[Elecraft] Tuner efficiency question

[Parker Buckley]

I still don't know what to think.  I came home from Hamvention today with
the tiny T1 tuner for my K2, based more on convenience of installation and
ability to use it with other rigs and portability.  If I eventually want an
auto tuner for higher power, I'll go through all this again, I guess.
Meanwhile, I'll keep the Hallicrafters connected to the Palstar tuner.

Hey, it was worth the price of the tuner, just to meet Don at the Elecraft
booth!

Parker

-----Original Message-----
From: Bill Coleman [mailto:aa4lr at arrl.net] 
Sent: Friday, May 20, 2005 2:24 PM
To: John, KI6WX
Cc: Don; Parker Buckley; elecraft at mailman.qth.net
Subject: Re: [Elecraft] Tuner efficiency question


On May 13, 2005, at 12:40 AM, John, KI6WX wrote:

> At high power, an inefficient tuner can generate significant  
> amounts of heat, which can destroy components.  A 1kW transmitter  
> into a 70% efficient tuner will generate 300 watts of heat in the  
> tuner.

This is why I tend to disbelieve tuner efficiency figures. From the  
QST tests, there seem to be a lot of tuners than have losses greater  
than 10% -- yet there is no evidence that any of these tuners heat up  
appreciably! At 1 kW, a 10% loss is 100 watts -- imagine how hot a  
tuner enclosure would get if you had a 100 watt light bulb inside it.

Even at 100 watts, 10% loss is 10 watts. That's still enough to  
induce a few degree change in a small enclosure.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901