A local ham (retired radio engineer) came over and we spent an
afternoon testing my setup. We were looking to see if I had caused
any problems with the length I proposed, and also to test a claim
by DX-Engineering that I needed to use 200 feet of LMR-400 to get it
to have a happy SWR on top band. We spent all afternoon testing
whether or not that claim was true, and whether or not the added
coax would cause other problems. We used the TLW program, and
my antenna analyzer, and a third program I cannot recall, and had
a grand time. He concluded my coax transmission line was an OK
length, not causing any high voltage problems on any band, but
we also discussed the ramifications and compromises having a single
length of coax for all operating bands might have.
As always... I am still learning every day.
Happy Trails.
======================= Richards / K8JHR =========================
On 2/16/2011 8:06 PM, Stuart Rohre wrote:
> Yes, thanks to Gerald for adding the missing "voltage point" along the
> line. If you review the texts, they usually show the variation of
> cycles of voltage along a transmission line. You don't want your tuner
> capacitor to be force to deal with the peak of voltage at a point of the
> line where it connects. You extend the line with added length, and you
> end up with the tuner at a different voltage point. (Or subtract some
> feedline, but most folks run just the length to fit the distance to the
> antenna and that is not practical.)
>
> -Stuart Rohre
> K5KVH
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|