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Tragic Ham Radio Story

Discussion in 'Amplifiers' started by 357, Apr 26, 2018.

  1. 357

    357 Walkin' the dog

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    something to keep in mind working on amps
     
    LeapFrog likes this.

  2. undertaker

    undertaker Undertaker

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    Wow!!!!!!
     
  3. 9C1Driver

    9C1Driver Sr. Member

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    Yea you don't mess with tube amps unless you know what your doing. Heck even a cap in a Texas Star will bite ya and really get your attention.
     
  4. 543_Dallas

    543_Dallas Sr. Member

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    I saw pictures of a guys hand with severe tussue damage. He wasn't working on the amp. He got bit by touching his watt meter. Garage built amp from some half assed amp builder had no choke to ground after the blocking cap. The plate blocking cap failed and lit him up.
     
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  5. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    NOT GOOD! That's how a couple thousand volts can end up on your antenna giving new meaning to the term putting fire in the wire.
     
  6. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    My wife HATED it when I would get called out in the middle of the night and have to go work on a transmitter that was off the air. She knew I would be tired and depending which TX was off the air it could be up to a two hour drive one way and I would be dealing with either 2500 volts, 3100 volts or 5000 volts and alone. I was never real fond of the idea but always managed to keep my wits about me. I always figured the drive back home when REALLY tired was the really dangerous part of the call out.
     
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  7. loosecannon

    loosecannon Sr. Member

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    well i think they have to take that amp out to a field and shoot it now that it has a taste for human flesh.

    too soon?
    LC
     
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  8. nomadradio

    nomadradio Analog Retentive

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    The RF choke that's in parallel with the Load control is called the "safety" choke.

    For a reason.

    73
     
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  9. loosecannon

    loosecannon Sr. Member

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    Nomad, I remember asking you about this choke in my amp build project. I was having some trouble figuring out what its purpose was and man am I glad you were there to explain it to me.
    LC
     
  10. 543_Dallas

    543_Dallas Sr. Member

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    They get left out of the big ceramic tube amps and it's scary. I hear there's a lot of wizard built amps without them. It would be a good thing for anyone that owns one to double check.
     
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  11. 357

    357 Walkin' the dog

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  12. loosecannon

    loosecannon Sr. Member

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    I think i've seen that arc flash video more than five times now.


    543, that is scary!

    i wonder if they get left out because people don't know how to determine the value and current handling capabilities.

    I know i would like to know how to do that.
    LC
     
  13. 543_Dallas

    543_Dallas Sr. Member

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    I don't think they know that it is needed and most are just copying someone else. I watched a couple of you tube videos of home brew tube amps earlier and didn't see a safety choke. They should know how to build one because it's the same theory as a plate choke.

    I would use a heavy enough choke to take a few times the rated current of the power supply for a few seconds. The glitch resistor or fuse on the primary side of the hv transformer should pop in less than a second. I don't see why you can't test the choke with low voltage at the same amperage but I'm no engineer.

    You can test your choke at the desired frequency with a grain of wheat light and a dummy load. If the bulb doesn't light with 100 watts carrier I call it good. It's really easy to do with mono band amplifiers.

    https://www.w8ji.com/rf_plate_choke.htm
     
  14. Staybolt

    Staybolt Well-Known Member

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    Smoked his ass, damn!!
     
  15. Onelasttime

    Onelasttime Well-Known Member

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    You know I trained to be a commercial pilot while doing my Aviation Technology Materials Science degree my first college degree. More commercial pilots die on the drive home from work than die flying. When you start out you start out doing fairly low paying work with terrible hours to build your turbine time up. So you end up working for a contract outfit doing mail runs for UPS and FEDEX flying to all the little airports in an area collecting mail and taking it to a regional airport where they have regional cargo jets and or large Jumbo Jets owned by the big boys like UPS/FEDEX/Global/DHL etc....So your operating very small turbine aircraft, you're doing some of your own loading or at the very least supervising the people loading to make sure your weight and balance is right so your CG is within limits and your fuel, oil, cargo and you are all within the limits etc.....The hours are super early because you working to the schedule of the carrier. Your taking off and landing in 0/0 weather the Ducks are not even flying and you might do that at 4-6 airports each night before your fly back to your own airport. You get done and you are crazy tired so you drive home, eat, shower sleep, etc...and before you know it you are up again to repeat. Sooner or later you fall asleep at the wheel it always happens sooner or later! I was once driving home from the airport and someone cut me off on the interstate and instead of hitting the brakes I pulled back for dear life on the steering wheel of my 4Runner as if I was going to fly up and over them! LOL Even though I was driving home my mind was still in "flight mode"
     

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