Some time ago I wrote to Hygain:

Sir,
Our Ham Radio Club owns 2 Hygain 18-AVT vertical antennas.
We are after 2 sets of black plastic shields which fit between the vertical
alloy tubing and the outer cover of the traps,
Can you supply them to us?

Harry



Hygain wrote back:

Sir,
The only parts available are tubing pieces.
Thanks,
Jim Shurden
Hygain Customer Service

Question is, what can I use as a substitute, I have tried truck wheel
cylinder boots, but the carbon in them upsets the apple cart.

Many thanks
Harry

Harry,
The first thing that comes to mind is an appropriately sized 'heat-
shrink' type tubing. Of course, that assumes that you can find such
an 'appropriate' size and that it will 'shrink' enough. I have no
idea if there is such a size or not.
Another one of those 'off the wall' ideas is to use the stuff
that's used in casting small parts in the R/C model hobby. It's a
'rubber-ish' kind of stuff molded/painted around the part, then pealed
off when cured and used as a mold for a new part. Don't ask me, I
have no idea what it is. No metal content that I'm aware of.
And then, I guess you could always fiberglass it?
- 'Doc

I had that problem with a trap beam. I went to a pipe supply & got some end
covers that are on pipes when they are shipped. Cut a hole in the middle to
fit over the tubing & silicone it on the trap & tubing. Never leaked.
"Harry H" wrote in message
...
Some time ago I wrote to Hygain:

Sir,
Our Ham Radio Club owns 2 Hygain 18-AVT vertical antennas.
We are after 2 sets of black plastic shields which fit between the
vertical alloy tubing and the outer cover of the traps,
Can you supply them to us?

Harry



Hygain wrote back:

Sir,
The only parts available are tubing pieces.
Thanks,
Jim Shurden
Hygain Customer Service

Question is, what can I use as a substitute, I have tried truck wheel
cylinder boots, but the carbon in them upsets the apple cart.

Many thanks
Harry

Howard K0ACF wrote:

I had that problem with a trap beam. I went to a pipe supply & got some end
covers that are on pipes when they are shipped. Cut a hole in the middle to
fit over the tubing & silicone it on the trap & tubing. Never leaked.
"Harry H" wrote in message
...

Some time ago I wrote to Hygain:

Sir,
Our Ham Radio Club owns 2 Hygain 18-AVT vertical antennas.
We are after 2 sets of black plastic shields which fit between the
vertical alloy tubing and the outer cover of the traps,
Can you supply them to us?

Harry



Hygain wrote back:

Sir,
The only parts available are tubing pieces.
Thanks,
Jim Shurden
Hygain Customer Service

Question is, what can I use as a substitute, I have tried truck wheel
cylinder boots, but the carbon in them upsets the apple cart.

Many thanks
Harry




Great idea Harry.

Irv VE6BP

Question is, what can I use as a substitute, I have tried truck wheel
cylinder boots, but the carbon in them upsets the apple cart.

Can you use pieces of suitably-large-diameter heatshrink tubing...
pick a piece comfortably larger in diameter than the innards of the
trap, slide it over, and heat it gently with a hairdryer just
sufficiently to shrink it to the necessary size? The safest size to
use would probably start out at roughly 2x the diameter of the trap
guts... it'd be a snug fit when fully shrunk.

Heatshrink tubing is available in multiple colors... I imagine that
some types of the black variety might have some carbon-black in it,
but it's also available in white and other dyed colors which ought to
have pretty good RF properties.

Otherwise, talk to your local general-purpose professional plastics
supplier, and see what kind of tubing they have in stock.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

"Harry H" wrote in
:

Some time ago I wrote to Hygain:

Sir,
Our Ham Radio Club owns 2 Hygain 18-AVT vertical antennas.
We are after 2 sets of black plastic shields which fit between the
vertical alloy tubing and the outer cover of the traps,
Can you supply them to us?

Harry



Hygain wrote back:

Sir,
The only parts available are tubing pieces.
Thanks,
Jim Shurden
Hygain Customer Service

Question is, what can I use as a substitute, I have tried truck wheel
cylinder boots, but the carbon in them upsets the apple cart.


Harry,

I had a 4BTV that suffered failure of the trap covers, a result of
destructive birds eating them.

I made replacement parts from PVC plumbing fittings, not because Hustler
couldn't supply parts, but there was little point repairing with same
fodder for the birds.

The repair is described at http://www.vk1od.net/H4BTV/hustler4btv.htm .
It might give you some ideas.

BTW, Hustler must have seen the article and sent me gratis a set of
original trap covers, they are still in the shed after twenty years...
the PVC works fine and the birds haven't attacked them (though they seem
to enjoy anthing else with exposed PE or vinyl).

Owen

"Owen Duffy" wrote in message
...
"Harry H" wrote in
:

Some time ago I wrote to Hygain:

Sir,
Our Ham Radio Club owns 2 Hygain 18-AVT vertical antennas.
We are after 2 sets of black plastic shields which fit between the
vertical alloy tubing and the outer cover of the traps,
Can you supply them to us?

Harry



Hygain wrote back:

Sir,
The only parts available are tubing pieces.
Thanks,
Jim Shurden
Hygain Customer Service

Question is, what can I use as a substitute, I have tried truck wheel
cylinder boots, but the carbon in them upsets the apple cart.


Harry,

I had a 4BTV that suffered failure of the trap covers, a result of
destructive birds eating them.

I made replacement parts from PVC plumbing fittings, not because Hustler
couldn't supply parts, but there was little point repairing with same
fodder for the birds.

The repair is described at http://www.vk1od.net/H4BTV/hustler4btv.htm .
It might give you some ideas.

BTW, Hustler must have seen the article and sent me gratis a set of
original trap covers, they are still in the shed after twenty years...
the PVC works fine and the birds haven't attacked them (though they seem
to enjoy anthing else with exposed PE or vinyl).

Owen


Thanks Owen,
I guess it was either the Galahs or the White Cockatoos that did the damage.

I know when I used to sell UHF CB to farmers out west, we used to have
trouble with them chewing on the top of the collinear antenna.

We used to slide some white PVC down over the vertical and anything over 3/4
to 7/8" in dia used to stop them.

It annoys me that Hygain will not supply them and must get a high enquiry
rate for these shields.

I will see if I can find the right diameter and machine them to fit snugly.

Thanks for the heads up on your experience!

Thanks to all those who have offered their advice too.

73
Harry

"Harry H" wrote in
:

....
Thanks Owen,
I guess it was either the Galahs or the White Cockatoos that did the
damage.

Sulphur Crested Cockatoos!

Still, I have sympathy for the ZLs where Keas eat the rubber seals out of
car windows.


I know when I used to sell UHF CB to farmers out west, we used to have
trouble with them chewing on the top of the collinear antenna.

We used to slide some white PVC down over the vertical and anything
over 3/4 to 7/8" in dia used to stop them.

Yes, I have built radomes from white PVC plumbing fittings to protect
antennas, eg MobileOne's 2m end fed which has a balun made from coax
wound around the outside of the antenna... good tucker for birs.

It annoys me that Hygain will not supply them and must get a high
enquiry rate for these shields.

I have had experience with Hy-Gain, and it was very poor... wound up
making the parts myself... http://www.vk1od.net/VB214/index.htm .

Mindful of that, I limit my exposure to products of the MFJ group.


I will see if I can find the right diameter and machine them to fit
snugly.

I am sure you will come up with a working solution, and possibly a better
one.


Owen

Dear Owen:

Experience here in the Upper Midwest is that ground dwelling animals will
chew PVC. but not PE. Had to replace a vast amount of PVC covered cable,
but PE covered coax and cable was untouched.

What have others found? 73, Mac N8TT

--
J. McLaughlin; Michigan, USA
Home:
"Owen Duffy" wrote in message
...


snip

I made replacement parts from PVC plumbing fittings, not because Hustler
couldn't supply parts, but there was little point repairing with same
fodder for the birds.

The repair is described at http://www.vk1od.net/H4BTV/hustler4btv.htm .
It might give you some ideas.

BTW, Hustler must have seen the article and sent me gratis a set of
original trap covers, they are still in the shed after twenty years...
the PVC works fine and the birds haven't attacked them (though they seem
to enjoy anything else with exposed PE or vinyl).

Owen

"J. Mc Laughlin" wrote in
:

Dear Owen:

Experience here in the Upper Midwest is that ground dwelling animals
will chew PVC. but not PE. Had to replace a vast amount of PVC
covered cable, but PE covered coax and cable was untouched.

Hi Mac,

I know that some animals (eg rats) will eat soft PVC. That motivates cable
sheaths impregnated with arsenic... which is worse? We don't have some of
the critters that you have, thankfully.

The other commonly used plastic I didn't mention was polypropylene, and I
think the trap covers may be polyprop... .

All in all, vermin resistance components, and ready availability are
important factors in the life of antennas etc... but we are tame buyers who
generally don't consider that until we need to repair the things.

Owen