[TowerTalk] shorty forty

[Pete Smith]

Well, this is a little categorical, I think, even though I would agree on 
the XM-240 as the better choice.  It's a lot "straighter-forward" than the 
F12.  The problem is that the EF-240X and EF-240S each consist of two 
identical elements.  The only difference between them is the position of 
the shorting bars, and just setting them to cookbook dimensions doesn't 
work well because there are too many possible physical variations (tension 
of loading wires, attachment of shorting bars, etc.).  That means that it 
is entirely possible to wind up with no F/B or even a reverse situation 
(been there, done that).  You really need to tune these antennas in real 
time using a signal source a few hundred feet away, adjusting the shorting 
bars on the reflector to bring the F/B peak to the frequency where you want it.

On the other hand, either the X or S versions are a lot lighter and easier 
to handle on the tower than the XM-240.  My "S" works quite well, now that 
I have it tuned, and there's no reason the "X", once tuned, shouldn't be 
close to the XM-240 in performance.

I was just visiting a friend yesterday who is putting up a new XM-240.  He 
had a lot to say about lousy quality control and errors in the 
instructions, but the basic antenna should be a fine performer, since it is 
electrically almost identical to the 40-2CD, though mechanically much 
superior, and cookbook dimensions do seem to work fine.

73, Pete N4ZR

At 08:23 AM 11/12/2004, Bill wrote:

>This is an absolute no brainer. I have had both and you should run, not
>walk, to the Cushcraft. The EF240X is a not an option. I was warned about
>the EF240 and I didn't listen, so I feel duty bound to do the same for you.
>
>This is the only F12 antenna that has not been first rate at my QTH.
>
>No tuning required on the XM240, just following the construction
>instructions and put it up.
>
>Bill, W5VX
>
> >-----Original Message-----
> >From: towertalk-bounces at contesting.com [mailto:towertalk-
> >bounces at contesting.com] On Behalf Of gary
> >Sent: Thursday, November 11, 2004 11:31 PM
> >To: towertalk at contesting.com
> >Subject: [TowerTalk] shorty forty
> >
> >Trying to decide between a F12 ef240x or C/C xm240 40 mtr yagi.
> >It will be on it's own tower so interaction is a non issue. Turning radius
> >is a problem so anything larger can not be installed.
> >Is tuning the xm240 straight forward ?
> >
> >thanks           Gary   VA7YO
> >_______________________________________________
> >
> >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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>
>_______________________________________________
>
>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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