RE: Low signal switching
Robert, I checked my tabulation of drive levels for the various test levels. When testing at 10V/m and 3V/m, I do have occasional adequate drive levels. However, when I test at 1V/m, I don't have sufficient drive. On the other hand, if I am testing at a 10-3-1 sequence, the first 2 in the sequence have already cleaned the contact. If I want to be sure of having cleaned contacts, I can put attenuation after the switch. This will cause my source to drive harder. I checked my numbers across the range. In my case I have 30 dB of head room, so I can easily insert 20 dB of attenuation and insure sufficient current cleaning of my contacts. Thanks for the insight. Best regards, Don From: robert Macy [mailto:m...@california.com] Sent: Monday, April 21, 2003 2:46 PM To: djumbdenst...@tycoint.com; emc-p...@majordomo.ieee.org Subject: Re: Low signal switching Don, It is my understanding that physical switch contacts are cleaned with current - and use. It is probably ok at the lower signal levels since from time to time you're running the higher levels through the switches. Is there someway you can switch and then verify contact? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Mon, 21 Apr 2003 13:27:38 -0400 djumbdenst...@tycoint.com wrote: Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Low signal switching
I read in !emc-pstc that djumbdenst...@tycoint.com wrote (in 846BF526A2 05F84BA2B6045BBF7E9A6A0532B3DB@flbocexu05) about 'Low signal switching' on Tue, 22 Apr 2003: It had not occurred to me that electronic switches might do the job. I don't know if isolation will be an issue, but contact resistance is out of the picture, and I can live with a couple of dB of insertion loss. Thanks for the idea. There are special diodes (not PIN diodes) made for switching at UHF, in TV tuners for example. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Low signal switching
Some of these attenuators use wiping contacts- self cleaning. If there are any microwave switches like that they will last longer during dry switching. There is one SA I know of that has an attenuator exercise cycle. When the unit is powered up it runs the attenuator through several cycles to clean the gold contacts. Dave Cuthbert From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Monday, April 21, 2003 5:20 PM To: drcuthbert; 'djumbdenst...@tycoint.com'; emc-p...@majordomo.ieee.org Subject: Re: Low signal switching I can certainly suggest a solution, although it would take a bit of research to totally determine the answer. There are any number of spectrum analyzers and EMI receivers out there with switchable front-end attenuators. An HP 8566 has a noise floor of -135 dBm with a 10 Hz bandwidth and full video filtering. An NM-37/57 has a much lower noise floor and these things have been around for close to forty years, with no problems that I know of with the attenuator switches fouling. So any of the manufacturers of EMI receivers spectrum analyzers should know what swtiches to buy. I checked out Mini-Circuits: http://www.minicircuits.com/ and the only amplitude related specs there were insertion loss and vswr. From: drcuthbert drcuthb...@micron.com Reply-To: drcuthbert drcuthb...@micron.com Date: Mon, 21 Apr 2003 14:58:57 -0600 To: 'djumbdenst...@tycoint.com' djumbdenst...@tycoint.com, emc-p...@majordomo.ieee.org Subject: RE: Low signal switching Don, I have encountered this problem with low-level signals. It seems to vary greatly from manufacturer to manufacturer (the company we had the best results with went out of business). When the contact(s) became dirty I would run a DC current and clean it. The problem would quickly return and the only real fix was to replace the relay. One to two years of life was typical. I also would like to know a good solution. Dave Cuthbert Micron Technology -Original Message- From: djumbdenst...@tycoint.com [mailto:djumbdenst...@tycoint.com] Sent: Monday, April 21, 2003 11:28 AM To: emc-p...@majordomo.ieee.org Subject: Low signal switching Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac
RE: Low signal switching
Ken, It had not occurred to me that electronic switches might do the job. I don't know if isolation will be an issue, but contact resistance is out of the picture, and I can live with a couple of dB of insertion loss. Thanks for the idea. Best regards, Don From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Monday, April 21, 2003 7:20 PM To: drcuthbert; 'djumbdenst...@tycoint.com'; emc-p...@majordomo.ieee.org Subject: Re: Low signal switching I can certainly suggest a solution, although it would take a bit of research to totally determine the answer. There are any number of spectrum analyzers and EMI receivers out there with switchable front-end attenuators. An HP 8566 has a noise floor of -135 dBm with a 10 Hz bandwidth and full video filtering. An NM-37/57 has a much lower noise floor and these things have been around for close to forty years, with no problems that I know of with the attenuator switches fouling. So any of the manufacturers of EMI receivers spectrum analyzers should know what swtiches to buy. I checked out Mini-Circuits: http://www.minicircuits.com/ and the only amplitude related specs there were insertion loss and vswr. From: drcuthbert drcuthb...@micron.com Reply-To: drcuthbert drcuthb...@micron.com Date: Mon, 21 Apr 2003 14:58:57 -0600 To: 'djumbdenst...@tycoint.com' djumbdenst...@tycoint.com, emc-p...@majordomo.ieee.org Subject: RE: Low signal switching Don, I have encountered this problem with low-level signals. It seems to vary greatly from manufacturer to manufacturer (the company we had the best results with went out of business). When the contact(s) became dirty I would run a DC current and clean it. The problem would quickly return and the only real fix was to replace the relay. One to two years of life was typical. I also would like to know a good solution. Dave Cuthbert Micron Technology -Original Message- From: djumbdenst...@tycoint.com [mailto:djumbdenst...@tycoint.com] Sent: Monday, April 21, 2003 11:28 AM To: emc-p...@majordomo.ieee.org Subject: Low signal switching Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All
RE: Low signal switching
-Original Message- From: djumbdenst...@tycoint.com [mailto:djumbdenst...@tycoint.com] Sent: Monday, April 21, 2003 10:28 AM To: emc-p...@majordomo.ieee.org Subject: Low signal switching Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic Don: The only ones I trust are the HP (now Agilent) coax relays. As for low-level reliability, this is what is used in my HP automated data acquisition system, and I have also seen them used in Watkins Johnson receivers. Both applications are small-signal (-110 dBm), low-loss, high isolation, high reliability applications. Did I mention that they're expensive? Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Low signal switching
Don, It is my understanding that physical switch contacts are cleaned with current - and use. It is probably ok at the lower signal levels since from time to time you're running the higher levels through the switches. Is there someway you can switch and then verify contact? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Mon, 21 Apr 2003 13:27:38 -0400 djumbdenst...@tycoint.com wrote: Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Low signal switching
I had occasion once to look at the input relay on an NM-37. The set acted as if relay contacts were corroded -- but the sealed reed relay was fine; the problem was a cold-solder joint. Relays sealed in inert gas or vacuum should never fail due to corrosion, and there's no need to limit their small-signal rating on account of that. Of course, the days when we used to carry relay burnishers and contact cleaner in our tool boxes are past, but I am now seeing relay-cleaning routines built into the firmware of Amateur radio equipment, routines which could be emulated by actually cycling input attenuators and switches once in a while instead of leaving them long enough for contact corrosion to become a problem. Cortland 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Low signal switching
Don, I have encountered this problem with low-level signals. It seems to vary greatly from manufacturer to manufacturer (the company we had the best results with went out of business). When the contact(s) became dirty I would run a DC current and clean it. The problem would quickly return and the only real fix was to replace the relay. One to two years of life was typical. I also would like to know a good solution. Dave Cuthbert Micron Technology From: djumbdenst...@tycoint.com [mailto:djumbdenst...@tycoint.com] Sent: Monday, April 21, 2003 11:28 AM To: emc-p...@majordomo.ieee.org Subject: Low signal switching Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Low signal switching
There was a thread on this some time ago and I think the consensus was that the -20 dBm limit must be a typo, or a misunderstanding by the sales dept that writes the catalog copy. if the switch is purely mechanical, the signal level shouldn't matter, except for here are some wool-gathering thoughts. If there is any kind of solid-state device in the path like a diode then there could be a lower limit to the signal that would be passed through. But also if it were a purely mechanical contact with any galvanic potential induced, that might inhibit the rf signal. -20 dBm is 87 dbuV which is about 22 mV (converting mentally) and perhaps a galvanic potential could corrupt signals at a level lower than that. Maybe someone else will have a more definitive reply. From: djumbdenst...@tycoint.com Reply-To: djumbdenst...@tycoint.com Date: Mon, 21 Apr 2003 13:27:38 -0400 To: emc-p...@majordomo.ieee.org Subject: Low signal switching Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
