HR-10b Project

Discussion in '"Boat Anchor" & Classic Equipment' started by W7UUU, Feb 13, 2016.

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  1. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Because "pain" is part of the fun of nostalgia. It reminds you how much better things are now.
    W1BR likes this.
  2. W1BR

    W1BR Premium Subscriber QRZ Page

    Why not?? The real question you are asking is why have a HR-10 if something else is better....
    You have a HR-10, a few BC-453 or R23 receivers laying about, and several other Command
    parts mules in the cellar that your kids are going to eventually dumpster... so why not?

    Why pair a HC-10 with a HQ-150 when you can buy a HQ-170?
  3. KE4OH

    KE4OH Ham Member QRZ Page

    Good on you Dave! I really love my old HR-10B. It was a wreck when I got it. It was really my first basket case fix rig when I got back into amateur radio after a 33-year absence. I got a lot of good advice here on Zed about it. I got it going with a resolder, recap, and some resistor replacements. Figured out how to get it aligned. Added a VR tube to keep the oscillators from wandering too much. Repainted the cabinet.

    It still drifts a bit, but I can live with it. 15m and 10m are deaf, but I've still used it for a few QSOs there. I added an outboard audio filter. And I've since make hundreds of CW QSOs on 80m/40m/20m with it. Best DX so far is Sweden on 40m, France on 20m.

    Is it a good receiver? Not really. But it's good enough. I use mine every week or so and have for years. Great fun! The HR-10 is what I would recommend as a first boatanchor for anyone who wants to dive in and learn how to fix tube gear. They are inexpensive, easy to work on, easy to modify, and actually work fairly well when you are done.
    WD4IGX and WA2LXB like this.
  4. WA2LXB

    WA2LXB XML Subscriber QRZ Page

    That sums up the HR-10B very well, and I like the VR tube idea. I homebrewed an outboard power supply for the HG-10 VFO to keep the DX-60 voltage stable. I've rebuilt the DX-60, the HG-10 and the SA-2060. My HR-10B is a beautiful example, but it is so miswired that I put it away until I got everything else working.

    Question for the HR-10B crowd: Has anyone used an outboard pre-amp or pre-selector with pre-amp for 10M and 15M? If so, please let me know what model you found useful.
  5. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    A far better approach, as pointed out by @N2EY though is still a converter for 80m instead. The reality is the 2nd osc harmonic (not the fundamental) is still used to derive 15 and 10. A preamp and/or preselector would not do anything to resolve that problem. Maybe a preamp to increase the level of that second harmonic but that would be a PITA to do IMO, and have it be stable in the end.

    Of course, as also pointed out, finding crystals for a converter these days isn't all that easy either.

    WA2LXB likes this.
  6. N2EY

    N2EY Premium Subscriber QRZ Page

    Let's do the math....

    To convert 15 meters to 80 meters, the classic approach is to use a 17.5 MHz crystal. That way 3.5 is 21, 3.6 is 21.1, etc.

    To convert the first 500 kHz of 10 meters to 80 meters, the classic approach is to use a 24.5 MHz crystal.

    Both can apparently be supplied by:

    DISCLAIMER: I have no connection to this supplier. The website is from 2009 but is still up.

    Note that the prices include postage.

    AF4K and Surplus Sales of Nebraska are another source. Plus of course the watery auction place.

    But there's more!

    In QST for August, 1962, W1ICP describes "A Three Band Crystal Controlled Converter". This design covers 40, 20 and 15 meters, but is easily modified for other bands.

    The trick with this converter is that it uses FT-243 fundamental crystals in an overtone circuit. Using a 3500 kHz crystal, the third harmonic was 10.5 MHz for 20 and the 5th harmonic was 17.5 MHz for 15.

    The circuit could be used with a 5.833 MHz crystal (3rd overtone is 17.5 MHz) and an 8.166 MHz crystal (3rd harmonic is 24.5 MHz).

    It's also possible to use crystal harmonics in the classic grid-plate circuit, using a tube such as a 6AU6 as the oscillator and tuning the output circuit to a multiple of the crystal frequency. In that way, an 8.75 MHz rock will give output on 17.5 MHz. Problem is, other harmonics, and the fundamental, may be present.


    And one more trick:

    A 25 MHz crystal will permit covering 15 meters and the 28.5-29.0 MHz section of 10 meters, simply by retuning the input circuit. The tradeoff is that 15 meters tunes backwards - 21 MHz is at 4 MHz on the receiver, and 21.5 MHz is at 3.5 MHz.


    One final thought:

    When the HR-10 was in production, HF crystals in FT-243 or HC-6/U holders crystals went for $2.95 to $3.95. Today they're $10 to $20, if you can find them.

    But $1 back then inflates to about $7 now.

    73 de Jim, N2EY
    WA2LXB and W7UUU like this.
  7. W1BR

    W1BR Premium Subscriber QRZ Page

    HR-10 was still a God-send for a Novice who started with a KT-200 Lafayette. It was not as bad as other equal price ranged sets being used by Novices.
    W7UUU likes this.
  8. WA2LXB

    WA2LXB XML Subscriber QRZ Page

    Nice fresh 243s from Bry:

    The consensus is... be happy with the HR-10B on 80, 40, 20 and be even happier when you have the odd QSO on 10 and 15.
    KE4OH and W7UUU like this.
  9. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Thanks for the link, Jim! 3.500 Mc rocks are not that hard to find - even in my own junk box!!

    Just the converter for my BC-454... not quite a Q5er but I do have a nicely working 454 (3.5-4.0 Mc)

    But that's a topic for another day - had not seen that QST article before!! :)

    N2EY likes this.
  10. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    I totally agree. And that, as I've posted, is my plan right now.

    HR-10b/DX-60b/HG-10b as an original builder would have experienced.

    The converter mentioned above will be for my other unrelated project - BC-454 (80m) with 40/20

    Still stuck in Salt Lake on business but home Friday and hope to dig into the final step in this HR-10b project: replacing the broken 80m antenna coil and aligning that band (the other bands have been aligned - 40 and 20 work GREAT right now!!)

    WA2LXB likes this.

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