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Spark Gap Radio Transmitter

Discussion in 'General Electronics Discussion' started by electronboy, Jul 19, 2011.

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  1. electronboy

    electronboy

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    Jul 19, 2011
    Last edited by a moderator: Jul 19, 2011
  2. poor mystic

    poor mystic

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    Apr 8, 2011
    Thank you then, electronboy.
    We can't use that sort of technology, not even for a second. We'd lose our licenses, and we'd deserve it too. We do know about spark gaps - its exactly the kind of thing that getting our licenses is all about.
    We are granted licenses to transmit radio signals on very strict provisions of power and bandwidth, so that the radio licensing authorities can be sure we won't ruin radio for the rest of the world. However a spark gap transmitter would ruin radio reception over a large area.
    So, perhaps you'll understand now that as steve said, this is not the kind of help we need!
     
  3. TBennettcc

    TBennettcc

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    Dec 4, 2010
    Spark-gap transmitters are illegal to use nowadays, for the very reason they're messy and cause lots of interference. As a side note, spark-gaps are still used in TIG welders. Boy was I surprised to find that out.

    Edit: Are you interested in ham radio? Ham radio is amazingly fantastic. There is so much to learn, and the people are wonderful.
     
    Last edited: Jul 20, 2011
  4. davenn

    davenn Moderator

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    Sep 5, 2009
    Ham radio people wouldnt dare put a transmitter on the air like that !!!
    it would cause horrific interference to every radio and television receiver within miles !!! :mad:

    Spark gap transmitters were ok 100 + years ago when you could count the number of transmitters and receivers in the whole world on 10 fingers.
    You just cant do things like that these days with out upsetting a hell of a lot of people including some govt. departments

    cheers
    Dave <<<--- Ham Radio Person

    VK2TDN
     
    Last edited: Jul 20, 2011
  5. poor mystic

    poor mystic

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    Apr 8, 2011
    But I do like the TIG welder post. Of course the TIG welder is very carefully NOT connected to an aerial!

    PS
    I also like the encouragement that TBennettcc is giving electronboy.
    I think that people is definitely where it's at in any healthy hobby, and it's good to see ham radio being promoted in this way.
     
    Last edited: Jul 20, 2011
  6. TBennettcc

    TBennettcc

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    Dec 4, 2010
    I don't know much about spark gaps... I note that you said "...not connected to an aerial..." How much interference do you think a TIG welder would cause to a radio? How close or far would it have to be to not cause interference?

    It's interesting, I was looking through a manual for a Miller TIG welding unit one day, and one section of the manual is how to ground everything around you in the welding shop so that they don't become radiators... pipes, metal on the wall, lighting fixtures (fluorescent lights especially), electrical conduit... I can't remember what else was in the diagram.

    You can probably image my surprise when I opened one for the first time and saw a spark gap inside. "WHATTT?!?! THEY STILL USE THOSE THINGS?!?!" I've never been on a radio while near a TIG welder, and I can only imagine the kind of interference it would cause.

    I got into ham radio back in 2009. I was at a space shuttle launch, probably November-ish 2008. Met a couple of guys from Georgia with a scanner, listening to Mission Control talk to the astronauts. Wow! Cool! How do I get one of those?! Well, I looked it up in the Florida laws. As it turns out, in the great state of Florida, it's illegal to carry a scanner in your car unless you are a licensed alarm contractor, fire, police, EMS, etc., or have a valid ham radio operator's license from the FCC. Wait, ham radio still exists?! No way! So I studied and got my Technician, and shortly after, my General license. I've always loved radio and technology, and this is the perfect hobby. Matter of fact, I'm getting ready to put up my first real antenna in the next week or so. A Carolina Windom 80 Compact. Sort of a folded dipole, fits in 69 linear feet. We'll see how it tunes up.

    Ham radio is about promoting international goodwill, in addition to learning about radios and electronics, and emergency communications, is it not? I would have to say, out of the hundreds of hams I've met in my short two years being a ham, I can count on one hand the number of nasty people I've met with bad attitudes. Ham radio can be expensive. I can't imagine someone going through all the trouble to get a radio, take the exams, gain the knowledge, etc., who didn't absolutely have a passion for it. You really ought to investigate, electronboy. I can't imagine you'll be disappointed. ;-)
     
  7. poor mystic

    poor mystic

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    Apr 8, 2011
    :)
    Looking at wikipedia (https://secure.wikimedia.org/wikipedia/en/wiki/TIG_welding) I see that the spark gap is part of a Tesla coil whose output voltage is used to strike the arc. It's a short arc and a low frequency, so the plasma itself won't be an efficient aerial.
    Beyond that I don't know much about the technology at all. An engineering firm I had a bit to do with at one time wanted a problem sorted out on a Miller welder, coincidentally, and thankfully I had sufficient sense to say straight off that they'd better get a specialist. Perhaps it was a test of my character - the foreman certainly knew I had no chance of curing the weird fault with no relevant experience.
     
  8. donkey

    donkey

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    Feb 26, 2011
    i would like to know more about ham, anyone who is an operator live in aus and can give advice?
    also i always wondered if shortwave recievers could pick up any ham communication. that would be fun to listen in. and lastly the legal aspects of using a predefined frequency over a large distance, could you "encode" the transmission?
    also i want to see what happens with the welder near a radio... anyone wanna video it for us? lol
     
  9. TBennettcc

    TBennettcc

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    Dec 4, 2010
    Shortwave receivers are fine for receiving. I haven't gotten into much short-wave listening (SWL), although I do have a receiver (Grundig G6). Did some research lately, and the built-in antenna is supposed to be more than enough to listen to anything you would want; the internal receiver gets overwhelmed easily by too much signal being fed into it.

    It's perfectly acceptable to talk all around the world; the high-frequency bands (HF, 3-30MHz) make this possible. As far as using a 'pre-defined' frequency, there's nothing in the rules to say you and a friend or family member can't agree to meet on a certain frequency at a certain day and time. There are a lot of hams that do this is groups; those meetings are called 'nets', and meet on a certain frequency at a certain day and time, daily, weekly, etc.

    It is illegal to 'encrypt' any amateur radio communication in such a way as to hide the content of the message.

    It is okay to 'encode' a message into a digital form, such as CW (continuous wave, aka 'Morse code'). There's also PSK31, phase-shift-keying, 31 Hz wide, RTTY (radio teletype), SSTV (slow-scan television, basically sending pictures back and forth), FSTV (fast-scan television, a live real-time television feed that you can typically receive on a standard cable television), packet radio, which can do a whole lot of things all by itself (for more information, check out APRS and WinLink 2000), and probably more modes I can't think of right now.

    As far as the welder being near a radio, the worst it would do is interfere with the signal being transmitted or received by the radio. My question was how much.
     
  10. poor mystic

    poor mystic

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    Apr 8, 2011
    Unless the noise from the welder gets into the modulating circuitry in the transmitter, the welder shouldn't affect transmission at all, but as for receiving the outcome depends on the sensitivity, selectivity, and propensity for overload in the receiver.
     
  11. electronboy

    electronboy

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    Jul 19, 2011
    you know what thank you for that because i was about to make one but it would be illegal thanks for saving me from the cops
     
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