As W1XT told me once: You have a driven element and a reflector, find out
where you DO have front to back. Stupid me had to receive an elementary
tutorial. Generate a signal from your remote antenna and observe f/b (or
lack thereof), on your 40M2LP, change the frequency of your generated signal
and observe f/b. Keep changing your generated signal frequency until you do
observe f/b and adjust your reflector to suit.
My WARC-7 had no front to back when first installed, and following W1XT's
suggestion I found the f/b was at 9.5 MHz. I adjusted the reflector and now
I have good f/b at 10.1 MHz.
de Paul, W8AEF
----- Original Message -----
From: "Don Moman" <ve6jy@3web.com>
To: <TOWERTALK@contesting.com>
Sent: Thursday, July 28, 2005 7:08 AM
Subject: [TowerTalk] M2 40m 2 el yagi dimensions
> I'm in the process of rebuilding a M2 2 el 40m yagi - I think it may be
> the
> model 40M2LP altho it may be an earlier version as the linear loading
> attachment looks different. And yes the linear loading setscrews have
> mostly
> all vanished, but I replaced them with 1/8 inch cable clamps and 3/16
> aluminum rod (from all my broken off metal fatigued 2m 13B2 Cushcraft
> elements, but I digress....) Original owner hasn't found the manual yet
> and
> Google hasn't found much either. Specifically I need the dimensions of
> the
> linear loading. I have it on the "test range" and while the SWR is fine
> where I want it, there is no front to back at all. For those curious,
> the
> test involves a dipole about 1500 feet distant, fed with about 2 watts.
> The
> FSVM/receiver measured about -30 dbm. F/S pattern showed 20-25 db. The
> 2el
> 40 is suspended on ropes between 2 tall towers so about 50 feet off the
> ground and well in the clear. The DE tuning as it stands now, has the
> shorting about 10 inches from the end. The other element - I am assuming
> it
> is the reflector - showed no front to back in various positions of the
> shorting strap, including maxed out. Next step may be to insert a few
> feet
> of tubing to extend the REF, but I shouldn't have to go to that length....
> so hence my request for the manual and especially what these dimensions
> are
> indicated to be. Thanks for any help.
>
> 73 Don
> VE6JY
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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