RG58 VS LMR400

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fredg

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I just made a 1/4 wave ground plane antenna. It works well but I have been wondering if is is worth the trouble to use LMR400 in place of the RG58 I have now.

I have another antenna up that has about 30' of LMR400 and it works great.

This new antenna only has 14 feet of RG58, so for such a short run would the LMR400 even make a noticeable difference?
 

mmckenna

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So, using UHF frequencies as a reference, since you didn't tell us what band you were listening on:
14 feet of RG58 is going to give you 1.5db of loss at 460MHz.
14 feet of LMR400 is going to give you 0.4db or so of loss at 460MHz.

So, about a 1 db difference on the UHF band, VHF will be a bit different., which isn't a whole lot. On the very fringes, you'll probably hear (or not hear) a difference.
What would likely make a difference is to get the antenna up higher than 14 feet. Likely the bigger difference between the two antennas is the height.

Coaxial cable loss changes based on frequency. Higher frequencies are going to have more loss than the lower ones, so what bands you are trying to use it on plays into this as well.

You can try crunching the numbers yourself here: Coax Calculator
 

fredg

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Thanks guys. I was not comparing the 2 antennas. The second antenna is mostly for real strong local signals and is only 7 feet up from my 1 story house, so maybe 18 feet total.

And I was looking at UHF 450-460. It sounds like for 1DB it would not be worth changing out the cable.
 

jackj

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Try it. If you're happy then you've saved some money. If not, you know what to do.
 
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