EMI/RFI "generator"

[[email protected]]

Back in the sixties and seventies when "build your own stereo
amplifier" was popular, I would use a 100W soldering gun and
fluorescent lights to determine susceptibility to interference by
switching them on and off in the vicinity of my circuit boards...Not
very professional. Are there affordable interference generating devices
made specifically for this purpose in the reach of the hobbyist?

 

[Jan Panteltje]

Back in the sixties and seventies when "build your own stereo
amplifier" was popular, I would use a 100W soldering gun and
fluorescent lights to determine susceptibility to interference by
switching them on and off in the vicinity of my circuit boards...Not
very professional. Are there affordable interference generating devices
made specifically for this purpose in the reach of the hobbyist?

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

Or else
http://www.amazing1.com/emp.htm

 

[martin griffith]

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

Or else
http://www.amazing1.com/emp.htm

Wow
EMP400 1.8 Gigawatts 170 kg/374 lbs

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


martin

 

[krw]

Back in the sixties and seventies when "build your own stereo
amplifier" was popular, I would use a 100W soldering gun and
fluorescent lights to determine susceptibility to interference by
switching them on and off in the vicinity of my circuit boards...Not
very professional. Are there affordable interference generating devices
made specifically for this purpose in the reach of the hobbyist?

Spark-gap Tesla coil?

 

[Speedskater]

Back in the sixties and seventies when "build your own stereo
amplifier" was popular, I would use a 100W soldering gun and
fluorescent lights to determine susceptibility to interference by
switching them on and off in the vicinity of my circuit boards...Not
very professional. Are there affordable interference generating devices
made specifically for this purpose in the reach of the hobbyist?

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.

 

[Bret Ludwig]

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.

 

[[email protected]]

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.

Excellent! Thanks!

 

[Winston]

Back in the sixties and seventies when "build your own stereo
amplifier" was popular, I would use a 100W soldering gun and
fluorescent lights to determine susceptibility to interference by
switching them on and off in the vicinity of my circuit boards...Not
very professional. Are there affordable interference generating devices
made specifically for this purpose in the reach of the hobbyist?

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

--Winston

 

[John Devereux]

Back in the sixties and seventies when "build your own stereo
amplifier" was popular, I would use a 100W soldering gun and
fluorescent lights to determine susceptibility to interference by
switching them on and off in the vicinity of my circuit boards...Not
very professional. Are there affordable interference generating devices
made specifically for this purpose in the reach of the hobbyist?

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.

 

[[email protected]]

How about one of those piezo-electric gas lighter guns?

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.

 

[John Devereux]

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.

 

[Frnak McKenney]

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.

"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? <grin!>


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
--

 

[[email protected]]

what would this interfere with?

 

[Al]

what would this interfere with?

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

 

[Speedskater]

what would this interfere with?

Just about anything!

From the Report:

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

HP 8552/8553 Spectrum Analyzer