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

lost in the amings of a DIY handheld antenna

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Greekman:
on a whim I "decided" to make my own HT antenna.
So i dove in the interweb and what I found was this:
http://www.arrl.org/files/file/Technology/tis/info/pdf/9803037.pdf.

I am perplexed, and cannot understand the instructions well. (let alone that the diagram is rather bad)
I know that he is building a "base-loaded short whip" by the coil he suggests.
But why is he using a short piece of coax sleeve?
I am assuming just to have some surface to coil the whip around.
Could there be another reason?

BTW, I will be making a 1/4 wave whip, so I just need to omit the coil....I think.

jerseyboy:
I never made one of these exactly. But yes, no coil if you are going to do a full quarter wave.

I think one of the things he is trying to show us is that the connector length is part of the electrical length of the antenna.

Let us know how it works out.

Jerseyboy.

Greekman:

--- Quote ---I think one of the things he is trying to show us is that the connector length is part of the electrical length of the antenna.
--- End quote ---

that is a non-issue, I think. that is if you are going to measure SWR and cut, you will already be starting long..
I guess the final result will show, what the difference with the theoretical length will be.

BTW, while we are at it....
I am looking at RG-142 core for the whip. I assume it will be less flexible being thicker and with a teflon dielectric.
I also assume that using RG-142 as a power line still maintains adequate flex, doesn't it?

Greekman:
one more question...
What other lengths would work without a loading coil?
I will assume 3/4? 1/8? (IIRC Carl once said that odd wavelength quarters do)

Carl:

--- Quote from: Greekman on August 16, 2017, 10:20:39 AM ---one more question...
What other lengths would work without a loading coil?
I will assume 3/4? 1/8? (IIRC Carl once said that odd wavelength quarters do)

--- End quote ---

Without special matching coils or capacitors,stick to 1/4 as the radio is half of the antenna and few radios are 15 inches or so long...you will have poor performance boost from anything over 1/4 wave and as you can't measure SWR without adding cable or analyzer to the mix...you will be better off to cut the antenna to length and LEAVE IT ALONE! Unless you plan to leave the coax and SWR meter permanently in line as they alter the antenna significantly.

Note that unless you have plenty of hardware laying around ,you can BUY this antenna at lower cost than building one from purchased parts and while it may work ,improper SWR from improper length can damage the radio Transmitter over time .

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