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Thread: Amplitude unit question should be dBm not dB

  1. #1

    Default Amplitude unit question should be dBm not dB

    I have a question about using SSIDer. It shows amplitude in dB. But I think it should be power level at receiving client and should be in dBm.
    What do you think of it. Thanks a lot!

  2. #2

    Default

    The use of dBm is accurate under Windows Vista & 7, but I'm not sure what unit Windows XP reports RSSI in. So, dB was used because it's reference-less. We'll probably change it to dBm sometime in the future.

  3. #3

    Default

    I'm using Windows 7 actually, but it shows dB as attachment in my previous post. Is it a bug?
    Thanks!

  4. #4

    Default

    Yes, I should have been clearer in my post. inSSIDer currently displays dB on all versions of Windows, where we should be using dBm.

  5. #5

    Default

    Hi,
    is there any possibility to include this change in the next release? or just release a patch for most of the users that have win 7 machines?
    thanks in advances for your help.

  6. #6

    Default

    I have added this fix to be in the next release.

  7. #7

    Unhappy Not sure how to read inssider

    Hi, I cant tell if inssider2 is working the way it is suppose to. Even though I know some devices (iPhone, Mac laptop) are being slowed down on the wireless D-Link router (dir615) because of Lorex wireless video cameras, I know this as they seem to work just fine when the cameras are unpluged. the inssider2 sofware is not showing any interference. Maybe I just need some white pages to read on how to operate it, but i sure could use some help. I have attached a screen shot of what i currently see when inssider2 is runing.

    thanksClick image for larger version. 

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  8. #8

    Default

    With respect to dB vs. dBm, I'm really not sure how InSSIDer (or any other 'casual' RSSI-monitoring product) could actually present dBm figures.

    dB is a relative scale; that is, 'A' may be 6dB hotter than 'B,' or a particular Wi-Fi signal may be received 20dB below another. But when you put the 'm' on the designation, making it dBm, you are then specifying an absolute power level of the signal at a particular point in space. Unless you have a calibrated antenna/receiver combination, there is no way you can even guess at the power level (in the air) of the received signal. For instance, if you use an appropriate, calibrated power meter to measure the signal, and then calibrate your Wi-Fi dongle and InSSIDer to show the same levell in dBm, you are good to go... sort of. Now, put a corner reflector behind that dongle and watch the signal shoot up! BUT, the power level of that signal at that point in space did not change at all, only the gain of the antenna. Same goes for the reading from a D-Link vs. a Netgear or Linksys. The level of the signal does not change, but the output from the three devices will undoubtedly differ.

  9. #9

    Default

    I think that your point is valid only is you are insterested in the Output power of the transmitter. In the case of InSSIDer, the use is mainly the meaurement of the received signal, because that is what finallly computers and other devices "see".
    Now, most important is how InSSIDer gets that value in dBm. If this is reported directly by the WiFi adapter I see no problem using this unit (dBm), however if the adapter is reporting RSSI value (0-MAX) or any other non standard unit and the InSSIDer transform this reading in to dBm you can probably say that could be an error in the scale.
    Besides that, I think that is most important to get an accurate reading at the lower end (power level) bacause I doesnt matter how good is the signal from certain level and up, It really matters below a certain level.

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