If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #902
Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040
Ok, today I just got my first oscilloscope off of craigslist (it was free, so I figured it would get me started: it is dual trace at 10MHz, good enough for most of my stuff... and only cost was the gas to pick it up) anyways, I decided to use a dedicated, hot shoe camera flash to test things out. So I hook the probe to the hot portion of the show, and the ground to ground. At this point i did not know how to turn off the second trace (never liked manuals lol) and I decided to plug it in to something, but since I didn't have a probe, I plugged in a BNC rubber duck antenna. The second trace with the antenna was nearly identical to the camera charging circuit trace... to test if it was the scope doing this, I detached the probe and ground from the flash and the scope, and the trace still showed the charging circuit's trace. I turned off the flash and the trace was gone, after turning it back on, I fired the flash and watched the trace do the same thing as when the flash was connected... Then, while the flash was on I moved it around in 3D space and the trace adjusted itself, even when my hand was brought in proximity of the flash rather that the antenna..
So here is my question: Doesn't the FCC or someone have rules about spurious RF emissions from consumer hardware? Should the flash put out this much? (it is a strong signal from a few feet...)
Registered Member #16
Joined: Thu Feb 02 2006, 02:22PM
Location: New Wilmington, PA
Posts: 554
The FCC has strict regulations regarding the level of unintentional radiation permitted. Most appliances have a statement somewhere on them regarding compliance with FCC Part 15 regulation.
The flash uses an inverter to get the ~330v it requires to charge the capacitor. As most hams have found out, cheap inverters and SMPSes are amazingly good at fouling up the RF spectrum. The waveform they use to drive the transformer is rich in harmonics, and there is zero filtering.
Any electrical appliance can become a radiator when old or damaged. Some appliances have a certain degree of inherent RF emission just due to their nature. Generally the FCC doesn't care about these incidental radiators until a part 15 complaint (interference with licensed users of the RF spectrum) is filed.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
consumer product RFI Sheilding - required?
