On Monday, March 16, 2015 at 3:40:35 AM UTC-4, Jeff wrote:
Should I follow your suggestion I would need to also provide protection for the radio connected to the third band segment.

Do you know of any reason why connecting two separate filters to the same feed line would not work.

Can I anticipate any ill affect from placing a coaxial Tee fitting across the output of one filter and connecting a jumper to the output of another filter in order to connect the transceivers to the multiband antenna?

Would there be any additional concerns be raised if one of the two filters was the dual band model with separate connections for each of it's two bands on the end being used for input connections?

What about if I make up the assembly using Three separate filters with Two of them connected to TEE fittings.


Hi

Using a tee piece is not a good idea as it would effectively be putting
a stub on your line, and depending on the length of the coax connections
and the frequencies that you are operating on and the out of band
impedances of the filters, it may or may not cause you problems.

As things have got a bit disjointed as the thread as progressed would it
be possible for you to give a short and accurate description of what you
are actually relying to achieve, and then perhaps a solution could be
suggested.

Jeff

Jeff

It is all here in the rest of the thread but here goes. I have only three antenna mounting points available on my home for antennas to serve:
a dedicated two meter transceiver for a digital node,
a dedicated Seventy Centimeter transceiver for a D-STAR hot spot.
a separate 120 CM transceiver
the six meter band of multiband transceiver
a dual band 146/446 transceiver

That is five radios that need to be able to use Six Separate VHF/UHF frequencies with as many as four transceivers operating at the same time. Two of those transceivers would be operating as automatic stations so as many as three of those transmitters may be transmitting at the same time. Two of the three may even be on the same band given that their will be an automatic station on both Two Meters and Seventy Centimeters and I may be operating as a manual control operator on either of those bands at any given time.

I initially asked for advise on which dual band antenna to use to serve a 144 Mhz and a 440 MHz digital stations.

Someone then suggested that I use two tri-band antennas in order to provide all band capability for FM operations on 6, 2, 1.25, and 0.7 Meter bands while still operating the two automatic stations on 144 & 440. I would use vertical separation to reduce the de-sensing on the common band stations.

I then asked for advise on any foreseeable problems with using the DCI filters to effectively separate the signals at the radios and yet allow the transceivers to share two multi-band antennas to cover the needed bands with only two mounting points.

I'm saving the third mounting point for stacked Yagi-Uda beams to provide additional range on 146/440 for the repeaters at the extreme ends of the service area of the Forecast Office that I am serving as Assistant Coordinator for Net Management in their Skywarn Program. I am hoping that between the beams and two amplifiers with receive pre amps I will be able to take reports when appropriate from some of the more distant sub nets. I have done this previously with temporary masts from this location so I am very hopeful that it will work using more permanently mounted beams. All of that is so you will know why the third mounting point is not available for the needed omnidirectional vertical antennas.

I hope that makes the expanding questions clear.

--
Tom Horne W3TDH