spworley@athena.mit.edu (Spaceman Spiff) (04/10/90)
Does anyone know how to measure the amount of RF energy that a computer (or anything) produces? My HP-28S handheld computer/calculator sometimes acts very strange when my Amiga computer is on, but when I turn off my Amiga, the 28S is happy again. Since there's no physical/electrical connection, my guess is it HAS to be RF. How can I measure/detect the RF being broadcast by my computer? I've thought of getting a wide-band shortwave radio, but this is very crude and I'd have to find one. Suggestions, anyone? Steve Worley
myers@hpfcdj.HP.COM (Bob Myers) (04/11/90)
A measurement of RF interference, the way it's done to verify compliance with
the various government regulations, requires very carefully-controlled
conditions, such as a test site of certain dimensions and including a ground
screen, the proper antennas, and a calibrated receiver or spectrum analyzer.
With all of this gear, meaningful measurements (usually expressed in dB over
a reference of - I think - 1 uV/meter) of the field strength can be made.
(I have the dubious honor of doing these tests right now, on a new product,
so this subject is currently near and dear. Sigh.)
You cannot duplicate these measurements in a meaningful way with simple equip-
ment. I agree that the Amiga may be causing a problem, but it'd be difficult
to show that the unit was not in compliance with the limits to which it was
originally qualified.
Bob Myers KC0EW HP Graphics Tech. Div.| Opinions expressed here are not
Ft. Collins, Colorado | those of my employer or any other
myers%hpfcla@hplabs.hp.com | sentient life-form on this planet.logajan@ns.network.com (John Logajan) (04/12/90)
spworley@athena.mit.edu (Spaceman Spiff) writes: >My HP-28S handheld >computer/calculator sometimes acts very strange when my Amiga >computer is on, but when I turn off my Amiga, the 28S is >happy again. Since there's no physical/electrical connection, my >guess is it HAS to be RF. I used to have problems with my modem until I realized it was too close to the magnetic fields generated by the CRT scanning coils. (60hz and 15750hz, not RF, but airborne never the less.) I don't know what the HP-28S has that may be sensitive to the magnetic fields, but does it have any magnetic media reading mechanisms? -- - John Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428 - logajan@ns.network.com, john@logajan.mn.org, 612-424-4888, Fax 424-2853