decent bench watts meters and power suply

Discussion in 'CB Radio Forum' started by usmc041127, Mar 25, 2011.

  1. usmc041127

    usmc041127 Light Load Member

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    Mar 2, 2011
    Jefferson City Missouri
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    I am wondering watts is a good watts meter one the reads power and modulation. I am thinking the Dosy is the way to go. One of the 3001 models.

    I am also wondering what is a good brand of power supplys for the home too. I kind of like the jetstreams and pyramids form what I am seeing on evil bay.

    I don't need proffesional grade stuff just something that is a good for the home expiermenter. Something that is at least halfway acuarate.

    Thanks
     
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  3. groundpounder

    groundpounder Road Train Member

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    Nov 13, 2009
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    I use Palstar for the meter and a Iota DLS-55 power supply, no complaints thus far..
     
  4. whttail101

    whttail101 Bobtail Member

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    May 6, 2011
    Mt. Vernon, TX
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    I am using a Pyramid power supply, it has lasted me for 6 years and works excellent.

    As far as meters, I would say the Dosy is a good choice. But to tell you the truth, I have had just as good of luck between any of the lower end meters with the Dosy, Workman, and Astatic.

    I have gone through a few of the cheaper meters over the past few years, and every so often I will get one that is crap, right out of the box. If you do not use yours on a constant everyday basis, you should not go throug one as fast as I do, lol.
     
  5. handlebar

    handlebar Heavy Load Member

    If I may make a different suggestion than the typical -- an inexpensive oscilloscope will show you much more accurate results than any inexpensive meter, and you'll be able to see the modulation directly instead of hoping a meter isn't showing "good time" watts.
    Take a look at used scopes on eekBay or some similar site. Since you're operating at just under 30 MHz, a 40-or greater MHz-rated scope will read directly from your antenna port, or a sniffer coil placed nearby.
    Wattage can be calculated easily since P = E squared over R, where P = power in watts, E = voltage, and R = resistance.
    Since your resistance can always be assumed to be 50 ohms (you're testing into a dummy load, right?) then you just read voltage on the scope to plug into the formula. You'll be able to see when your modulation is at 100%, and if you see distorted audio on the scope, you can guess it sounds "crappy", to use the technical term :) If you're not using a dummy load, just make sure your antenna is tuned as well as you can for minimum VSWR so that the "R" value can be assumed to be 50.
    A decent used scope can typically be had for less than $100. You don't need digital or even dual traces.
    It's also great for checking alignment on receivers, or tracing a board for a signal that disappears *somewhere* inside the radio.
    Then you can save your cheapie meter for just reading VSWR in a mobile. That's what I do. Even an inexpensive meter, as long as it's enclosed in a metal box instead of plastic, will be reasonably accurate. And if you know from your scope that you're putting out 4 or 10 or 20 watts deadkey, you can calibrate your meter to match it. Then your meter will be more useful, at least on "average" power settings.
    Modulation meters really just measure power, using a formula for how much power changes with modulation, and reading the change. But they're not smart, and can't show you if, say, half your power when you talk loudly is really on 54 or 81 or 108 MHz (harmonics).
    You'll find a lot more use for a scope than a sub-professional wattmeter, IMHO.
    FWIW, I use a lab grade scope (Tektronix 2430 dual trace digital) on the bench, a Bird wattmeter for when it really has to be accurate, and a $10 Lafayette CB wattmeter/SWR bridge for quick antenna checks and VSWR tuning. For more accurate antenna tuning, I use an MFJ 269 antenna analyzer for initial antenna tuning, because it also tells me if I've got a lot of inductive or capacitive reactance in my system, so I can adjust appropriately.
    YMMV.
    -- Handlebar --
     
    josh.c Thanks this.
  6. whttail101

    whttail101 Bobtail Member

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    May 6, 2011
    Mt. Vernon, TX
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    I agree with you completely handlebar. I have a Tektronix TDS1002B dual trace 60MHz on my bench. It works awesome.

    But, a lot of drivers are wanting a cheap bench meter that they can use at the house or in the truck while out on the road. Any of them are most deffinitely not accurate, but can give a good idea of how the radio is transmitting.
     
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