Many of you may know, as an EMC consultant, I’ve been partnering with one of the best EMC test labs in Colorado, EMC Integrity, in Longmont, north of Denver. EMC Integrity was founded by Vince Greb in 1993 and now owns two of only three 10m semi-anechoic chambers in the state (the other is owned by Hewlett-Packard in Ft. Collins). They specialize in both commercial and military EMC testing. Check them out at www.emcintegrity.com. They were recently featured in an article in the Boulder County Business Report (March 15-23, 2013). Check it out here…
I’ll be presenting a comprehensive two-day EMC design and troubleshooting short course there April 2-3 (sold out), with a possible follow-up course later this year.
Technician, Casey Lockhart running a radiated emission test at one of the 10m chambers. Photo courtesy BCBR (© Jonathan Castner).
Always on the lookout for useful, but inexpensive test equipment, I recently ran across the Triarchy Technologies USB spectrum analyzer, model TSA5G35. The one thing that really struck me was the whole thing was built into a USB dongle, just a little larger than a memory stick. What’s more, the advertised frequency range was 1 MHz to 5.35 GHz. This, I had to see for myself.
So, is a spectrum analyzer no larger than a pack of chewing gum that you can carry in your pocket good enough for EMC analysis and troubleshooting? For a total cost of $599 (through their store on eBay), I decided to take a chance and run this remarkable PC-based analyzer through the ringer.
Figure 1 – Photo showing the analyzer with supplied USB extension cable and 30 dB attenuator.
Figure 2 – A screen capture of a series of 16 MHz oscillator harmonics.
SPECIFICATIONS – Basic specifications include frequency coverage of 1 MHz to 5.35 GHz, resolution bandwidths of 50 through 500 kHz (not selectable), frequency spans from 1 MHz to 1 GHz, input level range of -110 to +30 dBm (using the supplied 30 dB attenuator for the higher power levels), and typical noise levels of -80 to -100 dBm (depending on the span and RBW). The maximum power level is +20 dBm for 1 minute (without the external attenuator) and +/- 25 VDC, which is excellent protection for this little instrument. The reference level range is -60 dBm to 0 dBm (no external attenuator) or -30 dBm to +30 dBm (with the external attenuator. the usable display range is 80 dB with a noise floor of -115 dBm at a 5 MHz span and -60 dBm reference level at 1 GHz. Amplitude accuracy is specified at less than 3 dB. All in all, not to bad for this little guy.
For more of this hands-on review on Test & Measurement World, click here…
I was honored to be the featured speaker at the 13th annual EMC Society Chapter of the IEEE Milwaukee Section “EMC Mini-Symposium” this last March 19th. Hosted and managed by EMC engineer Jim Blaha (GE Medical), this was actually no mini-symposium – but is the largest regional gathering of EMC engineers in the country. There were a record 180 engineers from around the area, as well as a record 42 vendors showing their wares. The event sold out within just a few weeks.
The title of my talk was a mouthful: “EMC Essentials and Pre-Compliance Testing with your own Affordable EMC Troubleshooting Tools Kit”. While I covered some of the major EMC theory for issues I generally end up addressing at various client companies, most of the day was spent on how to collect a set of useful tools, probes and measuring instruments to make up a portable EMC troubleshooting kit. I then went on to explain how I use these tools to perform pre-compliance and evaluation testing of prototype products.
I’d like to thank Jim Blaha for his superb organization and management of the event, all the vendors, who helped sponsor the event and Agilent Technologies for supplying the oscilloscope and spectrum analyzer for the demonstrations.
Here are a few pictures taken by my colleague and fellow EMC consultant, Jerry Meyerhoff. Thanks Jerry!
Jim Blaha from GE Medical manages the symposium and is providing introductory comments.
Chatting during one of the breaks.
A portion of the 180 attendees.
Here I am explaining why pigtail shield connections cause common-mode currents resulting in radiated emissions.
A very full house!
For those of you who regularly troubleshoot EMC issues, wouldn’t it be convenient to have all your “fix-it” parts all in one place? That’s what I thought as I was wandering around JoAnns (a fabric and hobby store) with my wife. I spotted this “photo keeper” storage box and thought it would be perfect to store all the little parts, gasketing, filters, etc., for quickly implementing fixes during the troubleshooting process.
I had a chance to use this kit in a real-life consulting application as I helped a client in Chicago recently. I transported the kit inside a large Pelican case and used a quantity of bubble-wrap to protect it from shifting around. It survived just fine and added a sense of professionalism in the client’s eyes.
Hobby stores sell many similar storage boxes and you may find several to your liking. Read on for more details…
These unusual EMI sources may be used to perform pre-compliance testing (radiated or conducted immunity) to help determine the immunity characteristics of your circuits or product.
1. Chattering Relay (120VAC powered) – can produce strong broadband emissions all the way out to at least 1 GHz.
2. 3 VDC Motor – produces strong emissions out to about 750 MHz.
3. Pocket Plasma – produces broadband frequencies up to 10 MHz.
Click here for more details…