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Thread: My impoved mystery crystal set by G0CWA

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  1. #1
    Join Date
    Apr 2012
    Location
    Near Manchester in UK
    Posts
    123

    Default My impoved mystery crystal set by G0CWA

    Hi as suggested by one of the forum members I have descided to present my home made radios as shown on http://makearadio.com/index.php The first of many I am going to show you is my version of the mystery crystal set with both improved sensitivity and selectivity.

    For a full write up and building instructions check http://makearadio.com/visitors/nick-mystery.php basically I have built a standard set but with an unusual twist to improve its perfomance.



    I hope you find this set worth your interest, or even having a go at yourself.

    I made the tuning scale by printing onto a printable mirrored cd and the tuning pointer is a small clock hand on the capacitor shaft

    Happy building and 73 for now Nick G0CWA

  2. #2
    Join Date
    Aug 2008
    Location
    SanDiego, People's Republic of California FEMA District 9
    Posts
    40,024

    Default

    That is very, very cool.
    Makes me want to build one.
    When it's time, and it may be sooner than you think.

  3. #3
    Join Date
    Apr 2012
    Location
    Near Manchester in UK
    Posts
    123

    Default

    Why not have a go Sue?
    Quote Originally Posted by AF6LJ View Post
    That is very, very cool.
    Makes me want to build one.

  4. #4
    Join Date
    Aug 2008
    Location
    SanDiego, People's Republic of California FEMA District 9
    Posts
    40,024

    Default

    Quote Originally Posted by G0CWA View Post
    Why not have a go Sue?
    It's been a project on the back burner for a while.
    An ex-coworker gave some galania (sorry spelling) from his families mine in Idaho.
    The plan has been to mount peaces of the crystal and build a crystal set.
    When it's time, and it may be sooner than you think.

  5. #5
    Join Date
    Feb 2004
    Location
    Bakersfield, CA
    Posts
    4,772

    Default

    Hi Nick, well another great posting and it got Sue's attention which is good.
    Sue needs to check out some of your other offerings like the mechanical audio amplifier using a carbon rod. That was really neat.
    73
    Gary

  6. #6
    Join Date
    Apr 2012
    Location
    Near Manchester in UK
    Posts
    123

    Default

    Hi Sue

    OK about the galena, but if you do build one put a small signal diode, eg an 1N34A in as well to tune in the stations first before setting the crystal detector it makes things alot easier mine is hidden under the board all you need to do to bring it into play is put the whisker on the brass drawing pin. Also mount the galena pieces in woods metal or low melting point solder usually available from model making shops to solder white metal castings.

    No Gary it is not cheating to use a diode as well!

  7. #7
    Join Date
    Feb 2004
    Location
    Bakersfield, CA
    Posts
    4,772

    Default

    Okay Nick.....but with a 1N34A you don't get to play with the contact whisker. Some times you can get it to surpass the sensitivity of the 1N34A. Other times... well try again. There have been tricks with the diodes to get them more sensitive. Applying a bias voltage to them works well but that is definately cheating.
    Have fun
    73
    Gary

  8. #8

    Default

    I especially like your carbon beam amplifier.

  9. #9
    Join Date
    Apr 2012
    Location
    Near Manchester in UK
    Posts
    123

    Default

    From the nice posative comments I can see the carbon amp should be the next one! thanks. I'll post it in a few days. Thank you for all the comments.

    73 for now Nick G0CWA

  10. #10

    Default

    Quote Originally Posted by AF6LJ View Post
    That is very, very cool.
    Makes me want to build one.
    Sue, if you'd like, I can drop a microwave diode in the mail to you. I've gotten much better results with them than the 1N34A.

    Quote Originally Posted by G0CWA View Post
    ...I made the tuning scale by printing onto a printable mirrored cd and the tuning pointer is a small clock hand on the capacitor shaft...
    Neat idea! Now we wanna see the back of the set.

    I have a set with a Tuggle front end, and solenoid and spiderweb coils on sliding tracks. One of these days maybe I can get picture of it. I also have a 76 tube on a wooden base that connects to it as a grid leak detector.
    "A Republic, if you can keep it" -- Ben Franklin

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