Re: Small EMC antenna
- From: Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx>
- Date: Wed, 03 Oct 2007 23:35:15 GMT
Andrew wrote:
Joerg wrote:
Vladimir Vassilevsky wrote:Someone, has already posted the design. I built a copy of the HP11966P broadband antenna,(check out the HP1995 catalog) from one I borrowed for a few weeks. But it is hardly aircraft portable. It will however do a full compliance test if I could ever be motivated to get a certificate for it. BTW It covers 30Mhz to 1Ghz with its wings attached. or 200Mhz to 1Ghz without.The LISN spec and designs are buried in the EMC specs somewhere. I haven't reproduced them but IIRC they are fairly simple.
Joerg wrote:
Hello Folks,
Many of you know the drill. When doing pre-compliance EMC work you either need to bring or rent a bicone and a log-perdiodic. Bringing is a challenge. Check it and chances are you'll find it turned into a pretzel at the baggage claim.
[...]
Preferably something that could go to 2.45GHz . It doesn't have to be very efficient because most pre-compliance work happens at the three meter range anyhow.
You won't be able to do any valid measurements without a shielded room unless the EMI from your device is really bad. The noise from the ambience obscures the results. Since you will be able to spot only the major problems, pretty much any antenna will do for that purpose. Of course, the basic antenna theory applies.
I know, it's just for pre-compliance. I've had pretty good luck so far doing that anywhere, always hoping it's not raining and we can measure out on the lawn away from computers and stuff. It works. Except that sometimes you'll have to deal with nosy people walking by, or animals. Once even a deer that decided that the grass between my antenna and the DUT was the best in the whole region. Totally unfazed by clicking relays and all that. Even left a "souvenir" for us.
As for the antenna, yes, I can calculate my own. I was just hoping someone had already kludged and measured one out and posted the "recipe" on the web :-)
I also did the accompanying preamp and made a cable out of LMR400 30 metres long.
Yep, that's the usual discone/logper combo. It's also in the 1999 catalog. Those things will raise some hackles at the checkpoint.
I'd rather get a used one if needed. By the time you bought all the aluminum and treated the bleeding knuckles it might not pay to build one.
The LISN isn't a big deal. What is a big deal is educating people to never, ever, power cycle the DUT while the analyzer is connected. Beep .... bzzzt ... $2000 repair and calibration.
--
Regards, Joerg
http://www.analogconsultants.com
.
- References:
- Re: Small EMC antenna
- From: Andrew
- Re: Small EMC antenna
- Prev by Date: Re: Parallel port hardware
- Next by Date: Re: HELP, I have non-linear gain in two channels
- Previous by thread: Re: Small EMC antenna
- Next by thread: Re: Small EMC antenna
- Index(es):
Relevant Pages
|
