EMI/RFI "generator"

On a sunny day (2 Jan 2007 11:29:51 -0800) it happened " snipped-for-privacy@hotmail.com" wrote in :

Car ignition coil, sparkplug, capacitor, thyristor, some driver... Connect an antenna too :-) Probably illegal, but jams anything from RF to 10GHz.

Or else

Wow EMP400 1.8 Gigawatts 170 kg/374 lbs

That should melt a few tinfoil hats, or almost get a DeLorean kick started

martin

Spark-gap Tesla coil?

We would use an AC Power Relay. With the incoming AC going through the normally closed contacts, then to the coil through a loop of wire. Plug it in and it turns itself off and on. It made lots of EMI. I have a 1980 full report by an intern, now a Project Manager (or something) at Keithley.

If you look through the JFK/MM era transistor hobby/fix-it books Pete Millett has published at his website, a couple have plans for a Motorola-designed noise disturbance generator. Pro noise boxes depend on carefully characterized noise diodes, but these home made things worked well.

They were commercially sold as "Mosquito" probes in the old days too.

Excellent! Thanks!

Speedskater wrote:

Pick up a sewing machine for cheap at a thrift store. The universal motor and resistive foot control are born - again RFI generators.

--Winston

How about one of those piezo-electric gas lighter guns? (Hand-held gadgets that generate a spark at the end when squeezed). Connect a wire from the hot "pin" to your board signal input, and connect the pin shield of the gun to circuit 0V. Should simulate ESD events quite well.

How about you placing same up that place on your anatomy where the sun don't shine then squeezing. The exercise should relieve you of the very thing you seem to be full of.

Err... pardon? If you don't like the suggestion, say why. Or just ignore it.

I have a commercially manufactured ESD simulator that works on the exact same principle, so I know the idea is not ridiculous.

"Night lights" with small (2" tall?) 110V incandescent bulbs used to be popular. You could replace the bulb with a similar lamp that had an embedded thermal switch that caused that bulb to periodically flash on and off -- with a nice RFI-generating spark that played havioc with nearby AM broadcast reception.

I imagine a parallel-wired Christmas-tree string of such flashing bulbs would generate a fairly loud and random broadband signal. Hm... wonder how the shape of the resulting spectrum would vary depending on the number of bulbs?

Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all)

-- As we enjoy great advantages from inventions of others, we should be glad of an opportunity to serve others by any invention of ours; and this we should do freely and generously. -- Benjamin Franklin

--

It's even better when you attach 300 ohm antenna twin lead to both sides of the relay contacts and connect them to a balanced antenna. You rotate it for maximum effect. Try it on your cell phone.

Al

Just about anything!

From the Report:

Conducted line noise: 200kHz - 30.0MHz. Radiated noise: 20.0MHz - 110.0MHz.

HP 8552/8553 Spectrum Analyzer