[Kenwood] TL-922A question

Thu Dec 8 01:46:57 EST 2011

RB,
Let's start with a callsign please? It's netiquette on the lists.
There are several things that will affect the output. It may be one or
more.
How are you measuring the drive power? Are you using ALC (correctly)? Did
it EVER put out the rated power for you? What is the match between the
driver and the amp? How are you tuning the amp? How are you measuring the
output?
(The 4:1 balun should be a 1:1, then let the tuner make up the difference.
The 4:1 creates more loss and a good tuner should be able to compensate with
the 1:1.)
What is your tuning procedure? Since you use an antenna tuner, you should
tune the antenna to 50 ohms with the driver and antenna tuner, tune the amp
into a 50 ohm dummy load with the driver, then bring the amp on line onto
the antenna and recheck the match before operating. 
There is a specific WAY to tune the amp too. Doing it wrong ONCE can put
the components at risk. You're dealing with very high voltage and current
and there is no room for mistakes in tuning. Once a part arcs or overheats,
there is no guarantee it will ever work again.
Are any components burnt, failed or broken? If tuned improperly, the finals
could be flat. Have they every been replaced? There are other ways to
damage them too. The power supply could have issues (set to 240 but
actually attached to 110v?). The list goes on and on.
You'll want to check EVERY setting and control, the components, the power
supply in a logical and clear manner. Then test it with other drivers. 120
watts of drive should produce near legal limit output. If it works to the
limit with another driver, you look at the Yaesu for issues...
Again, start at the driver then work through it in a clear, logical manner
and check EVERYthing in the path.
73,
Rick WA6NHC
-----Original Message-----
From: rb
I see I'm going to need some straightening out on my thinking of using
linear amps. I thought my exciter (Yaesu FT-101zd) would drive it full
output with maybe 50 watts or so. 
I'm finding I run maybe 150 watts into the TL0922A, and it still puts out
maybe 500 CW watts.
Now, I have a 160' dipole, feed with 450ohm ladderline. It comes into the
house through a 4:1 toroid, just outside my shack. I have a good 3KW
antenna tuner (with roller coil). My other exciters load it fine barefoot.
Using my TL-922A, I have the feeling that everything is "right", and it
seems to like my ant situation. I guess my big questions are:
A. Why does it take 150 watts to get 500 CW out?
B. What do I need to do to get more output?