Radial length for 2m 1/2 wave antenna

[qrsComms]

Hello!

I've had a 1/4 wave 2m NMO antenna set up on my roof for several years now, however, I'm planning on swapping it out for a 1/2 wave instead.
My radials are currently 24 inches long. If I swap to the 1/2 wave, will I have to change my radials, or are my 24-inch ones good to stay?

Thanks in advance!

 

[belvdr]

If I recall correctly, you don't need any for a 2m 1/2 wave.

 

[prcguy]

24" is too long for ground radials on 2m, they should be around 19-20" long and would not change for a 1/2 wave or 5/8 wave or any other type vertical radiator.

Hello!

I've had a 1/4 wave 2m NMO antenna set up on my roof for several years now, however, I'm planning on swapping it out for a 1/2 wave instead.
My radials are currently 24 inches long. If I swap to the 1/2 wave, will I have to change my radials, or are my 24-inch ones good to stay?

Thanks in advance!

 

[mmckenna]

If I recall correctly, you don't need any for a 2m 1/2 wave.

A ground plane is not required for a half wave antenna. However, adding a ground plane changes the radiation pattern and increases the gain.

 

[TXFitz]

24" is too long for ground radials on 2m, they should be around 19-20" long and would not change for a 1/2 wave or 5/8 wave or any other type vertical radiator.

Does it matter how many radials there are?

 

[Lauri-CoyoteFrostbite]

And here is yet another voice ----

QRS, when you say a 'half wave' are you referring to a commercial antenna or an actual half wave length of radiator, with no matching circuitry ?
You can, of course, match a half wave vertical to a coax feed, but it will require some extra stuff--- otherwise its a bugger to match what is an infinite impedance to any feed line.

Ok, assuming this is a commercial antenna, there is no compelling requirement for a groundplane, but as others have said, its performance will be enhanced by a better angle of radiation with one.



If you elect to go with a ground plane, at 2 metres 19" radials will be fine... or about any length you choose that is longer. And the more the merrier .

But what are you trying to achieve with the new antenna?
A half wave vertical may not show any real-world signal improvements over your current quarter wave- but its a great experiment anyway.

Go for it Cowboy

Lauri




.

 

[prcguy]

Just one radial makes an inverted V dipole antenna on its side. Two or more equal length radials running opposite directions will cancel radiation in the radials. More is better like three is better than two, four is better than three, etc.

Does it matter how many radials there are?