[ARC5] Using SCR-274N

[Kenneth G. Gordon]

On 28 Mar 2013 at 17:35, Geoff wrote:

> A pair of surplus crystals and a few other small parts would help narrow the 
> bandpass on the wide open sets. It could all be done with a couple of tacked 
> in solder lug strips and easy to reverse. I havent looked at what is 
> actually available but it wouldnt hurt to look.

Yes. Cheap and fairly easy to do, too. Good idea. I haven't done that one, but I'll add it to my 
"bag of tricks".
 
> Slight regeneration of an IF stage would also narrow it a bit without that 
> extreme hollow sound. No parts required maybe, just a gimmick feedback cap 
> grid to plate.

I have done that to my 10 meter '454, and it does help very noticeably.

> I believe Ken also mentioned that the 454 IF 
> transformers look possible to seperate the coils a bit.

Yes. What I am going to do is to make take a bunch of photos of the 1415 Khz IFs as they 
are now, carefully measure the actual IF bandwidth, then "operate" on them, reinstall, realign, 
and measure the resultant IF bandwidth. I expect it to improve, but am not sure how much.

Modifying the IF transformers would take about 15 minutes for each one, and it is fully 
reversible.

"No ARC-5 parts were damaged in the course of this investigation". (Hee hee!) :-)

Ken W7EKB