[amsat-bb] Re: Preamp for a Mobile Application

[Tony Langdon]

At 07:38 AM 4/3/2008, you wrote:

>The "dollars to dBs" value proposition for pre-amps in a mobile
>installation with short coax runs doesn't work out until after you
>have an incredibly large antenna system.

In the case of a mobile installation, I'd spend my money on the 
feedline.  Design the coax run for 1.2 GHz or higher.  Doing this 
means losses at 70cm will be negligible.  Next, select an antenna 
suitable for what you are attempting to do.  A 2m 1/4 wave might be a 
good option for mobile satellite work.  With a high quality feedline, 
I actually had very good results working mobile on a high gain mobile 
whip, much to my surprise!.  In any case, keep the gain low, you 
don't want all your radiation on the horizon, and directional 
antennas on a mobile are rarely practical (try aiming one on a 
winding road :D ).  But first of all, spend the $$$$ on the feedline.

73 de VK3JED
http://vkradio.com