Some time ago I asked for users comments on the OR 2800 rotator system.
I received about 15 responses and was asked by a number of people to
send them a summary. Here is the result of that survey plus some
additional information as follows:
1. My original posting for reference. A second posting was made assuring
respondents that I would not use their names or call signs. This
resulted in quite a few additional comments.
2. A summary of the comments.
3. Some direct quotations from various individuals.
4. Notes from a conversation with M2.
5. Some thoughts on how to improve the reliability of the reed switch
pulse system.
1." I am curious what experience the TT members have had with this
rotator.
At one time, I believe there were some problems with the pulse counting
direction indicator. I also heard that, at that time, the rotators could
be ordered with a potentiometer installed for driving an external ,
resistance sensing indicator. I have never heard of mechanical problems
with the rotator. Is anyone using it for rotating an 80 m yagi? Is there
a spot in the rotator mechanics such that a potentiometer could be added
later ? Thanks, Dan, N5AR "
2. Results Mechanical Performance: One guy has had trouble with the
output
shaft keyway chewing out. He is in Wisconson and is turning a KT
34/402-CD. I believe he had this problem more than once. He had some
problems, early on, with the direction indicator, but is satisfied now
with its performance after a trip back to M2. I notice in a new ad
in Comm. Quarterly that M2 has switched to a 6 spline shaft output.( I
liked the ad and the cut a way view of the interior of the rotator).
A second note from a W0 was critical of the"bad casting on the rotor"
He was not specific about what he means. I tried twice by e mail to get
him to tell me what he didn't like about the castings but got no
replies. During telecon with M2 I mentioned the comment but not the
name.
They knew instantly who the guy was and said the mounting bolt holes in
the
bottom were stripped by the installer. They repaired the rotator by
installing
Helicoil spring inserts but charged for doing it though the rotator was
in warranty,
A number of favorable comments were received about the mechanical
robustness of the rotator and reports of years of good
performance.Several were turning large stacks or 80m yagis.
Results Electrical Performance: A number of people have had problems
with the indicator system. It appears that the control unit is not the
problem (no complaints). The reed switch has been the source of
trouble. Sometimes the switch contacts were welded shut, presumably by
lightening induced surges. Sometimes the contact was intermittent. Some
people seemed to have gradual accumulated inaccuracy requiring
recalibration now and then. Some felt there might be cross coupling of
motor pulse noise in the cable. Several were using a separate cable for
the reed switch (one mentioned that M2 reccomended RG58 and he was using
that). Another felt his unreliability was due to electrical leakage in
the switch leads and planned to replace the cable. He mentioned his
cable leakage was 10k to 50k ohms for various conductors and that M2
specs call for at least 250k insulation.
3. Some Of The Comments Received:
I Have an M2 2800 rotator in my 89 foot US Tower that has been turning
a pretty
big HF/VHF stack for the past 5 years here in MT with winds I wouldn't
wish on
anyone. It has been a total non-maintenance item which I wish I could
say for the
rest of my equipment.
I do not have the fancy electronic control box, only the basic one.
The bottom line is that I couldn't be much happier and it fits inside
the top
section very nicely to boot!
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Same here. I have an M2 2800 rotator in my 72 foot US Tower turning a
22 sq ft stack. It works just fine and we can get some hellacious
winds up here in the High Sierras!
It's US made, too. If anything goes wrong, I can go beat on Mike after
only about a three hour drive! :)
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Hello ....., I have seen the emails going back and fort about the yaesu
rotors.I had a 1000GSX for a while but the winds here in the High Desert
took care of this toy real quick.
I have the M2 Orion 2800 and this is the king of the rotors!
Also the service is excellent. I had one small problems once and the
owner
him self was on the phone with me and did not hang up till the problem
was
solved. Well worth the money.
------------------------------------------------------------------------------------------
I have a M2 Orion 2800, I agree their service is excellent. My newly
purchased Orion 2800 had a few problems when I first installed it in the
tower, I called M2 on a Saturday and Mike Stahl answered and spent the
better part of the day helping me with the problem. Mike finally
decided it
would be better for me to send the 2800 back to him, I agreed. Instead
of
making me wait to complete my tower project while he checked out the
2800 he
sent me a new one 2nd day UPS and I packed up the original 2800 and sent
it
back to him, Mike picked up shipping charges both ways. Thats service.
The M2 Orion 2800 is turning an X9 at 73' and 16' above it a XM240 for
the last 6 months in Michigan were wind speeds can range up to 75 mph
without any problems.
------------------------------------------------------------------------------------------
Hi Dan,
I have a relatively new 2800 and have had a great deal of difficulty
with it. I first owned an AC unit and it developed indicator
problems. Then we tried a DC unit and it also has developed indicator
problems. I am not yet convinced that the problem is in
the rotor or controller. It seems that the 500 ft. long control line I
am using to sense the pulses that tell the indicator what
direction the rotor is pointing has gotten some water in it. The sensor
in the control box seems very sensitive to any load on the
lines other than the momentary short circuits as the reed relay in the
rotor (they call it a "positioner"). The spec calls for an
impedance >250K ohms. In my case, the impedance has been seen to be as
low as 5-10K ohms. That was no problem when
the cable was used with rotors using a pot-strip for indication, but it
doesn't seem to work with the Orion. We plan to replace
the cable this weekend.
As far as the positioner unit is concerned, it appears to be very
rugged. I am turning a large 40M 3 element array with it. The
antenna weighs 500 lbs. and is not aerodynamically very well balanced.
It tends to want to weather vane, but I have not seen
the antenna move at all since it has been put up. The mast is 3 inches
in diameter at the clamp and seems to seat very well.
In short, I would give the 2800 pretty high marks as far as mechanical
design and construction are concerned. The jury is still
out with regard to the electrical control design. I'm hopeful that the
new cable will make my unit work properly.
I hope that helps you some.
------------------------------------------------------------------------------------------------------------------------------
BTW, the bolt-circle drawing that comes with the rotator is slightly
off. There is some dimension that shows as 1.523, and it should
actually be 1.623. You can derive that if you assume that the four
corner bolts are on a 3 (2??)-inch square, and the other two are on a
circle of the same radius.
I'm not happy with M2 right now. I've sent them 3-4 e-mails, and gotten
nothing back. They may be tango uniform. They owe me bolts for a
3-inch mast, and I need another cable connector (the OR-2800 has a short
pig-tail with a connector on it).
-------------------------------------------------------------------------------------------------
Just finished an 8 hour day on top of the tower removing my 10 year
old T2X and installing a
new Orion 2800.
Before installing the rotor, I wanted to verify the Rohn 25 Rotor
mount had the right size
holes and layout.....All was fine. After removing the T2X and hosting
up the #45 pound rotor
I realized that the bolts were a different size!!! Seems that Rohn
had at least two styles
of Rotor mounts. The one I tested was an oblong hole and a 3/8 inch
bolt just fit through
OK....The one on the tower was drilled in 4 spots with a 1/2 inch
hole.....Ran back down the
tower grabbed the battery drill and drilled them out to 3/8 inch...No
problem.
After a whole lot of mods with a hax saw I was able to get the Orion
2800 mounted. M2'd
says the 2800 will only fit in the short top section of the Rohn 25,
without mods. Mine was
mounted 10 feet down. Cut at your own risk.....
After installing the steel clamps I noticed that I ran out of
threads
on the bolts supplied
with the rotor. Manual says Min size mast is 1.75 Inches....Mine was
2.0 and it wouldn't snug
up.....I installed a few extra washers and seems to be OK...Ill replace
them with Grade 5 all thread next week.
So far it looks REAL good....I need to replace the cable with
heavier gauge wire, and that will be done tomorrow.
Seemed like the T2X would work with lighter
gauge wire than the 2800....Even after the motor wires have been doubled
up.
Will take some time getting used to the digital readout...Sure miss
the Analog pointer on the Hy-Gain control..
-----------------------------------------------------------------------------------------------.
Dan,
I am using one for my small set of VHF arrays:
40 foot vertical stack of 4 2MXP20 on 144
20 foot vertical stack of 4 9 lambda on 432
10 foot stack of 4 22 el on 1296
super looper on 2304
IT has the problem of missing pulses, so that when I put it back to east
at the end of an EME pass, it is about 10 degrees east of where it
should
be.
M2 tells me this can be fixed with a new reed relay, but I will have to
take the rotor down off the tower to do it right. Needless to say, this
will
at least wait until spring.
------------------------------------------------------------------------------------
Discussion: After reading all the comments, I decided to go ahead and
order one of the units from Texas Towers.
I have now received my OR2800DC and hooked it up in my shack with a
short cable to familiarize myself with the programming and operation.
The indicator seems to be accurate and repeatable.I notice that when
turning ccw it runs smoothly with a bit of a growl from the gears. About
what I would expect from a gear box not filled with oil. However, when
turning cw there is a triple bump-de-bump sound 30 times per 360 degrees
of rotation. I cannot think of any rational reason for this except
possibly a bad gear tooth or something in the gear train hitting
something else. None of my e mail comments mentioned such a thing.
I am ready to install the rotator during a lull in the wx here but am
hesitant to do so. I talked to M2 and it looks like I will have to send
it in.
4. Conversation With Wyatt at M2. There are about 350 rotators in use.
About 35 have been sent in for repair. It is possible to install a 5k
360 deg. pot in the unit. There is a place for one and it can be done by
installing
several plastic drive gears.
They are always looking for better ways to generate the pulses and have
looked at a reflective IR sensor. I mentioned that the W.W.Granger
catalog
shows somesmall Hall effect sensors which might be usable. Any of these
might be
as vulnerableas reed switches to electrical surge pickup though.
I have heard that the control unit of the OR 2800 has been used with
prop pitchmotors. He confirmed that this is true but it is necessary to
install a
larger power xfmrand a larger power FET in the control unit. (One of my
replies was from
a friend in Texaswho is using a prop pitch motor with one of the M2
controllers).
5. Reed Switch Comments: I have a friend in Dallas who works for a
companythat builds custom testers for pc boards and components. These
machines
are in the $100k up category. I know that they built a machine for a
reed switch manufacturer in Oklahoma to test their products. I was
curious to find out what he knew about reed switch modes of failure and
expected life. I was concerned about the number of cycles and the speed
of operation for the reed switches in the 2800. I learned several things
during a phone call to him.
1. He felt that the speed at which the switches operate and the
number of operations per 360 degree rotation (3960) were probably not
the causefor failures.
2. He said that some switches are vacuum filled and some are filled
with inert gas. The latter can handle more current and can usually be
distinguished by a greenish color glass.
3. The lifetimes are millions of operation and should not be a
problem.
4. Near the end of life, contact bouncing can occur.
5. We both feel that the most likely reason for failure is pickup of
external field induced energy. I asked about using shielded twisted pair
to minimize this. The twisted pair sounded good to him but he suggested
being careful to avoid reactive elements like inductance and
capacitance. which can provide energy to the contacts much greater than
the internal current limited emf source. It would seem that a coaxial
cable would be a bad idea because the pickup along the shield is not
balanced by an opposite emf on the center conductor.
I have tried simulating cable leakage by shunting the reed switch leads
with 4700 ohms. The switch pulses are then about 9 V as I recall and
everything works fine. I plan to put a resistor in
series with the switch at the rotator end of the cable to limit the
current that can flow thru the contacts due to lightening induced surges
or even the charge stored in the capacitance between cable conductors.
I am also considering a 12 V zener at the tower rotator connector
location. Both parts could be in a small external box on the tower at
the rotator for
retrofitting, easily replacable. I am considering shielded twisted pair
with these components installed. I have asked M2 for comments.
I believe this would go a long way to improve the reliability of the
indicator system.
I also plan to install a set of surge arrestors on all 4 of the rotator
leads at the tower base.
73, Dan, N5AR
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