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VHF antennas and rotators


#1

All this talk of 2mt SSB has galvanised me into thinking about putting up a better 2mt antenna. However due to being disabled I am very limited in my knowledge of climbing ladders (hi hi) and installing such things, so can I call on your collective experience please?
A bit of background on my qth; I live in a mid terraced council house, I don’t have planning for my colinear, but it has been there nearly 5 years and there have never been any complaints. I did in my early HF days cause some tvi problems with one neighbour but he was very good about it. However I don’t want to attract attention to my activities. My qth is poor for vhf especially to the north as there is a housing estate and a hill in the way, so any horizontal antenna should be an improvement!

I have the antenna waiting in a bag ready to be built. It is a 3 element quad from Sandpiper, and won’t be a problem to construct. My 2mt colinear is atop a 10ft pole on the back of my house. The tip of the antenna just peeks over the height of the roof. My plan has been to add a lightweight rotator to the top of the pole, place the quad on the rotator and above that the colinear.
The rotator will only be a lightweight one with a weight limit of 45kgs. However the quad only weighs about 2kg and the colinear 3kgs.
My questions are, do I need to guy the pole if I put the rotator on top of it? My biggest fear would be the rotator, colinear and quad falling down in high winds. Is this likely? The whole system is protected from the north by the house, so perhaps reducing the wind risk.
Would I be safer putting the quad and rotator in my loft? I know this would reduce its effectiveness but it would still be better than the colinear. Or Sandpiper sell a small omnidirectional halo that does 6/4/2mts. Not as good as the quad but less risky for outside?
I may be able to get a friend to do this, but it is quite an imposition so I want to be clear what I am asking him to do.
Sorry for the long winded post and my ignorance.
All thoughts welcome.
Cheers
Q


#2

In reply to GW3BV:

Wimo (Germany) make an aerial called a “Big Wheel”. This is an omnidirectional aerial and will outperform a halo. They ship to the UK.

http://www.wimo.de/

73

Richard


#3

In reply to GW3BV:

I have serious doubts about the long-term survival of that quad outside, although it looks an attractive proposition: many types of plastic become brittle in sunlight. I would suggest a small yagi, say a 4 or 5 el. This would give many years of service. Even an HB9CV would be useful, though they can be the Devil to tune sometimes!

I operated for several years with a 4 el yagi on a rotator in the loft space. There was bound to be some loss through the tiles but it enabled me to work into the continent in openings.

I don’t think an omnidirectional antenna is a good choice, even if it has significant gain; the advantage of a directional antenna is that you can use the nulls to reduce the annoyance from the occasional overstrong or overmodulated station!

If the pole is reasonably robust you won’t need to guy it, but keep the stub mast on the rotator short to reduce wear on the bearing due to wind rock.

73

Brian G8ADD