I wonder if it was a calibrated field strength measurement. Shouldn’t the units be dB(uV/m) ? I won’t consider a -37 dBm signal at the input of the EMC receiver a particularly strong signal from a nearby intentional radiator. Ralph From: Ken Wyatt <k...@emc-seminars.com> Sent: March 24, 2025 10:08 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Tracking down interference at 915 MHz What really struck me was how busy the 915 MHz ISM band was utilized in an urban environment! See Figure 5 in the article. This was a swept measurement in Max Hold mode over a period of about a minute and you can see the average signal amplitude was 50 dBµV, with strong peaks from the drug store to 70 dBµV.
_______________________ I'm here to help you succeed! Feel free to call or email with any questions related to EMC or EMI troubleshooting - at no obligation. I'm always happy to help! Kenneth Wyatt Wyatt Technical Services LLC 8201 Lighthouse Lane Ct Windsor, CO 80528 On Mar 23, 2025, at 12:43 PM, Ken Javor <ken.ja...@emccompliance.com <mailto:ken.ja...@emccompliance.com> > wrote: My suggestion was not for the original installation, but as a suggested fix after Ken’s troubleshoot appeared to pinpoint the source of the interference. -- Ken Javor Ph: (256) 650-5261 From: Ralph McDiarmid <rmm.priv...@gmail.com <mailto:rmm.priv...@gmail.com> > Reply-To: ***** IEEE emc-pstc List ***** <EMC-PSTC@listserv.ieee.org <mailto:EMC-PSTC@listserv.ieee.org> > Date: Sunday, March 23, 2025 at 12:08 PM To: <EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> > Subject: Re: [PSES] Tracking down interference at 915 MHz I agree Ken. Unfortunately, installation companies don’t have that degree of technical prowess or care, they just go in, do a job as fast as possible, and move on. The owner of the gas station would be oblivious to the EMC concern. Ralph From: Ken Javor <ken.ja...@emccompliance.com <mailto:ken.ja...@emccompliance.com> > Sent: March 22, 2025 4:51 PM To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] Tracking down interference at 915 MHz Nice. Seems as if a simpler fix would be a set of directional antennas for the gas station’s 915 MHz link, yielding higher intentional signal and if the antennas are properly oriented relative to the suspected interference source, diminishing the interference level. -- Ken Javor Ph: (256) 650-5261 From: Ken Wyatt <k...@emc-seminars.com <mailto:k...@emc-seminars.com> > Reply-To: ***** IEEE emc-pstc List ***** <EMC-PSTC@listserv.ieee.org <mailto:EMC-PSTC@listserv.ieee.org> > Date: Saturday, March 22, 2025 at 3:35 PM To: <EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> > Subject: [PSES] Tracking down interference at 915 MHz Hi All, I thought this interference hunt to a gas station price sign might be of interest to the group. https://www.testandmeasurementtips.com/spectrum-measurements-shed-light-on-sign-malfunctions/ Cheers, Ken _______________________ I'm here to help you succeed! Feel free to call or email with any questions related to EMC or EMI troubleshooting - at no obligation. I'm always happy to help! Kenneth Wyatt Wyatt Technical Services LLC 8201 Lighthouse Lane Ct Windsor, CO 80528 _____ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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