Kaelus says there is no need for PIM testing at 40W

Discussion in 'The PIM Corner' started by Wireless Estimator, Jul 13, 2012.

  1. Wireless Estimator

    Wireless Estimator Administrator Staff Member

    There's an interesting white paper put out by Kaelus regarding the May 2012 update to IEC-62037 which covers PIM testing.

    One of the new requirements for PIM tests is that "Devices should be subjected to impact or movement while PIM testing."

    That appears to mean that you should move and/or tap on connectors, cables, assembles, filters and antennas.

    Kaelus also points out that the IEC kept the same recommendations that the original specifications had of using 2 x 20W test tones.

    They also go on to note that other testing equipment manufacturers' claims that testing should be conducted at 40W should be ignored because if carriers truly wanted to simulate the actual BTS environment they would need to transmit 100s of watts to capture the full range of transmit levels.

    Kaelus says in order to do that, the required test equipment would be "larger, heavier and more expensive and would pose safety risks to technicians performing the test."

    What are your thoughts?
  2. earla

    earla Friend of the Community

    The 40W boxes are not double the size of the 20W, so how big and heavy would they be?

    What would the safety risks be to the technicians?

    Regarding more expensive, of course it would be, but how much?

    Their argument to stay at 20W makes sense, but it would be nice if they provided a little more detail in regards to their four points of concern.
  3. TBell

    TBell Industry Observer

    We didn't get into the details of how much heavier, expensive and dangerious a 100W test set would be because that really wasn't the main point we were trying to make. The main point is that there is no technical advantage to changing the test parameters. Sorry if that didn't come across clearly.

    Lots of advertizing dollars these days are being spent these days claiming that PIM tests should be done at 40W to "better simulate the RF environment." If you believe this line of reasoning you will be replacing your PIM test gear every couple of years to keep up with the ever changing specifications (60W, 80W, 100W, LTE wave from rather than CW, 3-tones rather than 2-tones, etc.)

    All of these factors were considered and evaluated a decade ago by a wide cross section of industry experts (not just Kaelus!) The point we were trying to make is that 20W combined with dynamic testing gives you more than enough IM3 signal to accurately measure the non-linearity at a cell site. You don't need to increase test power (or change any of the other parameters of the test) to effectively find and eliminate PIM.
  4. canderson

    canderson Friend of the Community

    Now that Anritsu has come out with a 40W it's likely that Kaelus will be getting ready as well whether or not they believe its not necessary. In fact manufacturers like to create a need for new products otherwise their sales go down.

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