Although there is no AM broadcast below 530kHz, there are still many services using the frequencies between 200kHz and 530kHz, the most important of which is the aviation industry. Called NDB's, these low frequency signals are still used for navigation globally and instrument approaches in airports world-wide.
>From a vantage point several thousand feet above the local power lines, a 25ms burst once/hour would be no big deal, but if there are lots of 25ms bursts/hour in a given area, this could be a problem! Mike Hopkins Thermo KeyTek (pilot of small airplane who does not want the ADF needle going around in circles -- especially when in use by pilot trying to figure out which way's home) -----Original Message----- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, January 16, 2002 4:53 PM To: am...@westin-emission.no; emc-p...@majordomo.ieee.org Subject: Re: Company close down due to EMC phenomena A technical response from an American. I sympathize with the viewpoint that the duty cycle is very low and the on-time is very low and the potential for mischief is near nil. I would add a further argument. 55022 CE limits protect AM radio reception. In the USA there is no AM broadcast below 530 kHz. In the EU there is some LW broadcasting from I believe 150 - 300 kHz, and then MW picks up again at 530 kHz. So the potential for rfi is limited. That "officials" would even consider banning such a product is an argument against anyone having such power. ---------- >From: <am...@westin-emission.no> >To: <emc-p...@majordomo.ieee.org> >Subject: Company close down due to EMC phenomena >Date: Wed, Jan 16, 2002, 2:17 PM > > > Well, this might be the reality in a case I have been introduced to lately. > > Case: > A company are manufacturing PowerLine Communication products. They > communicate via the power lines and a typical link is between a consumer > residence and the nearest power station. The products can of course also > communicate inside the consumers residence. The communication protocol is > called CEBus http://www.cebus.org/which and make use of the frequency band > 100kHz-400kHz and the amplitude is approximate 2-5V. A typical length of a > transmission is 25ms and occurs approximate one time pr hour. > > First of all, AFAIK PowerLine Communication and PowerLine Transmission > (broadband 1.6MHz-30MHz) are now coming will full force in EU and > CENELEC/ETSI are working together regulate this type of transmission path > and also coming up with standards. > > The problem for the manufacturer is the conducted emission requirements in > EU. According to the EN55022B levels the maximum quasi-peak emission is > 66dBuV@150kHz, and a typical PLC (under transmission) which has been > measured, showed the value of 120dBuV (peak). With no transmission it had a > margin of 10dB (quasi-peak) and 30dB (average). The radiated emission had a > margin of 10dB. > > Well, conducted emission is the problem when transmitting. But, as I said, > the transmission occurs only 25ms/hour. > > The national authority will not allowed this product to be placed into the > marked because it do not fulfil the EN55022B limits (100kHz-400kHz) under > transmission mode. No way. > > Other national authorities have other approaches on this case, they say " as > long as you do not disturb other equipment, install it. If you do disturb, > we will come and remove it". They also say " install it even if it does not > fulfil EN550022B, but we will remove it if it disturb others". > > Two completely different approaches as you see. > > Questions: > 1. Is it possible to have different approaches within EU ? > 2. Since PLC/PLT is "quite new" technology and since we do not have any EU > product standard (no standard for whose who are using 100kHz-400kHz band), I > like the approach "as long as you do not disturb other equipment, install > it. If you do disturb, we will come and remove it". What is your opinion > about this? > 3. The transmission occurs very seldom. 25ms/hour, that is 7e-6 and > approximate 0,001% transmission rate. Can this seldom transmission rate be > an argument to not test the PLC product under continuous transmission ? I > would say yes, but which rate is acceptable / reasonable ? > > So, why should the company close down ? Because if the national authority > gets what they want, there will be one sale. Logical, but is it a correct > prohibition the authority call? > > > Best regards > Amund Westin, Oslo/Norway > > > > > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson: pstc_ad...@garretson.org > Dave Heald davehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > No longer online until our new server is brought online and the old > messages are imported into the new server. > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
