FCC Pretest Equipment

Electronics
#1

Looking to do some pre-FCC testing.

Does the Electronics Lab the following equipment?

Spectrum Analyzer: we need the rating of this to be 9 kHz to 10 Ghz (most likely not going to be just one unit). The sensitivity needs to be able to read down to 10 microVolts/meter

Either the spectrum analyzer will have the antenna built in, or it will have SMA coaxial connectors. If there are now antennas built in, then we will have to get 1 or more “Log Periodic” antennas to be able to read between the 9 KHz to 10 Ghz.

If anyone has experience in FCC testing, we would be interested in any advice you would have to share.

Thanks

#2

ELab has a Siglent SSA3021X. It does not meet all of your specs. We do not have the antennas. @richmeyer has experience in this .

2 Likes
#3

I’ve done a bit of this. Unless you want to build an antenna range, this is going to be ‘rough and ready’ testing. You’re going to be looking for hot spots, not doing any measurements that correlate with a regulatory test.

I have a near field trace probe that I use for some of this on the bench.

Few spectrum analyzers have integrated antennas. The only one I know of is made by Aaronia, and I wouldn’t use it for most testing, but it would be useful for this kind of ‘rough and ready’ test. The “10 microVolts/meter” spec you quote is a field intensity number - the combination of the antenna and spec an. And this is going to be frequency dependent as the antenna will have frequency dependent gain, which will likely be expressed as an ‘antenna factor’ for EMC testing.

I also wouldn’t plan on any testing much above 1 GHz without a real antenna range unless your product has some elements that make failure at these high frequencies likely.

The Siglent we have may need a preamp to be sensitive enough regardless of the attached antenna.

You can buy some useful antennas economical here:
https://wa5vjb.com/products1.html

I’ll be around later today, and certainly for electronics office hours on Thursday.

1 Like
#4

I no longer live in the area, I now live near Knoxville, TN.

The closest EMI Testing Center to DMS is:

National Technical Systems
1701 E. Plano Parkway, #150
Plano, TX 75074
(972) 509-2566

They have a full EMI Test facility that you can use at an hourly rate for pre-certification and final certification. They have the test equipment, the antennas, and the huge test chambers to give you accurate results. Of course, this is not free… they will charge you dearly for it. A good spectrum analyzer would cost you around $50K, add $5K for antennas, then another $1-2 Million for the test chambers. Definitely out of scope for DMS. If you are interested in this type of RF testing… perhaps they are hiring.

2 Likes
#5

A note of caution…

Whenever you are using a Spectrum Analyzer, always… always protect the sensitive analog input. The analog input cannot accept a DC signal without destroying the sensitive input circuitry of the Spectrum Analyzer. Even touching a standard 9 volt battery to the input will destroy it. So, I always start out with a 20dB attenuator pad on the front end until I know what the unknown input signal is. Once I know the limits of the input signal, then I can remove the attenuator pad. If you use DMS’s Spectrum Analyzer, there is a 20 dB pad in the box for a reason… use it! It is there for a reason.

1 Like
#6

For my personal SA, I have a range of attenuators, and also a DC block depending on how much distrust I have of the source.

I also have a cheap, wide range, low power meter to verify that I am in range before hooking things up. The one I have has checked within 3 db checked every 10 db against a HP communications service monitor as a source.

1 Like