I am also using an MA 550 (non-rotating) with factory standoffs, and have
found that attaching the coax and rotor control cable to an eighth-inch
steel cable with cable ties works well. I haven't had problems with them
catching on the standoffs when raising or lowering the tower, and the cable
takes the stress off of the coax. The biggest problem is the stress on the
coax at the top standoff, which should be distributed over as much of the
coax as possible. Also, wind can cause flexing at that point and fatigue
the coax. I have often thought that encasing it in a piece of heavy-duty
garden hose at the bend point might give added protection.
Ron
N6AHA
>Actually, I just use cable ties to fix the coax to the top standoff, so the
>ties don't travel through the standoff rings. I tape the coax along the
boom
>from the balun to the top standoff, which is fixed just a few inches under
>and to the side of the boom. Where the coax snakes through the top standoff
>ring, I have it attached to both sides of the ring with small black cable
>ties and Scotch 88 (to try to take the strain off the part of the coax held
>by the ties.) This is where a Kellems grip would be much better. From there
>the coax drops through the remaining standoff rings. Note that the tower
>rotates from the bottom, so there is no need for a large rotor loop at the
>top.
>
>> Bob, N6TV, uses a big 'net fish lander' and his cables coil into it
>on
>>the way down and uncoils from it on the way up - very slick and
practically
>>foolproof. The fishing device has a big aluminum round frame with a sock
of
>>fish net and a handle that you hold onto to land a fish (sorry - I'm not a
>>fisherperson).
>
>
>That's a neat idea. It must be a really big net. I've thought about doing
>something like that, but to work properly it would have to be mounted on
the
>tower itself, which would interfere with full rotation (it would hit the
>base vertical member.) Higher up, it would be too close to the motor
housing
>(too great a chance of coax snaking out of the net and wandering over to
the
>motor housing.) Above that, it would be very difficult to reach in the
event
>of a problem.
>
>A friend suggested a method used to dress cables on sailboats: 1) run the
>coax through a large plastic pulley so that the pulley is located about
>halfway up the bottom fixed section; 2) afix one end of a bungee cord to
the
>pulley and the other end to a tree about 30-40 feet away, with the
>attachment point well above the level of the pulley (I just happen to have
a
>tree in the correct positon.) The idea is that when the tower is lowered
the
>bungee cord pulls the pulley towards the tree, which in turn pulls the
>excess coax up and away from the tower. When the tower is fully extended,
>the pulley and coax are pulled back to the tower, the bungee cord
stretching
>to acommodate. Presumably, there would be enough stretch in the cord to
>allow my tower to rotate (not much give would be needed for that.) The
trick
>is to find bungee cord with the correct amount of stretch and tension.
>Someone else suggested that it would be much better to run a rope through a
>pulley on the tree and use some weights. I agree. I haven't tried this
>design because I suspect that the weak link is the large plastic pulley. I
>have a feeling that the coax will not travel smoothly through it. The
design
>needs some way for the coax to move smoothly through the point where the
>rope is attached. Any ideas?
>
>73, Dick, WC1M
>
>
>
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>
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