[AMRadio] Receive Preamp question


rbethman rbethman at comcast.net
Sun Nov 4 13:08:26 EST 2007


John,

The receiver board has MOSFETs on it.

Get out the manual and track down the "receive" MOSFET.

This same thing was fiddled with in Kenwood Transceivers.

They were initially built with 3SK45s.

We specifically replaced the 3SK45's with the 3N201s.

These four beasties, 40673s, NTE222s, 3SK45s, and 3N201s are all very 
close relatives.

We managed to get the 3N201s from someone working in the Bell Labs in 
Florida around 1980.

The 3N201 AND the 3N211 performed the best!  Dropped the noise floor a 
GOOD bit.  That makes the old FT-101 series, (And many others of that 
genre.), a good bit better than originally designed.

They are all also direct plugins for each other.  Sometimes the ONLY way 
to determine which one to use is simply try one of each in YOUR 
application.  The minor circuit differences between the radios can make 
all the difference.


Bob - N0DGN


John wrote:
> Does anyone have a good recommendation for a preamp to
> help my radio receive better. Thanks for any
> suggestions. 
>
> John W5HG
>
>   


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