Billy:
I've got more work to do on the short tower and am waiting on the VHF/UHF
antennas. I haven't been able to get the tower base in with all the rain
we've had. Don is scheduled to come out in November but I understand he's
behind too. If I can get more days in sunlight, I should make some progress.
I'll let you know and take lots of pictures ! :)
73, Jamie
WB4YDL
-----Original Message-----
From: Billy Cox [mailto:aa4nu@ix.netcom.com]
Sent: Monday, October 19, 2009 5:33 PM
To: James C. Hall,MD
Subject: RE: [TowerTalk] Trimming F12 240/340N elements
OK, with the same physical setup,
add in some more coax, say about
another 50' or so ... and see if
the measurements change any?
Is the short tower done now?
73/bc/NU
-----Original Message-----
>From: "James C. Hall, MD" <heartd0c@nwtcc.com>
>Sent: Oct 19, 2009 6:27 PM
>To: 'Billy Cox' <aa4nu@ix.netcom.com>
>Subject: RE: [TowerTalk] Trimming F12 240/340N elements
>
>Hi Billy:
>
>Thanks for chiming in ! :) I believe it is a 50 foot run of RG8X. I can get
>the element higher, but only to about 40 feet. I'll definitely add guying
!!
>
>Billy, this is part of the new MAG we talked about.
>
>73, Jamie
>WB4YDL
>
>-----Original Message-----
>From: Billy Cox [mailto:aa4nu@ix.netcom.com]
>Sent: Monday, October 19, 2009 5:23 PM
>To: James C. Hall,MD
>Subject: Re: [TowerTalk] Trimming F12 240/340N elements
>
>What length of coax are you
>using between the feedpoint
>and the meter on the ground?
>
>That might be part of it ...
>
>73/bc/NU
>
>-----Original Message-----
>>From: "James C. Hall, MD" <heartd0c@nwtcc.com>
>>Sent: Oct 19, 2009 5:53 PM
>>To: towertalk@contesting.com
>>Subject: [TowerTalk] Trimming F12 240/340N elements
>>
>>Hello TT:
>>
>>
>>
>>Does anyone here have experience with trimming the element lengths of the
>>driver and/or director of the F12 240/340N ? I have the 3 element version
>>and each element starts out the same length as the reflector with tips of
>>38.5". With coax and balun attached, I am to raise each element as a
dipole
>>and trim the driver and director to the correct frequency. I first started
>>with the reflector to verify that the frequency of 6.90 MHz was correct.
>>After mounting on a push up mast and raising to a height of 20 feet or so,
>>my meter indicates a dip in SWR at 7.017 MHz - 117 kHz higher than
>expected.
>>It would seem that the reflector is about 6" too short on each end.
>>
>>
>>
>>The instruction manual states that the element will shift upward in
>>frequency about 15 kHz between 15' and 30'. Below this height there is too
>>much ground coupling. I see the indicated 6.90 MHz at only 7' above
ground.
>>
>>
>>
>>Again does anyone have information on this process ?
>>
>>
>>
>>73, Jamie
>>
>>WB4YDL
>>
>>
>>
>>
>>
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>
>
>
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