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Modimying a mediocre HT antenna?

Greek Man
 

So I came to the possession of a mediocre V/U HT antenna, a copy of the SR901.
Being that I will try to cut it for the 220MHz band, but I am perplexed as if it too long or too short .
It has a base loading coil as all do, and a middle loading coil.
this is what perplexes me. I assume that the antenna from the middle coil Down works for the UHF, the whole length for the VHF

Took some reading with my SWR meter.
200MHz - 4.5
220MHz - 9.8
240MHz - 11.3
260MHz - 15.1

142MHz - 3.2
146MHz - 3.0
150MHz - 2.8

in the UHF, the SWR, in similar fashion, drops as the frequency gets larger.

so do these make it long or short for the 220Mhz band?
V/U performance tells me that it is short (as Chinese antennas always do).

What do you think?

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randall krippner
 

 generally if the swr goes down as you increase frequency the antenna is too short, and if it goes down as you decrease frequency it's too long. But that's for a standard wire type antenna. I've never played around with rubber duck style antennas. They can be difficult to deal with, especially the multiband ones because of the coils, and because the antenna itself is likely a coil inside of the rubber covering.

Greek Man
 








Check out my blogs!
http://greekpreparedness.blogspot.com/
https://survivalcomms.wordpress.com/
Στις Τρίτη, 21 Απριλίου 2020, 02:42:51 μ.μ. EEST, ο χρήστης randall krippner <randallkrippner@...> έγραψε:


 generally if the swr goes down as you increase frequency the antenna is too short, and if it goes down as you decrease frequency it's too long. But that's for a standard wire type antenna. I've never played around with rubber duck style antennas. They can be difficult to deal with, especially the multiband ones because of the coils, and because the antenna itself is likely a coil inside of the rubber covering.

Greek Man
 


that general guideline was what I was asking for.. thanks.

regarding Rubber ducks, do not worry, I will be doing the research anyway...
I need 3, which all will be DIY/Converted.

Στις Τρίτη, 21 Απριλίου 2020, 02:42:51 μ.μ. EEST, ο χρήστης randall krippner <randallkrippner@...> έγραψε:


 generally if the swr goes down as you increase frequency the antenna is too short, and if it goes down as you decrease frequency it's too long. But that's for a standard wire type antenna. I've never played around with rubber duck style antennas. They can be difficult to deal with, especially the multiband ones because of the coils, and because the antenna itself is likely a coil inside of the rubber covering.