[HBR] Cheap & Easy Selectivity

[William Hopkins]

Eddy, 

Please send me the info as well. Thanks so much 

ciao 
Bill Hopkins AA2YV 
Rochester NY 


----- Original Message ----- 
From: "Edward Swynar" <gswynar at durham.net> 
To: hbr at mailman.qth.net, "homebuilttuberadios" <homebuilttuberadios at yahoogroups.com>, "Old Tube Radios" <glowbugs at piobaire.mines.uidaho.edu>, AmRadGear at yahoogroups.com, boatanchors at mailman.qth.net, "Welcome to the Novice Rigs List!" <novice-rigs at mailman.qth.net>, antiquewirelessassociation at egroups.com 
Sent: Friday, August 21, 2009 9:51:50 AM GMT -05:00 US/Canada Eastern 
Subject: Re: [HBR] Cheap & Easy Selectivity 

Hi Gang, 

Well, 29 requests received here for scanned copies of the regenerative IF 
"RADIO" magazine article, 29 scans e-mailed to those very same interested 
parties... 

Last call---have I missed anyone...? 

~73!~ Eddy VE3CUI - VE3XZ 


*********************************************************** 


----- Original Message ----- 
From: Edward Swynar 
To: hbr at mailman.qth.net ; homebuilttuberadios ; Old Tube Radios ; 
AmRadGear at yahoogroups.com ; boatanchors at mailman.qth.net ; Welcome to the 
Novice Rigs List! ; antiquewirelessassociation at egroups.com 
Sent: Thursday, August 20, 2009 3:43 PM 
Subject: Re: Cheap & Easy Selectivity 


Hi Again Everyone, 

If anyone is interested, I just finished scanning the regenerative IF 
article from the November 1940 issue of "RADIO" magazine, and would be more 
than pleased to send it along to whomever it is that might be interested... 

It's two pages in length---I reduced the size & converted the files to jpeg 
format, so that they might be a bit easier to download for those of us 
(myself included!) who are still still on dial-up internet service. 

As mentioned previously, this particular design---according to the 
author---goes one step beyond the simple "...two wires side by side to 
achieve regeneration in an IF stage" approach. Indeed, he says that not only 
is the signal of interest boosted in strength by virtue of this circuit, but 
interfering signals are actually reduced by a corresponding amount. 

As anyone knows who has ever tried a regenerative IF stage, this does not 
happen by design, i.e. the reduction in signal strength of adjacent 
frequency QRM. 

Anyway, it all sounds like a very neat design, albeit requiring the trouble 
of having to wind a scramble-wound coil & installing it at the base of the 
secondary winding of the IF transformer. 

~73!~ Eddy VE3CUI - VE3XZ 


**************************************************** 
----- Original Message ----- 
From: Edward Swynar 
To: hbr at mailman.qth.net ; homebuilttuberadios ; Old Tube Radios ; 
AmRadGear at yahoogroups.com ; boatanchors at mailman.qth.net ; Welcome to the 
Novice Rigs List! ; antiquewirelessassociation at egroups.com 
Sent: Thursday, August 20, 2009 11:13 AM 
Subject: Cheap & Easy Selectivity 


Good Morning All, 

I just ran across a sweet little article in a 1940 issue of the old "RADIO" 
magazine on a fool-proof way of adding selectivity & gain in an IF stage 
that (supposedly) approaches that obtainable with a resonant crystal 
filter...but without the filter insertion loss, of course. 

The design is rather obscure in that I've never seen anything quite like it 
in any ARRL publication. Suffice it to say that it goes a bit extra beyond 
the mere "...place-the-plate-lead-into-the-IF-can" approach of achieving 
feedback, yet it still looks very "do-able", and I plan to incorporate it 
into my 1929-style 12-tube superhet here. 

If anyone has access to any of the West Coast Handbooks of the late 30's, 
you'll see the design used in the "Super/Ultra Gainer" receiver designs 
described therein... 

Wish me luck! 

~73~ Eddy VE3CUI - VE3XZ 


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