My point wasn't specsmanship - there are many others - most - who know more about what commercial spec applies to what product family/situation.
My point was technical: Class B limits are evaluated at three meters, Class A at ten meters, but victim antennas on a vehicle are much closer to the culprits than either of those separations. Therefore interference may be expected regardless of class, and that is why automotive RE limits are more stringent than FCC-type plus they are evaluated at one meter, and all the way down to 150 kHz, because automotive use of the spectrum (in Europe) extends that low. Even in the USA, it extends down to 530 kHz. Ken Javor Phone: (256) 650-5261 > From: Carl Newton <[email protected]> > Date: Mon, 01 Feb 2016 10:38:44 -0500 > To: <[email protected]>, Ken Javor <[email protected]> > Subject: Re: [PSES] AU CISPR 22 Class B Interpretation > > Ken, > > If you review IEC/EN 60101-2-1 you find that it applies CISPR 11. Clause > 6.1 and Annex D of that standard (2007) applies that rationale as well. > Within CISPR 11 the class is determined by whether or not the equipment > connects to the public AC mains or not. I've worked on medical > equipment/systems that have applied Class A rating because they are only > used within large facilities. This is not uncommon. > > Carl > > On Fri, 29 Jan 2016 13:27:02 -0500, Ken Javor > <[email protected]> wrote: > >> Looking at the radiated emission requirements on things that are part of >> the >> vehicle, they are much more severe than Class B. And the >> ambulance/emergency vehicle will be using more of the rf spectrum than >> the >> typical ground vehicle, and such use is not entertainment or even >> navigation, but may be in support of a life-or-death situation, or at >> least >> timely delivery of a patient to a hospital that is ready to receive said >> patient. I would say Class B is an absolute minimum. In the typical >> situation that a platform antenna is mounted within much less than three >> meters from the Class B device, I would not expect compatibility. I would >> expect interference unless the incoming signal is quite strong. >> >> Ken Javor >> Phone: (256) 650-5261 >> >> >>> From: Carl Newton <[email protected]> >>> Reply-To: Carl Newton <[email protected]> >>> Date: Fri, 29 Jan 2016 12:09:41 -0500 >>> To: <[email protected]> >>> Subject: [PSES] AU CISPR 22 Class B Interpretation >>> >>> Group, >>> >>> My customer builds vehicular laptop and tablet docking stations intended >>> for hard mounted use within emergency vehicles such as police and >>> ambulance, as well as work trucks and forklifts. The vehicular power >>> supply narrowly missed CISPR 22 radiated Class B limits. Then their AU >>> Responsible Party told us they called the ACMA and they "insisted" this >>> is >>> a Class B device. I then sent my own request to ACMA and received the >>> reply below. >>> >>> In my opinion the ACMA individual is clearly biased toward the Class B >>> rating, but the fact that he leaves the door open to the Class A rating >>> is >>> enough proof for me that he agrees that it is a Class A device. >>> However, >>> my customer is looking for safety in numbers. The author raises a valid >>> note of caution concerning receivers within vehicles, but these systems >>> are already compliant with CISPR 25 and are widely used within North >>> America and Europe with no interference problems so we're not concerned >>> with that warning. >>> >>> I would appreciate it if some of you would review this information and >>> provide your professional opinion as to whether vehicle mounted ITE >>> qualifies as Class A or Class B: >>> >>> +++++++++++++++ >>> >>> Dear Mr Newton >>> >>> Clause 4.1 of AS/NZS CISPR 22 (which is identical to CISPR 22, Ed. 6.0 >>> (2008)) includes the following; >>> >>> Class B ITE is intended primarily for use in the domestic environment >>> and >>> may include: >>> >>> - Personal computers and auxiliary equipment. >>> >>> Note: The domestic environment is an environment where the use of >>> broadcast and television receivers may be expected within distances of >>> 10 >>> m of the apparatus concerned. >>> >>> Given that the class B limits apply to ³personal computers² (which would >>> also include ³tablets²) it would seem logical that your mounting >>> stations >>> ³for computers and tablets² (which I would think fall within the >>> definition of ³auxiliary equipment²) should comply with the same limits >>> as >>> the devices they are intended to hold. >>> >>> I would also think that, because police and ambulance vehicles will >>> probably have a broadcast (AM/FM) receiver installed in them this would >>> probably constitute a ³domestic environment². I would also question >>> whether it would be prudent to have a device meeting the class A limits >>> installed in a vehicle that relies heavily on two-way >>> radiocommunications >>> equipment where said device may interfere with the operation of this >>> on-board radiocommunications equipment. >>> >>> Having said that, clause 4.2 of AS/NZS CISPR 22 includes the following; >>> >>> Class A ITE is a category of all other ITE which satisfies the class A >>> ITE >>> limits but not the class B ITE limits. Such equipment should not be >>> restricted in its sale but the following warning shall be included in >>> the >>> instructions for use: >>> >>> Warning >>> >>> This is a class A product. In a domestic environment this product may >>> cause radio interference in which case the user may be required to take >>> adequate measures. >>> >>> It is up to you whether you wish to comply with the class A or the >>> class B >>> limits however, I would personally err on the side of caution if an >>> ambulance or a police car were unable use its radiocommunications >>> equipment and it turned out it was due to interference from your device >>> the legal ramifications could be costly. >>> >>> Regards >>> >>> XXXXXXXXXX XXXXXXXXX >>> Technical Regulation Development Section >>> Australian Communications & Media Authority >>> >>> ++++++++++++++++++++++ >>> >>> Thanks group, >>> >>> Carl >>> >>> >>> >>> -- >>> Using Opera's mail client: http://www.opera.com/mail/ >>> >>> - >>> ---------------------------------------------------------------- >>> This message is from the IEEE Product Safety Engineering Society >>> emc-pstc >>> discussion list. To post a message to the list, send your e-mail to >>> <[email protected]> >>> >>> All emc-pstc postings are archived and searchable on the web at: >>> http://www.ieee-pses.org/emc-pstc.html >>> >>> Attachments are not permitted but the IEEE PSES Online Communities site >>> at >>> http://product-compliance.oc.ieee.org/ can be used for graphics (in >>> well-used >>> formats), large files, etc. >>> >>> Website: http://www.ieee-pses.org/ >>> Instructions: http://www.ieee-pses.org/list.html (including how to >>> unsubscribe) >>> List rules: http://www.ieee-pses.org/listrules.html >>> >>> For help, send mail to the list administrators: >>> Scott Douglas <[email protected]> >>> Mike Cantwell <[email protected]> >>> >>> For policy questions, send mail to: >>> Jim Bacher: <[email protected]> >>> David Heald: <[email protected]> >> >> - >> ---------------------------------------------------------------- >> This message is from the IEEE Product Safety Engineering Society >> emc-pstc discussion list. To post a message to the list, send your >> e-mail to <[email protected]> >> >> All emc-pstc postings are archived and searchable on the web at: >> http://www.ieee-pses.org/emc-pstc.html >> >> Attachments are not permitted but the IEEE PSES Online Communities site >> at http://product-compliance.oc.ieee.org/ can be used for graphics (in >> well-used formats), large files, etc. >> >> Website: http://www.ieee-pses.org/ >> Instructions: http://www.ieee-pses.org/list.html (including how to >> unsubscribe) >> List rules: http://www.ieee-pses.org/listrules.html >> >> For help, send mail to the list administrators: >> Scott Douglas <[email protected]> >> Mike Cantwell <[email protected]> >> >> For policy questions, send mail to: >> Jim Bacher: <[email protected]> >> David Heald: <[email protected]> > > > -- > Using Opera's mail client: http://www.opera.com/mail/ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
