Gary,
I do not know you received my previous mail about your problem.Did you check
the phasing unit bars ?
I got the same problem when installing a OB16-3 at a friends place on
10m.Otherbands where ok but 10m
was fluctuating SWR.One screw of the phasing unit was loose where it contact
the 10m driver.
73
Marc ON4MA
HNY
----- Original Message -----
From: <Gary.Stone@med.va.gov>
To: <towertalk@contesting.com>
Sent: Tuesday, January 10, 2006 3:11 PM
Subject: [TowerTalk] 40 meter problem
> Greetings fellow TT members,
>
>
>
> I may have posted something about this before but I have a situation in
> which I am looking for a creative fix this time. It is my OptiBeam OB17-4
> beam. For about 2 months now the 40 meter portion has an intermittent
> problem. When it hits the SWR spikes to about 2.5 or 3 to 1 and it is
> normally flat. The other bands are not affected. I have it set in the CW
> portion of 40 meters. When it acts up (not very often) I can begin to
> rotate the beam and as soon as it starts to move the problem corrects. I
> have tried to track when and how it happens and can find no definite
> pattern. The 40 meter section has 3 elements. The driven element has
been
> taken down and checked carefully. Tom, the owner of Optibeam suspects it
is
> something loose in the reflector.
>
>
>
> The Optibeam is a 17 element beam and it is on a mast with a Force12
WARC-7
> about 12 feet above the Optibeam. The tower is a Rohn 45G - 80 feet.
(78'
> actual with about another foot or so to the antenna boom).
>
>
>
> I first happened when the temp dropped to 8 degrees F and it does not
happen
> (that I have noticed) when the temp is warmer. That would lead me to
think
> one of the element transition bolts have come loose? An intermittent
> problem is so difficult at times to trace.
>
>
>
> To take the antenna down to the ground and check everything would mean I
> bring in an expensive crane. However, I can get a bucket truck for much
> less money. The antenna weighs 215 lbs and is on a 40 foot boom so I
don't
> want to risk using a bucket truck to bring the antenna to the ground.
> However, the bucket truck (antenna is 80 feet up) could take a person up
to
> the reflector and director to allow work up there. If it is something
> simple like a loose bolt it could be fixed from there. However, if it is
> still not clear I am wondering about a creative fix? What if each joint
> were taped with aluminum tape? I could cut it to about 1 inch strip and
it
> weighs almost nothing. Then if there is some odd temperature related
> movement between any of the transitions that would fix it I would think?
Or
> is this a crazy idea?
>
>
>
> Lastly, is there someone on TT that is comfortable working from a bucket
> truck at the 80 foot level within easy driving distance? I am about 70
> miles North of Dallas, Texas. I can rent a bucket truck that goes to 103
> feet so at 80 feet I would think it is quite stable. I am not physically
> able to do that work myself. So, is taping the elements a crazy fix or a
> reasonable idea?
>
>
>
> The other idea is to get a new radio - a Ten Tec that handles 3 to 1 SWR
> without any problem :-) Anyone have an Orion for a good price?
>
>
>
> Thanks for your input,
>
>
>
> Gary, N5PHT
>
>
>
>
>
> Gary Stone, BA, LCDC
>
> Case Manager, Bonham DSAP
>
> Sam Rayburn Memorial Veterans Center
>
> (903) 583-6411
>
>
>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.371 / Virus Database: 267.14.16/225 - Release Date: 9/01/2006
>
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|