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Question about a Bird 43A VS. 43P

Discussion in 'Ham Equipment' started by ExitThirteen, Mar 21, 2013.

  1. ExitThirteen

    ExitThirteen Grumpy, Cranky Repairman

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    I've had a burning question on my mind about a Bird 43A (no peak kit installed) VS. a Bird 43P.



    Would both meters read the same output on SSB? I've always assumed that they'd both read the same output, since you don't have a carrier (ie. AM). Is this true? An inquiring mind would like to know.

    Also, what would be a good meter to buy that measures accurate PEP output? Suggestions?

    Thanks!


    ~Cheers~
     
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  2. Beetle

    Beetle Well-Known Member

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    Depends on "how accurate" you have in mind.

    As to the 43 vs 43P: if you set the 43P to read average power (i.e. the PEP kit is turned off), they should be within ±5% of the full scale range. That said, one of them could be, say, 4.95% HIGH and the other 4.95% LOW, and they'd both be within the manufacturer's specified tolerance range. However, at 50 watts full scale (for example), the one would read 52.5 watts and the other one 47.5 watts (rounding).

    Which one would be right? Both of them.

    You couldn't use the 43/43A on SSB and expect to see PEP shown with any degree of accuracy or precision.
     
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  3. Shockwave

    Shockwave Sr. Member

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    The Bird 43A is only accurate on a stable carrier. That would be FM, or CW. Any variation in amplitude including SSB will require a peak reading watt meter. The Bird is nice but Captain Kilowatt has pointed out a nice cost effective alternative from Diawa in another thread.
     
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  4. ExitThirteen

    ExitThirteen Grumpy, Cranky Repairman

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    Excellent. Thanks for the posts! I'm just using my Bird 43A to check SSB output on my AEA LA-30 amp, and I didn't know how accurate I was with it on SSB.

    I saw the thread that you mentioned in your post Shockwave, and I'm going to go have another look at it to see what CK had to say.

    FYI, I'm checking the output on a 1000W slug, so I reckon the margin for error would be rather high.

    (edit) For example, 15W into the amp = 170W out right now. I'm thinking that this is somewhat in the ballpark, as the 3-500Z tube has an output multiplication factor of about 10x.


    ~Cheers~
     
    #4
  5. Shockwave

    Shockwave Sr. Member

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    If you already have the Bird 43A, Bird makes an add on board to convert it into the peak model. There is also an aftermarket company that sells a peak board for the meter at a fraction of the original cost. Sorry I forgot their name but it shouldn't be hard to Google. I may have even seen them on eBay.
     
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  6. Mudfoot

    Mudfoot Supporting Member

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    Is it Coaxial Dynamics?

    Birds are ok meters. There's only three reasons I don't own one.

    1. They cost an arm and a leg.

    2. They are ugly as hell.

    3. They are to damn tall.
     
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  7. RADIOOMAN

    RADIOOMAN Active Member

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    There is a method by which you can use a average responding wattmeter to reveal the PEP capabilities of your amplifier while transmitting SSB.
    However this method will not work for AM.
    But it will be better to spring for the PEP kit for your BIRD.
    For AM and SSB it is almost essential that you have a meter that is capable of PEP readings.
    I found a kit, quite inexpensivley, (board and schematic) at a hamfest quite a few years ago and now my BIRD is so much more useful.
     
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  8. W5LZ

    W5LZ Crotchety Old Bastard

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    There is also a simple way of using an averaging meter to for both AM and SSB. It uses the same basic method people have been doing for quite some time but in a way that is accurate rather that that 'common' way most people use. It requires a -constant- audio tone. That will give you a 'Pep' reading with SSB from an 'averaging' meter. The exact same method will work with AM too. I have yet to understand why a 'Pep' power reading is wanted with AM mode, it tells you absolutely nothing beneficial. All that it gives you is a larger number to brag about. It's also very confusing if when giving that 'Pep' reading you happen to forget to tell the one you are telling that it is a 'Pep' figure. Which will almost always lead to an incorrect 'goal' to shoot for.
    - 'Doc

    Of course, all that depends on someone understanding just exactly what AM mode is, how it's 'done', and the proper construction of the signal.
     
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  9. RADIOOMAN

    RADIOOMAN Active Member

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    What does that mean.
    Are you saying there is a simple way of using an averaging meter to indicate "AVERAGE POWER" or "PEP POWER".
    Somewhat ambiguous.
    Please specify.
    You have left this open to interpreatation and I don't want you to use that as an excuse to weasel out this discussion.

    Maybe you should outline the method that you think will work in the AM mode.

    It tells you if you are modulating your AM carrier to 100% modulation and if you are compliant with FCC rules regarding the limits as related to AM carrier modulation
    Tells you if your modulation is insufficient or tells you if it is too much.
    Not rocket science.
    I don't understand why you can't understand.

    Looks like you are trying to back track with that statement.
    You outline the method you would use to indicate PEP on a AM modulated carrier with a average responding BIRD 43 on a A3E double-sideband a full-carrier - the basic Amplitude modulation scheme.
     
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  10. W5LZ

    W5LZ Crotchety Old Bastard

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    And it's obvious that you don't understand what I said, isn't it. It would do no good at all for me to try explaining it so why don't you try going back over what a 'properly constructed' AM signal actually is, and how it's arrived at.
    As for 'Pep' being necessary to define the modulation percentage of an AM signal, that's just not true. It's very commonly, and accurately done with an averaging meter.
    - 'Doc
     
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  11. RADIOOMAN

    RADIOOMAN Active Member

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    Just what I expected; You're trying to weasel out of this discussion.

    Don't you want to share some of your vast knowledge about radios, antennas, propagation modes and wattmeters with the rest of us.
    You are in this forum rambling on everyday and now you decide that you don't want to share with us.
    Looks mighty suspicious to me.

    I am sure that there are numerous people in this forum who would like to know how you are going to use a average responding BIRD 43 to get PEP readings on a A3E double-sideband a full-carrier - the basic Amplitude modulation scheme.

    Kind of makes you wonder why they make a PEP meter if it is so easy to get the same numbers without one.
    Put up or shut up.
     
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  12. RADIOOMAN

    RADIOOMAN Active Member

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    Just what I expected; You're trying to weasel out of this discussion.

    Don't you want to share some of your vast knowledge about radios, antennas, propagation modes and wattmeters with the rest of us.
    You are in this forum rambling on everyday and now you decide that you don't want to share with us.
    Looks mighty suspicious to me.

    I am sure that there are numerous people in this forum who would like to know how you are going to use a average responding BIRD 43 to get PEP readings on a A3E double-sideband a full-carrier - the basic Amplitude modulation scheme.
    Looks to me like you don't know what you are talking about.

    Kind of makes you wonder why they make a PEP meter if it is so easy to get the same numbers without one.
    Put up or shut up.
     
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  13. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    I think what Doc is talking about in reference to a properly constructed AM signal is "normal" full carrier double sideband and not that crap that is so prevalent on 11m today. you know, 2 watts "swinging" to 35 watts. A normal AM signal would be about 8-9 watts of carrier and 100 % modulation for the exact same pep output however saying "swinging" 35 watts sounds SOOOOO much better than 9 watts carrier.
     
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  14. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    Time to ease up a bit. The tone of this discussion is going downhill fast .
     
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  15. RADIOOMAN

    RADIOOMAN Active Member

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    OK.
    But don't you think he needs to back up his remarks with the necessary correct information.
    I think there are numerous people who would be interested in this.
    I know the answer, I don't think I would rely on the method for accurate results.
    It will get you in the ball park but if you are trying to properly modulate your AM carrier to 100 % then you either use a 'scope/monitor' or a quality PEP meter.
    You don't use a average responding meter to generate PEP numbers without introducing an error factor of the magnitude 2.67 times the accuracy inherant to the meter being used.
     
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