[TowerTalk] M2 OR-2800DC summary
George Fremin III - K5TR
geoiii@kkn.net
Wed, 26 Jul 2000 10:20:43 -0700
Here is the summary of the answers to my question about how
well an M2 OR-2800DC would work turning a fullsized
3 Element 40m yagi on a 46'+ boom.
----
Someone K7LXC? mentioned mast clamps loosening... I have the 2800
clamps on my prop-pitch and they've not loosened that I've noticed.
Of course I haven't checked them since the p-p was installed several
years ago. But no slippage noticed. M2 sent nylon locking nuts for
the 6 mast clamp bolts so I can't imagine them getting loose.
I use the 2800 programmable controller on my p-p. Works fb. Use RG58
for the pulse switch feed to prevent "crosstalk" reported by some I've
heard. None here with the coax feed.
--------------
was using an M2 rotor to turn his 3el DX Engr. full size 40 for
several years before his move to a new QTH last fall. It replaced an
HDR300 which would not hold the antenna in any kind of wind. The M2
held it in place with no problem and turned it without difficulty
except in high winds. His M2 is several years old, not the lastest
model which has a number of upgrades, including more turning torque if
I remember right. The rotor is going back up at his new Qth but will
be used on one of his other stacks because he is going with 3 over 3
on 40 this time (I'm excited!!)
I also have a new OR2800 which replaced an HDR300. It is turning 100'
of 45G with three TH6's. Works great here but of course three TH6's do
not represent anywhere near the windload of a 3el fullsize 40.
---------------------
FWIW, the OR-2800DC controller is a pleasure to use. It has a preset
mode which allows you to toggle back and forth thru a half dozen
preset bearings using two front panel arrow keys. As soon as you hit
the preset you want you just leave it alone, and the controller does
the rest. No brake to fuss with (the OR-2800 uses a worm gear).
Don't know about the mast clamp. Ours has been up for a couple of
months now and I haven't had a chance to get back up the tower to
check all the hardware for tightness - next weekend perhaps. Checkout
out
----------------------
This and a prop pitch are the only two rotators that I'm familiar
with that +will do the job. (No, I don't have any direct or even
anecdotal info on the +Prosistel Big Boys yet.)
The biggest problem I've had personally is having the mast clamp
come loose. +This has been on 6 out of 6 of them that I've
installed. My cure is to double +nut them - that seems to take care of
it.
Service life seems good and I don't know of any consistant
problems/design +flaws like most all other rotators have (sticking
brake, weak mast clamp, +etc.).
For a little bit more money you can get a prop pitch with the M2
control box +and mast clamp. This set-up will remove any concerns you
might have.
-------
I have only one firsthand experience with this rotator. It was used to
turn the 80 Meter Capyagi. Since, I did the mechanical design for the
antenna I know that it was as torque neutral as possible, and was
within 20% of the lightest solution for a 120 Mph antenna. The only
torque it generated was created by the offset between the boom and
mast, which was the least possible for the connection.
The subject rotator usually turned the antenna no problem, but the
weak link became evident after a few storms. The mast/rotator clamp
was unable to hold the antenna. Rod reported the rotator turning, but
the antenna not moving during several high wind events. I witnessed
the same thing with another rotator on a full size 2 El 80 at N6ND's
years ago during CQWW, it was pointed into an 80 mph wind and couldn't
be turned until the wind cycled down to some magic speed (like ~50),
then it went out of control to a position 90 degrees from the last
one. You probably know the drill, run out there with a flash light and
see where it is pointing in the middle of a run....
This was an installation on a hill and subjected to regular high
winds. The tower and antenna survived 100+ mph winds many times, the
only problem was the clamp. Pinning the mast to the clamp voids the
warranty so....you might just end up living with it.
If it was mine to do, I'd only use a prop pitch with a bullet proof
mast connection. You can get one from K6NA.
I don't know anything about the Big Boys, except that the mast
attachment hardware I saw at Dayton in '99 was a complete joke! They
claim to have improved it. I'll leave that decision up to you.
OR2800 might just work fine for you, its weak link is the mast clamp.
Have fun being BIG on 40...
----------------------------
On Fri, 21 Jul 2000, George Fremin III - K5TR wrote: I am looking for
> real world input on the M2 OC-2800DC. I need to turn a fullsize 3
> ele 40 meter yagi. With this rotator work?
Yup. Spins my full size DX Engineering 3 element 40M beam like a
top. A ton better than the MixMaster rotating device I put up because
I didn't know any better.
> > Any problems with it etc....?
Just getting it to fit in a crank-up...but a quick trip to my
friendly machine shop...or a discussion with the guys at M2 before the
rotator is sent to you would've taken care of that little detail. The
rotator body fits just fine..but the heavy plate interface between the
rotator and the mast clamp is too big for my US Tower top section
without a bit of trimming.
-------------
This is what we used at N0NI for a full size 3 el 40. Worked fine
most of the time untill the wind hit 40 MPH.
-----------------------
I have a small stack ( 4ele 20m and 4 ele 15m) I'm turning with the M2
OC-2800DC - so no real help here.
I am also looking at a full sized 3 ele 40m, and considering turning
it with the M2 Rotator, M2 says no problem, but real world info is
whats needed :) Please let me know if you hear anything useful.
Matt, KC1XX, has installed several of M2's full sized 3 ele according
to M2, but not sure if any were with their rotator - you might contact
him.
I can say M2 is quite good on service - I burnt out my rotator and
control box (lightning hit, I think), and they are sending me a
replacement right away. Its under warranty, although I couldn't find
any receipt/documentation/etc.
---------------------------
> > For WIW, I think its an overkill..
> > I searched long and hard for a rotator for my M2-3L40.
> > I finally bought an hy-gain tailtwister and saved
> > several hundred bucks.....
> How long have you been using this rotator?
> Is this a fullsized 40m yagi? > 70 foot elements?
> What boom length?
Boom length=30'
Elements =46'
Been using rotator for about a yr
------------------------------
--
George Fremin III
Johnson City, Texas "Experiment trumps theory."
K5TR (ex.WB5VZL) -- Dave Leeson W6NL
geoiii@kkn.net
830-868-2510
http://www.kkn.net/~k5tr
--
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