[CQ-Contest] 2 tribanders on 1 mast for SO2R?

[N2TK]

Consider the W3NQN bandpass filters. They worked much better for us at V2
than the ICE filters in a side by side comparison.
Tony

-----Original Message-----
From: owner-cq-contest at contesting.com
[mailto:owner-cq-contest at contesting.com]On Behalf Of Leigh S. Jones
Sent: Monday, August 06, 2001 21:22
To: cq-contest at contesting.com
Subject: Re: [CQ-Contest] 2 tribanders on 1 mast for SO2R?


Using low power and ICE bandpass filters there will actually be a
moderately good chance that there will be very little cross-band
interference, or at least that it will not be so bad that you will be
seriously hampered by the interference.  There is a great deal that
you can do to improve the chances that the crossband interference will
be slight.  I've listed some of the helpful hints used at high power
for multi-single and SO2R operations below; keep applying fixes from
the list until you have the desired low level of interference:

First, to prevent coupling of signals from one coaxial cable to the
other, use an effective balun (or choke type balun) at each tribander
and separate the coaxial cables as much as practical.  Avoid ferrite
type baluns if harmonic interactions are an issue (i.e., 10 and 20
meters may be used simultaneously).  It may even be helpful in some
cases to feed the upper coaxial cable down through the middle of the
tower to add the tower to the effective shielding of the cable.
Ground the shields of the two cables at the first touchdown points to
two separate ground rods (don't tie the coaxial grounds together).
Maintain separate but effective grounding systems for the two
transceivers with a brute force RF filter on the AC leads for each
transceiver to cut down on coupling RF through the AC power leads from
one transceiver to the other.  A common mode filter (choke) on any
ground interconnects between the two rigs (such as is required for the
key leads).  It would be more effective to use two relays to help keep
the grounds from the key leads completely separate.

  ----- Original Message -----
From: "Dan Levin" <djl at andlev.com>
To: <cq-contest at contesting.com>
Sent: Monday, August 06, 2001 5:12 PM
Subject: [CQ-Contest] 2 tribanders on 1 mast for SO2R?


>
> I'm thinking about a temporary setup for NAQP SSB
> that would have a C-31XR tribander at ~80' and a C-3E
> tribander at ~40' on the same tower.  I would want to
> use the two antennas, each fed with 1 feedline, for
> separate radios for SO2R.  I would use ICE bandpass
> filters, but no stubs.  Does anyone have a sense of
> how much interference I am likely to have?  This is
> 100 watts remember - so not as bad as 'full' power :-)
>
> Thanks!
>
>
>                   ***dan, K6IF
>
>
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