[TenTec] Orion II AT tuner question

[Grant Youngman]

> Can you repeat the test with the tuner tuned to a low 
> frequency like 80 or 160 meters?

I did the test earlier with the tuner adjusted for 80M, and found the same
result on all bands.
 
> Or how about inputting a signal on 28 mhz that should be 
> about S9 with the tuner properly tuned for that band and then 
> seeing what it reads with the tuner tuned on a band far away 
> like 80 meters.

Some tests: (MAIN receiver only on ANT 1)

(1)500 Hz BW, LCW, AGC off, RF gain low 50's.    I set the tuner for 10M,
feeding a 50 ohm dummy load.  Removed load and connected signal generator
and set input signal of 28.0 Mhz to provide reference reading on 3400A.
Reattached load, tuned up at 1.88 Mhz with the internal tuner.  Went back to
28.0 Mhz, removed load and reapplied the input signal from the 8640B. 
  
(2) Same as above except I used an 80M dipole to make sure I had a pretty
severe mismatch on 160M for the tuner to chew on.

(3) Same as (1), and (2) except AGC SLOW, RF Gain 100, reference signal set
to read S-9

On (1) and (2), the change in output was less than -1/2 dB.  I'd have to
repeat several times to make sure that small change wasn't the result of
measurement error, receiver or generator drift, or something else.  It's
pretty close to zip.  On (3), there was no visible change in the S-meter
position.

> I find it hard to believe that tentec would not use the tuner 
> in receive also.  This would not work very well for long wire 
> antennas that are far from resonant when untuned.

There doesn't seem to be any significant impact on MDS or signal levels with
or without the tuner in the II adjusted for the selected band.  The
combinations I tested aren't exhaustive.  Maybe there are some where it
matters. 

Grant/NQ5T