cushcraft A3S Tribander HF beam

[les]

Just bought a secondhand A3S 3 element HF beam (bought it really cheap but
its as well!) The fibreglass isolator is cracked so managed to get a new
isolator.
What suprises me is that the isolator is made of fiberglass tube rather than
being solid especially as it must take quite a bashing in gales.
Question to owners of this or other beam with a similar isolator:
Anyone replaced it with stronger material and if so can you send me info
(taking out the spam trap in the email address)
Thanks in advance.

['Doc]

Les,
Hygain uses the same insulator for several of their
antennas, and it can be a problem with all of them.
Replacing it with a 'solid' insulator of some kind is
one solution. I'm still hunting for a replacement for
one for an 'R-7' (the only difference is in the length).
Thought about using 'Delrin'(sp) or some other type of
plexiglas/perspex, but haven't found a source yet.
Good luck...
'Doc

[Edward Lewis]

On Sun, 25 Apr 2004 07:58:12 -0500, 'Doc <***@cwis.net> wrote:
The center insulator that comes with the A744 40 meter kit for the A3S
is stronger than the insulator that comes with the A3S although it is
still not solid Maybe cushcraft has them for sale. My guess is that
the hollow insulator is not a problem at least not in california.

Post by 'Doc
Les,
Hygain uses the same insulator for several of their
antennas, and it can be a problem with all of them.
Replacing it with a 'solid' insulator of some kind is
one solution. I'm still hunting for a replacement for
one for an 'R-7' (the only difference is in the length).
Thought about using 'Delrin'(sp) or some other type of
plexiglas/perspex, but haven't found a source yet.
Good luck...
'Doc

[les]

Thanks for that.
I took it that Cushcraft would have tested the antennas to destruction, so
thought I was being over causious but have heard from others that the
fiberglass breaks down after a while as it ages.
I have managed to get hold of an original (or at least its on its way) If I
an get a replacement I will the first chance I get.
Will look at Delrin on the net and see what it is. Guess the insulator is
not soild due to the extra it would cost in manufacture.
Thanks again
Les

Post by Edward Lewis
The center insulator that comes with the A744 40 meter kit for the A3S
is stronger than the insulator that comes with the A3S although it is
still not solid Maybe cushcraft has them for sale. My guess is that
the hollow insulator is not a problem at least not in california.

Post by 'Doc
Les,
Hygain uses the same insulator for several of their
antennas, and it can be a problem with all of them.
Replacing it with a 'solid' insulator of some kind is
one solution. I'm still hunting for a replacement for
one for an 'R-7' (the only difference is in the length).
Thought about using 'Delrin'(sp) or some other type of
plexiglas/perspex, but haven't found a source yet.
Good luck...
'Doc

['Doc]

Edward,
I have 'good' days and 'bad' days. Seems like when
I posted that one, it must'a been a really 'bad' day.
Oh well. The 'R-7' is by Cushcraft (duh), but the rest
of it was correct. 'Delrin'(sp?) comes in all shapes
and sizes, just a form of plastic that handles RF and
sun light well. Also a brand name, and I have no idea
what the chemical composition is (other than a 47 letter
name that I could care less about). If it's an insulator,
the correct size, pretty strong, and a pretty shade of
red, almost anything would work in place of the original
fibreglass (I like red)...
'Doc

[Mark Keith]

Post by 'Doc
Les,
Hygain uses the same insulator for several of their
antennas, and it can be a problem with all of them.
Replacing it with a 'solid' insulator of some kind is
one solution. I'm still hunting for a replacement for
one for an 'R-7' (the only difference is in the length).
Thought about using 'Delrin'(sp) or some other type of
plexiglas/perspex, but haven't found a source yet.
Good luck...
'Doc

I've got a A4S which has the same thing on the driven element...I've
often wondered what I'll do if that thing ever breaks...Guess the
delrin rod is one idea. I've wondered about a wood dowel that is
varnished as one solution...Or convert to boom grounded, and replace
with aluminum...But then you'd have to add a matching device...MK

[D@LS]

Post by Mark Keith

Post by 'Doc
Les,
Hygain uses the same insulator for several of their
antennas, and it can be a problem with all of them.
Replacing it with a 'solid' insulator of some kind is
one solution. I'm still hunting for a replacement for
one for an 'R-7' (the only difference is in the length).
Thought about using 'Delrin'(sp) or some other type of
plexiglas/perspex, but haven't found a source yet.
Good luck...
'Doc

I've got a A4S which has the same thing on the driven element...I've
often wondered what I'll do if that thing ever breaks...Guess the
delrin rod is one idea. I've wondered about a wood dowel that is
varnished as one solution...Or convert to boom grounded, and replace
with aluminum...But then you'd have to add a matching device...MK

Call a fiberglass place and get a cheap resin/hardner and fill in the center.
Anything you don't want it to stick to, use vaseline. A pint of the r/h should do it.