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Hi all:

I want to turn a pair of rotatable dipoles into a 2 element beam like the Cushcraft "Big Thunder."

Now of course, you are going to ask,,,"Why don't I just get a "Big Thunder?" And the answer to that is that I live in a trailer park and can't have a cemented tower in the ground.

And the Big Thunder weighs 55lbs. And the pair of rotatable dipoles, 24lbs. So the crank up TV tower I have here should be good enough fora the antenna and a TV rotor..

I'm thinking about putting them on a 24' boom like the Big Thunder. I think I should still get the 7db gain with half the weight...

What do you think?

And ps. I need a couple of Cushcraft rotatable dipoles. Anyone have one, call
218-263-4697

Email kb0uzr@yahoo.com Thanks!

You are going to have issues to overcome that probably make it a bad proposition.
1. By the time you add a boom that will support the 12 lb elements on either end and the associated coax and hardware, you are going to be at the 50 lb range anyway.
2. You won't turn it with a TV rotator. The torque will tear it apart and it will end up spinning like a windmill.
3. You aren't going to able to develop the height necessary for decent performance.
4. How do you propose to feed it? In phase? Out of phase?
5. Are you going to make it function as a phase fed array? A director? A reflector?

My honest opinion? It ain't happening.

Just like the Big Thunder. Both of the elements are fed active. Like paralell dipoles I guess.

Wow! Hardly no one is around here.

UZR: K4KK pretty well answered your question. I think if you are waiting for someone to tell you to go for it, you are going to continue to hold your breath.

There are issues. He posted them. What else were you looking for?

73

Bill, W0LPQ

There are issues. He posted them. What else were you looking for?

73

Bill, W0LPQ

Well, I kinda figured that a bunch of people would jump in and tell what they think.
I guess I'm going to try out just one rotatable dipole and the smallest beam on that crank up tower. And see if I can find a rotor that will handle them fine and fit on the tower.

The small 10-20 beam I want to try is the MA5B. It has a 7' boom and I can't remember the longest element. I can look it up.

What I was thinking of doing was a little overboard. I don't think I would have room to turn it.

I think you have made a good decision. You should enjoy the performance from that limited space/lightweight antenna. I have heard good things about them. Obviously it isn't a multi-element monobander, but it will serve you well. The dipole on 40 will be competitive, also.

Good luck.

Hay,,Thanks for the reply...

What is the Smallest rotor that I could get away with for those 2 antennas?

I would think any of the "bell" rotors would work. Stay away from the "side straddle" type of small TV rotors. Even the 45 should handle it fine, though. A lot depends on overall mounting, too. If you mount it in a tower, you can use less rotor. If you "mast mount" it, you will need more due to the torque from the top swing.

Yah, that makes sense. But,,,

UPDATE, UPDATE

A friend of mine is going to send me his A4S. I didn't even know he had it and is going to trade me that for something he was going to buy from me.

Well,,,I said,,,But that would be too big for my TV tower and I wouldn't be able to turn it with a heavy duty TV rotor.

And He said just get a bigger rotor and guy wire the heck out of it and you'll be fine...

I live in a trailer park, man! And I AM going to put the 40m add on kit on it because I live mostly on 40m.
Well, how am I going to get that thing put up now. And I'm pretty sure that a Ham 2 rotor isn't going to fit in the TV crank up tower.

Anyway, that I'll try it thinking that I'll be able to leave off the front element and boom section will become identicle to the A3S. So I'll see how it works...

Does a 40m add on kit on one of those antennas work just as good as a 40m rotatable dipole??