[Antennas] Telescoping J-Pole

[David]

I would like to add two things:
1. Oh! I assumed a 2M J-Pole when using those measurements I used in my
first answer to you...just scale up...   (-:

2.  The "u" / "J" part of the J-Pole is a matching stub.
--You may have to lower the coax connection point to the main/long pipe in
order to get a good impedance match. (assuming that the bottom of the main
vertical element is 1" dia.)
David (W7DBH)



On Thu, February 18, 2016 8:09 am, David wrote:
** If you have, say, a design for a 1/2" in diameter copper pipe J-Pole, you
** can't go too far wrong starting with that length for the total antenna.
**
** I would try keeping the little 'u' ("J") portion in 1/2 inch and split the
** say, other ~36" length in 3 equal parts ~12" each (1", 3/4" & 1/2"
** pipes)...realizing that the larger diameters cause the radio/swr length of
** the long member to be slightly shorter....
**
** Then, with a swr meter or whatever, trim the top 1/2" pipe section to
** middle of the 2M band.
**
**
**
**
**
**
** On Wed, February 17, 2016 10:59 pm, charles berry via Antennas wrote:
** ** I would like to build a 6m J-Pole. Â I do not have enough copper to
** build from one piece of similar diameters. Â I do have enough if I taper
** with 1", 3/4" & 1/2" pipes. Â Any suggestions as to the lengths of each
** section? Â 
** ** Thanks,ChuckN7CHS
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-- 
David B.