that sounds almost typical of older 9913 coax. You will get better results with LMR-400. There may also be an issue with your antenna feed point (loose connector, cold solder joint, etc.). That or the antenna, itself, needs to be retuned. If you have someone there that has an Antenna Analyzer, have them stop by and do a couple of measurements (one at the radio and the other at the antenna). That will usually narrow down the problem.
-eric
On May 17, 2014, at 10:42 AM, Tom Behler wrote:
> 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
>
>
>
>
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