But this discussion seems to have evolved into
something difficult to relate to the thread title.
You might want to change the title!
Phil W7OX
On 4/27/16 10:25 AM, James Rodenkirch wrote:
Wow....lots of good stuff emanating from this discussion - tnx to all for
participating....
For Jerry - there are other reasons for employing an ATU in the shack - e.g.,
using open wire line feed line from the antenna back to the xmtr.
_____________________________________
From: Jerry <[email protected]>
Sent: Wednesday, April 27, 2016 10:10 AM
To: Ken K6MR
Cc: Jim Rodenkirch; [email protected]
Subject: Re: [Elecraft] Sherwood's receiver performance table updated
I always thought the ATU in the shack was specifically to allow operation where
there's an impedance mismatch (not necessarily non-resonant) specifically to
protect solid state equipment from the high voltages that can be present.
Obviously an antenna system can be resonant and still not match impedance of
the feed line and/or Radio.
Sent from my iPad
On Apr 27, 2016, at 11:36 AM, Ken K6MR <[email protected]> wrote:
“P.S. I don't subscribe to the notion that quality coax runs of < 150 feet
make it "ok" to have the ATU in the shack while operating an antenna on
multiple bands....what technical evidence of that posit do you have to
share????”
Jim:
Google “transmission line bounce diagram”. This is a simple concept easily
proven by mathematics.
On a practical level, this is the concept behind the use of open wire feed
lines. It’s been done for decades. The type of feed line does not change the
theory.
Ken K6MR
From: Jim Rodenkirch<mailto:[email protected]>
Sent: Wednesday, April 27, 2016 06:21
To: [email protected]<mailto:[email protected]>
Subject: Re: [Elecraft] Sherwood's receiver performance table updated
"It all depends" is/was the premise for my reply, Don.
If new and old hams don't understand the potential problems with long runs
of coax to/from an antenna they want to operate on multiple bands and an ATU
in the shack they will be surprised at how inefficient their system is.
P.S. I don't subscribe to the notion that quality coax runs of < 150 feet
make it "ok" to have the ATU in the shack while operating an antenna on
multiple bands....what technical evidence of that posit do you have to
share????
Note 1: I had a 43' vertical with top loading wires in a NORD-style config
with my external ATU at the base of the vertical and 120' of coax back to
the shack ---- never saw a VSWR delta of more than .2 between what was
"seen" at the input to the tuner and what was "seen" at the xmtr while
operating on 160 through 20 meters.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
