[Kenwood] TL-922A question

Thu Dec 8 02:07:46 EST 2011

On Thu, Dec 08, 2011 at 12:00:06AM -0600, rb wrote:
> 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?

What frequency are we talking about here?
I've never owned a 922, but I think you'll need 100 watts into the amp
on just about any band to get near full power out of it.
Most likely, if you're really tuning up the amp correctly and still only
getting 500 watts out, the tubes in your amp are shot. But, check the
less expensive possibilites first. How are you measuring the PO of the
Yaesu? Another possibility is that the input of the amp is presenting
a high SWR to the exciter: You might be feeding 150 watts into the 922
only to see 100 of them being reflected. I would think the FT101zd
could compensate for some mismatch, but neasure the SWR your exciter
sees when the amp is operating on the band in question and either tweak
it up if it is not within about 1.5:1, or retune the Yaesu appropriately
when feeding it into the amp.
> B. What do I need to do to get more output? 

Maybe a couple new 3-500zs, but hopefully something else will pan out.
Good luck,
Rob