[RFI] Mobile amps and vehicle issues

[Jim Brown]

On Thu, 12 Jan 2006 08:34:00 -0500, FoMoCo EMC wrote:

>The Crown Vics for police duty do have a number of differences in them for 
>safety, convenience of mounting police accessories, and they are required to 
>protect for radio reception in the radio bands above 30 MHz.

>Performance below 30 MHz isn't any better because of the police package.  
>There is a big difference 20 meter amateur reception and public service 
>VHF/UHF reception.  The two services are separated by an order of magnitude 
>in frequency 

<SNIP>

>Good radio performance above 30 MHz doesn't guarantee good performance below 
>30 MHz.

I agree completely, BUT the commonly accepted definition of "an order of 
magnitude" is a decade of frequency -- 10:1. The difference between the 20 meter 
band and public safety frequencies at low VHF (30-40 MHz) that are still used in 
some jurisdictions is only a bit more than 2:1 (that is, a bit more than an 
octave). The 10:1 difference does, of course, apply to the high VHF (150-170 
MHz) and UHF (450 and up) allocation.