[Milsurplus] BC-229, RU selectivity

[Hue Miller]

The objection, I suppose, is that to do this right, you kind of need an 
external (additional)
control box with a knob for selectivity/gain ?
I'm still thinking. Maybe a selective  regenerative RF gain stage BEFORE the 
receiver. At
3.8 MHz, one MOSFET.  Of course, that makes tuning around kind of a chore.
OR, if downconverting to the RU operating at LF, a Franklin type oscillator, 
single FET,
at the first tuned circuit in the RU, with a wire run out to an external pot 
for control.
This oscillator is a two-port, doesn't require addition of tuned circuit, 
uses tuned circuit
in place in this receiver.

Now re the BC-348, if the xtal is too sharp for A3, does it help to off tune 
the tuned
ckt associated with the crystal? That's how the xtal bandpass is determined 
in this
kind of crystal circuit, if the load is not variable.
Just thinking about how to keep them all flying.
-Hue

-----Original Message----- 
From: Jack Antonio
Sent: Friday, August 01, 2014 4:24 PM
To: Hue Miller ; milsurplus
Subject: Re: [Milsurplus] BC-229, RU selectivity

On 8/1/2014 3:38 PM, Hue Miller wrote:
>How about using a converter from the 80M band down to say, the 300-400
kcs range, and then using an
> LF coil in the rec?

I've done this.
......

Dave Stinson has reported success with regeneration to improve
RU selectivity, (and I applaud his efforts), but that approach just
never appealed to me.

Jack Antonio WA7DIA/4