[ARC5] Sharpening the RU Receiver with Regeneration

[Kenneth G. Gordon]

On 13 Apr 2013 at 13:02, David Stinson wrote:

> http://home.netcom.com/~arc5/GFRU.JPG

Very nice, David. What models are those?
 
> Here is a short .WMV video file showing what can be 
> done if you work at this.
 
> http://home.netcom.com/~arc5/RURegen.wmv

That sure sounds nice, all right.

> As with any regen receiver- if you move far in frequency,
> you must re-adjust the regeneration.

Well, that effect can be minimized by adding a compensating pot to the back 
of the tuning shaft. RCA did this with both the RAK/RAL and with the RBL. I 
think National did this with the RBL too, but I'd have to check mine to make 
certain.

One other reversible thing you can do to tighten up the passband at the 
detector is to 1) use as small a grid coupling cap as you can, with 2) as high 
value a grid-leak resistor as you can. 

Start with 20 pfd and 20 megohms and adjust both directions to get the 
passband you want. You can adjust the detector passband to the point that it 
will severely cut the sidebands making AM signals sound badly.

I don't know the mechanism for this effect for sure, but I suspect that it 
reduces the load on the tuned circuits which then makes them a lot higher 
"Q", but what do I know?
 
> I'm not trying to work
> the Itchy Armpit, Idaho QSO Party afterall. 

Ah, c'mon! That is one of our more popular events: we usually have at least 
15 stations on the air. ;-)

Most of us dress up formally for that event: a clean pair of jeans and a new T 
shirt.

We also have the Idaho Road Kill Meet, which meets once a year during 
snow season.

Kenneth G. Gordon W7EKB

"Courage is being scared to death but saddling up anyway."--- John   Wayne