FORUM PROJECT: 6AQ5 Transmitter from Bert Simon

Discussion in 'Homebrew and Kit Projects' started by AB8RO, Aug 10, 2008.

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  1. KL7AJ

    KL7AJ Ham Member QRZ Page

    Again....from the Opus. :)


    Let us now address each of these points in detail. Number one, electrocution, is a good place to start. Amateur Radio is an electrical hobby. Radio amateurs, for the most part (with a few notable exceptions), have bodies which are every bit as subject to the ill effects of electricity as other mortals. Fortunately, the modern ham shack is far safer in this regard than those of yore. Most modern, commercially made radios have nearly inaccessible sources of dangerous electrical currents. With the advent of low-voltage, solid state technology, you almost have to work at getting a lethal jolt.
    Contrast this with the typical radio shack of half a century ago, which consisted of a loose collection of extremely high-voltage components lashed together with uninsulated jumper cables, sitting on the edge of a water-soaked desk, all powered by a distribution panel populated entirely with glass “fuses” bypassed with corroded copper pennies, and operated by a pre-teen boy sitting on a steel folding chair donning nothing but damp swimming trunks.
    It really is amazing that anyone survived the hobby at all. But here we are.
     
  2. KL7AJ

    KL7AJ Ham Member QRZ Page

    More great crystal grinding tips

    http://www.qsl.net/n6ev/ft243.txt


    Note especially the line... "Go slow; check often." Wiser words never spoken. Use a LIGHT touch!


    Also...note points about applying more pressure near the corners...from several contributors. The reason for this is that you want more mass near the middle, away from where the crystal is suspended. Think of a crystal as a pendulum. The thinner the corners are, the more flexible it will be....thus a higher Q. A crystal with a CONCAVE surface is almost guaranteed not to "start".

    These are tips from decades of accumulated experience. Heed them well.

    But, in any case...DO this. It's a great deal of fun, and extremely educational.

    eric
     
  3. W4HAY

    W4HAY XML Subscriber QRZ Page

    The first thing we did (and do) when encountering any piece of equipment was to brush it gently with our knuckles! Even if the line capacitor is good you can feel a slight tingling as your knuckles drag across the surface.

    I recently purchased a Hammarlund HQ-100 that had the original two-prong power plug and capacitors tying each side of the line to the metal chassis and cabinet. Touching the chassis would give you a nice "buzz" regardless of the way the plug was inserted. It now has a 3-wire power cord and new line capacitors. It's also much less susceptable to power-line noise.
     
    Last edited: Aug 11, 2008
  4. WY6K

    WY6K Ham Member QRZ Page

    Isn't the schematic wrong in that it shows the neon bulb being shorted?
     
  5. AB8RO

    AB8RO Ham Member QRZ Page

    No, that's correct. It's common in old circuits like this. If you have enough power you don't even need one connection you can just tape the bulb to a wooden stick and bring it close to the tank.
     
  6. KL7AJ

    KL7AJ Ham Member QRZ Page

    Yep.....the Johnson Ranger did this. :)

    eric
     
  7. KL7AJ

    KL7AJ Ham Member QRZ Page

    And under certain conditions, the ne2 would change from a cute orange glow to a violent pink. :)
     
  8. W4HAY

    W4HAY XML Subscriber QRZ Page

    Last edited: Aug 13, 2008
  9. N6OMG

    N6OMG Ham Member QRZ Page

    This looks really cool. Two questions though, where would one find an XR-50 form at and the crystal in the schematic is for the frequency I want to operate on, correct?
     
  10. AB8RO

    AB8RO Ham Member QRZ Page

    Yes, the crystal is not doubled or an overtone crystal. The XR50 can be any slug tuned core of about the right dimension. Alternately, one could replace it with a fixed inductor and a variable cap.
     
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