[TowerTalk] Yaesu Rotors

Jim Reid jreid@aloha.net
Sat, 22 Nov 1997 14:56:08 -1000

At 07:20 PM 11/22/97, you wrote:
>Are the mounting holes in a Yaesu rotor the same as the ones in a Hygain
>Tailtwister or Ham IV, or do you have to drill new ones in the rotor plate?

Aloha,  No,  they are not the same.  The Yaesu uses 90 mm
hole diameters on a circle of a diameter of 119 mm,  of
all the crazy dimensions!!  We estimated the center of the
old Tailtwister pattern,  then used that to scribe a circle
of radius 59 1/2 mm,  at least as close as we could set the
scribe compass.  Then the 90 mm holes are at 90 degree
angles to each other.  You will have to set them offset,
sort of between the Tailtwister mounting holes in the
same plate.  Once you think you have them centered,
check to see if the holes are about exactly 84 mm
apart on a chord of the circle you scribed.  It
is tough to work in tiny mm and get good accuracy,
unless you have a good shop set up.  Anyway, we had to
drill out the mounting holes oversize by a fair amount
to, at last,  get the four Yaesu bolts through to the
mounting holes in the base of the rotor,  but thats
ok,  as the lock washers are large and will hold things
together just fine.  Don't overtighten the bolts,  you
can crack the rotor base!!

Have fun,

73,  Jim, KH7M
On the Garden Island of Kauai

FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search