Joe,
Hate to differ with you, but the Ham IV lower mast clamps will fit the
AB-577 adapter. I have three AB-557s: a 75-footer with a Tailtwister and two
50-footers with Ham IVs. Both rotor models use exactly the same lower mast
clamps, which I got from Norm's Rotor Service. Norm's part number is 51467,
which matches the Hy-Gain number.
I can think of two possibilities for the discrepancy: 1) You're thinking of
the smaller Hy-Gain rotors (Ham-M, Ham-2, etc.), or 2) There's more than one
adapter size for the AB-577. The latter suggested itself when I read K3BZ's
post that said the mast adapter is 2.75" OD. My three adapters are only
2.35" in diameter (I have a spare adapter in the garage and just measured
it.) I'm a bit skeptical of theory #2, as my adapters exactly match the
pictures in the Army installation manual.
A note of caution: if you use a Tailtwister or Ham IV with lower mast
clamps, apply thread lock on the rotor-to-clamp bolts and on the clamp
u-bolts. I didn't do that initially and found one of my Ham IV's rocking in
the wind! Tighten those bolts down good, but don't strip 'em. Also, be
advised that the rotor capacity is derated 50% when mast mounted.
[For those who are interested, the Tailtwister turns a 4-el SteppIR. Yes, I
know that's the absolute max load for the tower, but the guy anchors are in
real solid and haven't moved a bit in years. That AB-577 used to have a
40-2CD turned by an HD-73 (!) One of the Ham IVs turns a Force12 C3E and the
other turns a Force 12 5-el 15m monobander.]
73, Dick WC1M
> -----Original Message-----
> From: Joe Subich, K4IK [mailto:k4ik@subich.com]
> Sent: Monday, May 30, 2005 9:17 PM
> To: 'Dana Roode'; towertalk@contesting.com
> Subject: Re: [TowerTalk] Rotor on AB577
>
>
>
>
> > I have a AB577 mast and I need to put a rotor on it - if
> someone out
> > there has done this and would like to share your approach with me,
> > please drop me a line. I built an adaptor I am not completely
> > satisfied with out of the top piece I got for the 577. Does anyone
> > know if other top pieces for the mast are available somewhere? For
> > example, a mast adaptor to take the 5" diameter mast down to 2"?
>
> The lower mast adapter for a Tailtwister (P/N -10) will fit the
> AB-577 antenna adapter (stock number 5820-00-973-0200) just fine.
> Unfortunately, the lower mast adapter for the Ham-IV (etc.) series
> is just slightly small.
>
> 73,
>
> ... Joe, K4IK
>
>
>
>
_______________________________________________
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.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|