Topband: Preamp power supply

[John Rogers]

----- Original Message -----
From: "N1BUG" <paul at n1bug.net>
To: <topband at contesting.com>
Sent: Thursday, February 24, 2005 3:35 PM
Subject: Topband: Preamp power supply


>
> I am looking for suggestions on *aggressive* power supply
> decoupling / filtering for my W7IUV preamp.  The preamp
> works great when powered from a battery but is totally
> useless on the power supply I built for it.  Experiments
> thus far have not led to an acceptable solution.
>

I had similar noise problems, building the PSU and preamp in the same box,
which eventually were fixed by a small ferrite choke in series with the DC
supply and an extra 0.47uF capacitor, both on the PSU PCB.
Choke value - estimated at 200uH - made by winding about 100 turns of 24
guage wire on small ferrite choke former.

73's
John G3PQA