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Author Topic: I need a coaxial phasing harness for the CushCraft A-147 which uses two A-147 ya  (Read 2024 times)
K3SEW
Member

Posts: 2




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« on: November 14, 2012, 05:44:34 AM »

I need a coaxial phasing harness for the CushCraft A-147 which uses two A-147 yagi for 22 elements. It has one "T" connector and two PL-259 connectors. Where can I purchase this? OR what are the specifications to homebrew one?

Thank you .....
Ron, K3SEW
k3sew@comcast.net

 Huh
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W9GB
Member

Posts: 2616




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« Reply #1 on: November 14, 2012, 06:21:25 AM »

Cushcraft A147-22 Manual
http://www.boxspringsonline.com/cushcraft/1116-a147-22-yagi/download

DIY Phasing Line construction
http://www.kcvhfgridbandits.com/linked/phasinglineconstruct.pdf

Cushcraft/MFJ sells the PD-2 Power Divider -- $70 retail
http://www.cushcraftamateur.com/Product.php?productid=PD-2

Power Divider Harness for Boomers
Our power dividers make it a snap to stack Cushcraft Boomers.
Just add equal lengths of 50-Ohm coax to each of the antenna feed points.

PD-2 - For two A13B2 or two A17B2 beams.
PD-4 - For four A13B2 or four A17B2 beams.
==
Other DIY Phasing Harness web sites -- It is ALL about Materials and Math.

Jon Finley
http://www.jonfinley.com/hobbies/harness.html

Make your own VHF/UHF Phasing Harness
Frederick R. Vobbe, W8HDU
August 10, 2008   
http://hf-antenna.com/phasing/

UNKNOWN COAX?  Measure the Velocity Factor

http://m.youtube.com/#/watch?feature=plcp&v=Il_eju4D_TM&desktop_uri=%2Fwatch%3Fv%3DIl_eju4D_TM%26feature%3Dplcp
« Last Edit: November 14, 2012, 06:42:41 AM by W9GB » Logged
KB4QAA
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Posts: 2335




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« Reply #2 on: November 16, 2012, 12:56:56 AM »

Not to mention:

ARRL Handbook

ARRL Antenna book
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N8WWM
Member

Posts: 26




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« Reply #3 on: November 21, 2012, 12:19:12 PM »

Just keep in mind that when people say 1/2 wave at this freq, 1/4 wave at that freq, etc....in coax cable there's also velocity of propagation to plug into the equation.

If the VP of a given coax type is .81, for example, you'd calculate the length formula and then multiply by .81. If you don't do that you end up with a harness that works at 19 percent lower frequency than you want.

Different cables have different VP's. You have to get the correct one for your cable. White foam inner insulation versus translucent plastic are also quite different VP, regardless of type of cable. 2 pieces of RG-8/U can have totally different VP, for example.

It aint as hard as it may sound. Belden lists VP of their cables on the website. Don't neglect this or you will be PO'ed at your radiation pattern to say the least.
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KQ6Q
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Posts: 971




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« Reply #4 on: November 22, 2012, 07:27:26 PM »

Or you could buy a ready-built phasing harness from PAR electronics - they sell them to go with their horizontal omni antennas. They might be close enough to work on the upper end of the band. They're made of RG-11 coax.
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N6AJR
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Posts: 9914




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« Reply #5 on: November 25, 2012, 01:12:22 PM »

Have you called MFJ/Ameritron/Cushcraft
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