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need to get frequency readings... older used O-scope or NEW Chinese freq counter?

Discussion in 'General CB Services Discussion' started by mr_fx, Dec 26, 2011.

  1. mr_fx

    mr_fx Sr. Member

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    need to get frequency readings... older used O-scope or NEW Chinese freq counter?



    The biggest reason is I have a pair of President/Uniden HR2510 radios... and as such I can not get by with just using my FC390 anymore... lol :LOL:

    if you look at the alignment info it calls for an O scope... BUT, and Old O-scope might not be in proper working order... however an old O-scope can be had for a 20 dollar bill over here in the USA...

    then there is the VC3165 Frequency counter, direct from China... usually this unit can be had for under $125 to your door, I have even seen it for as little as $89 shipped... it gets GREAT reviews on eham... http://www.eham.net/reviews/detail/7839

    another option is a DIY frequency counter kit... BUT I would need to calibrate it...

    Frequency Counter for VHF/UHF or test equipment

    Frequency Counter

    so which way should I go so I can align this unit and other like it in the future???

    ...and do NOT tell me to just take it in... I do this for fun... not to make money... well for the most part anyway
     
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    Last edited: Dec 26, 2011
  2. Robb

    Robb Yup

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    Get a scope for testing wave forms for aligning the VCO and PLL, as well as checking the modulation. You can use an o-scope as a freq counter; but they must be calibrated first. That will take time and $$$. But even a scope that hasn't been aligned should be capable of giving accurate wave forms.

    As far as a freq counter goes, I would NOT chose either of the selections from those links. You need a test-grade type of counter. They can be had on eBay for $50-$100 used/new and will precisely what you demand of it without modifying or calibrating them.

    Here is a fine example that should work quite well:

    VC3165 Precision Frequency Counter Meter 0.01Hz~2.4GHz | eBay
     
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  3. mr_fx

    mr_fx Sr. Member

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    thank you... I actually put a link to that unit as well
     
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  4. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    Using a scope to determine frequency is not very accurate at all. It will tell you if you are close but definitely not exactly what the frequency is regardless of calibration. This is because you must make a physical measurement of how many reticles the waveform occupies on the screen and multiply that by the sweep speed. Making a physical measurement means the result is dependent on human error, rounding off, and basically making a judgement call. There are accurate ways to use a scope to determine frequencies but they involve a two channel scope, a signal generator with accurate display of some sort and knowledge of Lissajous patterns.
     
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  5. GnG8d

    GnG8d Well-Known Member

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    For $99, I just bought a Tektronix 2236 with freq counter and DVM. You have to be patient for the good deals, just place a low bid to lock out the BIN and let it ride. It may take a half dozen attempts over a period of weeks, but ask questions and bid on the right units. The last known calibration on this unit was 2-11, due 8-11. It had some dust and adhesive residue on it, but it cleaned up nice and checks out spot on.
     
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  6. 2RT307

    2RT307 Sr. Member

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    I leave a true alignment to a professional. But, when I have a simple transmit being off a bit, I use a known good radio that I use as a monitor while tuning the transmit VR to get as close as I can. Seems to work pretty darned good!

    73,
    RT307
     
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    Last edited: Dec 27, 2011

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