On 5/2/2014 10:09 PM, Patrick Greenlee wrote:
Close to the antenna feed point is etter. There are a lot more makers
of remote automatic tuners than MFJ.
Patrick NJ5G
-----Original Message----- From: Tony
Sent: Friday, May 02, 2014 6:45 PM
To: towertalk@contesting.com
Subject: [TowerTalk] In Shack Tuner Vs. Remote Tuner for Multi-Band
Antennas
All:
Technically the tuner at the antenna is better, but with good coax and
low bands it's hardly worth the effort, but look up the chart in the
handbook for additional loss Vs SWR at a given cable loss. Basically, at
160, 75, and even 40, it makes little difference whether the tuner is in
the shack or remote. Unless it's a long run, if you are using good,
low loss coax, the difference is likely only a few tenths of a db. Look
up transmission line basics (20.1) in the current 2014 book. This
chart has been in there for years, so if you have a different version,
just look gor transmission line basics. It's much faster if you have
the digital version A quick look will answer your question.
73
Roger (K8RI)
Need some advise on getting the best performance out of a multi-band (80
through 20) wire antenna and tuner. My first option is the in-shack
auto-tuner feeding a doublet with a short run of coax and remote balun.
The alternative option was to go with a remote auto-tuner mounted near
the antenna feeding an 80 meter dipole with ladder line. There would be
an 80 foot run of coax from the rig to the remote tuner. I can add
dipoles to the remote setup if need be.
I have a 500 watt amplifier so I was considering the 500 watt Elecraft
in-shack auto-tuner. The MFJ remote tuner (600 watt version) is
reasnably priced, but unfortunately, didn't get good reviews.
Regarding doublets: I plan on using one for portable operation cut for
30 meters with an Elecraft KX3 QRP rig and internal tuner. Any tips on
the best ladder line and dipole lengths would be appreciated.
Thanks...
Tony
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