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Regenerative Converters

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  • John Berry.
    Hi All.The postings on this remided me,as a kid (back in the Stone Age now,hi,hi)I had a Short Wave Converter This was in a BIG wooden case with COPPER
    Message 1 of 6 , Nov 1, 2006
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      Hi All.The postings on this remided me,as a kid (back in the Stone Age
      now,hi,hi)I had a Short Wave "Converter" This was in a BIG wooden case
      with COPPER screening tacked to the base and front panel,was truly
      1920's with Plugin Airspaced coils for Aerial/Tuning/Regeneration
      etc.Used a 2vlt Triode (HL2)as conventional Grid Leak detector,the
      Anode of the Tube went through a Massive RF choke to HT with a 500pf
      capacitor OUT !! (There was NO AUDIO OUT),you connected the 500pf to
      the Aerial socket of another RX tuned to LONG WAVES,ajusted the Regen
      on the "Converter" untill it JUST Oscillated and tuned the short wave
      trough it !!!.Worked well into TRF set,even better into Superhet,hi,hi.
      Was so good in later years (in my teens) built similar on Metal
      Chassis with a 455kcs IF strip,this also worked well,plenty of
      stations,PERHAPS most were IMAGIES hi,hi.Oh those good old days !!!
      Only wish I had that original now.John G1WOS.BRISTOL Uk.
    • Gary Johanson
      I got the idea of making that converter regenerative thanks to a 1938 issue of QST. While leafing thru it one day i came across a double regenerative
      Message 2 of 6 , Nov 1, 2006
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        I got the idea of making that converter regenerative thanks to a 1938
        issue of QST. While leafing thru it one day i came across a "double
        regenerative" receiver where the author made the front end, a
        conventional pentode RF amp, regenerative. I thought "hey, why not
        try that?" so.... i did. It didn't take more than extending the
        plate connect so that i could get a few winds around the top part of
        the front end LC. Generally, impedances in the cathode are fairly
        low, i used a 50k pot only because it was the only one i had. More
        than likely i could fare better with 10k or less, and have a bit more
        precision in the control, but tuning a Q multiplier like this really
        doesn't require that kind of control. Generally you just give it a
        little "nudge", and run the feedback as low as is adequate for your
        needs.

        Initially i needed it to attenuate images from marine station NMR.
        Now, of course, all those stations are closed. Funny..... i would
        love to hear those images again. They represent another era slipped
        away.

        gary // wd4nka

        "dah-dit dah-dah di-dah-dit,
        dah-dit dah-dah di-dah-dit,
        dah-dit dah-dah di-dah-dit,
        dah-di-dah"

        ...sigh!



        --- In regenrx@yahoogroups.com, "John Berry." <jbbr35487@...> wrote:
        >
        > Hi All.The postings on this remided me,as a kid (back in the Stone
        Age
        > now,hi,hi)I had a Short Wave "Converter" This was in a BIG wooden
        case
        > with COPPER screening tacked to the base and front panel,was truly
        > 1920's with Plugin Airspaced coils for Aerial/Tuning/Regeneration
        > etc.Used a 2vlt Triode (HL2)as conventional Grid Leak detector,the
        > Anode of the Tube went through a Massive RF choke to HT with a
        500pf
        > capacitor OUT !! (There was NO AUDIO OUT),you connected the 500pf
        to
        > the Aerial socket of another RX tuned to LONG WAVES,ajusted the
        Regen
        > on the "Converter" untill it JUST Oscillated and tuned the short
        wave
        > trough it !!!.Worked well into TRF set,even better into
        Superhet,hi,hi.
        > Was so good in later years (in my teens) built similar on Metal
        > Chassis with a 455kcs IF strip,this also worked well,plenty of
        > stations,PERHAPS most were IMAGIES hi,hi.Oh those good old days !!!
        > Only wish I had that original now.John G1WOS.BRISTOL Uk.
        >
      • Hue Miller
        Gary: Your BC-453, did you set up the IF coupling for max selectivity, or ssb bandpass? Did you renumber the dial plate at all? Do you have a ballpark figure
        Message 3 of 6 , Nov 1, 2006
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          Gary:
          Your BC-453, did you set up the IF coupling for max
          selectivity, or ssb bandpass?
          Did you renumber the dial plate at all?
          Do you have a ballpark figure on how many kcs per revolution of
          tuning knob, this thing delivers?

          Also, with the 'dual conversion' command sets routine, is the LF
          receiver used as a kind of 'incremental tuning', where the 3-6 or
          6-9 receiver is set to, say, the nearest 50 or 100 kcs mark and
          the rest of the tuning done with the BC-453?
          Tnx- -Hue
        • Gary Johanson
          (this is somewhat related to Regen in topic in that a regen converter is being utilised, although the bulk is information on the BC-453. But there may be some
          Message 4 of 6 , Nov 2, 2006
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            (this is somewhat related to Regen in topic in that a regen converter
            is being utilised, although the bulk is information on the BC-453.
            But there may be some on list interested, so i'll go ahead and post
            my whole response to Hue.)

            Hi, Hue:

            --- In regenrx@yahoogroups.com, "Hue Miller" <kargo_cult@...> wrote:
            >
            > Gary:
            > Your BC-453, did you set up the IF coupling for max
            > selectivity, or ssb bandpass?

            ***** What i did was peak the IF by ear. Then i offset what i
            think to be the final IF for SSB. I don't have a lot of documentation
            on the BC-453, what i have is a mental collection of hints and kinks
            given to me over the years. There is a tuning port on the bottom
            right side of the '453 that permits ss filtering of one sideband or
            the other. I assume it's LO tuning. (If there is a way i can further
            narrow the filtering for CW, i would like to know.)

            Heh, the only documentation i have regarding the BC453 is an old
            manual from the '40s on how to convert it to receive 10m by tearing
            out the front end and making extensive irreversible modifications.
            So i am certainly open to more information and suggestions! As it is
            now, it comfortably receives SSB, does quite well for cw, although i
            wouldn't mind a little more audio attenuation of the "highs". It is
            too narrow for AM, although i can tune to the side of an AM sig to
            pick up enough of the highs to make sense of the information on the
            carrier. If i tune dead in the middle the way it's set, i cannot hear
            a whole lot of intelligence.

            One other comment i'll make about my BC-453: at the time i got it,
            back around 1977, i knew nothing about it, what it was, or that there
            was a whole raft of command sets around. I had an old 1961 QST that
            had some tips on connecting them, and that's how i found out what
            output when where. Never saw the first schematic for it until i
            joined Glowbugs back in '97 and Ken directed me to a link. I took
            one look at it and said to myself "hah, ok. I'll just leave 'er as
            she is." So much for my technical bravery (and academic prowess.)
            One thing that always dogged me was the low audio output. Fine for
            headsets, but i always wanted a little "headroom". I did change out
            the tubes and that quieted her some, but volume was still pretty
            moderate. The regen converter really souped it up in that area. Like
            day and night! Oddly enough, the noise did not increase all that
            much as far as i noticed, but cw/ssb is very comfortable with the
            audio just cracked open a tad. Far as i'm concerned, the REAL guru
            is Ken Gordon. That guy is incredible. And helpful enough to call me
            up from Montana to walk me thru the tuning of an SB102. Next time you
            talk to him, tell him gary says hi!

            > Did you renumber the dial plate at all?
            > Do you have a ballpark figure on how many kcs per revolution of
            > tuning knob, this thing delivers?

            > Also, with the 'dual conversion' command sets routine, is the LF
            > receiver used as a kind of 'incremental tuning', where the 3-6 or
            > 6-9 receiver is set to, say, the nearest 50 or 100 kcs mark and
            > the rest of the tuning done with the BC-453?
            > Tnx- -Hue
            >

            ***** Initially i used 2 xtals for 40m, a 6700 and 6900kc set. The BC-
            453 did the tuning. I extrapolated directly from the dial with about
            as much accuracy as you can from, say, a Drake 2a or b. 6700 put the
            cw subband at 300 - 450 kc, which is where the '453 is quietest and
            there is less chance of birdies. Naturally, 6900 brought the phone
            portion (7200 - 7300kc) within that same relative range, 300 - 500kc.

            80m was different. Originally i only had a colourburst xtal, so that
            threw the dial off for direct easy extrapolation. If you note in the
            photos on that link, there is a grey dial plate which i bolted over
            the original. It was slightly smaller so i could still read the
            original dial for 40m. I calibrated that grey plate by pencil. It
            was fine . . . i could hear 75m very nicely, although i am not a 75m
            phone op. I was interested in the 75m AM window at the time, despite
            the narrowness of the passband. Eventually one of my Regenerodynes
            took over AM reception duty and i took that dial plate off.

            About a year ago, Bry located a 3500kc xtal, and i procured a 6800kc
            xtal as well. 80/75 tunes 3700-4000, giving me just a bit of cw and
            all of the phone band with 200kc - 500kc. Making that converter
            regenerative helped the image situation down at the 200kc range. And,
            of course, 6800 gives me 7000-7300 tuning 200-500kc.

            Would you believe i never changed a single cap in this thing? Still
            use the original bathtubs. I figure if it ain't broke, don't fix it.
            :>)

            Sorry for the longish post. Hope this info is useful.

            Good Providence in all your endeavours!
            gary // wd4nka
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