Screw-on telescopic antenna with loose base?
 

I am using screw-on telescopic antennas for my doppler rig.

These have four dimples at the base securing the tube to the base.

After a while, the tube comes loose from the base and the antenna will
no longer screw off or on because the tube turns freely about the
base.

I have tried using a pointed punch to increase the dimples, to no
avail.

They are $5 apiece from Mouser, so if possible, I would like to
salvage them. I seem to get around eight on-off cycles per antenna. I
am tightenting them only by hand.

It is possible that some of the loosening is cause by the bending
force of the 55 mph wind on a 19" whip.

Any suggestions?

Ken KC2JDY

Screw-on telescopic antenna with loose base?
 

"Ken C" wrote in message
...
I am using screw-on telescopic antennas for my doppler rig.

These have four dimples at the base securing the tube to the base.

After a while, the tube comes loose from the base and the antenna will
no longer screw off or on because the tube turns freely about the
base.

snip

Any suggestions?

Ken KC2JDY

Hi, Ken,

Maybe you could try a product called "Gorilla Glue." I have been using
it successfully for bonding metal-to-metal (among other combinations) for
about six months. It is unique among my various adhesives in that it
expands about 50 percent while curing. Thus you get a dual effect -- some
adhesion and some physical jamming.

The excess can be trimmed with a very sharp knife or maybe a pick. Good
luck.

"Sal"
(KD6VKW)

Screw-on telescopic antenna with loose base?
 

Sal M. Onella wrote:

Ken C wrote:
I am using screw-on telescopic antennas for my doppler rig.

These have four dimples at the base securing the tube to the base.

After a while, the tube comes loose from the base and the antenna will
no longer screw off or on because the tube turns freely about the
base.

snip

Any suggestions?

Ken KC2JDY

Hi, Ken,

Maybe you could try a product called "Gorilla Glue." I have been
using
it successfully for bonding metal-to-metal (among other combinations) for
about six months. It is unique among my various adhesives in that it
expands about 50 percent while curing. Thus you get a dual effect -- some
adhesion and some physical jamming.

The excess can be trimmed with a very sharp knife or maybe a pick. Good
luck.

"Sal"
(KD6VKW)


Gorilla Glue is a brand name -- Borden has their version. The generic name
is polyurethane adhesive. It reacts with moisture to cure. Hardware stores
& home improvement stores carry it.
73,
Bryan WA7PRC

Screw-on telescopic antenna with loose base?
 

On Tue, 29 May 2007 20:37:59 -0700, "Sal M. Onella"
wrote:
Maybe you could try a product called "Gorilla Glue."

The RF current flows into the base and from there into the tube. I
don't think putting an insulator between them is a viable solution.

I have thought about some conducting epoxy, thinned a bit so it seeps
in, but I am not even confident about that.

Ken KC2JDY

Screw-on telescopic antenna with loose base?
 

On May 30, 11:42 am, Ken C wrote:
On Tue, 29 May 2007 20:37:59 -0700, "Sal M. Onella"

wrote:
Maybe you could try a product called "Gorilla Glue."

The RF current flows into the base and from there into the tube. I
don't think putting an insulator between them is a viable solution.

I have thought about some conducting epoxy, thinned a bit so it seeps
in, but I am not even confident about that.

Ken KC2JDY

if the base is big enough in thickness, how about making a small hole
thru and thru the bottom of the whip and the base then pinning it with
a piece of wire run through both? If you were to sand off the plating
at the bottom of the whip, you will most likely find it is brass or
some other alloy. A thin piece of brass or copper wire, or a thin
brass screw would then take to solder along with the whip where the
plating is ground away. This would hold the bottom and the whip fairly
well together.

Screw-on telescopic antenna with loose base?
 

On Thu, 31 May 2007 21:57:31 -0700, KEYCLOWN AUCTION RATOUT CENTRAL
wrote:

if the base is big enough in thickness, how about making a small hole
thru and thru the bottom of the whip and the base then pinning it with
a piece of wire run through both? If you were to sand off the plating
at the bottom of the whip, you will most likely find it is brass or
some other alloy. A thin piece of brass or copper wire, or a thin
brass screw would then take to solder along with the whip where the
plating is ground away. This would hold the bottom and the whip fairly
well together.

Right you are!

Previous attempts to heat the base and flow in solder failed, so I
assumed it was steel.

Turns out to be nickel-plated brass:
http://www.mouser.com/catalog/specsheets/114269.pdf

So, I should be able to drill a small hole and solder in a small
copper or brass pin. Or grind a small crater and let some solder flow
in.

Ken KC2JDY

Screw-on telescopic antenna with loose base?
 

"Ken C" wrote in message
...
I am using screw-on telescopic antennas for my doppler rig.

These have four dimples at the base securing the tube to the base.

After a while, the tube comes loose from the base and the antenna will
no longer screw off or on because the tube turns freely about the
base.

I have tried using a pointed punch to increase the dimples, to no
avail.

They are $5 apiece from Mouser, so if possible, I would like to
salvage them. I seem to get around eight on-off cycles per antenna. I
am tightenting them only by hand.

It is possible that some of the loosening is cause by the bending
force of the 55 mph wind on a 19" whip.

Any suggestions?

Ken KC2JDY

Hi Ken

I wonder if you could increase the life by forcing a sleave over the tube
where the dimples are. Actually, I thought of a small clamp around the
tube where the dimples are, but I suspect the tube is rather small diameter.
Besides, I'm not sure I am understanding the problem properly.

Jerry