Hi, all.

 

Well, I was out at the RV camp site briefly yesterday afternoon, and
re-tested my TMV71A out there with the dual-band mobile antenna that is now
attached to the RV, and using my TW2 to take the needed readings.

 

Now that I've learned how to do the TW2 band switching properly, I'm happy
to report that the readings out there look good, and make perfect sense.
SWR's on both 2 meters and 440 are no higher than 1.2 to 1, and the output
power readings on both bands are in line with what I'd expect for the
TMV71A.

 

However, I still think I might have an issue with my Diamond X200A antenna
that is mounted on the roof here at the home QTH, especially on 440.  The
antenna is near the peak of the roof, up about 40 feet or so, and is fed by
RG9913 coax.

 

Here are some readings I get with the TMV71A, and my TW2:

 

2-meters on 146.47 MHZ simplex:

 

SWR = 1.2 to 1;  Forward Power = 41 watts;  Reflected Power = 0.6 watts.

 

Not too bad in my opinion.

 

440 on our local repeater frequency of 443.900:

 

SWR = 2.4 to 1;  Forward Power = 30 watts;  Reflected Power = 5 watts.

 

I'd be interested in anyone's thoughts as to what these readings are telling
me.  Although not terrible, my SWR and power readings on 440 are not what
I'd like them to be, and I suspect that the lower forward power readings are
due at least somewhat to the fact that the TMV71A may be folding back a bit
due to the 2.4 to 1 SWR.  I'm not exactly sure how to re-tune the Diamond
X200A for 440 to allow it to perform better, and certainly don't want to get
someone to climb up on the roof with an antenna analyzer to help until I
have a very good idea as to what adjustments need to be made.

 

In the meantime, I guess I'm fortunate in that the only 440 repeater in our
local area is about a mile from my house, and can be hit easily with 5
watts.

 

Part of me just says:  "If it ain't broken, don't try to fix it.";  but the
slightly elevated SWR on 440 does concern me a bit.

 

Tom Behler: KB8TYJ