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Re: Call for comment on circuits found on the web (LNS)

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  • Bill Cromwell
    Hi Les, I would like to point out some of the penalties of using solid state devices in place of vacuum tubes. If you need to add a function or another gain
    Message 1 of 8 , Nov 1, 2007
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      Hi Les,

      I would like to point out some of the penalties of using solid state
      devices in place of vacuum tubes. If you need to add a function or
      another 'gain block' or two or three ... well they cost pennies. Less
      than a drink of water in many places. You will have to find someplace
      else for your money.

      They won't fill up a big cabinet like vacuum tubes and their
      associated parts. Whole radios might be small enough to misplace.

      They consume so little energy that your car battery will get fat n
      lazy running them. You will be unable to keep your coffee hot because
      they produce inadequate warming heat.

      And finally you won't get that warm fuzzy glow or the 'scent' from the
      hot dust.

      On the other hand... a lot of people seem to get very good performance
      from them.

      And now I'm back to my tube regenerodyne project. Please keep us posted.

      73 (and a wink),

      Bill KU8H
    • Les Smith
      Bill: ... Your well aimed humour has struck a mark. In every way I can see it s a step back-wards to move away from valves ... More seriously, there has been
      Message 2 of 8 , Nov 1, 2007
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        Bill:
        Quote:
        >" I would like to point out some of the penalties of using solid
        >state devices in place of vacuum tubes."

        Your well aimed humour has struck a mark. In every way I can see it's
        a step back-wards to move away from valves ...

        More seriously, there has been a LOT of discussion in our local radio
        club about lack of home-brew, promoted to a large degree by Geoff,
        VK2GL. He produced a list of projects called 'bring back home brew',
        and a regen set was one item on his list. But Geoff can't do all the
        work himself, and I've ALWAYS wanted to make a supergainer since I
        read the Frank Jones Radio Handbook. This was the 1937/8 edition, and
        I read it in 1971. I noticed an 'interesting' design, with a seperate
        "Q" multiplier. But Mr Jones set called for valves that I didn't have
        in 1971!

        There is no doubt in my mind that a valve super-gainer would give
        better performance, device for device, but (and here is my secret
        weapon) if I build one extra stage THAT will compensate. Plus, (I
        thought) a printed circuit card will allow even novice club members to
        build their "own" radio. That meant (horror) SOLID STATE. So,
        realising I was on an inferior road, I set off ... collecting circuit
        (from Arnie, Gary J, Charles K, and so on). I had interesting
        correspondence with fellows like Bill M. And I collected a hoard of
        knowledge from Regen Rx - my secret source of knowledge.

        Here is my second secret weapon. Nothing (nothing) promotes ham radio
        more than the satisfaction of HOMEBREW - yet so few people build. The
        WWII surplus market created an entire generation of enthusiasts. In
        our club at Westlakes we have over 200 hundred members, but only about
        10 people under 30 years of age. (Notice I don't even ask 'why?')
        There is much less satisfaction in operating a commercial set than
        building your own, and there simply isn't a surplus source of radios
        now. So we need to make our own, but the original 'pool of knowledge'
        that was once every radio repair shop has gone - it's all in China!
        It's not easy to build a radio - even a regen - from scratch. Regen
        sets are the very best compromise between performance and simplicity.
        Enough performance to use daily on 80 meters, yet simple enough to
        actually build. So, promoting regens as a homebrew rig is a good
        idea.

        As soon as some club members laid down the rule "all new parts" for a
        project, valves (toobs) were out. So the design must be solid state -
        with their inferior performance. BUT - isn't that a challenge? To
        discover the reason why valves perform better? Hint: see my original
        post.

        Next point: It's clear from carefully reading the various postings on
        RegenRx that low gain devices perform better as a detector. Low mu
        tubes perform more smoothly as regen detectors. 42 tubes perform
        best of all. Why, dear reader, is this so? Only an un-natural lack
        of curiosity could avoid asking this question!

        And the glorious answer? A regen detector operates as a negative
        resistance device, or more precisely about the point of zero
        resistance. Consider the slope of the resistance curve as we approach
        the critical operating point. On one side (as we approach
        regeneration) it is positive. On the other side (in oscillation) it
        is negative. The change from positive resistance (ie regenerating) to
        negative (oscillating) is a 'nose', and the slope of the resistance at
        this point is zero. Best control (smooth regeneration) takes place
        'on the nose' and a broad noses mean less sensitive adjustement of the
        regen control.

        Since transistors (FETs) have lower gain than valves, then perhaps
        this can be an advantage? We'll know after the club builds a few
        dozen of these little sets.

        One final point: Gary J has shown the way in terms of solid
        mechanical construction. Some builders "skimp" on the most important
        part of the set, and then performance suffers. (Of course builders of
        "authentic" sets should continue what can only be called "fine"
        reproductions, with read wood-grain etc showing) but 'reproduction'
        regen sets have a completely different purpose - historical accuracy -
        than a functional receiver.) I built my prototype regen rig in an
        aluminium diecast box, and I hope the club will promote a 'robust'
        style of mechanical construction. Not just a card, with a cap and
        coil 'floating in space', but a chassis and solid dial mechanism.
        Again, us 'solid state types' can learn a good deal from the earlier
        construction styles used in valve rigs. But please, I beg: No
        construction like the Hammarlund "Super". 50 kgs for a radio IS too
        much! Note this Bill: Some tube types do go 'over the top' and
        Hammarlund was one ....

        Now Bill, your original post was a joke, and I've ruined it by giving
        a serious response ... That's the way with us Aussies. We're poor
        sports. We can never see a joke. We ruin everything ... except
        cricket ... Cricket is different. Come over here and try us out ...

        Les

        (original message from Bill follows)

        --- In regenrx@yahoogroups.com, "Bill Cromwell" <w_r_cromwell@...>
        wrote:
        >
        > Hi Les,
        >
        > I would like to point out some of the penalties of using solid state
        > devices in place of vacuum tubes. If you need to add a function or
        > another 'gain block' or two or three ... well they cost pennies.
        Less
        > than a drink of water in many places. You will have to find
        someplace
        > else for your money.
        >
        > They won't fill up a big cabinet like vacuum tubes and their
        > associated parts. Whole radios might be small enough to misplace.
        >
        > They consume so little energy that your car battery will get fat n
        > lazy running them. You will be unable to keep your coffee hot
        because
        > they produce inadequate warming heat.
        >
        > And finally you won't get that warm fuzzy glow or the 'scent' from
        the
        > hot dust.
        >
        > On the other hand... a lot of people seem to get very good
        performance
        > from them.
        >
        > And now I'm back to my tube regenerodyne project. Please keep us
        posted.
        >
        > 73 (and a wink),
        >
        > Bill KU8H
        >
      • Larry Beaty
        Les, So nice to hear of your project. all new components . Just where are you going to get the tuning cap? That question has bugged me for some time. I do
        Message 3 of 8 , Nov 1, 2007
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          Les,

          So nice to hear of your project. "all new components". Just where are you
          going to get the tuning cap? That question has bugged me for some time. I
          do hope you have a solution.

          Larry



          From: regenrx@yahoogroups.com [mailto:regenrx@yahoogroups.com] On Behalf Of
          Les Smith
          Sent: Thursday, November 01, 2007 1:56 AM
          To: regenrx@yahoogroups.com
          Subject: [regenrx] Call for comment on circuits found on the web (LNS)





          Hello RegenRx Group:
          I have followed group discussion with great interest for some time.
          Collectively there is a great deal of pooled knowledge in the minds of
          group members, and the RegenRx archives. Some-day I plan to 'trawl'
          the archives and collect the various comments into summaries on
          various topics.

          Now I wish to participate. Graham Firth (G3MFJ) published a circuit
          for a solid state regenerative set. I send the circuit, observing
          that I believe Arnie Coro may have commented on this cct previously.
          In short the set has a convential bipolar RF amplifier, followed by an
          "anode" bend (or 'drain-bend') regen detector. This is rather like a
          cathode (or emitter) follower, where the detected signal is taken from
          the top of the source resistor. Regeneration is provided by a
          Colpitts "Q" multiplier, capacatively coupled to the grid (errr ...
          gate) of the detector.

          Three stages of directly coupled AF amplification drive headphones.
          In summary a nice solid state receiver. I built several experimental
          version of the detector and "Q" multiplier prior to drafting the
          artwork for a PC card. I wish to build a club project - a "Jones"
          supergainer. A supergainer is, (IMHO) slightly more difficult to
          assemble than a regenerodyne (since the stability depends on a well
          constructed VFO, and building THAT demands some skill). At the same
          time I believe the selectivity will be marginally better than the
          regenerodyne, as the detection will take place at either 450, 900 or
          1800 kHz (ie the chosen IF frequency.) Pay a little more ... get a
          little more ...

          Q1. How many people in the group have built a Regen Rx with a 'drain-
          bend' FET detector? Mr Kitchin has published FET detectors which use
          the 'drain-bend' as a regenerative detector, and has commented on the
          quality (i.e. lower distortion) achived with this circuit. I will
          read any comment on this circuit with great interest. Some version of
          this circuit I built were NOT distortion free.

          Q2. The G3MFJ circuit uses a "Q" multiplier circuit to provide
          regeneration. Mr Jones published a circuit similar to this in the
          1937 (or 38) "Jones Radio Handbook". He wrote that this method of
          regeneration gave 'smooth' regeneration. I can say this was true for
          several of the 'test' circuits I built, although I found the component
          values were frequency dependent. However, for a Jones supergainer,
          the fixed IF frequency will avoid this problem. The circuit has
          another advantage - no need to find a 'throttle' capacitor to control
          the feedback. Newer constructors may not always find a 200 pF
          throttle capacitor in their parts box.

          Plus, I wish to present this set as a club project for the Westlakes
          Radio Club; every part must be available new, not from the junk box.
          Hence my interest in a circuit that avoids the 'throttle' capacitor.

          Again, I welcome comments from group members who have used this "Q"
          multiplier circuit (or even a valve version of the same). Recently
          Wes W7ZOI described & published a similar circuit for a zero power
          receiver - that is within the last month. (Oct 2007)

          Q3. This (Q3) is on the subject of coils. There are many posts on
          the subject of coils, and a number of very informative web sites about
          this. Again Wes Hayward has published experimental work describing
          results he obtained from various styles of tank coil construction. He
          specifically refers to basket weave coils, standard 'solenoid'
          construction, coils wound on FT-114-61 toroids and ferrite rod and he
          reports attaining a "Q" of around 350 for coils wound on #61 ferrite.
          Since the entire unit depends on the detector tank circuit, this needs
          to have highest Q and be readily copied. Interestingly W7ZOI's work
          suggests that a tank built on #61 ferrite gives performance comparable
          with basket weave coils, and superior to a conventional solenoid coil.


          I wait comment from any group member who has experience with coils
          built on ferrite rod. I used some tank inductors wound of -43
          material. Sigh - regen tank circuits wound on FR-50-43 ferrite cores
          NEVER worked.

          Q4. Charles Kitchin/ARRL published a circuit for a regen set using a
          cascode RF stage and conventional 'grid-leak' detector. This used a
          'tickler' winding to achieve feedback. Classic 0V1 from the 40's ARRL
          handbook. The 'tickler' winding eliminates one transistor from the
          cct - the bipolar "Q" multiplier, but (I suspect) is not so 'smooth'
          in control. In terms of getting a 'throttle' cap, it seems that this
          may be formed by a series combination of a fixed cap (eg 1000 pF) in
          series with a variable capacitance diode. The fixed cap isolates the
          Vcc from the diode 'throttle' capacitor, and the VCD acts as the
          'throttle'.) I have never built the circuit, (or tried a var. cap.
          diode as a 'throttle) but would be interest to get comment from
          anyone who has built the 1995 ARRL/Kitchin regen set. (or tried a VCD
          throttle).

          There seems to be a greater interest in 'tube' regen sets, and the
          reason for this is clear in my mind. The higher operating voltage
          demands a higher value of load (plate) resistor. This results in more
          gain, and with only 3 or 4 active stages giving x1,000,000
          amplification every part HAS to contribute. I would like to promote
          an interest in getting the same performance with solid state regen
          receivers - even if we need to add an additional stage.

          So, in concluding, I "I'm waiting to read a collection of interesting
          comments from group members".

          Les.

          (Circuits mentioned come from the web, and are in the folder "Solid
          State Regen Ccts (LNS)"





          [Non-text portions of this message have been removed]
        • Les Smith
          ... components . Just where ... question has bugged me ... solution. ... Hello Larry: Very interesting Q: Where will I get a tuning cap? Generally this
          Message 4 of 8 , Nov 1, 2007
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            --- In regenrx@yahoogroups.com, "Larry Beaty"
            <hlbeaty@...> wrote:
            >
            > Les,
            >
            > So nice to hear of your project. "all new
            components". Just where
            > are you going to get the tuning cap? That
            question has bugged me
            > for some time. I do hope you have a
            solution.
            >
            > Larry

            Hello Larry:
            Very interesting Q: Where will I get a tuning
            cap? Generally this question needs to be asked
            in the bigger context of 'what sort of dial
            drive will I use?' The mechanical design of
            the set is at least as important (maybe more
            important) than the electrical design. Gary J.
            will agree with this point, I'm certain.

            Answer:
            When I lay out the PC card I intend to provide
            several alternative layouts, including room on
            the card for a tuning system using variable
            capacitance diodes (eg available from www dot
            kitsand parts.com) (well suited to tuning the
            mixer tank circuit) and conventional air caps.

            Back to back Zeners:
            For a limited tuning range two back-to-back 5.6
            zeners will give 60-75 pF variation. I mean
            that the pair of zeners is effectively a
            capacitor min=60pF and max=75 pf, a variation
            of 15 pF. (The range is NOT 60-75). This will
            suit the BFO, for example. For an 1800 kHz IF,
            20uH with 390 pF tunes to 1800 kHz. 375 pF
            gives 1810 kHz. Since this is spread over one
            full turn of a pot (ie 270 degrees) this
            amounts to a tuning rate of about 10 kHz per
            revolution, and for 'touching up' SSB, this
            will be very useful.

            As I wrote above, I plan to lay out the PC card
            to allow builders to use theur own 'junk-box
            specials' - good quality air caps salted caps
            away for 'that special project'. At least one
            of the sets I build will use one of these I got
            from eBay. There are a nice air caps at
            times. Mine has a 50:1 worm reduction, with
            anti-back-lash worm drive AND an extended shaft
            that would take a dial drum. (Do you not feel
            a little twinge of envy, Gary? Not an HRO
            dial, but still very nice ....)

            I note that Jackson brothers still sell air
            caps and reducation drives. Expensive? Yes.
            Quality? Yes.

            The mixer tuning is the easy part. The VFO
            (main local oscillator) tuning is more
            demanding. I have found that any specific
            capacitor has it's own thermal coefficient, and
            this makes a problem for a club project, as it
            requires individual compensating caps. N150
            and N750 caps are available. P100 or P150 are
            much rarer.

            I have some 'dreams' about the VFO, VFO dial
            and tuning capacitor but I prefer to say nil
            about this until I have a working model. I
            think the VFO is sufficiently important to be
            built on a separate card. This is more
            expensive than including the VFO on the main
            card, modular construction has good advantages.
            It is more expensive, but allows
            experimentation and modification.

            The 'command' sets (ARC-5, design by F. Drake)
            have a very flexible design, based on modular
            construction. By changing all the modules (IF
            transformers, Mixer/VFO coil box, BFO unit &
            co) any ARC radio can be converted to a
            different model. Not only that, but every
            radio in the set (BC-453, 454, 455 or 946) can
            be exchanged for another radio in the receiver
            rack. While these are single band sets, it is
            very instructive to study both their circuit
            and their construction, taking notice of the
            modularity in the design.

            I have never seen a proposal for a ham band
            radio with a modular design. Yet care thought
            given to a modular design would provide an
            interesting test bed for home-brewing. For
            example if the IF-detector system in a
            supergainer consisted of a single plug in
            module, fed by a separate mixer converter, it
            could be replaced, turning a super-gainer into
            a conventional superhet, perhaps with a crystal
            filter. Built a CW set, and need to upgrade
            the exciter to SSB? Don't thow away the rig,
            just pull out the CW exciter and use the
            existing linear and power supply! The main
            difficulty in such a design would come in
            anticipating the design (and interconnection)
            of future modules, and running control wiring
            to the control panel.

            But I am straying from topics regenerative in
            general and "where to get current capacitive
            components" in particular, so I end.

            AR K


            Les.


            PS Larry, I took careful note of the two diode
            limiter circuit you put on RegenRx a week or so
            ago. This cct may find a home in this regen.


            >
          • Ian Foster
            G day Les. I m an Ozzie and take exception to your comments about sense of my humour, sorry about yours! :-) Hi Hi See my ealier posts about some upgrading I
            Message 5 of 8 , Nov 2, 2007
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              G'day Les.

              I'm an Ozzie and take exception to your comments about sense of my
              humour, sorry about yours! :-)
              Hi Hi
              See my ealier posts about some upgrading I did the the Dick
              Smith "Fun Way". An emiter coupled Q multiplier turned a slug in a
              useable receiver, even need a an RF gain control and fine tuning.
              Worked well on AM and could resolve SSB quite well.

              73s
              Ian

              --- In regenrx@yahoogroups.com, "Les Smith" <les.au49@...> wrote:
              >
              > Bill:
              > Quote:
              > >" I would like to point out some of the penalties of using solid
              > >state devices in place of vacuum tubes."
              >
              > Your well aimed humour has struck a mark. In every way I can see
              it's
              > a step back-wards to move away from valves ...
              >
              > More seriously, there has been a LOT of discussion in our local
              radio
              > club about lack of home-brew, promoted to a large degree by Geoff,
              > VK2GL. He produced a list of projects called 'bring back home
              brew',
              > and a regen set was one item on his list. But Geoff can't do all
              the
              > work himself, and I've ALWAYS wanted to make a supergainer since I
              > read the Frank Jones Radio Handbook. This was the 1937/8 edition,
              and
              > I read it in 1971. I noticed an 'interesting' design, with a
              seperate
              > "Q" multiplier. But Mr Jones set called for valves that I didn't
              have
              > in 1971!
              >
              > There is no doubt in my mind that a valve super-gainer would give
              > better performance, device for device, but (and here is my secret
              > weapon) if I build one extra stage THAT will compensate. Plus, (I
              > thought) a printed circuit card will allow even novice club
              members to
              > build their "own" radio. That meant (horror) SOLID STATE. So,
              > realising I was on an inferior road, I set off ... collecting
              circuit
              > (from Arnie, Gary J, Charles K, and so on). I had interesting
              > correspondence with fellows like Bill M. And I collected a hoard
              of
              > knowledge from Regen Rx - my secret source of knowledge.
              >
              > Here is my second secret weapon. Nothing (nothing) promotes ham
              radio
              > more than the satisfaction of HOMEBREW - yet so few people build.
              The
              > WWII surplus market created an entire generation of enthusiasts.
              In
              > our club at Westlakes we have over 200 hundred members, but only
              about
              > 10 people under 30 years of age. (Notice I don't even
              ask 'why?')
              > There is much less satisfaction in operating a commercial set than
              > building your own, and there simply isn't a surplus source of
              radios
              > now. So we need to make our own, but the original 'pool of
              knowledge'
              > that was once every radio repair shop has gone - it's all in
              China!
              > It's not easy to build a radio - even a regen - from scratch.
              Regen
              > sets are the very best compromise between performance and
              simplicity.
              > Enough performance to use daily on 80 meters, yet simple enough to
              > actually build. So, promoting regens as a homebrew rig is a good
              > idea.
              >
              > As soon as some club members laid down the rule "all new parts"
              for a
              > project, valves (toobs) were out. So the design must be solid
              state -
              > with their inferior performance. BUT - isn't that a challenge?
              To
              > discover the reason why valves perform better? Hint: see my
              original
              > post.
              >
              > Next point: It's clear from carefully reading the various
              postings on
              > RegenRx that low gain devices perform better as a detector. Low
              mu
              > tubes perform more smoothly as regen detectors. 42 tubes perform
              > best of all. Why, dear reader, is this so? Only an un-natural
              lack
              > of curiosity could avoid asking this question!
              >
              > And the glorious answer? A regen detector operates as a negative
              > resistance device, or more precisely about the point of zero
              > resistance. Consider the slope of the resistance curve as we
              approach
              > the critical operating point. On one side (as we approach
              > regeneration) it is positive. On the other side (in oscillation)
              it
              > is negative. The change from positive resistance (ie
              regenerating) to
              > negative (oscillating) is a 'nose', and the slope of the
              resistance at
              > this point is zero. Best control (smooth regeneration) takes
              place
              > 'on the nose' and a broad noses mean less sensitive adjustement of
              the
              > regen control.
              >
              > Since transistors (FETs) have lower gain than valves, then perhaps
              > this can be an advantage? We'll know after the club builds a few
              > dozen of these little sets.
              >
              > One final point: Gary J has shown the way in terms of solid
              > mechanical construction. Some builders "skimp" on the most
              important
              > part of the set, and then performance suffers. (Of course
              builders of
              > "authentic" sets should continue what can only be called "fine"
              > reproductions, with read wood-grain etc showing)
              but 'reproduction'
              > regen sets have a completely different purpose - historical
              accuracy -
              > than a functional receiver.) I built my prototype regen rig in an
              > aluminium diecast box, and I hope the club will promote a 'robust'
              > style of mechanical construction. Not just a card, with a cap and
              > coil 'floating in space', but a chassis and solid dial mechanism.
              > Again, us 'solid state types' can learn a good deal from the
              earlier
              > construction styles used in valve rigs. But please, I beg: No
              > construction like the Hammarlund "Super". 50 kgs for a radio IS
              too
              > much! Note this Bill: Some tube types do go 'over the top' and
              > Hammarlund was one ....
              >
              > Now Bill, your original post was a joke, and I've ruined it by
              giving
              > a serious response ... That's the way with us Aussies. We're
              poor
              > sports. We can never see a joke. We ruin everything ... except
              > cricket ... Cricket is different. Come over here and try us
              out ...
              >
              > Les
              >
              > (original message from Bill follows)
              >
              > --- In regenrx@yahoogroups.com, "Bill Cromwell" <w_r_cromwell@>
              > wrote:
              > >
              > > Hi Les,
              > >
              > > I would like to point out some of the penalties of using solid
              state
              > > devices in place of vacuum tubes. If you need to add a function
              or
              > > another 'gain block' or two or three ... well they cost pennies.
              > Less
              > > than a drink of water in many places. You will have to find
              > someplace
              > > else for your money.
              > >
              > > They won't fill up a big cabinet like vacuum tubes and their
              > > associated parts. Whole radios might be small enough to misplace.
              > >
              > > They consume so little energy that your car battery will get fat
              n
              > > lazy running them. You will be unable to keep your coffee hot
              > because
              > > they produce inadequate warming heat.
              > >
              > > And finally you won't get that warm fuzzy glow or the 'scent'
              from
              > the
              > > hot dust.
              > >
              > > On the other hand... a lot of people seem to get very good
              > performance
              > > from them.
              > >
              > > And now I'm back to my tube regenerodyne project. Please keep us
              > posted.
              > >
              > > 73 (and a wink),
              > >
              > > Bill KU8H
              > >
              >
            • Jim Hill
              Could you provide a link to G3MFJ s site? He s treasurer of the GQRP club, and their tech site http://www.interalia.plus.com/q_tech.htm doesn t have info on
              Message 6 of 8 , Nov 2, 2007
              • 0 Attachment
                Could you provide a link to G3MFJ's site? He's treasurer of the GQRP
                club, and their tech site http://www.interalia.plus.com/q_tech.htm
                doesn't have info on regen sets. Another search gave me photos he has
                taken, one link is http://www.g3mfj.fsnet.co.uk/g3mfj/.
                Jim



                At 10:56 PM 10/31/2007, you wrote:



                >Hello RegenRx Group:
                >I have followed group discussion with great interest for some time.
                >Collectively there is a great deal of pooled knowledge in the minds of
                >group members, and the RegenRx archives. Some-day I plan to 'trawl'
                >the archives and collect the various comments into summaries on
                >various topics.
                >
                >Now I wish to participate. Graham Firth (G3MFJ) published a circuit
                >for a solid state regenerative set. I send the circuit, observing
                >that I believe Arnie Coro may have commented on this cct previously.
                >In short the set has a convential bipolar RF amplifier, followed by an
                >"anode" bend (or 'drain-bend') regen detector. This is rather like a
                >cathode (or emitter) follower, where the detected signal is taken from
                >the top of the source resistor. Regeneration is provided by a
                >Colpitts "Q" multiplier, capacatively coupled to the grid (errr ...
                >gate) of the detector.
                >
                >Three stages of directly coupled AF amplification drive headphones.
                >In summary a nice solid state receiver. I built several experimental
                >version of the detector and "Q" multiplier prior to drafting the
                >artwork for a PC card. I wish to build a club project - a "Jones"
                >supergainer. A supergainer is, (IMHO) slightly more difficult to
                >assemble than a regenerodyne (since the stability depends on a well
                >constructed VFO, and building THAT demands some skill). At the same
                >time I believe the selectivity will be marginally better than the
                >regenerodyne, as the detection will take place at either 450, 900 or
                >1800 kHz (ie the chosen IF frequency.) Pay a little more ... get a
                >little more ...
                >
                >Q1. How many people in the group have built a Regen Rx with a 'drain-
                >bend' FET detector? Mr Kitchin has published FET detectors which use
                >the 'drain-bend' as a regenerative detector, and has commented on the
                >quality (i.e. lower distortion) achived with this circuit. I will
                >read any comment on this circuit with great interest. Some version of
                >this circuit I built were NOT distortion free.
                >
                >Q2. The G3MFJ circuit uses a "Q" multiplier circuit to provide
                >regeneration. Mr Jones published a circuit similar to this in the
                >1937 (or 38) "Jones Radio Handbook". He wrote that this method of
                >regeneration gave 'smooth' regeneration. I can say this was true for
                >several of the 'test' circuits I built, although I found the component
                >values were frequency dependent. However, for a Jones supergainer,
                >the fixed IF frequency will avoid this problem. The circuit has
                >another advantage - no need to find a 'throttle' capacitor to control
                >the feedback. Newer constructors may not always find a 200 pF
                >throttle capacitor in their parts box.
                >
                >Plus, I wish to present this set as a club project for the Westlakes
                >Radio Club; every part must be available new, not from the junk box.
                >Hence my interest in a circuit that avoids the 'throttle' capacitor.
                >
                >Again, I welcome comments from group members who have used this "Q"
                >multiplier circuit (or even a valve version of the same). Recently
                >Wes W7ZOI described & published a similar circuit for a zero power
                >receiver - that is within the last month. (Oct 2007)
                >
                >Q3. This (Q3) is on the subject of coils. There are many posts on
                >the subject of coils, and a number of very informative web sites about
                >this. Again Wes Hayward has published experimental work describing
                >results he obtained from various styles of tank coil construction. He
                >specifically refers to basket weave coils, standard 'solenoid'
                >construction, coils wound on FT-114-61 toroids and ferrite rod and he
                >reports attaining a "Q" of around 350 for coils wound on #61 ferrite.
                >Since the entire unit depends on the detector tank circuit, this needs
                >to have highest Q and be readily copied. Interestingly W7ZOI's work
                >suggests that a tank built on #61 ferrite gives performance comparable
                >with basket weave coils, and superior to a conventional solenoid coil.
                >
                >
                >I wait comment from any group member who has experience with coils
                >built on ferrite rod. I used some tank inductors wound of -43
                >material. Sigh - regen tank circuits wound on FR-50-43 ferrite cores
                >NEVER worked.
                >
                >Q4. Charles Kitchin/ARRL published a circuit for a regen set using a
                >cascode RF stage and conventional 'grid-leak' detector. This used a
                >'tickler' winding to achieve feedback. Classic 0V1 from the 40's ARRL
                >handbook. The 'tickler' winding eliminates one transistor from the
                >cct - the bipolar "Q" multiplier, but (I suspect) is not so 'smooth'
                >in control. In terms of getting a 'throttle' cap, it seems that this
                >may be formed by a series combination of a fixed cap (eg 1000 pF) in
                >series with a variable capacitance diode. The fixed cap isolates the
                >Vcc from the diode 'throttle' capacitor, and the VCD acts as the
                >'throttle'.) I have never built the circuit, (or tried a var. cap.
                >diode as a 'throttle) but would be interest to get comment from
                >anyone who has built the 1995 ARRL/Kitchin regen set. (or tried a VCD
                >throttle).
                >
                >There seems to be a greater interest in 'tube' regen sets, and the
                >reason for this is clear in my mind. The higher operating voltage
                >demands a higher value of load (plate) resistor. This results in more
                >gain, and with only 3 or 4 active stages giving x1,000,000
                >amplification every part HAS to contribute. I would like to promote
                >an interest in getting the same performance with solid state regen
                >receivers - even if we need to add an additional stage.
                >
                >So, in concluding, I "I'm waiting to read a collection of interesting
                >comments from group members".
                >
                >Les.
                >
                >(Circuits mentioned come from the web, and are in the folder "Solid
                >State Regen Ccts (LNS)"
                >
                >


                [Non-text portions of this message have been removed]
              • Leslie Smith
                Hello Jim. The link for the circuit was and is: http://www.radiohc.org/Distributions/Dxers/regen2.html so my reference to Graham Firth, and my knowledge of the
                Message 7 of 8 , Nov 2, 2007
                • 0 Attachment
                  Hello Jim.

                  The link for the circuit was and is:
                  http://www.radiohc.org/Distributions/Dxers/regen2.html

                  so my reference to Graham Firth, and my knowledge of
                  the circuit comes from acknowledgement given on that
                  site. I hope this is the information you seek.

                  It's an interesting circuit, and I have learned a good
                  deal from studying it; I'm grateful to both G3MFJ and
                  CO2KK for the opportunity to do that.

                  Les Smith





                  --- Jim Hill <slimjimwas@...> wrote:

                  > Could you provide a link to G3MFJ's site? He's
                  > treasurer of the GQRP
                  > club, and their tech site
                  > http://www.interalia.plus.com/q_tech.htm
                  > doesn't have info on regen sets. Another search gave
                  > me photos he has
                  > taken, one link is
                  > http://www.g3mfj.fsnet.co.uk/g3mfj/.
                  > Jim
                  >
                  >
                  >
                  > At 10:56 PM 10/31/2007, you wrote:
                  >
                  >
                  >
                  > >Hello RegenRx Group:
                  > >I have followed group discussion with great
                  > interest for some time.
                  > >Collectively there is a great deal of pooled
                  > knowledge in the minds of
                  > >group members, and the RegenRx archives. Some-day I
                  > plan to 'trawl'
                  > >the archives and collect the various comments into
                  > summaries on
                  > >various topics.
                  > >
                  > >Now I wish to participate. Graham Firth (G3MFJ)
                  > published a circuit
                  > >for a solid state regenerative set. I send the
                  > circuit, observing
                  > >that I believe Arnie Coro may have commented on
                  > this cct previously.
                  > >In short the set has a convential bipolar RF
                  > amplifier, followed by an
                  > >"anode" bend (or 'drain-bend') regen detector. This
                  > is rather like a
                  > >cathode (or emitter) follower, where the detected
                  > signal is taken from
                  > >the top of the source resistor. Regeneration is
                  > provided by a
                  > >Colpitts "Q" multiplier, capacatively coupled to
                  > the grid (errr ...
                  > >gate) of the detector.
                  > >
                  > >Three stages of directly coupled AF amplification
                  > drive headphones.
                  > >In summary a nice solid state receiver. I built
                  > several experimental
                  > >version of the detector and "Q" multiplier prior to
                  > drafting the
                  > >artwork for a PC card. I wish to build a club
                  > project - a "Jones"
                  > >supergainer. A supergainer is, (IMHO) slightly more
                  > difficult to
                  > >assemble than a regenerodyne (since the stability
                  > depends on a well
                  > >constructed VFO, and building THAT demands some
                  > skill). At the same
                  > >time I believe the selectivity will be marginally
                  > better than the
                  > >regenerodyne, as the detection will take place at
                  > either 450, 900 or
                  > >1800 kHz (ie the chosen IF frequency.) Pay a little
                  > more ... get a
                  > >little more ...
                  > >
                  > >Q1. How many people in the group have built a Regen
                  > Rx with a 'drain-
                  > >bend' FET detector? Mr Kitchin has published FET
                  > detectors which use
                  > >the 'drain-bend' as a regenerative detector, and
                  > has commented on the
                  > >quality (i.e. lower distortion) achived with this
                  > circuit. I will
                  > >read any comment on this circuit with great
                  > interest. Some version of
                  > >this circuit I built were NOT distortion free.
                  > >
                  > >Q2. The G3MFJ circuit uses a "Q" multiplier circuit
                  > to provide
                  > >regeneration. Mr Jones published a circuit similar
                  > to this in the
                  > >1937 (or 38) "Jones Radio Handbook". He wrote that
                  > this method of
                  > >regeneration gave 'smooth' regeneration. I can say
                  > this was true for
                  > >several of the 'test' circuits I built, although I
                  > found the component
                  > >values were frequency dependent. However, for a
                  > Jones supergainer,
                  > >the fixed IF frequency will avoid this problem. The
                  > circuit has
                  > >another advantage - no need to find a 'throttle'
                  > capacitor to control
                  > >the feedback. Newer constructors may not always
                  > find a 200 pF
                  > >throttle capacitor in their parts box.
                  > >
                  > >Plus, I wish to present this set as a club project
                  > for the Westlakes
                  > >Radio Club; every part must be available new, not
                  > from the junk box.
                  > >Hence my interest in a circuit that avoids the
                  > 'throttle' capacitor.
                  > >
                  > >Again, I welcome comments from group members who
                  > have used this "Q"
                  > >multiplier circuit (or even a valve version of the
                  > same). Recently
                  > >Wes W7ZOI described & published a similar circuit
                  > for a zero power
                  > >receiver - that is within the last month. (Oct
                  > 2007)
                  > >
                  > >Q3. This (Q3) is on the subject of coils. There are
                  > many posts on
                  > >the subject of coils, and a number of very
                  > informative web sites about
                  > >this. Again Wes Hayward has published experimental
                  > work describing
                  > >results he obtained from various styles of tank
                  > coil construction. He
                  > >specifically refers to basket weave coils, standard
                  > 'solenoid'
                  > >construction, coils wound on FT-114-61 toroids and
                  > ferrite rod and he
                  > >reports attaining a "Q" of around 350 for coils
                  > wound on #61 ferrite.
                  > >Since the entire unit depends on the detector tank
                  > circuit, this needs
                  > >to have highest Q and be readily copied.
                  > Interestingly W7ZOI's work
                  > >suggests that a tank built on #61 ferrite gives
                  > performance comparable
                  > >with basket weave coils, and superior to a
                  > conventional solenoid coil.
                  > >
                  > >
                  > >I wait comment from any group member who has
                  > experience with coils
                  > >built on ferrite rod. I used some tank inductors
                  > wound of -43
                  > >material. Sigh - regen tank circuits wound on
                  > FR-50-43 ferrite cores
                  > >NEVER worked.
                  > >
                  > >Q4. Charles Kitchin/ARRL published a circuit for a
                  > regen set using a
                  > >cascode RF stage and conventional 'grid-leak'
                  > detector. This used a
                  > >'tickler' winding to achieve feedback. Classic 0V1
                  > from the 40's ARRL
                  > >handbook. The 'tickler' winding eliminates one
                  > transistor from the
                  > >cct - the bipolar "Q" multiplier, but (I suspect)
                  > is not so 'smooth'
                  > >in control. In terms of getting a 'throttle' cap,
                  > it seems that this
                  > >may be formed by a series combination of a fixed
                  > cap (eg 1000 pF) in
                  > >series with a variable capacitance diode. The fixed
                  > cap isolates the
                  > >Vcc from the diode 'throttle' capacitor, and the
                  > VCD acts as the
                  > >'throttle'.) I have never built the circuit, (or
                  > tried a var. cap.
                  > >diode as a 'throttle) but would be interest to get
                  > comment from
                  > >anyone who has built the 1995 ARRL/Kitchin regen
                  > set. (or tried a VCD
                  > >throttle).
                  > >
                  > >There seems to be a greater interest in 'tube'
                  > regen sets, and the
                  > >reason for this is clear in my mind. The higher
                  > operating voltage
                  > >demands a higher value of load (plate) resistor.
                  > This results in more
                  > >gain, and with only 3 or 4 active stages giving
                  > x1,000,000
                  > >amplification every part HAS to contribute. I would
                  > like to promote
                  > >an interest in getting the same performance with
                  > solid state regen
                  > >receivers - even if we need to add an additional
                  > stage.
                  > >
                  > >So, in concluding, I "I'm waiting to read a
                  > collection of interesting
                  > >comments from group members".
                  > >
                  > >Les.
                  > >
                  > >(Circuits mentioned come from the web, and are in
                  > the folder "Solid
                  > >State Regen Ccts (LNS)"
                  > >
                  > >
                  >
                  >
                  >
                  === message truncated ===


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