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Bird 43 wattmeter advice

Discussion in 'Radio and Communications' started by Mosaic, Jul 25, 2017.

  1. Mosaic

    Mosaic Well-Known Member

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    Hello, I need some advice on a mod I want to do to scale the slug power. Does nyone use this type of RF power meter here?
     
  2. RadioRon

    RadioRon Well-Known Member

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    I do not own one, but have used them many times. I note this web site where you can read some description of the insides of the slug. These are pretty simple, in theory, so scaling should be possible.
    http://www.hayseed.net/~jpk5lad/BIRD Slugs/birdslug1.htm
    which leads to other sites like this one:
    http://www.hayseed.net/~jpk5lad/BIRD Slugs/birdslug4.htm

    I would guess that as long as the slug you want to modify is at the same frequency that you want it to operate at, then adjusting the value of the internal resistor may be all that's needed to scale it.
    I guess you could also scale the slug power without opening up the slug, and doing it in the meter instead, but this would scale the power for every slug you put into it then, which doesn't seem like a good idea. Scaling is just a matter of voltage drop.
     
  3. Mosaic

    Mosaic Well-Known Member

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    RadioRon

    Well, RF has always interested me and I've finally acquired some decent instrumentation and tooling along with assorted components, attenuators, couplers etc.
    Refitting old gear with new tricks is also an interest of mine and this seems like really vintage stuff.

    I plan to leave the slugs intact and remap the scaling for the meter , prob in a 1/4, 1/2,1,2,4 stepping. Amplifying millivolts (42mV FS), passing that into an ADC doing the log mapping and then reversing the process to drive the meter will take a bit of doing.
     
    Last edited: Aug 4, 2017

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