

Thanks Bob

I shall give it a try and see how it works, you are correct for this application it is mobile as a one off temp. system for 6 days

Regards
Mike