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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

    Jim said - "Use old chassis to make a chassis frame - just the sides and interior shield partitions, but no top. The top consists of various flat plates of aluminum, each with a section of circuitry, that are bolted to the frame. The sections could be: Converter, 80 meter tunable front end, IF, BFO, AGC, audio. Put the power supply on a separate chassis to free up space and reduce heat. That way different ideas could be tried easily."

    I once owned an HBR-16 (someone else built) that was built this way. Each module was on it's own piece of aluminum plate, each plate machine screwed to the chassis, and then interconnects made. It was a mechanical masterpiece and the builder had to been a machinist. Yes it worked well.

    This method would take more time to build but I can see the advantages of being able to simply disconnect wiring to and from the module, then replace just the module. It would certainly be wonderful for experimenting.
     
    N2EY likes this.
  2. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    Karl-Arne wrote: "...Otherwise, making the receiver in sections, each built in the Eddystone/Hammond die-cast boxes is a very tractable way.
    A suitable division could be:
    • Front end, 7360 + first LO and mechanical filter in one box
    • IF, product detector, AGC and BFO in another
    • AF stage and power supply in a third
    Each functional block can be tested and "debugged" separately, and the superior shielding properties of the boxes makes handling of any stability issues much easier.
    If one is really shielding-conscious, a very good way of preserving the integrity is to make an internal partition in each box, with feedthrough filters for all supply voltages after they have entered the box through a suitable connector."


    I have thought about a similar implementation for a first (for me) SS receiver design that I am considering putting each section in it's own shielded box, feed thru's for the DC connections, 50 ohm input output impedance, tiny coax connector/cables for passing signals from one stage to the next.
     
  3. WA9WFA

    WA9WFA XML Subscriber QRZ Page



    Agreed. It is very difficult for those of us with 'light junk boxes' to come up with those exact parts, so like you had to do with your receiver, I'll have to make design changes where necessary to accommodate parts on hand or parts that I can purchase from friends. On the mixer comment, I am coming to that conclusion from my very beginner experience that there are no "miracle mixers" out there, or at least I am not aware of them. So there are plenty of good mixer circuits in the Handbooks that will work well if I don't want to use the expensive tubes.
     
  4. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    N2DTS wrote "Yes, you can also build sections on PCB boards.
    That allows for changes without needing to re do a chassis, having extra holes, or running out of space.
    Once the section works well, it can be added to the finished product.
    At first, I laid parts out on the desk and tac soldered parts together to test LO designs.
    I did not want tickler coils and other complex designs, I wanted one easy to make/get coil and an air variable cap
    as the main parts.
    Testing a few designs got me a good working LO in the ball park for range and output"

    This points out a problem that I am struggling with right now with my Mate for the Mighty Midget receiver. McCoy used air wound coils on 7/8" plastic tubes, with no fine tuning adjustments at all, no compression caps, nothing except adding or subtracting 1/2 a turn on the coils... It's maddening. Even changing silver mica cap LC values have been difficult because the small value changes required. The RF input/output coils around the RF amp have been difficult align tracking, and the HF oscillator alignment is nuts.. I will never, never-ever, nope, Mmm no, uh no, use air wound coils for any oscillator. Nooope.. I will use adjustable coils so I can actually tune the frequency into alignment without aggravation! And you can forget 'tickler coils' to.. hi hi. Since I'm on a roll, any tuned circuit will have adjustability. I don't have any compression caps yet, I'm shopping for them, but once I get some I'm putting them on the RF input/out coils, and the local oscillator so I can just set and forget.

    Speaking of testing designs, I recently had problems with a chassis built oscillator that was crammed into a small space so I built the local oscillator on a breadboard to see if I could get it working properly and tuned to frequency. Then I built it on the chassis. It was way off frequency... Adjustability will be important.
     
  5. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    N2Ey wrote:My solution has been to collect slug-tuned forms and then wind whatever coils are needed, checking inductance and Q on the Q meter.

    I have come to that realization after searching for adjustable ceramic coil forms. Ceramic forms are difficult to find, and pretty much impossible to find at the value that I need. The easier approach is removing turns from a ceramic form until the right inductance is reached, although that ignores the Q. The harder part is winding a coil form and planning for Q. Eventually I will have to learn how to wind a ceramic coil form.
     
  6. WA9WFA

    WA9WFA XML Subscriber QRZ Page

    I think this comment from you Jim hits the nail on the head. I'd like to keep the circuit as close to the HB-67 as reasonably possible because I am uncomfortable going out too far into the weeds with this little experience on board. Your suggestion is spot on: re-draw the '67 schematic into sections, go through each section asking myself how buildable is it based on component availability, commercially available compactron tube prices, or out and out known problems with the circuit.

    I would be comfortable building any deviations on a protoboard and testing them out. It only took me a few hours to build up an HF oscillator circuit and test it out. I recently learned of a technique that all of you already know about, using a 2 channel signal generator to drive both the RF input and the HF oscillator in order to test a MIXER circuit. Gads that works well. My new 2 channel Siglent signal generator helps :). 73 Scott WA9WFA

    I'm still chuckling over your comment about "Fast, good, inexpensive - pick any two". Truer words never spoken.. har har. In my case, I'll go with the fast (meaning getting it done in less than 6 months) and 'good' option. I put a lot of time and effort into these project so I'm not concerned if it's inexpensive or not.
    Thanks. 73 Scott WA9WFA
     
  7. N2DTS

    N2DTS Ham Member QRZ Page

    As far as air wound vs slug tuned coils, the air wound (B+W coil stock) have high Q and seem to be much more stable.
    Coils normally have caps in series or parallel with them to provide the adjustment needed.
    You can get ceramic adjustable coil forms (or you could not that long ago) but they vary a lot with temp changes.
     
  8. N2EY

    N2EY Ham Member QRZ Page

    I should mention that, here at Southgate Radio, the process is....somewhat different.

    The way a "product" comes to be is that the design is based on the parts on hand or easily available. And there should be at least two, preferably three, of each part so that spares are available.

    The result is radios that bear little resemblance to published designs - but they work.

    Ah - almost time for CWT. 81 Qs this morning, 70 Qs this afternoon. Let's see what the Type 7 can do tonight.

    Tally Ho!

    73 de Jim, N2EY
     
    KA9P likes this.
  9. KA9P

    KA9P Premium Subscriber QRZ Page

    [QUOTE

    Ah - almost time for CWT. 81 Qs this morning, 70 Qs this afternoon. Let's see what the Type 7 can do tonight.

    Tally Ho!

    73 de Jim, N2EY[/QUOTE]

    ……surviving during a CWT has to be the true mark of a great homebrew rig
     
  10. N2EY

    N2EY Ham Member QRZ Page

    Surviving?

    https://www.3830scores.com/findcall.php

    Put in my call (upper right corner) and see the scores. 100 watts unassisted.

    Best CWT was 86 Qs in 1 hour, all S&P. 6,880 points.

    Thanks for the kind words

    73 de Jim, N2EY
     
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