Has Anyone Built the HB-67 from the 1967 ARRL Handbook?

Discussion in '"Boat Anchor" & Classic Equipment' started by WA9WFA, Oct 6, 2021.

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  1. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    I am thinking about the next tube receiver project and this HB-67 5 band superhet looks intriguing. It's from the 1967 ARRL Handbook. It is typical of the 1960's design, with the RF being applied directly to the mixer (meaning no RF amplifier), then a Collins mechanical filter, two IF amplifier stages, diode detector, an audio derived AGC, and a couple of audio amplification stages.

    Has anyone here built the HB-67? I'd sure like to hear about it. Thanks. 73, Scott WA9WFA
  2. N2DTS

    N2DTS Ham Member QRZ Page

    I have built two similar receivers and they work fantastic.
    This is the 2nd one:


    Single conversion, no rf amp, mixer feeds right into the KIWA filters (they make the receiver).
    Very low drift, digital freq counter with 455 KHz offset to directly read the frequency, no calibration needed.

    Very low noise, 100 volts on the 6C4 LO, 150 volts on the rest, more then enough gain on 160 to 40 meters and likely 20 with a good antenna.
    The receivers are silent with no antenna connected, and work as well or better then any modern RX even new SDR receivers
    like the 7610 and Flex 6400m.
    They were built to be High Fidelity AM receivers and they work great at that.
    KX4OM, W1BR, KA9P and 2 others like this.
  3. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    Thanks Brett for the photos and information on your HB-67. What a beautiful build! I must say you are a master builder for sure. I looked at your webpage and was amazed at the amount of gear you've built. The HB-67 appears to have all the right parts for a good performing communications radio, including the mechanical filters and two stages of IF amplification. If I recall the article correctly, the HB67 is an 80 meter single conversion with no RF amp, then for 40m or 20m they use a converter which essentially makes it a dual conversion on 40m. Does that sound right?

    I'm at the other end of the building spectrum, and just on my third project. My first receiver was the HBR-13 which was totally the wrong receiver for a beginner. It turned out pretty good, photos on my QRZ page, but it will work better once I get it back on the bench with all this new knowledge and my new test gear. My 2nd receiver was the 1966 Mate for the Mighty Midget. I crammed it into the same space that Lew McCoy did because I wanted the same look and feel. It worked but not well. I was thinking of abandoning it but there was much more to learn so I am in the process of building a 2nd Mate breadboard fashion with lots of space and room. I have it working and it's performance is spectacular so far on both 40m and 80m (using the signal generator for the HF oscillator). I am building the HF oscillator now. Once I'm done with the breadboard Mate I will go back to the "crammed Mate" with my newfound knowledge and confidence, and I figure out the problem.

    I will PM you about details of your HB-67. Thanks! 73, Scott WA9WFA
  4. N2DTS

    N2DTS Ham Member QRZ Page

    I did not build the HB-67 receiver, mine were my own design and built for AM.
    There are some things the same, I used a 6C4 as the LO but with a slightly different setup, and 6BA6 IF amps.

    I used a 6BE6 as the mixer, my antenna input looks similar but only one coil and cap.
    I think I would use a 455 KHz crystal in the bfo over the tuned circuit used in the HB-67.

    Instead of converters, I just move the LO frequency for 160, 80 and 40 (1st receiver) or 80 and 40 on the 2nd one.
    20 would be fine I think but the input tuning would need to be changed (switched coil or a plug in).

    But what I was trying to say was they are not that hard to build, do one stage at a time and test it.
    I did the LO first, trying different designs and component types and found a very stable setup that even worked
    down to 20 volts on the 6C4 plate.

    A cheap or better sdr dongle will help in the testing and calibrating of the stages, you can look at tuning range, drift, amplitude,
    and IF shape with one like the airspy hf+ discovery.

    The biggest problem with building receivers today is the IF transformers and getting a very good low loss IF filter.
    Kiwa used to make great ones but I think they are gone.

    Pictures of my design here, page forward to next stage...
  5. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    Brett you mention something that I learned the hard way on my Mate breadboard receiver, that the best way to build a receiver is to do it one stage at a time, and then test each stage before proceeding. I built my HBR-13 and 'compact Mate' all at once, and then spent an inordinate amount of time troubleshooting AND learning at the same time. With the breadboard Mate I built the RF amp first, and tested it completely before moving on to the HF mixer where I used the 2 channel signal generator for RF and HF oscillator during testing. Ditto for the IF amp, detector, audio, bfo. I am in the middle of building the HF oscillator now, the last piece.

    The other thing I learned is that I need space on a chassis to spread out things. I can't work in a crammed chassis like my compact Mate. I spread out my HBR13L more than Alex Stewart did and that helped me a lot. On the compact Mate, I was trying to duplicate McCoy's work but he was an expert in squeezing circuits in a tiny chassis, I am not. :)

    Your strategy of using a single LC ahead of the mixer was a good call. Tracking of multiple sections can be difficult I've found. On my breadboard Mate I still haven't been able to achieve RF input/output tracking on 80m. I have 40m tracking down cold but on 80 I keep needing to add 47 pF in parallel with the input LC. It's maddening but critical to achieve great sensitivity like I have on 40m.

    I will print out your design and study it. Many thanks for sharing it with me! Your version must be a good performer because I see it front and center in your shack.

    Yes I'm having trouble finding Miller 455 KC IF transformers, and some of the Miller variable inductors. I am buying a Collins 2.1 Kc mechanical filter from a close friend that I plan to use with my HB-67. I might look for a cw filter as well if the receiver works out like I think it will.

    On the converters that W1DX used with his HB-67, I've pondered your strategy as well of just changing the HF oscillator and then provide appropriate LC filtering on the front end. I'd like mine to cover at least 80m, 40m, 30m, 20m and 17m as those are my favorite bands.

    I know there are tons of IF transformers and variable inductors out there in hams parts bins but I haven't been able to shake the tree and free them up. I'd like to find a Miller 2112 dual variable 365 pF variable for my Mate project. If someone has a parts bin with spare IF transformers, please contact me. 73, Scott WA9WFA
  6. N2DTS

    N2DTS Ham Member QRZ Page

    Here is the first receiver I built:

    This was very experimental so I left lots of space between things.
    I like/love octal tubes but learned they are not the best for the LO.
    I also found out slug tuned coil forms for the LO was no good for drift reasons, plus a lot of space between things is not always good.
    Its great at audio, but at RF it can cause problems, so the next receiver had all the stages close together.
    I had to change the IF tubes to tame a feedback problem, lots of gain and things far apart was a bad combination.
    I collected 455 IF cans made for car radios, long ago they had tubes!
    I wanted a broad band IF strip as the filter would do all the selectivity and these were built for AM.
    Mounting the IF cans was an issue as they had a complex pattern, so I used octal sockets.
    That way I could plug in different ones/kinds without rework.
    This receiver covers 160, 80 and 40 with nothing needing changed.
    It drifts quite a bit for the first 5 minutes then is quite good, the drift is from the coils and the big octal tube in the LO.
    That receiver also works very well and sounds slightly better, maybe due to the octal tubes...

    The 2nd one drifts very little from a cold start and almost zero after 2 minutes because I used B+W coil stock for the LO coil and a 6C4.
    Different 6C4 tubes acted much different in drift, some were much more stable then others.
    I suspect that is true no matter what tube is used in the LO, some will be much better then others.

    I have a big collection of parts and did tests with N150, 330, 750 caps to compensate for things warming up.
    Those have negative temp drift to compensate for positive drift of tubes and coils heating up.

    The old handbooks have a lot of great info about IF amp tube types and resistor values and so on.

    If you are building for cw and ssb, different things are important, filtering and drift become the most important things and are harder
    to get great results.

    Simple tube receivers can be super quiet and have a very wide dynamic range if done right, but stability is harder to get high.
    Keep in mind, most receivers back in the 60's were very poor on ssb and cw by todays standards, even the top ones.
    A ham could build one almost or as good as most.
    Now? Not with tubes.
    For AM, my receivers work as good or better then most modern rigs which tend to be noisy and low fidelity.
    The VERY low noise in the receiver circuits and a very good filter make them work very well on AM.

    I wrote up the 2nd receiver in Electric radio magazine and quite a few people built it, most better looking then mine.
    One person made circuit boards for each stage, lo/mixer, if strip, detector/agc/s meter and it looked sharp!
    At that time I gave away a lot of the IF transformers I had got from an old TV repair shop going out of business.

    At one time I thought about building a CW rig using the basic RX #2 design but never did.
    Single signal reception kind of threw me, CW offsets, and so on...
    You can do all that and more with half a fist full of chips and so on so it seems a bit silly...
  7. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    Hi Brett, Many thanks for the details of your first receiver project. For a first project that was definitely a complicated radio. I will check out your 2nd receiver article in ER magazine. I have all the ER issues since No. 1.

    I can appreciate your 'experimental nature' of your first receiver. I built my Mate for the Mighty Midget to match McCoy's look and feel. He was a master builder, I am not. I had a lot of problems debugging it, so many that I decided to build a new breadboard version of the Mate where the circuits are spread out, reducing unintentional cross coupling, leaving me room to troubleshoot and experiment. I'm working on the HF oscillator now.

    I'm curious about the vernier drive(s) on your 1st receiver. From my view, it looks like there is a National Velvet Vernier on the front panel, and then a separate vernier dial behind the Velvet Vernier. Am I seeing that right? If so, what is that 2nd vernier drive behind the VV? I've never seen one like that before.

    For your 'similar to HB-67' receiver, what did you use for the AGC transformer, 10K primary, 40K split winding push-pull secondary?

    No I didn't know that someone made pc boards for your #2 tube receiver project. That must have been so fun to build! Who did that?

    I'm starting to look for the 'unobtainium' parts for my HB-67. If anyone has an oversupply of tube radio parts, I'd like to talk about buying some IF transformers and other parts.

    Thanks, 73 Scott WA9WFA
  8. N2EY

    N2EY XML Subscriber QRZ Page

    @WA9WFA & friends....

    The 1967 Handbook was my second Handbook, obtained when it was just out, even before I had a license. (My first was the 1949 edition - and if you think things change rapidly today, you should see how much changed in those 18 years!) I've studied the HB-67 design ever since - it has its strong and weak points. Some observations:

    Strong points:

    1) The HB-67 is relatively simple and straightforward - the basic receiver section is only 6 tubes plus voltage regulator, the converter section is only 2 tubes.

    2) The circuitry is conventional - no trick circuits.

    3) Alignment requires only very basic test equipment.

    4) Mechanical design doesn't require a lot of fancy metal work. Chassis, front panel, two shield partitions and done.

    Weak points:

    5) The HB-67 uses a number of parts that were common in 1967 but will be hard to find and/or expensive today. The 7360 mixer tube, the two Compactrons, the various slug tuned coils, the audio iron, the crystals, the mechanical filter, the dial/coupling/tuning capacitor and bandswitch present some serious challenges if you don't have them already. There are work-arounds for some of these issues.

    6) The HB-67 covers 80/75, 40, 20, 15, and the first 600 kHz of 10 meters. No provision is made for full 10 meter coverage nor for the WARC bands (which of course were far in the future in 1967). These issues can be fixed but a larger chassis will be needed to accommodate the added parts, most of which are in the hard-to-find category - plus the bandswitch.

    7) The HB-67 is optimized for SSB, and has some problems with CW and AM. The mechanical filter is far too wide for anything but very casual CW, while it is far too narrow for AM - and the BFO can't be turned off.

    8) In the HB-67, 40 meters tunes backwards (7.0 is at 4.1 MHz on the dial, 7.1 at 4.0 MHz, etc.) This is a minor annoyance if you're not used to it.

    9) There is no 100 kc. calibrator, nor provision to adjust the tunable oscillator for heterodyne crystals that aren't dead on the marked frequencies.

    10) The AGC is very basic audio-derived AGC, which is only applied to the two IF stages.

    11) There is no gain control of the converter section; all stages operate at full gain all the time.

    12) The tuning capacitor may not be the best choice for stability. Also, the unbuffered tunable oscillator isn't the most stable implementation.

    13) The chassis layout is generally good but doesn't allow much room for expansion, parts substitutions or changes.

    14) There's no provision for muting the receiver when transmitting, which is odd, considering that the HB-65 predecessor had a muting jack.

    15) The 600 kHz tuning range means that with a 36 turn dial the tuning rate is 16.6 kHz per turn. That's fast IMHO, although pretty common back-when. I'm not sure if the MD-8 dial is 36 turns for a half-revolution of the output shaft (actual reduction 72 to 1) or only 18 turns (actual reduction ratio 36 to 1).

    16) The audio output is low impedance but the schematic says "PHONES". This may mean the overall gain isn't enough to drive a speaker - or - it may just mean they didn't provide switching to choose 'phones or speaker.

    Most of the above can be fixed up. I can list what I'd do if anyone is interested.

    73 de Jim, N2EY
  9. VE3CGA

    VE3CGA XML Subscriber QRZ Page

    nice build !
    that layout looks very familiar and I may have built one of those
    can some one please post a schematic or the article of it,
    7360 mixer, collins mech filter sounds familiar and 40M being backwards on the dial, wasnt the front end coil double tuned or something?
    This might have been my version
    I do remember using it and changing the front end for dual gate mosfets. That woke it up for 20 & 15M
    My first attempt at circuit boards, custom design with a tiny model brush + nail polish. I might still have those around in the "old stuff" pile
    Might have built it around 1973ish
    It sounded very "Drake "like with the audio derived agc and fed into a pacer 8 spkr

    it was a nice project but really needed the fet front end
  10. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    Jim, I for one would love to hear what your recommendations would be. I am not concerned about duplicating the article 100% as I wouldn't want to duplicate problems that have been identified since then.. I'd like to build a nice 60's era tube receiver that is stable, good for both SSB and CW, selective, (who wouldn't, right?). For CW I was thinking of adding a 500 Hz or 800 Hz mechanical filter. I have a 2.1 Kc filter now. I had not looked into the compactron prices, took a look, yikes.. On the AGC, yes it is audio derived. I would prefer IF derived but I don't have much experience with either.

    I've been looking at various mid 60's receiver designs and thought this one could be a nice compromise between performance and complexity. I built an HBR-13 and it took me years, difficult mechanicals, and my first ever receiver project so I was way out of my comfort zone.

    Your buffered oscillator comment is good. I'm working on a receiver now and would prefer no pulling or anything. Honestly in the back of my mind I'm wondering if I should try one of the new Si5351 synthesizer module with an Arduino micro driving it. I've seen SS receivers using this rock stable oscillator with one channel driving the HF oscillator and the 2nd channel driving the BFO. For me, the oscillators have been the most difficult to implement. A tube oscillator with a buffer would be a big step towards that.

    I have a 6:1/36:1 Jackson Bros drive now.

    I would have a BFO on/off switch and a panel mounted variable cap as well.

    Why would its 3 gang tuning capacitor not be the best choice for stability?

    So yes your experience and suggestions would be very helpful to me. Thanks. 73 Scott WA9WFA
    KA9P likes this.

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