Hmmmm oh boy, not bad
----- Original Message ----- 
From: "Howard Kaufman" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, September 01, 2012 12:47 AM
Subject: Re: Description of a J Pole antenna


> Other uses?
> Never thought of it, but you could make a UHF water pipe j-pole into an
> effective bong!!!  Nice way to hide a pipe!  LOL!!!
> ----- Original Message ----- 
> From: "John Miller" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Monday, August 27, 2012 8:02 PM
> Subject: Re: Description of a J Pole antenna
>
>
>>I had a real nice one made out of water pipe, I built it when I was in
>> college to use in the dorm, then it found various other uses, like as a
>> scanner antenna for a long time but it was stolen at my last apartment. I
>> had it in the storage unit and the first time it was broken in to that 
>> was
>> stolen. One of those things I know who did it but couldn't prove it. Then
>> people wonder why I'm so anal about locking everything up since then. 
>> when
>> my room for ham radio is built over here, that will be locked as well.
>> ----- Original Message ----- 
>> From: "Ronald E. Milliman" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Monday, August 27, 2012 8:49 PM
>> Subject: Description of a J Pole antenna
>>
>>
>>> Howard,
>>>
>>> several days ago you asked if one of us could describe a J Pole antenna
>>> to
>>> you in enough detail so you could build one.  Well, I will try.  Here it
>>> goes...
>>>
>>>
>>> construction for a 2 meter J Pole :
>>>
>>> First, imagine the print letter J . This represents the shape of the
>>> antenna. It has one long side and one short side all connected at the
>>> bottom or said another way, one continuous length of conductor shaped
>>> into
>>> a J.
>>>
>>> Now turn or flip the J backwards as if you were writing it with the 
>>> short
>>> side on the right rather than on the left.  I say this simply because
>>> this
>>> is the way it is usually shown in the ham mags and on most web pages.
>>>
>>> The J is one single "conductor" in the shape of a J.
>>> From the top of the long side of the J to the bottom, for 2 meters, is
>>> about 58 inches long before it turns horizontally a couple of inches and
>>> then goes vertical for about 19 1/4 inches. So you have a total length 
>>> of
>>> about 77 1/4 inches forming a single J shape.
>>>
>>> The center conductor of the coaxial feedline is attached to The long
>>> section of the J Pole and the braid or shield of the feedline is 
>>> attached
>>> to the short section.  These feed points for the coax are spaced up from
>>> the bottom of the J or antenna about two inches, and they need to be,
>>> initially, adjustable , until you find the optimum tap or feedpoint that
>>> gives minimum SWR. So, do not make a permanent feedline connection yet.
>>> Once you have these feedpoints adjusted to produce minimum SWR, you can
>>> solder them for a permanent connection.
>>>
>>> Again, the shield of the 50 ohm coax is attached to the short section
>>> about
>>> 2 inches up from the bottom.
>>> The center conductor of the 50 ohm coax is attached to the long section
>>> about 2 inches up from the bottom. Both the center conductor and the
>>> shield
>>> should now be side by side on the vertical elements equal distance from
>>> the
>>> bottom. One on one vertical side and the other on the other vertical
>>> side.
>>> BOTH are connected equal distance from the bottom of the antenna and are
>>> adjusted up or down equally for lowest swr. This is the tricky part. 
>>> Some
>>> method of making temporary connections for tuning will be needed or they
>>> can just be tack soldered for testing and tuning.=20
>>>
>>> For tuning, you can mount the J Pole on top of a short pole, a length of
>>> PVC, a push-pole, etc., or you can mount it on a temporary support like 
>>> a
>>> wooden ladder.
>>>
>>> Then, once you have it tuned, you will need some method of mounting the
>>> antenna to a mast, pole, etc in your final installation.
>>>
>>> Most builders just add about 15 to 20 inches to the long side at the
>>> bottom
>>> for mounting.
>>> This extra length becomes invisible to the operation of the antenna;
>>> thus,
>>> not effecting its operation.  So, it can be metal tubing for a J pole.
>>> Adding this length would make the long side about 58 plus 15 inches =3D
>>> 73
>>> inches...or
>>> 58 plus 20 inches =3D 78 inches.
>>> =20
>>> Of course, you want to mount the antenna in a location about 1/2 wave
>>> length away from any metal surface near the antenna in any direction
>>> except
>>> the bottom of the antenna.
>>>
>>> The lengths and spacing of the J element is not very critical due to the
>>> variable tuning section. The main thing is to get the final swr down as
>>> low
>>> as possible.
>>>
>>> Also, it is recommended to add about 4 or 5 turns of coax in a neat coil
>>> with coils side by side at the bottom of the antenna making an air
>>> choke=9D
>>> out of it to keep stray rf off of the coax outer conductor.
>>>
>>> It is a challenge to describe something like this, but there you have 
>>> it.
>>> I hope you are able to visualize it well enough to take a shot at
>>> actually
>>> building one.  Alternatively, they are available to purchase either 
>>> fully
>>> assembled or the parts that you can put together yourself. =20
>>>
>>> Ron, AC4HM