Connect with us

TemCell Woes

Discussion in 'Electronic Design' started by Blarp, Dec 20, 2008.

Scroll to continue with content
  1. Blarp

    Blarp Guest

    In our company we make stuff that must meet EMC requirements. Usually
    the radiated emissions are the most challenging. We have these checked
    in accredited test houses, which are expensive.

    So we try to pre-check the products to see if there is fair chance of
    success.

    We have no OATS or anechoic room, so we make do with a logper antenna
    in an empty office room. The ambient radio smog is making this
    virtually impossible nowadays.

    I recently bought a secondhand 3m TemCell, intending to use it the
    wrong way around (not immunity, but unwanted radiation).

    After reading up on the matter I became convinced that it should be
    possible to get at least a fair -albeit uncalibrated- impression of
    the radiated spurious of the EUT.

    Not so however. If a EUT with known radiation characteristics is
    placed in the TemCell, all I see is a Flat line on the spectrum
    analyzer. I might as well have connected a dummy load. Even with a
    preamp I see nothing.

    Connecting the same spec on the same setting on the antenna, the
    screen lights up. And the EUT does radiate..

    Question:

    Anybody else out there doing what I do? Am I expecting something that
    is not there? Does a TemCell not work both ways (reciprocal)?

    Or is the cell just broken...and do I need to tear it open for
    repairs?

    Thanks in advance!

    Best Regards, Rene
     
  2. | In our company we make stuff that must meet EMC requirements. Usually
    | the radiated emissions are the most challenging. We have these checked
    | in accredited test houses, which are expensive.
    |
    | So we try to pre-check the products to see if there is fair chance of
    | success.
    |
    | We have no OATS or anechoic room, so we make do with a logper antenna
    | in an empty office room. The ambient radio smog is making this
    | virtually impossible nowadays.
    |
    | I recently bought a secondhand 3m TemCell, intending to use it the
    | wrong way around (not immunity, but unwanted radiation).
    |
    | After reading up on the matter I became convinced that it should be
    | possible to get at least a fair -albeit uncalibrated- impression of
    | the radiated spurious of the EUT.
    |
    | Not so however. If a EUT with known radiation characteristics is
    | placed in the TemCell, all I see is a Flat line on the spectrum
    | analyzer. I might as well have connected a dummy load. Even with a
    | preamp I see nothing.
    |
    | Connecting the same spec on the same setting on the antenna, the
    | screen lights up. And the EUT does radiate..
    |
    | Question:
    |
    | Anybody else out there doing what I do? Am I expecting something that
    | is not there? Does a TemCell not work both ways (reciprocal)?
    |
    | Or is the cell just broken...and do I need to tear it open for
    | repairs?
    |
    | Thanks in advance!
    |
    | Best Regards, Rene

    According to this site (http://www.temcell.com/tc5060.html),
    Yes, you should be able to pick up any radiated emissions (RF) from a
    DUT.
    Did you try rotating the DUT? otherwise it sounds like bad connectors.

    Cheers
     
  3. Blarp

    Blarp Guest

    Thanks for all answers so far...The Cell is rated up to 300 MHz, and
    the EUT I selected (because it was emasured in a testhouse before, and
    has known radiations) - happily radiates in the 100MHz .. 1 GHz range.

    I would not be amazed by a dropoff above 300 MHz, but a flat line..

    @ Martin: Yes, I did rotate the EUT any witch way.. Had representative
    wiring connected. In free air (using the logper antenna) it (the EUT)
    even "outradiates" the considerable local radio smog.

    I think I indeed need to check the connectors and such.

    Thanks! - Rene
     
  4. Blarp

    Blarp Guest

    ....but it's a BNC...

    After the Xmas holidays I will check if the septum has broken loose
    from the connector - should have done that in the first place I
    guess..
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-