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I just finished setting up my spectrum analyzer and I would like to ensure that everything is as accurate as possible. I was thinking of getting some kind of RF transmitter that transmits at a frequency between 30MHz-1GHz with a known dB level. If it helps the test is against CISPR 11 and I am going to test my unit at 3 Meters. My antenna is 30MHz-1GHz.

Anyone know of something that could fit this need?

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  • \$\begingroup\$ For a better answer, please provide the make and model of your spectrum analyzer and antenna. Many analyzers have a built in calibration source that could provide a check on the analyzer itself. In lieu of that, a calibrated RF generator could be used. To test the antenna would require generating a signal that would produce a known power level at the antenna. This is difficult to control outside of an RF shielded room since otherwise all objects in the room will affect the transmitting as well as the receiving antenna due to unwanted reflections. \$\endgroup\$
    – Barry
    Apr 16, 2021 at 0:14
  • \$\begingroup\$ It is the Tektronix RSA306B, the software I use is SingalVu and EMCVu. Unfortunately I don't think that there is any check in the software that accomplishes the test I am looking to do. I had to add in gains for the pre-Amp, dB losses for the cables, the antenna factors etc... I agree being in a anechoic chamber would be ideal, but its not always an option. Fortunately I had the equipment pre scanned in one to let me know where the frequency failures are. I just need something with a known dB level to use as a baseline to see how close my setup is. \$\endgroup\$
    – Ih8th3c0ld
    Apr 16, 2021 at 1:29

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You should bring it to a calibration lab.

If you want to do it your self you need an RF signal generator and a coax cable.

Before you begin you need to measure the insertion loss of the cable.

It's not difficult but you have to read articles.

For real pre-compliance EMC tests I suggest you to spend 80 bucks an hour and go to a certified lab.

You'll learn a lot of things.

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  • \$\begingroup\$ $80/h is cheap… we spend more than 2k eur just for emission precompliance! \$\endgroup\$ Apr 16, 2021 at 8:19
  • \$\begingroup\$ Conducted emissions: I started at 110 €/h back in 2012 and now I got 90 €/h for slots of 8 hours. Radiated emissions: cost 15% more. \$\endgroup\$ Apr 16, 2021 at 9:12
  • \$\begingroup\$ As I said above I did bring it to a pre compliance lab, and it was tremendously helpful. I have already accounted for cable insertion loss, pre amp gains, entered in the antenna factors and done signal alignment. I also know the frequencies that the system fails at from the pre compliance test. All I am looking for is to see how accurate my setup is. \$\endgroup\$
    – Ih8th3c0ld
    Apr 16, 2021 at 13:26
  • \$\begingroup\$ If you don't have a semi anechoic room your measurements will be polluted by external RF fields. Some spectrum analyzers allow you to measure the surrounding RF energy and than subtract it but I don't know how much the absolute error might be. \$\endgroup\$ Apr 16, 2021 at 13:34
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    \$\begingroup\$ EMCVu by Tektronix has an ambient scan that helps you subtract external RF from your view. Its not perfect but when you already have your areas of interest defined its more than good enough. As for the RF signal generator, that would be somewhat helpful. I could connect it into the pre amp, which helps verify the cable, pre amp and SA offsets. that wouldn't verify the antenna which is 50% of this unfortunately. \$\endgroup\$
    – Ih8th3c0ld
    Apr 16, 2021 at 13:49

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