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bird43 myths

Discussion in 'Ham Equipment' started by bob85, Aug 11, 2009.

  1. bob85

    bob85
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    there is much confusion and myth surrounding the humble bird 43,
    many people claim birds ignore signals that fall outside the rated frequency range including the harmonics of hf signals,
    i will have one last go at clearing this nonesense up but i doubt it will change many minds,

    this is NOT TRUE, it is a cb myth invented by a retard, the myth has been banded around cb forums for so long the line between truth and fantasy has become obscured, why people take what others tell them as gospel without doing their own tests is beyond me but hey thats cbradio for ya,

    a while back freecell came up with the notion of harmonic oversampling based on the idea that as you move up in frequency the line section length becomes a larger percentage of the wavelength of the test frequency and as such will oversample frequencies that are higher than the rated frequency range of the meter, the claim is that the meters will sum all these sampled readings together giving a higher reading than what is really there,
    he suggested a simple test of measuring known vhf/uhf signals to confirm this idea,

    how many people have actually done any testing?, very few i would presume from what i read on cb forums,
    freecells claims made sense to me so i did the tests with more than one radio and several meters of differing quality and type of line section, i used a good quality dc-2ghz 50ohm dummyload not some homebrew or mfj/palstar pos, i connect the meters straight to the load with no jumper,

    my bird43 with hf slugs DOES NOT oversample nor does it ignore signals above 30mhz,
    signals on 50mhz 70mhz 144mhz 440mhz all read much lower than the actual power applied,
    from memory a 10w signal @144mhz reads about 2w on the bird using a 10w hf slug,
    when using a vhf slug the bird reads very close to the tellewave and welz sp600,

    on some of my meters mainly the stripline coupler cb type meters i do see significant oversampling as freecell claimed,
    from what i see with the bird hf slugs i presume they have some form of frequency tailoring that attenuates vhf and above signals within the slug, maybe a shunt capacitor,
    the bird certainly responds less to high frequency signals than my other meters including the ones using wideband torroidal couplers,

    since i do not have any means to add a measured amount of harmonic content along with a clean hf signal and observe how each meter responds i cant say how any of them are effected when measuring amplifiers or clipped radios with high harmonic content,
    i believe they will all show more power than is actually on frequency if high harmonic content is present and the bird43 using hf slugs would likely be less effected than many other meters going by what i see in my simple tests but i cant prove it,

    what i can prove is that anybody telling you the bird43 using hf slugs do not see signals above 30mhz is talking the same kind of cb bullshit that ampower spouts to his retarded followers, they do not have a majical filter that cuts off sharp at 30mhz, the response of bird hf slugs rolls off as frequency increases above design frequency,
    some meters do increase sampling as frequency increases above design frequency,



    the bird also acts different to my other meters when measuring amplitude modulated signals ( not what its designed for ),
    on some radios i can see forward swing, swap the meter to the bird43 and i see little forward or even backwards swing, my other meters do not do that, i dont know why that is but thats what it shows,

    dont take my word for it go do your own tests, use a quality wideband dummyload, report your findings.
     

  2. W5LZ

    W5LZ
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    Heresy! Pure, unadulterated... CB heresy!

    Now that I've gotten that requirement out of the way, I have to agree with you. I think I would have gone just a bit further, but not having any 'believable' testing to back it up, I won't. Which does agree with what 'Bird' says about their 'superfragelistic' meter too, but they're just being modest, ain't they!
    Big differences between fact, fiction, and faith. Facts are kind'a hard to deal with sometimes when they don't agree with fiction and faith. That's when it usually turns into one'a them 'secrets' 'they' don't want to tell you for some odd reason. Reminds me a lot of politics! Now that's a nasty thought, isn't it?
    Good luck 'bob85'! You'll need a lot of it to make anyone change their minds. Oh well.
    - 'Doc
     
  3. TonyV225

    TonyV225
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    You know I often looked at those bird meters and read the articles and had seen various articles stating glitches in some just like anyother so called(best meter around ) units as the manufactures put it in the advertisments. Kind of funny how your the $h!+ in citizens band world if you have or posess a bird meter.

    In all actuality one has to ask themselves is anything really perfect and flawless?? Is there somesort of bu!!$h!+ were being handed mixed in this smoke and mirrors Im not seeing? Amazing that all it takes is for someone to get bored and take the time to do a little research and I am sure that once things start to appear a person just has to dig deeper.

    Hell thats what I would do and if everyone or atleast more people would take the time to do this just for the sake of seeing or proving to themselves I think there would be ALOT LESS BU!!$H!+ handed out to consumers.;);)
     
    #3 TonyV225, Aug 11, 2009
    Last edited: Aug 11, 2009
  4. dudmuck

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    bob85: yes, another CB myth. Just like the 18 foot coax myth.

    Here is all the details of the bird element A Photo Tour of a Bird Wattmeter Element

    I doubt you'll find anyone coming onto this thread defending the claim that birds dont read CB harmonics.
     
  5. TonyV225

    TonyV225
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    Thats a cool interesting and informative article dudster (y)
     
  6. Beetle

    Beetle
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    My main "complaint" about CBers and Bird 43 meters is the implied belief that since it's a Bird, it must be perfect in both accuracy and precision.

    The basic Bird meter has a maximum error of five percent of full-scale value. That maximum error has to be added to the maximum error of the slug. Two identical slugs used in the same meter may not produce the same degree of accuracy.

    For many years (and it may still be the case) a Bird 43 HAD to be calibrated every three months, ALONG WITH the slugs it used. You had to show the QA inspector that the slug you were using matched the meter by serial number.

    Oh - and that +/-5% maximum error goes up to +/-8% when you install and use the PEP circuitry. Still +/-5% on average, though.

    Ask your "tech" when the last calibration was done on his Bird. Ask to see the documentation. If he's legit, he'll have a very detailed document attesting to the calibration, including identification of the standard or standards used. If he "calibrates" it against another Bird 43, you might walk away. I would.
     
  7. mackmobile43

    mackmobile43
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    Even though I have a bird meter with an aftermarket pep board installed I rarely use it, I use it for input swr readings and output tuning on amplifiers other than that I have no further use for it and it sets idle on the top shelf.
     
  8. C2

    C2
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    You made shelf space for yours?
     
  9. mackmobile43

    mackmobile43
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    It has sentimental value.:D
     
  10. Crusher

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    So here is a myth that needs to be dispelled as well. For instance, Say you have an amplifier that DK's 5000 watts but when you talk, it swings backwards to say 3500 watts. There is a myth that that is all audio. When in fact you are shutting your audio down. Anyone agree or disagree. by the way, hello bob, been awhile been busy on this end.
     
  11. W5LZ

    W5LZ
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    Not just 'audio'... :)
    - 'Doc
     
  12. mackmobile43

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    I would say it's a sign of input reflect, when modulated the input reflect rises thus reducing input drive and that coupled with inadequate power supply gives your backswing.
     
  13. W5LZ

    W5LZ
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    Sounds good, but that's not the typical reason for that 'backswing'. The most common reason is over modulation, more than 100%, which means 'dead' spots in the radiation, the whole signal is reduced to zero for some period of time. It's very apparent when viewed on a scope when transmitting a constant tone. Not so apparent when a varying tone or voice is used, but it's still there.
    - 'Doc
     
  14. Crusher

    Crusher
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    actually, I was thinking about a few guys around here that make a 16 pill/transistor amp that DK's 5kW. A few guys i really laugh at when they come close to 4200watt DK, but swing back to almost 2000 watts. Lots of issues. But they will say that is all audio. When in fact there are about 5 issues together that would case that. It's not pretty.
     
  15. freecell

    freecell
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    "So here is a myth that needs to be dispelled as well. For instance, Say you have an amplifier that DK's 5000 watts but when you talk, it swings backwards to say 3500 watts."

    "16 pill/transistor amp that DK's 5kW."

    there's only one issue, *excessive drive. the first myth that needs to be dispelled is the one that has these idiots thinking that a 2879 produces 312.5W of power. all of the ensuing "issues" are of their own making*.

    secondly, with respect to the unmodified bird 43, it doesn't measure PEP and that's a big problem when the 2879 is rated in PEP.
     
    #15 freecell, Aug 20, 2009
    Last edited: Aug 20, 2009

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