I may be missing something here that is obvious to the others, and if so, please advise. CS103/104/105 are conducted susceptibility tests meaning two things: It‘s conducted (why are we talking about 200 V/m or MIL-STD-464 EMEs?), and It’s a susceptibility requirement, so proper operation is the metric, not whether you blow the thing up or not. The point I really don’t understand is the leap from the CS103/104/105 type conducted limit vs. discussion of the RS environment, whether that be a -461 RS103 type limit, or a -464 EME table type EME. In order to make that leap, you need to assume an antenna. When a receiver is tested, it is a standalone product from some manufacturer and no one knows to what type of antenna it will be connected. Being redundant here to make sure I am not misunderstood, or perhaps to illuminate my lack of understanding of previous posts, the requirement can only be a CS type when procuring a radio receiver.
If you are trying to determine whether or not the actual EME is going to damage the receiver, you have to include antenna characteristics, and that is an integration issue, not a radio procurement issue. -- Ken Javor (256) 650-5261 From: Michael Viau <[email protected]> Reply-To: Michael Viau <[email protected]> Date: Friday, May 29, 2020 at 1:32 PM To: <[email protected]> Subject: Re: [PSES] Unreasonable Design Penalties on Receivers Thanks Patrick, I appreciate the input. Then I guess my next thought would be that it seems a little redundant to test it twice. Since thresholding and describing failures during the heck blasting method tells you how you would perform in the lower power test, why run it twice? Both requirements exist for the given system. Both should be met. It seems like the reasonable thing would be to test CS104 to the expected environment levels after installation, and then to ameliorate any issues with the appropriate filters or a better antenna or better front end defense on the receiver itself. It almost seems like 461 is saying, “Don’t put the burden on the equipment manufacturer to meet EME levels. Thats the responsibility of the integrator.” But that leaves this massive gap between the levels they test to vs. the levels they may be capable of performing up to, and the EME tables in 464. It just seems strange to me that the wording in the 461 Appendix wouldn’t be more along the lines of encouraging testing at higher levels but setting clear expectations for the manufacturer as to the degree of performance they should be able to provide at those levels. Thanks again. Maybe I’m nitpicking, but it seems like it’s almost encouraging undertesting with its current wording. - Michael On May 29, 2020, at 9:01 AM, Patrick <[email protected]> wrote: Hi Michael I've also wondered about this series of tests and relationship to -464. I think this breaks down to two considerations- a) the environment is friendly or not, and b) the receiver is expected to operate or just survive. My conclusion is that the CS10x tests are examining the receivers ability to operate as expected in a non-contested environment. That environment contains other friendly tx/rx comm channels and the receiver under test needs to be able to reject those other friendly comms and operate without error. Whereas the -464 environments represent a different environment that is either contested or non-friendly, or maybe just the top deck of an Aircraft carrier. In that case the receiver under test "might" not be expected to operate, but is expected to survive and recover. So for the first case we test with standard levels expected to be seen in a friendly environment. And for the second case we blast the heck out of it to see if it survives!! I'm not an expert, just trying to figure this out myself... -Patrick On Thu, May 28, 2020, 9:31 PM Michael Viau <[email protected]> wrote: Can someone help me circle this square? MIL-STD-461 (E-G) mentions in the Appendix for CS103/4 that we shouldn’t attempt to apply external levels like 200 V/m to this test. Even when accounting for antenna characteristics they mention that it would place unreasonable design penalties on the receiver. But it doesn’t seem unreasonable in light of the 464 EME requirements, which even go so far as to recommend lab testing for verification. I understand why we may want to leave CS103 as its own hunt for intermods, but for antenna connected receivers there seems like no better test than CS104 for verifying the subsystem would be operational in a 464 Table X environment. I’m also aware that 464 recommends in-line filters to meet the needs for these methods but it’s easier to find a good and airworthy 20 dB filter than it is a 60 dB one. So it seems totally reasonable to at least test CS104 to the expected EME levels to find your vulnerabilities/thresholds and get the filter based on those. What am I missing here? Why is the wording so benevolent to the equipment manufactures in this case? Thanks! And long time reader, first time poster. Michael - ---------------------------------------------------------------- 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]> - ---------------------------------------------------------------- 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]>
