Change the separation between the antennas and note
any SWR differences. It is quite possible that you
have interaction between them (or other antennas
within their near-field) that is affecting the
outcome.
Ideally...install a single antenna, sweep it from
140-150 MHz and plot the SWR. Then install the second
one and repeat. Then, change the spacing between the
two and repeat again -- noting the effect. Strategize
accordingly.
Ev, W2EV
--- wbr wf4r <wbr@verizon.net> wrote:
> David, Tony, et all,
> I had the very same trouble with the M2
> 18xxx yagi's.( I had a
> pair of them until Isabell.) I could never get a
> satifactory answer to the
> problem from the folks at m2 either. The best vswr
> I could get was about
> 1.7:1. The symptom was identical to what you've
> described. The antennas
> indicated resonance below the band. I tried
> everything I could think of and
> rechecked all the element dimentions etc. Nothing
> worked. I finally gave
> up at put them up on the tower thinking that what I
> was observing was due to
> the close proximity to the ground. It was not. The
> antenna's behaved
> exactly the same at 80 feet plus. The antennas
> obviously worked but I was
> never satisfied that they were optimized. The one
> thing that I did not do
> was to check the length of the RG59 with the "F"
> connectors. I did not know
> the velocity factor of the coax. You may try
> different length(s) just to
> satisfy your curiosity.
> If you figure it out please let me know the
> solution.
> GL es 73,
> Bill, WF4R
>
> ----- Original Message -----
> From: "t3" <T3@semarg.ath.cx>
> To: <VHFcontesting@contesting.com>
> Sent: Saturday, September 10, 2005 4:47 PM
> Subject: Re: [VHFcontesting] 2M5WL issues - Advice ?
>
>
> >
> >
> > Is that a new antenna?
> >
> > the M2 antenna's are setup differently then any
> other...
> > the elements are not in line from largest to
> shortest like other brand
> > antenna's
> > make sure the antenna is made "by the book" better
> yet take it all apart
> > and follow the
> > directions step-by step, i had the same problem,
> when the elements are
> > not installed correctly.
> >
> > Tony
> > NN1D
> >
> >
> >
> > Dave Vondrasek wrote:
> >
> >>While I wait for the Insurance to pay off next
> week, I've been working on
> >>the arrays, this week was bury the cable time. Lot
> of work, I'm to the
> >>point
> >>were I have a T-joint to intersect with the Tropo
> tower and run several
> >>cable to the same pipe. SO I figured I'd give the
> Tropo antenna's a good
> >>tuning. The only rig that works after the
> lightning is a FT-736 I had
> >>setting in the closet, so I started at the bottom
> of the stack and worked
> >>up. They are on a hazer system so it's not hard
> really to work on with a
> >>step latter. I got the 5-ele M2 6mtr to tune flat
> at 50.1, I have the 432
> >>tuned flat at 432.1, the 220 is also tuned fine,
> But I'll be ^&#^*#$ if I
> >>can get the 144 antenna to tune. It's showing the
> antenna is tuned below
> >>144.0 someplace. The SWR drops as I tune down the
> band and I run out of
> >>band
> >>before it gets to a 1:1. I have moved the two
> shorting bars from one
> >>extreme
> >>to the next on the driven element 1/4" at a time
> and it never moves the
> >>SWR.
> >>I've changed feed lines and meters and it is just
> not going to change.
> >>Could
> >>the fancy sealed feed point be blown somehow ? I
> didn't have this issue
> >>till
> >>after the lightning and it's leading me to think
> that this was the focal
> >>point of the strike. There are no burn marks on
> any of the lines or
> >>antennas, but most of the 2meter gear was toasted.
> No fancy antenna
> >>analyzers at this shack so it's radio and meters
> only. Ideas ?
> >>
> >>Needless to say I will not be contesting this
> weekend
> >>
> >>David - N5ITO / EM23
> >>http://david.davidv.net
> >>
> >>_______________________________________________
> >>VHFcontesting mailing list
> >>VHFcontesting@contesting.com
>
>>http://lists.contesting.com/mailman/listinfo/vhfcontesting
> >>
> >>
> >>
> >
> > _______________________________________________
> > VHFcontesting mailing list
> > VHFcontesting@contesting.com
> >
>
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> >
>
>
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>
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