Redid the coax cable on my Antron 99!!

[AmericanEagle575]

Good Morning my Radio Friend's,well I decided to change out my cable from RG 8 to RG 213 and go from 50 ft down to 25 ft as that's all I needed from the roof to the window of my room where I have The station set up!! I noticed my Swr went from 1.5 on 1 and 40 to flat 1.0 on both. The cable I had on it originally was 2 years old and kinda of cheap and I noticed that the Swr kept changing around if that makes sense with it,plus the 213 seemed like a durable good choice to make and I wanted to get it done before winter set in-Hope all of my radio friends are doing well and God Bless you all!!

Steve

 

[sp5it]

I noticed my Swr went from 1.5 on 1 and 40 to flat 1.0 on both.

It's a bad sign. Mike

 

[bob85]

There are a few things that can cause vswr to change when changing coax,

all else been equal your vswr should have gone up with the shorter lower loss coax,

low vswr is not always a good thing, it keeps the radio happy but its not good if the vswr is low because the coax is VERY lossy, i doubt that even if you bought crappy quality 213,

End fed 1/2waves are only 1/2 of an antenna,

a99 does have a short coax & metal tube for return currents so they will give good vswr in isolation even without coax or a mast to provide the missing half,

but they can be sensitive to coax length,

if you pick an unlucky length that causes high common mode current vswr will move around when you move the coax or grip it and slide your hand along the coax,
when they are acting like that you have bad cmc on the braid,

you will pick up every pop click & fart that goes off near the coax from noisy electrical goods & your radiation pattern won't be anything like you want it to be,

it could also be your mast, it also has common mode currents,
did you change the mast length or isolate it or ground it,

any of those thing can effect no radial end-feds including 1/2wave A99's.