Hi Tom:
Thanks for the comments.
1. In my long post (sorry again), I did include matched line loss in my final
statements - please check again. I think I compared the two cases with equal
one way loss.
73 Steve
______________________________ Reply Separator _________________________________
Subject: Re: [TowerTalk] Mismatch Loss and Tuners
Author: w8ji.tom@MCIONE.com
Message-id: <0EY8008266Q9IN@PM02SM.PMM.MCI.NET> at
InterNet
To: <towertalk@contesting.com>
Date: 8/25/98 12:22 AM
Hi Steve,
You wrote:
> SUMMARY - A matched antenna will significantly outperform a
> mismatched antenna with a tuner. A tuner cannot introduce
"reflection
> gain" to change this fact.
1.) Assuming "significant" is a noticeable amount, that summary is
incorrect. It ignores transmission line loss between the tuner and antenna.
Matched line loss MUST be included in your statement, or it is meaningless.
2.) The tuner does indeed add "reflection gain" that exactly cancels
"mismatch loss" when adjusted for a conjugate match. The only loss
remaining is the transmission line loss which is, as you and Walt pointed
out, is increased by the higher circulating power. If the initial matched
line loss is very low (as it can be in many cases), multiplying loss
several times will not cause "significant" loss.
At least we are beyond thinking reflected power is dissipated in the tuner
or transmitter, it's only a small step to accuracy now.
73 Tom
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|