TopBand: rcvr pre-amp schematic missing

[km1h @ juno.com]

That was a DeMaw August 1988 QST article using a MPF-102 ahead of the
MC-1350 IC.

Be very careful of your application when using this circuit. The gain is
way, way too high for a beverage and maybe even a loop. 
The problem arises when you use the gain control.....every dB of gain
reduction equals 1 dB increase in the 1350P device noise figure. This is
documented right in the Motorola book but was never mentioned in the QST
article. 

So if you reduce the full 45dB of gain to 20dB you now add that 25dB NF
to your existing 10-15dB 160M NF of most radios. Not a very pleasant
thought. 

I used to sell a kit of that preamp until a customer brought the above to
my attention. I can still provide the schematic if you wish.

73   Carl   KM1H



On Thu, 09 Oct 1997 08:35:38 -0500 Derrick Belbas
<DBELBAS@citygw.City.Winnipeg.MB.CA> writes:
>Hi.  I put together a pre-amp, based on a design I saw in CQ or QST a
>year or three back, a two-stage circuit, one of which was built around 
>a
>MC1350.  Lost the schematic.  Anyone remember this one?  What issue
>of what magazine?  Help!
>
>Thanks.  73..
>
>Derrick  VE4VV
> -
> ---
>FAQ on WWW:               http://www.contesting.com/topband.html
>Submissions:              topband@contesting.com
>Administrative requests:  topband-REQUEST@contesting.com
>Problems:                 owner-topband@contesting.com
>
 -
 ---
FAQ on WWW:               http://www.contesting.com/topband.html
Submissions:              topband@contesting.com
Administrative requests:  topband-REQUEST@contesting.com
Problems:                 owner-topband@contesting.com