Once to chase down interference signal, phone company pointed a very big finger at us. Some photos of site indicated a previous system had been there, and replaced by a newer one.The installers removed the old antennas but left the controller amp in place with power breaker turned off with note attached - do not turn on. Some helpful soul had turned it on, so after a couple of decades, it came to life powering up a couple of open circuit coax cables. Building mgr shut off power. Phone tech says yup that fixed it.
Yahoo Mail: Search, Organize, Conquer On Mon, Mar 24, 2025 at 2:25 PM, Jim Bacher<[email protected]> wrote: <!--#yiv3062226692 filtered {}#yiv3062226692 filtered {}#yiv3062226692 filtered {}#yiv3062226692 filtered {}#yiv3062226692 p.yiv3062226692MsoNormal, #yiv3062226692 li.yiv3062226692MsoNormal, #yiv3062226692 div.yiv3062226692MsoNormal {margin:0in;font-size:12.0pt;font-family:"Aptos", sans-serif;}#yiv3062226692 a:link, #yiv3062226692 span.yiv3062226692MsoHyperlink {color:blue;text-decoration:underline;}#yiv3062226692 span.yiv3062226692apple-converted-space {}#yiv3062226692 span.yiv3062226692EmailStyle21 {font-family:"Calibri", sans-serif;color:windowtext;}#yiv3062226692 .yiv3062226692MsoChpDefault {font-size:10.0pt;}#yiv3062226692 filtered {}#yiv3062226692 div.yiv3062226692WordSection1 {}--> Ken, I am not surprised. RFID, EAS and other items run at those frequencies Jim Bacher, WB8VSU [email protected] or [email protected] https://www.trc.guru/ From: Ken Wyatt <[email protected]> Sent: Monday, March 24, 2025 1:08 PM To: [email protected] 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 <[email protected]> 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 <[email protected]> Reply-To: ***** IEEE emc-pstc List ***** <[email protected]> Date: Sunday, March 23, 2025 at 12:08 PM To: <[email protected]> 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 <[email protected]> Sent: March 22, 2025 4:51 PM To: [email protected] 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 <[email protected]> Reply-To: ***** IEEE emc-pstc List ***** <[email protected]> Date: Saturday, March 22, 2025 at 3:35 PM To: <[email protected]> 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. 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher at: [email protected] To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher at: [email protected] To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher at: [email protected] To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher at: [email protected] To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher at: [email protected] To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher at: [email protected] To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 - ---------------------------------------------------------------- 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
