Hy-Gain Five Element Long John Beam (CB)
Teddy Banks
mine and it has some elements broken and I need to try to find a source for
aluminum tubing to repair it and I need to know how long they were.
Thanks
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Mad Dog
5% longer and the
first director is 5% shorter.This link will help you-
http://www.diana.bib.uniurb.it/arrl/yagi.htm
--
714 Sandpile,
The Mad Dog wavin' good bye
"Teddy Banks" <TBa...@fox-net.net> wrote in message
news:3ab4d...@Newsfeeds.com...
BadaBing
"Mad Dog" <lg...@netzero.net> wrote in message
news:992mbo$4762h$1...@ID-20128.news.dfncis.de...
Jay in the Mojave
HY-Gain will sell you the old out of production antenna manuals for 5
dollars. The phone number is 800-973-6572
Hy-Gain used (and still does on their new beams) a construction
technique called swag reduction. What this does is reduce the aluminum
tubing diameter to a smaller diameter to allow the next smaller size
diameter tubing to fit inside the reduce swaged tubing.
This is done for two very good reasons:
1) It allows the aluminum tubing to be tapered to a smaller sizes,
allowing the elements to be lighter, while still being very strong.
2) When aluminum tubing is sold in mass quantities, (they don't tell ya
this in the books) differences in wall thickness will raise their ugly
head. Most aluminum tubing used in antenna construction is .058 inches
in wall thickness. Just under a 1/16 inch. This allows tubing in 1/8
inch increments to fit inside each other, or telescope inside each
other.
Example: 1" .058 wall thickness tubing will allow 7/8 inch diameter to
fit inside.
7/8 inch .058 wall thickness tubing will allow 3/4 inch diameter to fit
inside, and so on.
Now the reality bits ya in the ass............
Most aluminum tubing wall thickness has a tolerance of + or - 10%
This means the aluminum tubing for .058 inches wall thickness can be
+ .0058 or -.0058 inches difference in wall thickness.
If the tubing comes from the manufacture with a thicker wall thickness
of +.0058 inches, the wall thickness will be .058" + .0058" = .0638".
So now the smaller size tubing will not fit inside the too thick wall
thickness tubing now. Let me tell how this will humble ya.
Because of the tubing wall thickness (crap shoot) problem, reduced
swaging is a good thing allowing the manufacture not to worry about the
tubing wall thickness tolerances.
However, most modern aluminum tubing 6061-T6 and 6063-T8 tubing is
pretty good about keeping the tolerances very close to .058 inches wall
thickness. But when I walk into the aluminum tubing store, I have a few
samples of tubing, to make sure all the tubing pulled off the racks is
well within my allowable tolerances.
Most metal supply houses, have left over pieces of tubing called Rim's
that might have what you want. Just ask em.
The Hy-Gain reduced swaged joints can be replace very easily. If I
remember correctly, there 3 sizes that make up the beams elements.
are:
1) 7/8" tubing reduced swaged to 5/8" about 24 to 30 inches long
2) 5/8" tubing reduced swaged to 7/16" about 50 to 60 inches long
3 7/16" tubing, has no reduced swag, about 52 1/8" inches long
If you have the manuals for their present 20 meter, 15 and 10 meter
beams, it's very possible that they may have replacement tubing in
stock. But with different part numbers that whats in the CB 5 element
beam manual.
The 7/8" tubing can have a short 4", 3/4" .058" WT tubing adapter sleeve
put in the end to allow the the 5/8" tubing to fit inside. You may half
to cut the adapter sleeve length wise, and use two hose clamps to make
it tight.
1/2" tubing will fit inside the 5/8" tubing without any adapter sleeve.
Or the 5/8" tubing can be cross cut length wise, about an inch long, on
the end, and the 5/8" will just reduce down with the hose clamp to
tightly hold the 7/16" tubing.
Use good stainless steel marine grade hose clamps.
Hope this wasn't too much info, and hope this helps.
Jay in the Mojave
Mad Dog
--
714 Sandpile,
The Mad Dog wavin' good bye
"BadaBing" <bada...@home.com> wrote in message
news:po5t6.30886$H5.70...@news1.rdc2.pa.home.com...
tn...@mucks.net
wrote:
>Does anybody know where I can find a manual for this antenna, I have lost
>mine and it has some elements broken and I need to try to find a source for
>aluminum tubing to repair it and I need to know how long they were.
>
>Thanks
Antennas:
http://www.agtannenbaum.com/h_cat.html
oh8mfh
"BadaBing" <bada...@home.com> wrote in
news:po5t6.30886$H5.70...@news1.rdc2.pa.home.com...
> MadDog what if the elements are 1/2 " dia as compared to 3/8" dia
elements?
Download a program called "Yagimax", punch in YM311, feed in the dimensions
of the antenna with the elements as they are, and change the diameter of the
tubing. No maths needed, let the computer do it for you. 73 Gary