On Sunday, March 15, 2015 at 12:36:28 PM UTC-4, Brian Reay wrote:

It depends.

For example:

Some, duplexers are just an LPF and a HPF. Say your 2m filter is LPF and
your 70cm filter is HPF and your 3rd band is 220MHz (the one you wish to
Tee in).

If the Cut Off frequency of the HPF is such that is will allow too much
of the 220 MHz to pass to the 70cm radio, you could have an issue with
enough 220MHz reaching the 70cm radio to be an issue. Likewise of for
the 2m radio but with the LPF cut off.

You really need to know the performance of the filters you are using.

I don't know the unit you mentioned, I would suggest you study the data
sheet and see what its performance is at the frequency you plan to 'Tee'
in.

Ideally, build (or buy) a unit designed to work with three signals,
which you may be able to do using the unit you have when you know the
characteristics.

Brian

I was specifically referring to the Digital Communications Incorporated band pass filters that I had identified earlier in the thread. I have in hand a DCI-146-444-DX-DB I was thinking of adding a DCI-223.5-3H for 125 Centimeter band for the 146/220/446 tri-band antenna. That would give me three separate input ports to attach the three separate transceivers to.

On the 6,2,& 0.7 Meter multi-band antenna I would buy a DCI-146-444-DB and a DCI-6M-53 MHz-2-4p. That way I could connect a dual band 146/446 Mhz radio to the dual band filter and the Six Meter Transceiver to the Six Meter band pass filter inlet.

The spec sheets for all of these filters can be seen at the manufacturers web site at
http://www.dci.ca/?Section=Products&SubSection=Amateur.

--
Tom Horne W3TDH