I just realized, on that website it does not say the spacing between
elements, only the length of the elements. How would I find out that?

wrote

I just realized, on that website it does not say the spacing between
elements, only the length of the elements. How would I find out that?

22/freq (in Mhz)

See: http://www.hamuniverse.com/jpole.html

Roy has pointed out that a Balun is a good idea. The above site recommends
at least 4 coils of feedline at the feedpoint as an RF choke. I used neither
and had phenomenal "luck" with a 60' feedline and later added full lightning
protection with no detectable change in the prop.

Jack Painter
Virginia Beach VA

What are those red things on the top? They look like wire twisters.

I just realized, on that website it does not say the spacing between
elements, only the length of the elements. How would I find out that?

The little red things on top are just plastic caps.

Element spacing & element size are critical.
Check the "Parts Catalog" & the "Instructions"
for element spacing. It's all there, even a photo of the bracket.

If you change the diameter of the elements, you will need to start
over with the spacing to tune the antenna.

As for Stainless Steel, don't bother, been there, done that.
Tried making some out of Stainless Steel CB Whips.
A very noticeable difference in performance.

You really want to build your own ?
Buy one from Arrow Antenna, copy it,
then send it back for a refund. Only cost you for shipping.
Got to warn you though, I have not got one back yet.

73 Al Lowe N0IMW
A HREF="http://ArrowAntennas.com/"ArrowAntennas.com/A
Arrow Antenna

N0IMW wrote:
What are those red things on the top? They look like wire twisters.

I just realized, on that website it does not say the spacing between
elements, only the length of the elements. How would I find out
that?

The little red things on top are just plastic caps.

Element spacing & element size are critical.
Check the "Parts Catalog" & the "Instructions"
for element spacing. It's all there, even a photo of the bracket.

If you change the diameter of the elements, you will need to start
over with the spacing to tune the antenna.

As for Stainless Steel, don't bother, been there, done that.
Tried making some out of Stainless Steel CB Whips.
A very noticeable difference in performance.

You really want to build your own ?
Buy one from Arrow Antenna, copy it,
then send it back for a refund. Only cost you for shipping.
Got to warn you though, I have not got one back yet.

73 Al Lowe N0IMW
A HREF="http://ArrowAntennas.com/"ArrowAntennas.com/A
Arrow Antenna


Why would stainless steel provide different performance? Can you use
regular mild steel for the angle iron bracket? Maybe paint it so it
would not rust?

If you do change the element size, how do you determine the proper
spacing?

I appreciate your help! I like the design of the antenna and its
simplicity.

Just a suggetion -- go to a swap meet and buy your antennas for less than
the materials to build one

Or here is the scoop on yagi antenna design including a design program
http://www.hamuniverse.com/yagibasics.html

--
El Enforcer

wrote
If you do change the element size, how do you determine the proper
spacing?

I appreciate your help! I like the design of the antenna and its
simplicity.

When you earlier asked this question I answered it. The specific dimensions
are ALL provided in my previous post/reply to you. Here is is again!

wrote

I just realized, on that website it does not say the spacing between
elements, only the length of the elements. How would I find out that?

22/freq (in Mhz)

See: http://www.hamuniverse.com/jpole.html

73,
Jack

Why would stainless steel provide different performance? Can you use
regular mild steel for the angle iron bracket? Maybe paint it so it
would not rust?

If you do change the element size, how do you determine the proper
spacing?

I appreciate your help! I like the design of the antenna and its
simplicity.


At one time I had a chance to acquire a large number of Stainless Steel CB
whips, cheaper than the cost of aluminum.
I used 8 of them to make a 4 element Yagi just like our regular 146-4S.
It works, SWR is low, but it just does not work as well as the aluminum
elements.
Used a couple to make an OSJ, because of the smaller diameter, the spacing is
closer to get it to match But like I said there was a very noticeable drop in
performance. I really wanted it to work, would have been a good market for
them for mounting on 18 wheelers.
(Don't ask, I won't sell ether of them.)

As for making the bracket out of steel, Why ? it's harder to drill, harder to
tap. The 3/16" stress aluminum angle is a lot stronger than it needs to be.

As for determining the proper spacing, if you know the exact impedance
of the 1/2 wave, there is a formula for figuring the diameter & spacing.
Easier to just adjust the spacing for lowest SWR.

Unlike other types of J-Poles the OSJ does Not need a balun or choke.
It was designed for direct connect to coax.

73 Al Lowe N0IMW
Arrow Antenna

wrote in message
ups.com...
New to ham radio. Interested in building an antenna for a base station.
I dont have anything yet, just in the planning stage.


Thought about buying a handheld and using that as part of my "base
station" one maybe capable of 2 440 and 6. These seem cheaper used than
the home units.


My question is, is there information out there on how to build one? I
have a radio shack book at home that has a plan for a 440. It uses
aluminum ground wire. What I find when working with this stuff is it is
impossible to make it perfectlyu straight. Doesn't that effect the
performance? I mean it comes coiled and when I cut it to length I cant
get it perfectly straight.


Also, it is posisble to have good performance with one antenna for all
the bands? Or is it absolutely necessary to have one antenna for each
band? I have limited room.


If you go to the ARRL web page, you can find a very good antenna book. It
well worth the price. One of the fun aspects of being a ham is experimenting
with and building antennas (or is it antennae) . To enhance your fun with
expermenting one of your first purchases (after a radio) might be an antenna
analyzer like the MFJ 259 . You'll find yourself experimenting with matching
sections and different transmision lines as well. You can be an antenna nerd
in no time!



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