[Amps] Titan 425 Reflected Power

[Jim Brown]

On Sun, 24 Sep 2006 16:42:28 -0500, Robert B. Bonner wrote:

>It sounds like you have a fairly high SWR on your system.  First I would
>improve the situation at the antenna.  That is the correct fix.

Wrong. My antennas are typically better than 2:1 over the bands they 
cover, except on 160 and 80/75 are >10% bandwidth, and I operate both CW 
and SSB -- in other words, that full bandwidth. 

>If your antenna is 50 ohms, the best length of coax is 1/2 wave long
>electrically.  

If the antenna is 50 ohms and there's a decent balun in the system, the 
length of 50 ohm coax doesn't matter. 

>The end goal is to be able to SELL YOUR SHACK MOUNTED TUNERS ON EBAY. 

>The only one I use is at the bottom of my 75 foot vertical to tweak it 
from
>one end of 80 and 160 to the other.

Which is what I do with mine. 

Thanks for the transmission line lecture, which is both incorrect and 
irrelevant. (My undergrad thesis was in the application of matching stubs 
to broadband a dipole to cover both 80 and 75). 

>When your amplifier is standby the path of bypassing the amp through 
>the amp will almost always change the SWR indicated by your exciter as
>the amp is an impedance bump.  Only the "best" of the amp manufacturers
>were concerned with this path.

This is exactly what I was asking about, and what I included in my 
troubleshooting -- I connected the exciter straight to the tuner, with and 
without the switches, and an indicated match occurs on all three bridges 
(the tuner, the Bird, and the exciter) at the same tuning. When I re-
connect the tuner output and exciter back to the amp without changing the 
tuning, the exciter bridge does not. And when I take amp out of standby, 
the Titan bridge shows a mismatch. Thus my troubleshooting of the problem 
strongly suggests that it is on the OUTPUT side of that circuitry. 

So I repeat my question -- does anyone know anything about this issue in 
this particular amp?  

73,

Jim Brown K9YC