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[Towertalk] 40-2cd on 30 metres

To: <towertalk@contesting.com>
Subject: [Towertalk] 40-2cd on 30 metres
From: w2up@mindspring.com (Barry )
Date: Fri, 06 Dec 2002 00:30:08 -0000
Speaking from personal experience, the 402CD is a lousy antenna for 
30m. It does work reasonably well on 12 and 17m though.
Barry, W2UP

On 5 Dec 2002 Ken Kinyon - W7TS wrote:

> Does anyone know what the radiation pattern of the 40-2CD looks like when
> used with a tuner on 30?
> If I bought one of the antenna modeling software programs, would I be able
> to plot this?
> regards,
> Ken W7TS
> 
> -------------------
> Kenneth E.  Kinyon
> 34 Princeton Circle
> Longmont, CO 80503-2106
> Voice: (303) 684-0037
> Fax:  (303) 776-5088
> E-mail: W7TS@attbi.com
>         W7TS@qsl.net
>         W7TS@arrl.net
> ALPCA #8339
> ARRL-LM
> -------------------
> 
> -----Original Message-----
> From: towertalk-admin@contesting.com
> [mailto:towertalk-admin@contesting.com]On Behalf Of EUGENE SMAR
> Sent: Thursday, December 05, 2002 16:10
> To: TexasRF@aol.com; stevek@jmr.com; n4gi@tampabay.rr.com
> Cc: towertalk@contesting.com
> Subject: Re: [Towertalk] New Rotator In Place; Mast Now Binds
> 
> 
> TT:
> 
>      To avoid (or minimize the likelihood of) binding with a thrust bearing,
> you might want to look at a self-centering flange mount bearing assembly
> instead.  Last year I purchased one of these monsters from a local bearing
> supply place.  The bearing itself is somehow pressed into place in a cast
> iron flange.  The cross section of the opening in the flange allows the
> bearing to pivot so that minor deviations from coaxial installation of the
> mast in the bearing (up to about 1.5 degrees, I think the specs say) can be
> accommodated.  That is, this type of bearing is more tolerant of slight
> misalignments of the mast/rotator/shelf below it than a strict TB3, TB4 or
> similar.
> 
>      This is the gizmo that I said I relubed last week during an annual
> inspection of the tower.  I used marine grease which is water resistant (It
> takes quite a bit of rubbing with a cloth to remove it from your hands.  The
> grease just laughs at soap and water.)
> 
>      The cast iron base for mine is 6-1/4 inches square and slightly over an
> inch thick.  It's a Fafnir SCJ series flange cartridges; the bearing
> assembly is a GYA-RRB (that's what the spec sheet says.)  I bought it from
> Applied Industrial Technologies (www.appliedindustrial.com ).  Sorry, but
> their spec sheet is faxed and I can't read their model number.
> 
>      The best thing about this device is it was a few $ less than a TB3 -
> around $72 in DC area.  I had to get the model next in size above a nominal
> 2 inch ID.  The 2 inch OD CM mast I bought was too large for the first
> bearing I had.  I shimmed out the small difference with a piece of stainless
> sheet.
> 
>      IMHO, if you're planning on using a Rohn flat top, this would very
> easily fit and work quite well.
> 
> 73 de
> Gene Smar  AD3F
> 
> -----Original Message-----
> From: TexasRF@aol.com <TexasRF@aol.com>
> To: stevek@jmr.com <stevek@jmr.com>; n4gi@tampabay.rr.com
> <n4gi@tampabay.rr.com>
> Cc: towertalk@contesting.com <towertalk@contesting.com>
To: <towertalk@contesting.com>
> Date: Thursday, December 05, 2002 5:26 PM
> Subject: Re: [Towertalk] New Rotator In Place; Mast Now Binds
> 
> 
> >Here is the straight skinny on 25G top sections:
> >
> >Several years ago (ten or more) Rohn redesigned the 25AG2 and 25AG3 top
> >sections to use a 2.25 inch o.d. 14 gauge wall top support tube. After
> >galvanizing these top sections will fit with a 2 inch o.d. mast (also
> >galvanized) and have a clearance of about .050 inch left over.
> >
> >Before the redesign a 1.9 inch o.d. mast would fit ok but a 2 inch o.d.
> mast
> >would bind in the top tube.
> >
> >As a side note, Rohn also redesigned the TB3 thrust bearing to fit the 2
> inch
> >o.d. masts instead of the older 1.9 inch o.d. masts.
> >
> >I just tested a new 2 inch o.d. mast in a 25AG2 top section and the fit is
> >just right for free rotation of the mast. The clearance is close enough
> >though that without shims in a Ham 4 or T2X rotator there will be binding
> of
> >the mast. Also, the associated AS25G rotator plate is not exactly a
> precision
> >built piece of equipment and some "adjustment"  of the mounting ears might
> be
> >required to center the rotator mast clamp with the support tube.
> Aditionally
> >the 25AG2 or 25AG3 top section suport tube can be out of plumb just enough
> to
> >cause binding; they are not exactly precise either. Adjustments of the
> >rotator plate can accomodate all of these errors but some patience might be
> >needed.
> >
> >73 de Gerald Williamson/K5GW/Texas Towers
> >
> >
> >--- StripMime Report -- processed MIME parts ---
> >multipart/alternative
> >  text/plain (text body -- kept)
> >  text/html
> >---
> >_______________________________________________
> >AN Wireless Self Supporting Towers at discounted prices,
> >See http://www.mscomputer.com
> >
> >Wireless Weather Stations now $349.95. Call Toll Free,
> >888-333-9041 for additional information.
> >_______________________________________________
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> 
> _______________________________________________
> AN Wireless Self Supporting Towers at discounted prices,
> See http://www.mscomputer.com
> 
> Wireless Weather Stations now $349.95. Call Toll Free,
> 888-333-9041 for additional information.
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
> 
> 
> _______________________________________________
> AN Wireless Self Supporting Towers at discounted prices, 
> See http://www.mscomputer.com 
> 
> Wireless Weather Stations now $349.95. Call Toll Free, 
> 888-333-9041 for additional information.
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk

--
Barry Kutner, W2UP              Internet: w2up@mindspring.com
Newtown, PA                     Frankford Radio Club
         


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