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

Jeff Mock jeff at mock.com
Mon Mar 31 09:52:38 PST 2008


It's not clear that a preamp will improve your reception.  The 2720H has 
a pretty sensitive receiver.  The preamp will help you if the noise 
figure of the preamp is better than the noise figure of your radio. 
It's not clear to me that you can make much of an improvement here.

I have a preamp on the masthead at home, but I have a long feedline from 
my receiver to the antenna, I have about 7db of loss from the antenna to 
the radio at 70cm and I get a noticeable improvement with a preamp.  The 
main job of my preamp is to overcome the loss of the feedline, otherwise 
the preamp is not that much better than the radio.

jeff
AD6EO

Kent R. Frazier wrote:
> Hi all,
> 
> I am really enjoying the satellite aspect of the hobby and have enjoyed the
> contacts I have made with my Icom IC-2720H with a 19" whip antenna from my
> vehicle. I have seen talk recently of using a preamp to improve the
> reception. From what I've read and understand, it appears that a "switching"
> preamp is needed for a setup using only one antenna for Tx and Rx such as
> mine. Is this correct?
> 
> It also appears that most of the preamps are mast mounted. Since this would
> not be an option for me can the preamp be put near the transceiver? Are
> there any issues that result of doing so?
> 
> Lastly, what preamp(s) would you recommend for an application such as mine?
> 
> 
> Thanks,
> 
> Kent
> 



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