Regenerative receivers. - UK Vintage Radio Repair and Restoration Discussion Forum

ms660 · 16th Nov 2014, 2:37 pm

Has anyone tried this concept for consistent regen level:

http://www.kearman.com/vladn/hybrid_feedback.pdf

I've also read that a similar effect can be got in the Armstrong topology by using a CR combination in the feedback network. If I can find the link for that I will post it.

Lawrence.

ms660 · 16th Nov 2014, 2:48 pm

Found the link:

http://theradioboard.com/rb/viewtopic.php?f=1&t=5894

Lawrence.

G6Tanuki · 16th Nov 2014, 2:52 pm

I've never thought of "Vackar-izing" a regenerative stage - though I've used Vackar (and related Seiler) circuits in VFOs.
They're probably the easiest way to get relatively-linear tuning and good frequency stability if you need only a small range of tunability (my application was as an 8MHz VFO that got multiplied to cover 144-146MHz).

"AGC" in a regen stage is an interesting idea - it of course would only really work in situations where you're trying to receive a signal where there's a constant carrier. Given the relatively poor selectivity of regen stages when the regen's not turned-up very much I'd be concerned about the AGC being activated by strong off-frequency local signals. Still, it's an interesting thing to think about!

[my personal interest is in phase-locked synchronous detectors]

ms660 · 16th Nov 2014, 3:48 pm

Here is the guy who wrote the article in the first link, it's a utube video in 2 parts, here is the 1st part, I will add another link for the 2nd part to this post if I can find it.

In this 1st part he shows the tuning range of the hybrid Vackar/Armstrong Regen and also the amplitude of the osc across that range when set to the sweet spot, the range is approx 3.3 Mhz to approx 9 Mhz so a tuning ratio of nearly 3x

http://www.youtube.com/watch?v=Frg5RYz84gs

EDIT: Here's the link for the 2nd part, same frequency coverage, he has set the Regen threshold for the sweet spot for AM reception as that is the best test.

http://www.youtube.com/watch?v=zKRpV...ature=youtu.be

Lawrence.

16th Nov 2014, 2:37 pm	#1
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Regenerative receivers. Has anyone tried this concept for consistent regen level: http://www.kearman.com/vladn/hybrid_feedback.pdf I've also read that a similar effect can be got in the Armstrong topology by using a CR combination in the feedback network. If I can find the link for that I will post it. Lawrence.

16th Nov 2014, 2:48 pm	#2
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Regen's Found the link: http://theradioboard.com/rb/viewtopic.php?f=1&t=5894 Lawrence.

16th Nov 2014, 2:52 pm	#3
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: Regen's I've never thought of "Vackar-izing" a regenerative stage - though I've used Vackar (and related Seiler) circuits in VFOs. They're probably the easiest way to get relatively-linear tuning and good frequency stability if you need only a small range of tunability (my application was as an 8MHz VFO that got multiplied to cover 144-146MHz). "AGC" in a regen stage is an interesting idea - it of course would only really work in situations where you're trying to receive a signal where there's a constant carrier. Given the relatively poor selectivity of regen stages when the regen's not turned-up very much I'd be concerned about the AGC being activated by strong off-frequency local signals. Still, it's an interesting thing to think about! [my personal interest is in phase-locked synchronous detectors]

16th Nov 2014, 3:48 pm	#4
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Regenerative receivers. Here is the guy who wrote the article in the first link, it's a utube video in 2 parts, here is the 1st part, I will add another link for the 2nd part to this post if I can find it. In this 1st part he shows the tuning range of the hybrid Vackar/Armstrong Regen and also the amplitude of the osc across that range when set to the sweet spot, the range is approx 3.3 Mhz to approx 9 Mhz so a tuning ratio of nearly 3x http://www.youtube.com/watch?v=Frg5RYz84gs EDIT: Here's the link for the 2nd part, same frequency coverage, he has set the Regen threshold for the sweet spot for AM reception as that is the best test. http://www.youtube.com/watch?v=zKRpV...ature=youtu.be Lawrence. Last edited by ms660; 16th Nov 2014 at 3:55 pm. Reason: Link and text addition