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Oscilloscope help please

Discussion in 'CB and Export Equipment and Accessories' started by TruckerKevin, Jun 28, 2019.

  1. TruckerKevin

    TruckerKevin Active Member

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    hey guys, be forewarned this is a real noob question if there ever was one. I picked up this old hitachi scope from some people that don’t know anything about it and obviously neither do I lol.

    I only wanted it to monitor my modulation, and to learn on. I have no probes for it. All I have is a bnc to pl259 cable. I’m running it off channel 1 to an antenna coax switch on a port I’m not using (thanks to a YouTube video) so I can try to pick up an rf sample to feed into the scope.



    I took a picture, all I have is the dot in the center, no line. Nothing. Over. And nothing I seem to do makes any difference.

    Is there a setting I have to make? Or will this not work with what I want it to do?

    Disclaimer, I have never used a scope a day in my life I have only gone by videos I’ve watched on various ham sites
     

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    Shadetree Mechanic likes this.

  2. TruckerKevin

    TruckerKevin Active Member

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    And yes I know not to turn the switch to the active port and feed rf into my scope lol
     

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  3. Robb

    Robb Yup

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    Good find.
    Congratulations!

    Now you will need to make an RF sampler . . .

    Q: what is the model # of that scope?
     
    rabbiporkchop likes this.
  4. TruckerKevin

    TruckerKevin Active Member

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    I made this Rf sampler about a year ago when I was going to buy a scope but never used it. I think I got the tutorial off of this site. The thing you see on the top I was trying to find a way to lower a 100 kHz tone down to a 1 kHz tone

    The model is VC-6020
     

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  5. LeapFrog

    LeapFrog Wielding Hanlon's Razor

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    Looks like it might be a problem with the scope, you should be able to get a "straight line" trace, I'd check sweep time delay and trigger settings.
     
  6. TruckerKevin

    TruckerKevin Active Member

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    Well crap
     
  7. Grinder74

    Grinder74 KE8EOJ

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    I made a sampler pickup out of a coax T. Works great. T has 2 females, opposing each other, and 1 Male. Un screw the Male appendage and cut it off, flush, with the insulator. File a screw driver slot in the end so you can screw it in, plus it's now udjustable.
     
  8. TruckerKevin

    TruckerKevin Active Member

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    Yeah, but I don’t think the sampler is the issue here. I can’t get the dot to move into a line
     
  9. Road Squawker

    Road Squawker Sr. Member

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    I can't tell,... is your input set to AC or DC?
     
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  10. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    If it came with a cable that has a BNC on one end and a PL259 on the other end then it sounds like someone plugged the scope into their radio...... Unfortunately scopes are not made to take any kind of power.
     
  11. TruckerKevin

    TruckerKevin Active Member

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    1. Coupling is set to DC, Channel 1 is neither AC or DC it’s on gnd. But I’ve been playing with these and switching them back-and-forth all day and hasn’t made a difference.

    2. It did not come with the BNC to PL 259 cable . I had that cable already
     
    Shadetree Mechanic likes this.
  12. Robb

    Robb Yup

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    I guess you didn't get a set of scope probes either - eh?
    If so; then hook the scope probe to a speaker on a radio connected to an antenna and test it for an audio waveform.

    I don't like your RF sampler.
    Looks pretty leaky . . .

    Also, watch a few YouTube viddys on basic scope operation. Pretty fast way to get a clue of how to use one. There are LOTS of them, so it might help to watch a few. Get that out of the way.

     
    Shadetree Mechanic likes this.
  13. TruckerKevin

    TruckerKevin Active Member

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    Yeah my rf sampler was made in my very very early days.

    I didn’t get a set of probes, I’ll try and find a set locally tomorrow
     
  14. Radio Tech

    Radio Tech Radio Operator

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    It looks like you have channel one set to ground coupling. Since you want to look at an rf signal put it on AC. To look at voltage put it on DC.

    It is hard to tell from your picture where all the controls are set to. With a dot in the middle of the screen looks like it is in X/Y mode but I see it is not. Also make sure the center knobs (calibrate) on the volts per division and timebase are in their locked positions. Remove the coax and insert a small wire into the center of the BNC and touch the calibrate port with the other end.

    When rotating the "position" knobs does the dot move?
     
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  15. TruckerKevin

    TruckerKevin Active Member

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    Hi Radio Tech thanks for the reply

    I hooked the scope back up and tried what you said.

    I made sure the center knob are in their locked position,, by turning it all the way to the right until it clicked, but on the time/division I am unsure of where the locked position might be.

    The cursor does indeed move from left to right when I change the position knob . As far as I can tell, everything else works on the scope I just can’t get a line out of it .

    I touched the center pin on the bnc to the calibrate port but it didn’t seem to do anything.

    I am trying to take another picture more closer up with some better lighting to see if maybe there something I’m over looking.

    Also edit, I’d like to add that the buttons on the top of the controls that say non store/normal/hold/single/plot seem to be stuck on the non store and they are unresponsive
     

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