RE: 2 Meter Collinear J Pole Antenna

Sat Jan 26 12:23:42 CST 2013

Hello Jeff,

I built a regular J-pole from 300 ohm twin lead which I use indoors and am very happy with.  Most J-poles are shown with a stub descending below the feed point, with the coax coming off at a 90 degree angle to the antenna.  I allow the coax to hang straight down, and have the stub coming out at a 90 degree angle.  This works well for me because I support the antenna from the top.  You could hang it below a rain gutter and seal exposed parts with a glue gun, then maybe wrap the glued parts with black electrical tape for some UV protection?

For tuning it I used my MiniVNA.  I bought a new VHF SWR meter at a hamfest for about $70 but the meter itself is junk and is already destroyed.  The MiniVNA is used infrequently, but gives me so much information that it makes experimenting more fun.

On tuning the J-pole, I changed the length of the stub to get the desired impedance.  I think I ended up hacking the stub and replacing it a few times.  The stub is of course made from some of the twin lead so it is easily replaced by soldering it to the feed point.  The SWR will change depending on where you hang the antenna and what is nearby it, but now that it is built, I don't worry about that so much.

Sean AI4ID

From: Jeff Scaparra
Sent: ‎January‎ ‎26‎, ‎2013 ‎1‎:‎04‎ ‎AM
To: Tacos AMRAD
Subject: 2 Meter Collinear J Pole Antenna

Hello All,

I have followed this mailing list for a while and enjoy learning all I can. Sadly I have only been able to attend one meeting do to scheduling conflicts. I am a new ham who is interested in programming for software defined radio and learning more about electronics and antenna design. I have wanted a better 2 meter antenna for my home for a long time. I live in a townhouse and I need to be careful not to piss off the neighbors but I don't think there is anything to keep me from erecting an antenna. I have been researching the 2 Meter Collinear J Pole Antennas for a while and think I would like to build one of these. While I have some basic tools I don't have an antenna analyzer or SWR meter. By following plans online I would think I could get pretty close to an optimal antenna. I am trying not to buy more than I have to right now as I am saving up for my wedding in August. I was wondering if any of the more experience in the group had any advice for me. Also I am not a registered member of AMRAD and I am interested in becoming one. It seems to me that some of these tools like antenna analyzers are only used once or twice a year. Is that something that is ever part of a ham club. I know hacker spaces kind of work like that and for newer members that don't want to get too invested just yet it is very enticing. 

Thanks!

Scap KK4EPP
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