The issue with teh AM BC Strong Signal interference is addressed in
the Nov/DEC NCJ
( National Contest Journal ) magazine article
..and article uses exact same antenna analyzer as Dick is using !
73, Dennsi N6KI
On Thu, Dec 4, 2008 at 6:09 PM, Tom Osborne <w7why@verizon.net> wrote:
> Hi Dick
>
> You can get some screwy readings if there is a BC station nearby. I can't
> even use my analyzer here on my 160 inverted L because of RF from the
> local.
> I have to use the SWR bridge in the shack. 73
> Tom W7WHy
>
>
>
> > Hi Guys,
> >
> > I'm trying to set up a 160-m. Inverted L for ARRL-160 this weekend but am
> > having an interesting tuning problem. All thoughts appreciated!
> >
> > The Inverted L is made up of #12 stranded copper wire 136' in total
> > length:
> > 82' vertical and 54' horizontal. The vertical wire is spaced 6' from a
> > 88'
> > self-supporting tower with a Cushcraft XM-240 mounted on top. (XM-240
> > elements
> > are not grounded) Initial radial system is 2- 135' radials laying on
> > the
> > ground- not much but two similar radials worked pretty well on my 60'
> > tower last
> > year as the towers are 150' from a salt water river.
> >
> > Placing the Antenna Analyzer (AIM 4170) at the base of the Inverted L
> gets
> > the following measurements:
> >
> > 1) With the coax braid connected to the tower base which has two 8'
> ground
> > rods: lowest SWR is 3.9 at 1.776 Mhz and Z = 79.
> >
> > 2) With coax braid only connected to the two radials (and not the tower
> > base): lowest SWR is 1.62 at 1.614 Mhz and Z = 81.
> >
> > It was my understanding that the coax braid should be connected to both
> > the
> > radials and the base of the towers gnd system, but as you can see the the
> > minimum SWR and resonant freq. go crazy when I do.
> >
> > Any recommendations what I can do to get it working before tmw night?
> >
> > 73,
> > Dick- K9OM
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|