Hello Edgar.
29 Oct 97 12:44, Edgar Mckinney wrote to Rob Dennis:
 EM> Re: Where is part 4
 EM>
 >>  >> SUBJECT:  LPA Series - 500 MHz to 1300 MHz
 >>  EM> I saw 1,2,3,5,6,7 but no part 4.
 >>  EM> Please advise or send me the part 4 cause i did "capture " the
 >>  EM> resr.
 >> Edgar I am missing part 4 myself and trying to find it among my
 >> disks. If anyone else has the missing part I'll appreciate it being
 >> posted and then I plan on re-posting it all again sometime in
 >> December and the new year.
 EM>
 EM> Thanks and I'm also looking for 220 and 440 'J POLE' Plans If any has
 EM> them. I plan to us them in a rough enviroment such as on a mountain
 EM> top repearer.
Take this plan and delete whatever you want to get to 220, 440...
                              Tri-band j-pole
     The Copper pipe Tri-Band "J" Antenna, by Dale Kubichek, N6JSX
           _                                        _   _   _
          |-| >>| |      `----=- 146 Mhz.
  copper  |_|                             "Kuby", N6JSX
   pipe    \\
            \`----------=- 220 Mhz.       Dale Kubichek
             `----------=- 440 Mhz.       Rowland Hts., CA
Note: All matching elements were placed 120 degrees from one another.
The "J" antenna design goes back many-a-year, way before I became a HAM.
What interested me about the "J" antenna design is:
*  Very low - nearly straight-out angle of radiation
*  no ground plane required
*  Possibility of multiple bands in one antenna with separate feedlines
   for each band
*  Simplicity of construction and inexpensive to make
The "J" antenna low angle of radiation gives the user the most
distance. This will prove to be a great antenna for the Midwest or
the flat Central Plains of the USA.  Conversely, the "J" is not the
best for near mountain top repeater usage.
A "J" requires NO ground plane or special counter poise.  This makes
the "J" ideal for mobile use.  Doing some fact finding I found
claims that the "J" has approximately 3db of gain over a 1/4 wave
ground plane antenna and can be made from almost any material;
copper pipe, steel whips, & even TV twin lead.
                         What is a "J"?
Technically, the "J" antenna is an end-fed 1/2 wave antenna that
uses a 1/4 wave matching stub. To some of the old old timers it
might be called an "end-fed ZEPP" bent 90 degrees. In actuality, the
conductor is 3/4 wave length long and the match is 1/4 wave length
long. The matching stub creates the 1/2 wave loading point.  This
makes the antenna effectively an omni 1/2 wave length. The "J" is in
best terms a balanced 1/4 wave matching stub feeding an unbalanced
1/2 wave load.
A "J" can be fed by ladderline or coax. I found using coax cable
RG-58u to be the best. I have designed a Tri-band and Dual-band "J"
antenna with aps. Using rigid copper pipe makes it a snap to
assemble. Simple plumbers soldering techniques are used for solid
construction.  These materials will withstand a lot of abuse and
weather. Each band has its own feedline and all three radios can be
run simultaneously. I have made a mobile 2 meter "J" from a Radio
Shack 104" CB whip. The whip has a mounting bolt on the bottom for
easy attachment to mounting clamps. I fabricated a plastic insulator
and metal support bracket for the 1/4 wave matching section. The
coax was connected by using electrical
... Gone crazy, be back later, leave a message.
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