[Elecraft] OT: Vertical doublets (was: Home made Sigma-GT5 & KRC2 or SGC?)

[George, W5YR]

Just a comment re tuner loss:

Frank Witt, AI1H, has written in QEX an excellent article on measuring tuner
loss using an impedance meter such as the MFJ 259B. I and several others
have performed numerous tests on various types of tuners and have yet to
find one with an inherent loss exceeding one dB. Most come in the range of
0.5 to 0.75 dB on 20 meters. One KW tuner was measured at 0.11 dB!

As a rule, and according to theory, L networks tend to show less loss than T
or PI networks.

Any tuner will exhibit larger losses when "mistuned" or when one attempts to
tune a load that is outside the envelope for the tuner.

There are excellent computer programs available for tuner analysis that
include calculation of losses in real components with finite Q values. They
confirm the minimal power loss in a well designed and adjusted tuner.

73, George W5YR
Fairview, TX
w5yr@att.net
http://www.w5yr.com


----- Original Message ----- 
From: "Ron D'Eau Claire" <rondec@easystreet.com>
To: <elecraft@mailman.qth.net>
Sent: Tuesday, March 23, 2004 10:48 AM
Subject: RE: [Elecraft] OT: Vertical doublets (was: Home made Sigma-GT5 &
KRC2 or SGC?)


The "guru" who insists repeatedly that the losses in an ATU (or any matching
network) are significant is proof that saying something over and over again
doesn't make it so. The ATU easily can be the most efficient part of a
typical antenna system. As Don said, some ATU's are more efficient than
others. The L-match used in the Elecraft ATU's is, overall, the most
efficient system we have. But even the much-maligned "T" match networks can
be very efficient, if used correctly.