Survivalism & Self Sufficiency Topics > Amateur Radio How-To's

Inpedance matching for Collapsible Yagis (for field use)

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Greekman:
hi all!
I am moving slooooowly forward with a VHF Yagi antenna that it will be able to be diassambled and stored within half its boom.
I have sorted out all issues but the impedance match one.

I consider using DK7ZB 4-element Yagi design and one of his impedance chokes
http://www.qsl.net/dk7zb/dk7zb-match.htm
scroll down half way where you can see this pic.

Questions.
1- will this choke work?
2- boom outside diameter is 1and1/4 inch. I rather have it inside the beam if applicable
3- anything else I am missing?

armymars:
  I use to have a friend who use to match J Poles with a telescoping hair pin match. This aloud him to match his antenna for it's environment and frequency. He moved around the plant a lot and what steel was around him made a differences.

Carl:
The HAIRPIN MATCH is by far easier to use as done with this antenna....

http://w8jxn.com/files/Download/2m_df_antenna.pdf

Greekman:
thanks...

But here comes another question.
Assuming I cut the elements to design specs and the hairpin match too.
And i see aconsiderable SWR on my meter. How do i know it is the match or the elements that are out of spec?

Carl:

--- Quote from: Greekman on November 21, 2015, 02:21:31 AM ---thanks...

But here comes another question.
Assuming I cut the elements to design specs and the hairpin match too.
And i see aconsiderable SWR on my meter. How do i know it is the match or the elements that are out of spec?

--- End quote ---

You are correct,How will you know that even your SWR METER is working correctly?


Enough antennas and hairpin matches have been made to accept that when correctly cut and constructed that
'something else' must be wrong when impedance is not acceptable.

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