Great description!
But it still leaves my original question.  On the original ham universe 
site, there is mention of a gap, and a copper sleeve that can be moved to 
adjust the tuning...where is this gap and sleeve?
There was mention of a bolt/nut arrangement and a link to a 2 meter loop 
article that explained how to use this bolt/nut arrangement to tune the gap 
spacing...I understand the general instructions and construction of the J 
pole and the measurements provided on the ham universe website, it's just 
this gap thing that has me confused.
Also, has anyone ever read of, or tried a J pole fed with a gamma matching 
system?
The other question is if there are any good descriptions, such as the one 
provided here, for a dual band J pole, or is the 2M version just used on 
70CM because it happens to tune up there?
73
Colin, V A6BKX
-----Original Message----- 
From: Oriano
Sent: Saturday, May 02, 2015 9:29 AM
To: [log in to unmask]
Subject: Re: Slim Jim VHF UHF Antenna

Nice description of a j-pole antenna from the handiham website.
How to Construct a 2-Meter J Pole
wa0tda
How to Construct A Double Bazooka Dipole Antenna
wa0tda
Courage Kenny Handiham World Weekly E-Letter for the week of Wednesday, 04
June 2014
wa0tda
June Events On the Air - By N1YXU
wa0tda
Radio Camp
wa0tda
Courage Kenny Handiham World Weekly E-Letter for the week of Wednesday, 28
May 2014
wa0tda
How to Construct a 2-Meter J Pole
Submitted by wa0tda on Wed, 06/11/2014 - 12:39
By Ronald E. Milliman, Ph.D. K8HSY
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 publications 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 79 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 feed point that gives minimum SWR. So, do not make a
permanent feedline
connection yet. Once you have these feed points 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;
that is, 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.
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 affecting its
resonance. So,
it can be metal tubing for a J pole. Adding this length would make the long
side
about 58 plus 15 inches = 73 inches...or 58 plus 20 inches = 78 inches.
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, to keep stray RF off of the coax outer conductor, it is highly
recommended
to add an air choke at the bottom of the antenna. For 2 meters, the coil is
4 turns
of coax with coils side by side in a neat coil 5 inches in diameter. You
should get
good results with the choke within 3 or 4 inches of the feed point. You can
simply
use the last part of your feedline as the choke before attaching to the
feedpoint!
Hopefully, I have described this antenna well enough so you can construct
one if
you want to give it a try. Alternatively, they are available to purchase
either fully
assembled or the parts that you can put together yourself.
Good luck!
Ron, K8HSY


-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Gerry Leary
Sent: Saturday, May 02, 2015 5:09 AM
To: [log in to unmask]
Subject: Re: Slim Jim VHF UHF Antenna

Hello again and thanks. I use a J pole, made by arrow antennas and it works
r= eally really well. But I do not know the differences between the two
yet. I w= ill probably buy and assembled one if I can just to experiment
with it. Espe= cially if I can get 220.

Sent from my iPhone this time=20

> On May 1, 2015, at 1:04 PM, Colin McDonald <[log in to unmask]>
> wrote:=

>=20
> I wouldn't mind to build this antenna, but the ham universe page
>doesn't=20=

> give any sort of building instructions, just measurement instructions.
> For instance, they speak about spacing and a gap, I understand spacing
> to=20=

> mean the distance between the two vertical elements of the antenna,
> one=20=

> being 3/4 wave and the other being 1/2 wave etc...but the gap and
> using a=20=

> sleeve to adjust the gap doesn't make sense to me yet.
> I have never brailled a J pole or slim jim etc, so perhaps I am
> forgetting=
=20
> or totally missing some aspect of the antenna that would make this gap
> thi=
ng=20
> perfectly obvious lol.
> I have made a twin lead J pole before with less than excellent
> results, bu=
t=20
> I can't quite visualize the copper slim jim design.
> Maybe a description from someone who has a copper slim jim would
> help...th=
e=20
> parts are easy and cheap to get, and with the tw2, I can at least get
> a=20=

> general SWR to tune the thing.
>=20
> 73
> Colin, V A6BKX
> -----Original Message-----=20
> From: Oriano
> Sent: Friday, May 01, 2015 12:10 PM
> To: [log in to unmask]
> Subject: Re: Slim Jim VHF UHF Antenna
>=20
> Yes, very similar. The radiation pattern is low to the horizon around
>8  degrees compared to a j-pole which is probably around 30 degrees. I
>am not=

> certain about the j-pole so someone is likely to correct me.
> Generally, if=

> one lives on a hill the slim jim works better with lower to the
>horizon  radiation pattern. A j-pole may do better if one is in a bit of a
valley.
>=20
> Best,
>=20
> Oriano VE7 D Y Z
>=20
>=20
> -----Original Message-----
> From: For blind ham radio operators
>[mailto:[log in to unmask]]=

> On Behalf Of Gerry Leary
> Sent: Friday, May 01, 2015 10:57 AM
> To: [log in to unmask]
> Subject: Re: Slim Jim VHF UHF Antenna
>=20
> Or the slim Jim's similar to a J pole?
>=20
> Sent from my iPhone this time=3D20
>=20
>> On May 1, 2015, at 7:23 AM, Adrien Collins
>> <[log in to unmask]> w=3D
> rote:
>> =3D20
>> Hi=3D20
>> =3D20
>> I used to use a home brew slim jim years ago on 2 meters, it  was
>> surprising the distances I could get on that aerial.
>> =3D20
>> Regards
>> =3D20
>> Adrien
>> =3D20
>> -----Original Message-----
>> From: For blind ham radio operators
>> [mailto:[log in to unmask]] On Behalf Of Blake  Hailey
>> Sent: Thursday, April 30, 2015 1:08 AM
>> To: [log in to unmask]
>> Subject: Re: Slim Jim VHF UHF Antenna
>> =3D20
>> I agree I have used them from N9TAX on 144/220/440 MHz and  they all
>> work great especially if you live in a apartment or  condo.  The hang
>> on the wall and still work great. =3D20
>> 73 Blake KA5POW
>> =3D20
>> =3D20
>> -----Original Message-----
>> From: For blind ham radio operators
>> [mailto:[log in to unmask]]
>> On Behalf Of Oriano
>> Sent: Wednesday, April 29, 2015 12:26 AM
>> To: [log in to unmask]
>> Subject: Slim Jim VHF UHF Antenna
>> =3D20
>> I purchased a slim jim antenna from N9TAX for about $23.00  and it is
>> a great omni dual bander. No problems with  repeaters over 100k away.
>> One can build it using the  following instructions:
>> http://www.hamuniverse.com/slimjim.html
>> =3D20
>> or purchase one as I did from:
>> http://2wayelectronix.com/Dual-band-2m-70cm-Slim-Jim-Antenna
>> -dual-slim.htm
>> =3D20
>> I turned it into a base antenna using the following
>> instructions:
>> http://www.n9tax.com/Slim%20Jim%20Info.html
>> =3D20
>> 73s
>> =3D20
>> Oriano VE7 D Y Z=20