[Antennas] Mast design equations & rules of thumb?

Thu, 4 Mar 2004 22:22:23 -0600

This sounds similar to the HyGain 14AVQ. You might check with HyGain;
they probably will sell you the section separately. I recently bought
some of the top sections to repair my 14AVQ.
Dave W9LYA
What wrought doG hath?
On 2004年3月04日 21:24:33 -0500 Don Havlicek <[email protected]>
writes:
> John,
> Back in the late 70's, Dentron marketed a 40m vertical 1/4-wave whip 
>> antenna that had a very good, insulated mount and a fairly 
> heavy-walled 
> bottom section.
> The mount was shaped like this : ] with a hole in the top flange, 
>> through which the vertical passed, insulated by plastic tubing 
> [might 
> even be PVC, not sure].
> They mount on a pipe driven in the ground, and have SO-239 connector 
> at 
> the base.
> It would be easy to fabricate a 'fold-over' connection at the base 
> by 
> paralleling another flat plate that would be mounted to the 
> ground-driven pipe and connected with spacers, which could be 
> connected 
> by bolts/lockwashers/nuts .. then, you could simply remove all but 
> one 
> of those bolts to allow the antenna to fold down.
> I have five of them [none for sale].
> Don
> N8DE
>>> JAKidz wrote:
> > Greetings:
> > I'd like to build a tip up, free-standing 1/4 wave 40m 
> vertical,
> > base at 11 feet, out of small town available materials (e.g., 
> chain link
> > fence rail, electrical conduit, water pipe). No guys (small lot 
> with a
> > bunch of house stuff in the way) so support has to be close to the 
> base.
> > Due to CC&R's, I have to tip it up for use and down the rest of 
> the time
> > so wind loading would be moderate at most. What diameter and wall
> > thickness does the base need to be to withstand repeated bending 
> from
> > being pushed up but not overkill? Only one old guy is the pushup 
> force
> > so it can't be 34 feet of 3 inch water pipe on top of the 11 foot 
> base.
> > I'm guessing that for less weight but adequate rigidity, it is 
> best to
> > have reduced cross-sections with height but how many and how long 
> for
> > each is optimum? I figure a Radio Shack steel CB whip can top it 
> off.
> > Any good thumb rules or design equations for such things? As fence 
> rails
> > and metal electrical conduit come in a variety of wall 
> thicknesses, I'd
> > like to run the numbers for some confidence that the thing isn't 
> like to
> > make a big dent in my noggin or my roof.
> > 
> > Thanks and 73,
> > John, K7JG.
> > 
> > - - - 
> > 
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> > Larry Wilson KE1HZ [email protected]
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