EMC pre-compliance testing 5

[MagicSmoker]

I'd like to be able to do some basic "pre-compliance" testing of high power dc motor drives in house. I'm a power electronics kind of guy, not a compliance engineer, but it looks like all I need to do basic far field (10m) testing is an antenna (preferably calibrated) and a spectrum analyzer.

I haven't found an antenna yet, but I did stumble across this seemingly ideal gadget called the Signal Hound (

http://www.signalhound.com/index.htm)

which turns a laptop into a 4GHz spectrum analyzer.

It *seems* to be a much better solution than buying either a 30 year old HP or a cheap Chinese spectrum analyzer off of ebay, but this might be wishful thinking on my part... Anyone here used one of these Signal Hounds? Even if not, any comments as to why it might or might not be a good choice for what I want to do?

(Oh, and any suggestions for an antenna - biconical or bi-log seem to be used the most - would be welcome, too.)

 

[biff44]

All that stuff is so outrageously priced, it is a joke for a small company to buy. And used stuf does not have a valid calibration or is damaged a little. A slightly damaged antenna with a response null right where you might have a valid signal is of little use too.

I do not undertand why some enterprising Chinese manufacturter is not selling 30 to 2000 MHz biconilogic antennas for $500, and double ridge waveguide antennas from 1 - 18 GHz for $500 somewhere! The market is ripe for some competition!

http://www.MaguffinMicrowave.com

Maguffin Microwave wireless design consulting

 

[MagicSmoker]

I received the Signal Hound and started playing around with it. For the price it seems to be a very capable little device. The sweep rate is, indeed, slow as Christmas. One other major annoyance is that the resolution bandwidth setting is really coarse, and doesn't include the all-important (for EMC testing, anyway) 120kHz.

In other news, it appears our products should be tested to EN 61800-3, which would be excellent if true, as we already pass the radiated emissions portion. Haven't yet done a conducted emissions test, but I can whip together an H field probe this week to see how we fare in the range of 0.15-30MHz.

Received one of those cheap Discone antennas (bought a "Jetstream JTD1"), now I just need to find a non-conductive tripod to mount it on. The antenna is supposed to attach to "standard" 1.25" mast, whatever that is (like most tubing/pipe sizes, the stated value for the diameter seems to have no correlation to reality).

My understanding is that the Discone is not terribly sensitive to being mounted on a conductive mast, however, so maybe I'll just weld something up out of metal tubing.

 

[biff44]

You can go to home depot and get some pvc plumbing fittings/pipe to make up a antenna stand. At the base, just add larger fittings until you can attach to a flange, and mount the flange onto a square piece of plywood.

I keep a fiberglass step ladder around to strap antennas to when I need to do a horizontal field.

http://www.MaguffinMicrowave.com

Maguffin Microwave wireless design consulting