Log Periodic 'singing' in the wind...need to suppress
 

My Tennadyne T12 'sings' in the wind, and it can be annoying. I think it's
due to the ends of the elements being open, and they act like little organ
pipes, creating a rather mournful sound.

I would not care about this, but unfortunately my neighbors can hear it,
they say it does not bother them, but I think it would be a good idea if I
could suppress this sound.

The ends of the elements are likely open so that they will drain any water
than might get in, but I don't think it would be wise to cap them.

All that would seem to be needed was some material which could be placed in
the ends, which would allow water to pass through, but be sufficient to
suppress the organ pipe effect.

Any solution to this?

Ron, N5IN

Ron wrote:
My Tennadyne T12 'sings' in the wind, and it can be annoying. I think it's
due to the ends of the elements being open, and they act like little organ
pipes, creating a rather mournful sound.

Gives a whole new meaning to the concept of tuning your antenna.

Any solution to this?

My suggestion is tune it to whistle "Dixie".
--
73, Cecil http://www.qsl.net/w5dxp



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"Ron" wrote in message
...
My Tennadyne T12 'sings' in the wind, and it can be annoying. I think
it's
due to the ends of the elements being open, and they act like little organ
pipes, creating a rather mournful sound.

I would not care about this, but unfortunately my neighbors can hear it,
they say it does not bother them, but I think it would be a good idea if I
could suppress this sound.

The ends of the elements are likely open so that they will drain any water
than might get in, but I don't think it would be wise to cap them.

All that would seem to be needed was some material which could be placed
in
the ends, which would allow water to pass through, but be sufficient to
suppress the organ pipe effect.

Any solution to this?

Ron, N5IN




Maybe sticking some pieces if Bath sponge in there will stop the air
getting in but allow water to seep out.

One solution (I have seen work) is to squirt 'Great Stuff' into a foot or so of
the open end, and let it form around a skewer. After it dries, pull the skewer
out for the drip hole.

Great Stuff (comes in a can) is a foam insulation, much like styrofoam, used to
seal window joints, and so on. It is transparent to RF below about 3 GHz

When you squirt it in it hardens up and suppress the driven oscillations.Bummer
that you have to pull down the antenna though...

Also, some folks use nylon rope in the elements as a damper. Perhaps someone
who has succeeded with that will respond.

Best of luck on this or other solutions.

73,
Chip N1IR

You can also use fiberglass mesh (the stuff screens on screen doors use),
which can be bought by the foot at most hardware stores. Just wad some up,
stuff it in the end. Stops the wind from whistling through it but is plenty
porous enough to let water run out.

Stuff a wad of fiberglass insulation in each one? But if you make the
plug too long and it gets wet, it will add some weight to the ends of
the elements. Foam in insulation around a small tube instead of a
rod, so you don't have to withdraw the rod? (That "Great Stuff"
polyurethane foam is really sticky!)

If it's really an organ-pipe or whistle effect, that should do it. If
the mode is a bending of the elements, you need some different damping
for that. I know a company that specializes in vibration damping in
all sorts of situations that could undoubtedly help you--for a price.
But if you think about the modes, you can probably take care of it
with something like Nylon twine between the elements at the right
points. Expect to have to replace it occasionally because of UV
exposure, or use UV-stabilized line.

Cheers,
Tom


(Fractenna) wrote in message ...
One solution (I have seen work) is to squirt 'Great Stuff' into a foot or so of
the open end, and let it form around a skewer. After it dries, pull the skewer
out for the drip hole.

Great Stuff (comes in a can) is a foam insulation, much like styrofoam, used to
seal window joints, and so on. It is transparent to RF below about 3 GHz

When you squirt it in it hardens up and suppress the driven oscillations.Bummer
that you have to pull down the antenna though...

Also, some folks use nylon rope in the elements as a damper. Perhaps someone
who has succeeded with that will respond.

Best of luck on this or other solutions.

73,
Chip N1IR

On 21 Oct 2003 02:19:28 GMT, Dick Carroll
wrote:

Ron wrote:

My Tennadyne T12 'sings' in the wind, and it can be annoying. I think it's
due to the ends of the elements being open, and they act like little organ
pipes, creating a rather mournful sound.

I would not care about this, but unfortunately my neighbors can hear it,
they say it does not bother them, but I think it would be a good idea if I
could suppress this sound.

The ends of the elements are likely open so that they will drain any water
than might get in, but I don't think it would be wise to cap them.



Ron:

I have a T-10 up in the wind at 75' and have not had this problem, but
do not doubt your situation.Have you tried contacting Chuck at
Tennadyne (http://www.tennadyne.com/)? He has always been extremely
helpful with tech support issues; maybe they have run into this before
and/or have hardware to help you resolve.
Good luck
73
Dan (K0DAN)

Two suggestions: Cap the elements or glue a piece of clothes line inside the
elements. Both work.

Phil, KB2HQ

"dt" wrote in message
...
On 21 Oct 2003 02:19:28 GMT, Dick Carroll
wrote:

Ron wrote:

My Tennadyne T12 'sings' in the wind, and it can be annoying. I think
it's
due to the ends of the elements being open, and they act like little
organ
pipes, creating a rather mournful sound.

I would not care about this, but unfortunately my neighbors can hear
it,
they say it does not bother them, but I think it would be a good idea
if I
could suppress this sound.

The ends of the elements are likely open so that they will drain any
water
than might get in, but I don't think it would be wise to cap them.



Ron:

I have a T-10 up in the wind at 75' and have not had this problem, but
do not doubt your situation.Have you tried contacting Chuck at
Tennadyne (http://www.tennadyne.com/)? He has always been extremely
helpful with tech support issues; maybe they have run into this before
and/or have hardware to help you resolve.
Good luck
73
Dan (K0DAN)