mag mount issues with 800 MHZ

[ACU1000]

Anyone have any experience with issues on 800 MHz getting choppy when you start moving.

I have an Uniden 996 connected to a Antennex NMO mag mount and a wide band receive antenna that does great on everything but certain 800MHz systems get choppy as soon as I start moving.

Not sure it could be the mag mount, but thought I would ask if anyone else has the same problem. Perhaps even the mag mount has limitations like not good for low band use or not good for 800 use.

Anyone with comments or help?

Thanks,

 

[rfradioconsult]

It most likely Rayleigh Fading that you are experiencing. When stopped you can move slowly forward and the signal will increase and decrease with very little movement; at higher speed it will almost sound like crackling. This is more noticable at 800 than at lower frequencies because of the shorter wavelength. Google Rayleigh fading or Rayleigh scattering for more information.

 

[zz0468]

Anyone have any experience with issues on 800 MHz getting choppy when you start moving.

As stated, sounds like Rayleigh fading. I'd also like to add that it's nothing unique to your particular antenna or scanner, and is a bane to radio engineers everywhere. Minimizing it is expensive (as in millions), and it never 'goes away'. All that can be done is saturate the desired coverage area with enough signal that those 40 db fades are still above the quieting threshold of the desired receivers.