Bob;
TX/RX 's band couplers are basically designed for coupling
entire combiners hence the 1000w rating per port. The VHF and UHF
split version crosses somewhere around 250 mhz from one port to the
other, anything below goes to one , anything above goes to the
other.... the pass band is REALLY WIDE!!!
I cascaded a VHF/UHF and a UHF/900 with the UHF/900 split
closest to the feedline and couple APRS, a UHF TX-RX 4 channel
combiner and an 927 repeater with a duplexer to a single tri-band
antenna.. no problem.
The UHF/800-900 splits about 600 mhz or so and does not roll off on
the bottom port until well below 100 mhz.....Anyhow , they are very wide......
The band couplers they sell are more like stripline technology, no
cans involved.... These are not cavity or hybrid type technology
per-se, just non tuneable passive brick couplers.
My uhf ports span 70 mhz and pass with less than a db difference.....
VHF is rated wide as well...
Doug
KD8B
At 10:51 AM 11/14/2005, you wrote:
>The commercial diplexer might only have to deal with
>two transmit or receive frequencies feeding one
>antenna. As such wouldn't the bandwidth on each port
>be relatively narrow?
>
>For use with two repeaters, the VHF port would need to
>pass both the TX and RX freqs at 600 kHz or 1 MHz
>separation, and the UHF port would need to pass two
>freqs 5 MHz apart. I would think that this kind of
>bandwidth on each port would be rather difficult for a
>diplexer, as now you're actually talking about four
>freqs through the feedline/antenna.
>
>Perhaps this is why TXRX said they couldn't or
>wouldn't provide something.
>
>Or am I all wrong about the bandwidth issue? I'm
>looking at it from a duplexer point-of-view.
>
>Bob M.
>======
>--- Doug Bade <[EMAIL PROTECTED]> wrote:
>
> > Kevin;
> >
> > Their perspective is the commercial world
> > and dual band
> > single antenna repeater systems do not really exist
> > in these bands
> > using that narrow view..... split in at the bottom
> > and split out at
> > the top they do, but not a dual band antenna. You
> > are quite correct
> > that it is not an issue if the antenna is a dual
> > band, but not in
> > their version of the world... Never ask the factory
> > those kind of
> > questions.. :-) They are not very amateur centric in
> > this realm.
> >
> > I think as I mentioned, they mis-understood
> > what he needed..
> >
> > They also do not know that a T-pass
> > combiner can be used
> > cross band (VHF/UHF) also, but that is another
> > discussion .... :-)
> >
> > TX/RX has great stuff but sometimes it is
> > tough to get
> > someone who thinks outside the box on the support
> > staff.....although
> > there are several folks there who are quite
> > knowledgeable and
> > normally very helpful.
> >
> > Doug
> > KD8B
> >
> >
> > At 09:55 AM 11/14/2005, you wrote:
> > >n2len wrote:
> > >
> > > >Thanks for the info, I called them this morning
> > they explained to me
> > > >they can build a combiner using the same feedline
> > feeding different
> > > >antennas but not a combiner using the same
> > antenna for 2 different
> > > >uhf & vhf repeaters...
> > > >
> > >
> > >I don't know why they would have told you that,
> > unless they didn't know
> > >that companies make multi-band antennas...
> > >
> > >The diplexer doesn't know (or care) how it is being
> > used, and in this
> > >scenario, only one diplexer is needed; at the
> > bottom.
> > >
> > >Kevin
>
>
>
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