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Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
¿ªÔÆÌåÓýI think you can just move the cables that connect the couplers to the samplers without having to move hardware around. ? From: [email protected] <[email protected]> On Behalf Of Rich Miller via groups.io
Sent: Saturday, March 05, 2022 11:48 PM To: [email protected]; [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? I think I confused everyone, sorry!? ? What I have done now is swapped both couplers. The problem stays does not follow. It is something in the Port 1 line beyond the coupler. I do have extra samplers here, I suppose no harm in trying it.? ? I should note, I am now seeing these wild results below 3GHz, but nowhere as bad as I see it above 3GHz. 4 - 5 GHz is where it's most consistently bad. ? Let me take a look at the service manual, and determine which sampler I need to swap. Would be nice if that were the issue! ? Rich?? ? On Saturday, March 5, 2022, 11:34:04 PM EST, n8zmTWH@... <n8zmtwh@...> wrote: ? ? Agreed, but does the switch ¡®know¡¯ about the band change? That¡¯s what is curious here. ? ¸é¾±³¦³ó¡You said that the problem follows. Do you mean that the problem still occurs with the port 2 coupler? So it did not follow the coupler, but remained on the port 1 side. ? I wonder if it is a sampler problem instead. Maybe a bad cable from the coupler to the sampler, or from the sampler to the A/D? ? There is also a clue in that it stays OK when first turned on, until it is actually switched. ? From: [email protected] <[email protected]> On Behalf Of Lothar baier ? You are correct about the source switching above 3GHz BUT nothing changes at the source if you switch between S11 and S22 , if you have a source issue than its almost always symmetrical which means it appears on S11 and S22 . The Switch is a solid state switch that is a cascade of multiple cells to increase isolation , each branch has ESD protection diodes which are supposed to protect the switch cells from ESD if those diodes get damaged the effects appear most significant at higher frequencies than at lower ones first S11 and/or S22 of the switch also degrades which affects the source operation asymmetrical ! ? Sent from for Windows ? From: n8zmTWH via groups.io ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ? From: [email protected] <[email protected]> On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ? From: [email protected] <[email protected]> on behalf of Rich Miller via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ? From: Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ? From: Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ? ? ? ? |
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Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
I think I confused everyone, sorry!? What I have done now is swapped both couplers. The problem stays does not follow. It is something in the Port 1 line beyond the coupler. I do have extra samplers here, I suppose no harm in trying it.? I should note, I am now seeing these wild results below 3GHz, but nowhere as bad as I see it above 3GHz. 4 - 5 GHz is where it's most consistently bad. Let me take a look at the service manual, and determine which sampler I need to swap. Would be nice if that were the issue! Rich??
On Saturday, March 5, 2022, 11:34:04 PM EST, n8zmTWH@... <n8zmtwh@...> wrote:
Agreed, but does the switch ¡®know¡¯ about the band change? That¡¯s what is curious here. ? ¸é¾±³¦³ó¡You said that the problem follows. Do you mean that the problem still occurs with the port 2 coupler? So it did not follow the coupler, but remained on the port 1 side. ? I wonder if it is a sampler problem instead. Maybe a bad cable from the coupler to the sampler, or from the sampler to the A/D? ? There is also a clue in that it stays OK when first turned on, until it is actually switched. ? From: [email protected] <[email protected]> On Behalf Of Lothar baier
Sent: Saturday, March 05, 2022 10:32 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? You are correct about the source switching above 3GHz BUT nothing changes at the source if you switch between S11 and S22 , if you have a source issue than its almost always symmetrical which means it appears on S11 and S22 . The Switch is a solid state switch that is a cascade of multiple cells to increase isolation , each branch has ESD protection diodes which are supposed to protect the switch cells from ESD if those diodes get damaged the effects appear most significant at higher frequencies than at lower ones first S11 and/or S22 of the switch also degrades which affects the source operation asymmetrical ! ? Sent from for Windows ? From: n8zmTWH via groups.io ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ? From: [email protected] <[email protected]> On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ? From: [email protected] <[email protected]> on behalf of Rich Miller via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ? From: Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ? From: Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ? ? ? ? |
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Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
¿ªÔÆÌåÓýAgreed, but does the switch ¡®know¡¯ about the band change? That¡¯s what is curious here. ? ¸é¾±³¦³ó¡You said that the problem follows. Do you mean that the problem still occurs with the port 2 coupler? So it did not follow the coupler, but remained on the port 1 side. ? I wonder if it is a sampler problem instead. Maybe a bad cable from the coupler to the sampler, or from the sampler to the A/D? ? There is also a clue in that it stays OK when first turned on, until it is actually switched. ? From: [email protected] <[email protected]> On Behalf Of Lothar baier
Sent: Saturday, March 05, 2022 10:32 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? You are correct about the source switching above 3GHz BUT nothing changes at the source if you switch between S11 and S22 , if you have a source issue than its almost always symmetrical which means it appears on S11 and S22 . The Switch is a solid state switch that is a cascade of multiple cells to increase isolation , each branch has ESD protection diodes which are supposed to protect the switch cells from ESD if those diodes get damaged the effects appear most significant at higher frequencies than at lower ones first S11 and/or S22 of the switch also degrades which affects the source operation asymmetrical ! ? Sent from for Windows ? From: n8zmTWH via groups.io ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ? From: [email protected] <[email protected]> On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ? From: [email protected] <[email protected]> on behalf of Rich Miller via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ? From: Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ? From: Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ? ? ? ? |
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Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
Hi Lothar: Yeah that is what I was afraid of regarding the switch. Maybe it would be useful in a 3GHz machine. I think you did misunderstand. In essence, I swapped couplers, and the problem stayed at Port 1. The problem did not move with the exchange of the couplers. Rich?
On Saturday, March 5, 2022, 11:30:32 PM EST, Lothar baier <lothar@...> wrote:
First of if you physically swapped the coupler and the problem is gone than it appears your coupler has a issue and not the switch unless I misunderstand what you did . As far as repairing a bad switch goes it would depend on your capabilities ?? those switches are not build using regular surface mount parts , the switch uses a gold plated block that has channels machined , inside those channels you have GaAs Switch dies that are wire bonded and attached using solder or conductive epoxy , its not trivial to remove and replace the dies you need wire bonders and die attach machine and finding the correct die is a whole different story , its not trivial at all ? ? ? Sent from for Windows ? From: Rich Miller via groups.io
Sent: Saturday, March 5, 2022 9:43 PM To: [email protected]; [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? Hi Lothar: ? I switched the physical coupler (did not modification around the swtich). I just moved Port 2 into Port 1 position. I have not installed the other coupler yet, so Port 1 (as seen from the front of the instrument) has my old Port 2 Coupler in it. Port 2 is Blank. ? On Saturday, March 5, 2022, 10:38:59 PM EST, Lothar baier <lothar@...> wrote: ? ? Just to double check if I understand this correctly , did you swap the couplers or did you flip the switch ports and switch ? ? Sent from for Windows ? From:
Rich Miller via groups.io ? Just got done removing Port 2 Coupler and placing it in the Port 1 Position. Problem follows, so I think this is kind of pointing towards the switch. I can say for sure the source is providing the correct power at 3.0 GHz. Whatever it's producing above 3 GHz I can say for sure, but it is stable. No erratic behavior when switching between the ports.? ? Bit of a tricky fault..? ? Rich? ? On Saturday, March 5, 2022, 09:24:07 PM EST, Rich Miller via groups.io <av8torrich@...> wrote: ? ? I was not able to take those measurements prior to pulling it apart.. What I can state is; S22 was rock solid with no such fluctuations, and passes all test without issue. Furthermore, S22 never fluctuates when moving to another measurement and back again. When I did power up the 8753E, the S11 response is normal, and remains normal until such time as I switch between another measurement. As a matter of fact, simply hitting S11 multiple times will straighten the response out, and also cause the response to go nutty. In short, if I cycle S11 multiple times I can either get a normal RL response, or something similar to what I showed in my original post. ? What I am attempting now, is swapping Port 1 with Port 2, and see if the problem follows. I have it down in my lab in the basement where I do have a small ESD work area near where I solder. Good news is, we are at >70% humidity here in the mid Atlantic today so that should help eliminate some of the ESD Risk. ? 73 ? Rich, AJ3G ? On Saturday, March 5, 2022, 09:11:18 PM EST, n8zmTWH@... <n8zmtwh@...> wrote: ? ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ?
From: [email protected] <[email protected]>
On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ?
From:
[email protected] <[email protected]> on behalf of Rich Miller
via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ?
From:
Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ?
From:
Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ?
? ? ? ? |
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Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
Lothar baier
¿ªÔÆÌåÓýFirst of if you physically swapped the coupler and the problem is gone than it appears your coupler has a issue and not the switch unless I misunderstand what you did . As far as repairing a bad switch goes it would depend on your capabilities ?? those switches are not build using regular surface mount parts , the switch uses a gold plated block that has channels machined , inside those channels you have GaAs Switch dies that are wire bonded and attached using solder or conductive epoxy , its not trivial to remove and replace the dies you need wire bonders and die attach machine and finding the correct die is a whole different story , its not trivial at all ? ? ? Sent from for Windows ? From: Rich Miller via groups.io
Sent: Saturday, March 5, 2022 9:43 PM To: [email protected]; [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? Hi Lothar: ? I switched the physical coupler (did not modification around the swtich). I just moved Port 2 into Port 1 position. I have not installed the other coupler yet, so Port 1 (as seen from the front of the instrument) has my old Port 2 Coupler in it. Port 2 is Blank. ? On Saturday, March 5, 2022, 10:38:59 PM EST, Lothar baier <lothar@...> wrote: ? ? Just to double check if I understand this correctly , did you swap the couplers or did you flip the switch ports and switch ? ? Sent from for Windows ? From:
Rich Miller via groups.io ? Just got done removing Port 2 Coupler and placing it in the Port 1 Position. Problem follows, so I think this is kind of pointing towards the switch. I can say for sure the source is providing the correct power at 3.0 GHz. Whatever it's producing above 3 GHz I can say for sure, but it is stable. No erratic behavior when switching between the ports.? ? Bit of a tricky fault..? ? Rich? ? On Saturday, March 5, 2022, 09:24:07 PM EST, Rich Miller via groups.io <av8torrich@...> wrote: ? ? I was not able to take those measurements prior to pulling it apart.. What I can state is; S22 was rock solid with no such fluctuations, and passes all test without issue. Furthermore, S22 never fluctuates when moving to another measurement and back again. When I did power up the 8753E, the S11 response is normal, and remains normal until such time as I switch between another measurement. As a matter of fact, simply hitting S11 multiple times will straighten the response out, and also cause the response to go nutty. In short, if I cycle S11 multiple times I can either get a normal RL response, or something similar to what I showed in my original post. ? What I am attempting now, is swapping Port 1 with Port 2, and see if the problem follows. I have it down in my lab in the basement where I do have a small ESD work area near where I solder. Good news is, we are at >70% humidity here in the mid Atlantic today so that should help eliminate some of the ESD Risk. ? 73 ? Rich, AJ3G ? On Saturday, March 5, 2022, 09:11:18 PM EST, n8zmTWH@... <n8zmtwh@...> wrote: ? ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ?
From: [email protected] <[email protected]>
On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ?
From:
[email protected] <[email protected]> on behalf of Rich Miller
via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ?
From:
Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ?
From:
Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ?
? ? ? ? |
|
Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
Hi Lothar: I switched the physical coupler (did not modification around the swtich). I just moved Port 2 into Port 1 position. I have not installed the other coupler yet, so Port 1 (as seen from the front of the instrument) has my old Port 2 Coupler in it. Port 2 is Blank.
On Saturday, March 5, 2022, 10:38:59 PM EST, Lothar baier <lothar@...> wrote:
Just to double check if I understand this correctly , did you swap the couplers or did you flip the switch ports and switch ? ? Sent from for Windows ? From: Rich Miller via groups.io
Sent: Saturday, March 5, 2022 9:29 PM To: [email protected]; [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? Just got done removing Port 2 Coupler and placing it in the Port 1 Position. Problem follows, so I think this is kind of pointing towards the switch. I can say for sure the source is providing the correct power at 3.0 GHz. Whatever it's producing above 3 GHz I can say for sure, but it is stable. No erratic behavior when switching between the ports.? ? Bit of a tricky fault..? ? Rich? ? On Saturday, March 5, 2022, 09:24:07 PM EST, Rich Miller via groups.io <av8torrich@...> wrote: ? ? I was not able to take those measurements prior to pulling it apart.. What I can state is; S22 was rock solid with no such fluctuations, and passes all test without issue. Furthermore, S22 never fluctuates when moving to another measurement and back again. When I did power up the 8753E, the S11 response is normal, and remains normal until such time as I switch between another measurement. As a matter of fact, simply hitting S11 multiple times will straighten the response out, and also cause the response to go nutty. In short, if I cycle S11 multiple times I can either get a normal RL response, or something similar to what I showed in my original post. ? What I am attempting now, is swapping Port 1 with Port 2, and see if the problem follows. I have it down in my lab in the basement where I do have a small ESD work area near where I solder. Good news is, we are at >70% humidity here in the mid Atlantic today so that should help eliminate some of the ESD Risk. ? 73 ? Rich, AJ3G ? On Saturday, March 5, 2022, 09:11:18 PM EST, n8zmTWH@... <n8zmtwh@...> wrote: ? ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ? From: [email protected]
<[email protected]> On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ? From:
[email protected] <[email protected]> on behalf of Rich Miller
via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ?
From:
Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ?
From:
Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ?
? ? ? |
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Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
Since this is apparently a intermittent failure of one of those diodes, I doubt I would find it. Just in case, are they even replaceable, or does one simply scrap the switch? Shame, seems like it could be useful to at least 3GHz. Maybe I can find something else to use it with.
On Saturday, March 5, 2022, 10:32:24 PM EST, Lothar baier <lothar@...> wrote:
You are correct about the source switching above 3GHz BUT nothing changes at the source if you switch between S11 and S22 , if you have a source issue than its almost always symmetrical which means it appears on S11 and S22 . The Switch is a solid state switch that is a cascade of multiple cells to increase isolation , each branch has ESD protection diodes which are supposed to protect the switch cells from ESD if those diodes get damaged the effects appear most significant at higher frequencies than at lower ones first S11 and/or S22 of the switch also degrades which affects the source operation asymmetrical ! ? Sent from for Windows ? From: n8zmTWH via groups.io
Sent: Saturday, March 5, 2022 8:11 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ? From: [email protected] <[email protected]>
On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ? From:
[email protected] <[email protected]> on behalf of Rich Miller via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ? From:
Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ?
From:
Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ?
? ? ? |
|
Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
Lothar baier
¿ªÔÆÌåÓýJust to double check if I understand this correctly , did you swap the couplers or did you flip the switch ports and switch ? ? Sent from for Windows ? From: Rich Miller via groups.io
Sent: Saturday, March 5, 2022 9:29 PM To: [email protected]; [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? Just got done removing Port 2 Coupler and placing it in the Port 1 Position. Problem follows, so I think this is kind of pointing towards the switch. I can say for sure the source is providing the correct power at 3.0 GHz. Whatever it's producing above 3 GHz I can say for sure, but it is stable. No erratic behavior when switching between the ports.? ? Bit of a tricky fault..? ? Rich? ? On Saturday, March 5, 2022, 09:24:07 PM EST, Rich Miller via groups.io <av8torrich@...> wrote: ? ? I was not able to take those measurements prior to pulling it apart.. What I can state is; S22 was rock solid with no such fluctuations, and passes all test without issue. Furthermore, S22 never fluctuates when moving to another measurement and back again. When I did power up the 8753E, the S11 response is normal, and remains normal until such time as I switch between another measurement. As a matter of fact, simply hitting S11 multiple times will straighten the response out, and also cause the response to go nutty. In short, if I cycle S11 multiple times I can either get a normal RL response, or something similar to what I showed in my original post. ? What I am attempting now, is swapping Port 1 with Port 2, and see if the problem follows. I have it down in my lab in the basement where I do have a small ESD work area near where I solder. Good news is, we are at >70% humidity here in the mid Atlantic today so that should help eliminate some of the ESD Risk. ? 73 ? Rich, AJ3G ? On Saturday, March 5, 2022, 09:11:18 PM EST, n8zmTWH@... <n8zmtwh@...> wrote: ? ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ? From: [email protected]
<[email protected]> On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ? From:
[email protected] <[email protected]> on behalf of Rich Miller
via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ?
From:
Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ?
From:
Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ?
? ? ? |
|
Re: HP-8753E S11 Intermittent Results - Switch or Bridge?
Lothar baier
¿ªÔÆÌåÓýYou are correct about the source switching above 3GHz BUT nothing changes at the source if you switch between S11 and S22 , if you have a source issue than its almost always symmetrical which means it appears on S11 and S22 . The Switch is a solid state switch that is a cascade of multiple cells to increase isolation , each branch has ESD protection diodes which are supposed to protect the switch cells from ESD if those diodes get damaged the effects appear most significant at higher frequencies than at lower ones first S11 and/or S22 of the switch also degrades which affects the source operation asymmetrical ! ? Sent from for Windows ? From: n8zmTWH via groups.io
Sent: Saturday, March 5, 2022 8:11 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP-8753E S11 Intermittent Results - Switch or Bridge? ? ¸é¾±³¦³ó¡ ? From your picture, the problem is above 3 GHz. The Source oscillator does a major band switch at about 3 GHz, which suggests that might be where the problem is. The SS switch ¡®could¡¯ be erratic, but it just doesn¡¯t seem likely, especially since you are not seeing any power level changes. ? When you power up and just let it run for a while without changing anything, does it stay good? ? If you put a through between ports 1 and 2, and look at S21and S12, what happens? ? Also, does S22 behave properly? From your original post, I believe it must be OK, but I¡¯m double checking that conclusion. ? One caution about cables. They can build up static charge between the center and outer, which dumps into the ports when? connected. Usually only a concern with long cables, but¡ ? From: [email protected] <[email protected]>
On Behalf Of Rich Miller via groups.io ? I just got done measuring the power out at Port 1. To my surprise, I cannot detect any significant power output fulgurations. I have tried 3GHz, 3.707GHz (worse offender in S11 Response), 4GHz and 5GHz.? They all look very stable, when switching back and forth. I am using a power meter which is not rated for accuracy at 3 - 6 GHz, but I can set the output to 0dBm look at the measurement, and switch back and forth and look for any relative change. It is not fluctuating whatsoever.? ? I also checked 3GHz with my MDO, and that is a accurate power measurement. Now I am scratching my head again.
? On Saturday, March 5, 2022, 07:16:43 PM EST, Lothar baier <lothar@...> wrote: ? ? Try to find a cheap working 85047A ,? it uses the same inerts as the 8753D/E/ES including the solid state switch and you get 2 couplers as added bonus . ? Take one word of caution though ,? when handling the switch use a ESD mat and wriststrap or at least put some esd caps or terminations on the SMA connectors ,? those suckers are really sensitive to ESD ? Sent from for Windows ? From:
[email protected] <[email protected]> on behalf of Rich Miller via groups.io <av8torrich@...> ? Yes, I am leaning this way (switch being the issue). I think it could also be that I was running a bunch of two port calibrations using a Agilent 85093 this morning (testing eCal out). I had some averaging on, 1601 Points, and 300KHz of IF B/W Set. Needless to say there was a lot of switching going on today. Let me check the power output now, and then flip it over and pray that one of the connectors on the switch is loose. ? Looks like the parts hunt is likely on! ? Rich ? On Saturday, March 5, 2022, 06:55:27 PM EST, Lothar baier <lothar@...> wrote: ? ? The reversing switches are notorious for failures especially if a unit is used in a environment that is not ESD protected .? what you can also do and you have to be cautious if you do this is to remove the switch , remove the hardline from the switch to coupler port 1 and connect the coupler directly to the source , if your trace is consistent then you definatly have a bad switch ! ? ? Sent from for Windows ? From:
Rich Miller via groups.io ? Hi Lothar: ? It just started failing Port 1 Test. I was doing this just as this email came in. It is failing it consistently. I do not have a power meter, but I can take a look with my Spectrum Analyzer to see if there are power fluctuations at 3GHz. This problem seems to focus at frequencies higher than 3GHz.? ? Once I have a look at the output power, I will open and have a look. This is a new problem, as I never saw this before. ? Rich ? On Saturday, March 5, 2022, 06:38:56 PM EST, Lothar baier <lothar@...> wrote: ? ? If the S11response changes when you switch back and forth than this would point towards a repeatability issue with the solid state switch the fact that this changes with temperature would also point towards this direction , so here are a few things to try : ?
? Sent from for Windows ?
From:
Rich Miller via groups.io ? All: ? ? I have an issue with S11 (Port 1). It showed it's head now that I am running two port calibrations, thus I have not detected it just yet. My hunch is I have a problem with the switch, but not the Bridge. Here is what I am observing: ? 1. Upon boot up I get a good/normal S11 RL Response into a good 50 Ohm Load. This Condition will persist until I do one of the steps below. ? 2. If I switch to Port 2 (i.e. S22 Measurement), and then back to Port 1 the S11 Response has gone nutty (See Attached Picture).? ? 3. I have noticed, that if I depress the S11 MEAS multiple times, the S11 RL Response returns to normal.? ? 4. If you look at the enclosed picture, I have captured what I refer to as a normal S11 response, which I saved to memory (Smooth), and what it looks like after pressing S11 again (Wild variations in response). ? I have noticed there is a stark difference between instrument, cold and warm on S11. I do not however see this behavior our of any of the Port 2 Measurements regardless of temperature. Is there anywhere else this could be coming from other than the Solid State Switch, or am I way off base in my thinking here?? ? ? Rich? ? ?
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