Power is a valid point that I have already considered as follows:
1) The intended use cases are SO2R and M/S. That is, there is no expectation
for prolonged times when power is more than 1500W combined.2) Sadly, there are
losses in the system- feed line, SO2R switch, HP BPFs, triplexer, and stack
match. While not a reliable solution, it needs to be taken into consideration
as the power that reached the tribander is less than 1500W3) My entire system
is sized for 3,000W- LMR600 everywhere, SO2R switch, BPFs, triplexer, and
tribander baluns. No margin, but acceptable given #1 and #2 above
Rudy N2WQ From: Jim Thomson <jim.thom@telus.net>
To: towertalk@contesting.com
Sent: Wednesday, March 22, 2017 12:37 AM
Subject: [TowerTalk] triplexers and stacking
Date: Tue, 21 Mar 2017 21:50:34 -0400
From: Mike DeChristopher <mfdechristopher@gmail.com>
To: towertalk@contesting.com
Subject: [TowerTalk] triplexers and stacking
I know some of you are using (or have used) a triplexer with your
tribander. Having very limited experience with triplexers and
tribanders, I'm hoping you can assist with a thought experiment we're
working through.
73,
Mike N1TA
## what I would like to know is... how the heck can you stuff 3 x amps, each
running 1.5 kw
simultaneously, into just one coax, that in turn feeds just one balun, that
feeds the tribander ?
A TH7 or mosely would go up like a roman candle, so a real tribander would be
required.
Even then, the poor balun would take a beating, along with the 213-U. I would
think you
would at least require some heavy duty coax going up the tower, and then some
flexible
heavy duty coax for the rotor loop, like perhaps LMR-600UF or RG-393. As
far as the balun goes,
I dont know if RG-303 or RG-400 would work...since both only have a 18 ga
center conductor.
What might work is RG-304, which has a 14.5 gauge center conductor, and is
aprx .280 OD on the
outer jacket, has a teflon dielectric. It’s a tiny bit bigger OD than RG-8X, so
may well be able to wind on
a stack of 2.4 OD torroids. RG-393 has a 11 ga center conductor and also
teflon dielectric, but has
a .390 outer sheath, and is a bitch to wind on torroids, and keep the assy
compact, however, it can be done.
Trying to achieve high values of RS from 20-10m is yet another trick, so the
torroids dont heat up with
4.5 kw through them on the upper 3 bands. With 393, you need 2 x CM chokes in
series, stagger tuned.
With 304 coax, you could do it with a single stack, but 2 x CMs in series is
not a big issue, provided that
304 can be wound tightly like 8X can.
Jim VE7RF
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