[amsat-bb] Duplexer to Dual-Band Vertical

[k5oe at aol.com]

This can be done with a pair of inexpensive du/diplexers (e.g., Comet, MFJ,
etc) and a coax tee.  From the antenna, on the coax to/in the shack, insert
a coax tee and from the two other ports install a diplexer, one from common
to VHF and the other from common to UHF (leave the other port open, or if
concerned you can put a 50 Ohm load on it... I never did / had to).  This
has a slight mismatch, but is tolerable.

73,
Jerry, K5OE

-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of VA3ASE via AMSAT-BB
Sent: Tuesday, February 11, 2020 7:07 AM
To: AMSAT-BB <amsat-bb at amsat.org>
Subject: [amsat-bb] Duplexer to Dual-Band Vertical

Good morning,

I was chatting with a friend about his experimentation with amateur
satellites and have been pondering if his setup is "safe" for his radio. He
is running an FT-847 through a duplexer (diplexer if you want to be
pedantic) and into a dual-band vertical base antenna on his roof.
Definitely not an ideal setup, but meant to be temporary until time and
better weather allow. He has managed to make some FM contacts on AO-92 with
it.

My concern is him using a duplexer in this manner while running full duplex.
I suppose this is similar to what people must do if using an Elk antenna. I
just worry about there being enough isolation between the ports and damaging
his transceiver. Are there others using similar setups or is this something
to avoid?

73,
Alex VA3ASE
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