Monday, August 3, 2015

Building a new antenna at N6QW ~ Part VII

A New Direction

 
Sadly experience can be costly. In my quest to get something up in the air and quickly, I acted in haste when I purchased the Rohn H950. It is probably ideal for holding up a 2 Meter Dipole made from #36 wire but for my application is simply unsuitable if not outright dangerous. I have only myself to blame and take full responsibility.
 
The new direction is to use a bottom mounted rotor assembly ( the Yaesu G450 can do bottom mount) and to rotate the whole mast. I have been in contact with SpiderBeam and it appears their 10M HD product will work for this application. I am still asking a lot of questions before I flash the plastic and thus more cautious about this approach versus my foray with the H950.
 
Yet I have not received a crisp answer from Spiderbeam about running the coax so it does not interfere with the two sets of guy wires and that remains an open item.
 
Thus if any one reading this blog has a Spiderbeam mast I would appreciate hearing from you about your experience and how you installed it.
 
My plan is for a concrete base to which is affixed an elevated rotor base plate that is secured to the concrete base with anchor bolts. It will also have a sleeved house bracket  to provide a bit more rigidity to the whole assembly which consists of a section of PVC pipe that is slightly larger in diameter and is affixed to the eaves of the house.
 
 
So if any reader has info on a SpiderBeam Mast installation please email me with details.
 
 
73's
Pete N6QW

2 comments:

  1. I have no experience with the Spiderbeam products so my thoughts may be worth less than what you paid for them.

    Have you considered running the coax inside the mast? You would need to leave a loop at the bottom to allow for rotation. As each section is pushed up, a helper feeds more coax into the mast. This keeps the coax out of the guys and avoids any twisting of the coax except the the turning loop at the bottom.

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  2. Hi David,

    Thanks for the suggestion. Bill N2COR also suggested that possibility and merits further evaluation. One communication from SipderBeam said I should just tape the coax to the mast leaving a loop at each guy point (two places).

    Well I am having difficulty with that suggestion since the mast rotates and the guy rings remain fixed. It looks like there would be an interference problem. Supposedly there are thousands of these beams and likely a goodly number of their masts in use worldwide -- so there should be some documentation available stating exactly this is how it is done. Perhaps I am making this too complex but the answer just is not obvious and maybe the taped loop at each guy location will work perfectly. My experience with the H950 has left me dubious about any mast installation.

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