What is pep?

Discussion in 'General Technical Questions and Answers' started by G4ALA, Jul 24, 2008.

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  1. AG3Y

    AG3Y Guest

    In my UHF television engineering days, we had a very complicated test involving two thermometers and a bunch of look-up tables. These thermometers were installed in the dummy load cooling system. One was on the input side of the load, and the other on the output side. The transmitter was run with black video and normal sync pulses, ( the maximum power it was licensed for ) and the two thermometer's readings were taken and calculated for temperature rise of the cooling liquid as it went from one side of the load to the other.

    We only did that test during "Proof of Performance" since it was extremely critical and rather difficult to do correctly. It usually took at least a couple of hours since the transmitter needed to be stabilized, and the heating and cooling effect of the liquid had quite a latency to it.

    73, Jim
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    ::I'm familiar with that. True RMS desktop power meters (microwatt or milliwattmeters) use a thermistor or bolometer and a resistive load and although their thermal mass is small so you get a good reading quickly, holding your hand on the "mount" would influence the reading. So would a fan or A/C system cycling. I used to use thermally insulated gloves to work with those...and the room temp had to be stable!

    WB2WIK/6
     
  3. AB8RO

    AB8RO Ham Member QRZ Page

  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I take it that would be a rally for PEP?
     
  5. AB8RO

    AB8RO Ham Member QRZ Page

    Oh, I think that I know pep when I see it, and let me tell ya, that's some pep right there!
     
  6. WA9SVD

    WA9SVD Ham Member QRZ Page

    IF you're young enough to notice...:D:D
     
  7. W5HTW

    W5HTW Ham Member QRZ Page

    Wow, I need more PEP.

    (In Spanish, it is PEP Si)
     
  8. K4AVL

    K4AVL Ham Member QRZ Page

    OK, let me play here too. Suppose you are using an output wattmeter connected to the start of a feedline (in my case ladder line to a dipole). My Icom is rated at 100 watts output on CW and that's what the meter shows at near perfect SWR.
    Is the 100 watts the PEP, or is that the RMS, in which case the PEP would be 141.4 watts?
     
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    ::It's PEP. 100W CW = 100W PEP. That's equivalent to 100W PEP on SSB, but usually only about 20-30W average power on SSB. Normal stuff, nothing to worry about.

    Since we are using product detectors which capture the entire envelope of the signal during modulation, PEP is actually what matters.
     
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    ::Great, relevant comment! I'll check it all out immediately!:eek:
     
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