HP 8341B RF sweeper has reduced output
Hi all
My HP 8341B sweeper looks like output down 10dbm~13dbm from requested level output...measured on a Boonton 4200 power meter know good.?
I rarely use it above 1Ghz... IIRC <2Ghz is band 0 didnt test other bands. I suspect an output step attenuator problem? a 10db pad "stuck"?
Looking at power meter at right of front panel on 8341B I see it matches requested power output...shouldnt be showing -10~13dbm down from requested value if there is an attenuator problem since that value is measured at output?
Anybody very familiar with these HP sweepers suggestions/tricks to save me time to address this? Ive fixed lots of test equipment but never this 8341B and its a *75 pound beast* that id like to fix and put back where it lives asap...its no fun to handle, flip over and move...
Thanks all
|
Ordered a 6ft cable, will report back with my results. I have tried slow sweep, less points, zero span. No luck.
|
Re: Spectrum analyser in a high traffic strong signal environment
IIRC, Metamagnetics considers the 4 dB the insertion loss.? In an interference-limited receiver, that would probably be acceptable.
Jim
Sent from my T-Mobile 4G LTE Device
toggle quoted message
Show quoted text
-------- Original message -------- From: "Brooke Clarke via groups.io" <brooke@...> Date: 3/3/22 2:11 PM (GMT-08:00) Subject: Re: [HP-Agilent-Keysight-equipment] Spectrum analyser in a high traffic strong signal environment
Hi Jim: Interesting.? It seems that the weak (desired) signal is attenuated about 4dB while the strong signal is knocked down to the limiting level.? See: https://patents.google.com/patent/US20190267960 The device makes use of circulators/isolators to maintain a reasonable VSWR. I looked since a simple diode limiter does the same thing, except it knocks down all signals and has a high VSWR. -- Have Fun, Brooke Clarke, N6GCE https://www.PRC68.com axioms: 1. The extent to which you can fix or improve something will be limited by how well you understand how it works. 2. Everybody, with no exceptions, holds false beliefs.
|
Re: Spectrum analyser in a high traffic strong signal environment
Hi Jim:
Interesting.? It seems that the weak (desired) signal is attenuated about 4dB while the strong signal is knocked down to the limiting level.? See:
The device makes use of circulators/isolators to maintain a reasonable VSWR.
I looked since a simple diode limiter does the same thing, except it knocks down all signals and has a high VSWR.
--
Have Fun,
Brooke Clarke, N6GCE
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
|
Seems ike you could mitigate the problem by slowing the sweep down.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
This just FYI !
I talked to a friend of mine this morning who was working as a test engineer at raytheon for 20 years , they used 8510 systems and in some applications had to use the testsets in a different location than the VNA itself.
His comment was that HP recommended to him not to exceed 5ft length on the control cable for the 8516A to ensure reliabile operation
On Mar 2, 2022, at 23:00, Lothar baier via groups.io <Lothar@...> wrote:
?Regardless it is best practice to keep cable lengths at a minimum, DB25 cables retail from $5 to $20 depending on make and length so its not cost prohibitive to aquire a short cable
On Mar 2, 2022, at 22:15, Bruce via groups.io <bruce@...> wrote:
?Thanks - Excellent, now he can test his cable.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Pin 4
Pin 10
Pin 11
Pin 17
Wired straight through !
I am using a DB25 cable from Amazon 3ft works flawless
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 9:57 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
If you know the cable connections please POST it to the board. That
way, he can check his cable and "fix" it if necessary.
BTW - IS the cable straight through? If so, which conductors are needed?
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
I bought mine on ebay for $800 , spend quite a bit of time trying to
figure out the cable
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 7:13 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Seems like the wrong wearing due to a cross over or some other
"defect" could cause intermittent operation.
How about using a break out box to look at the signals. I've never
owned an 8516 (owned most of the others). Just looked in my 8510
service manual set and have no 8516 schematic - do have for most of
the others - He could look at the output from the doubler to see if it
is working - possible connector damage is a risk.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
There is no schematic for the 8516 only a few block diagrams , the
switching isn¡¯t done by relays but rather with pin diodes inside the
brick , the doubler control board is buttoned up on the Doubler ,
the only information to be gathered from the service manual is that
there are 4 control lines that go to a PAL that acts as adress
decoder , from there are 5 lines one goes to the doubler to switch
it in and out the other 4 lines go to a block labeled filter control
which outputs 5 lines that go to the actual doubler block so there
is quite a bit of switching going on but there is no info on the
switch points or details on the filters .
Having a crossover cable definatly might be a concern but he also
mentioned that it used to work ¡°intermittent¡± so that¡¯s also
something to think about
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:48 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Sure but it is comparatively slow - Normal 8510C sweep is relatively
slow, and the problem can be avoided by only weeping 50-20 and say
25-40GHz.
I think the best first step is to look at the doubler switching module
to see if the relay is actually switching the doubler in. I don't
seem to have a schematic diagram for the 8516, but hopefully, HP
included a LED on the module?
In any case need to check the cable connections and determine whether
the doubler is being energized - actually, maybe just watching the +
supply to the doubler itself might work.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Disagree with you on this, dont forget that the synthesizer is swept
so if you do a 45MHz to 40GHz sweep the doubler is switched in and
out constantly so your DC now becomes a squarewave , also the
control signal not only switches the doubler but also switches in
and out filters to clean up the signal so there is some activity
going on those control lines !
One way to find out would be to tack a scope probe on the control
lines and look at the shape of the control signals
On Mar 2, 2022, at 18:30, Bruce via groups.io
<bruce@...> wrote:
?Missed that - the 20 ft cable seems NOT likely to be a problem -
these ar DC control signals. I recall some discussion that it is a
straight through cable without cross over based on looking at 8341
and 8516 schematic diagrams - I think that I'd focus on
investigating the wiring of the cable.
1) Determine which conductors are used and be certain that the
cable has those conductors 1-1 without cross over.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
He mentioned earlier in this thread that its only 20-40GHz but he
also mentioned using a 20ft cable ? which could be the problem, I
am not sure what the control interface is , the part number of the
control cable says RS232 and there are 4 lines connected in the
testset BUT the doubler control uses a PAL as a decoder so I think
it¡¯s a parallel interface and having a 20ft cable could be a bit
much
Sent from Mail<>
for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:21 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Does the IF error occur below 20 GHz ?? If not, the doubler is
suspect - if so, look at the switching or the test set.
Nexg step would be to try and look at the test set VTO. It is
difficult because they pipe it directly into the samplers.
Cheers!
Bruce
Quoting ratn9ne@...:
Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has
something to do with the doubler I assume. Any span or frequency in
this range has this error. I have seen >20GHz work for a little
while but only randomly. My next idea is a shorter DB25 cable as
mine is about 20 feet long. Tried turning up the LO power coming in
on the sweeper with no luck. I can't find a replacement doubler on
ebay to test with. These must be very rare. Can they be serviced?
This display/sweeper/control box setup has been tested with an 8515
and no errors at all.
|
This just FYI !
I talked to a friend of mine this morning who was working as a test engineer at raytheon for 20 years , they used 8510 systems and in some applications had to use the testsets in a different location than the VNA itself.
His comment was that HP recommended to him not to exceed 5ft length on the control cable for the 8516A to ensure reliabile operation
toggle quoted message
Show quoted text
On Mar 2, 2022, at 23:00, Lothar baier via groups.io <Lothar@...> wrote:
?Regardless it is best practice to keep cable lengths at a minimum, DB25 cables retail from $5 to $20 depending on make and length so its not cost prohibitive to aquire a short cable
On Mar 2, 2022, at 22:15, Bruce via groups.io <bruce@...> wrote:
?Thanks - Excellent, now he can test his cable.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Pin 4
Pin 10
Pin 11
Pin 17
Wired straight through !
I am using a DB25 cable from Amazon 3ft works flawless
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 9:57 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
If you know the cable connections please POST it to the board. That
way, he can check his cable and "fix" it if necessary.
BTW - IS the cable straight through? If so, which conductors are needed?
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
I bought mine on ebay for $800 , spend quite a bit of time trying to
figure out the cable
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 7:13 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Seems like the wrong wearing due to a cross over or some other
"defect" could cause intermittent operation.
How about using a break out box to look at the signals. I've never
owned an 8516 (owned most of the others). Just looked in my 8510
service manual set and have no 8516 schematic - do have for most of
the others - He could look at the output from the doubler to see if it
is working - possible connector damage is a risk.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
There is no schematic for the 8516 only a few block diagrams , the
switching isn¡¯t done by relays but rather with pin diodes inside the
brick , the doubler control board is buttoned up on the Doubler ,
the only information to be gathered from the service manual is that
there are 4 control lines that go to a PAL that acts as adress
decoder , from there are 5 lines one goes to the doubler to switch
it in and out the other 4 lines go to a block labeled filter control
which outputs 5 lines that go to the actual doubler block so there
is quite a bit of switching going on but there is no info on the
switch points or details on the filters .
Having a crossover cable definatly might be a concern but he also
mentioned that it used to work ¡°intermittent¡± so that¡¯s also
something to think about
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:48 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Sure but it is comparatively slow - Normal 8510C sweep is relatively
slow, and the problem can be avoided by only weeping 50-20 and say
25-40GHz.
I think the best first step is to look at the doubler switching module
to see if the relay is actually switching the doubler in. I don't
seem to have a schematic diagram for the 8516, but hopefully, HP
included a LED on the module?
In any case need to check the cable connections and determine whether
the doubler is being energized - actually, maybe just watching the +
supply to the doubler itself might work.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Disagree with you on this, dont forget that the synthesizer is swept
so if you do a 45MHz to 40GHz sweep the doubler is switched in and
out constantly so your DC now becomes a squarewave , also the
control signal not only switches the doubler but also switches in
and out filters to clean up the signal so there is some activity
going on those control lines !
One way to find out would be to tack a scope probe on the control
lines and look at the shape of the control signals
On Mar 2, 2022, at 18:30, Bruce via groups.io
<bruce@...> wrote:
?Missed that - the 20 ft cable seems NOT likely to be a problem -
these ar DC control signals. I recall some discussion that it is a
straight through cable without cross over based on looking at 8341
and 8516 schematic diagrams - I think that I'd focus on
investigating the wiring of the cable.
1) Determine which conductors are used and be certain that the
cable has those conductors 1-1 without cross over.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
He mentioned earlier in this thread that its only 20-40GHz but he
also mentioned using a 20ft cable ? which could be the problem, I
am not sure what the control interface is , the part number of the
control cable says RS232 and there are 4 lines connected in the
testset BUT the doubler control uses a PAL as a decoder so I think
it¡¯s a parallel interface and having a 20ft cable could be a bit
much
Sent from Mail<>
for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:21 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Does the IF error occur below 20 GHz ?? If not, the doubler is
suspect - if so, look at the switching or the test set.
Nexg step would be to try and look at the test set VTO. It is
difficult because they pipe it directly into the samplers.
Cheers!
Bruce
Quoting ratn9ne@...:
Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has
something to do with the doubler I assume. Any span or frequency in
this range has this error. I have seen >20GHz work for a little
while but only randomly. My next idea is a shorter DB25 cable as
mine is about 20 feet long. Tried turning up the LO power coming in
on the sweeper with no luck. I can't find a replacement doubler on
ebay to test with. These must be very rare. Can they be serviced?
This display/sweeper/control box setup has been tested with an 8515
and no errors at all.
|
Re: HP 1727A CRO: Problem with the vertical output amplifier.
Switching the input coupling to GND makes no difference as far as I can tell.
Also, does anybody have any recommendations for mosfets to use for a replacement circuit? or important specs at least.
|
Re: Keysight 3458A Front panel grounding clip
Just made a few calls to Keysight and 1460-1311 grounding clip is definitely not orderable.
I have the dimensions of the clip so I will try and manufacture a clip out of BeCu sheet metal.
Thanks,
Victor
|
OT: Leader instruments manual
Hi everyone and sorry for the OT, but this group has the best chances
to help in this case.
Does anyone happen to have the Leader LVG-1600 manual? Even only the
user manual would greatly help.
Thanks in advance and best regards.
Frank
|
Re: 8350B *restoration adventure?*
Ok Yves, makes sense now. My figures are a bit different, but looks ok overall. Thanks for your helpful data again.
|
Regardless it is best practice to keep cable lengths at a minimum, DB25 cables retail from $5 to $20 depending on make and length so its not cost prohibitive to aquire a short cable
toggle quoted message
Show quoted text
On Mar 2, 2022, at 22:15, Bruce via groups.io <bruce@...> wrote:
?Thanks - Excellent, now he can test his cable.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Pin 4
Pin 10
Pin 11
Pin 17
Wired straight through !
I am using a DB25 cable from Amazon 3ft works flawless
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 9:57 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
If you know the cable connections please POST it to the board. That
way, he can check his cable and "fix" it if necessary.
BTW - IS the cable straight through? If so, which conductors are needed?
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
I bought mine on ebay for $800 , spend quite a bit of time trying to
figure out the cable
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 7:13 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Seems like the wrong wearing due to a cross over or some other
"defect" could cause intermittent operation.
How about using a break out box to look at the signals. I've never
owned an 8516 (owned most of the others). Just looked in my 8510
service manual set and have no 8516 schematic - do have for most of
the others - He could look at the output from the doubler to see if it
is working - possible connector damage is a risk.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
There is no schematic for the 8516 only a few block diagrams , the
switching isn¡¯t done by relays but rather with pin diodes inside the
brick , the doubler control board is buttoned up on the Doubler ,
the only information to be gathered from the service manual is that
there are 4 control lines that go to a PAL that acts as adress
decoder , from there are 5 lines one goes to the doubler to switch
it in and out the other 4 lines go to a block labeled filter control
which outputs 5 lines that go to the actual doubler block so there
is quite a bit of switching going on but there is no info on the
switch points or details on the filters .
Having a crossover cable definatly might be a concern but he also
mentioned that it used to work ¡°intermittent¡± so that¡¯s also
something to think about
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:48 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Sure but it is comparatively slow - Normal 8510C sweep is relatively
slow, and the problem can be avoided by only weeping 50-20 and say
25-40GHz.
I think the best first step is to look at the doubler switching module
to see if the relay is actually switching the doubler in. I don't
seem to have a schematic diagram for the 8516, but hopefully, HP
included a LED on the module?
In any case need to check the cable connections and determine whether
the doubler is being energized - actually, maybe just watching the +
supply to the doubler itself might work.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Disagree with you on this, dont forget that the synthesizer is swept
so if you do a 45MHz to 40GHz sweep the doubler is switched in and
out constantly so your DC now becomes a squarewave , also the
control signal not only switches the doubler but also switches in
and out filters to clean up the signal so there is some activity
going on those control lines !
One way to find out would be to tack a scope probe on the control
lines and look at the shape of the control signals
On Mar 2, 2022, at 18:30, Bruce via groups.io
<bruce@...> wrote:
?Missed that - the 20 ft cable seems NOT likely to be a problem -
these ar DC control signals. I recall some discussion that it is a
straight through cable without cross over based on looking at 8341
and 8516 schematic diagrams - I think that I'd focus on
investigating the wiring of the cable.
1) Determine which conductors are used and be certain that the
cable has those conductors 1-1 without cross over.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
He mentioned earlier in this thread that its only 20-40GHz but he
also mentioned using a 20ft cable ? which could be the problem, I
am not sure what the control interface is , the part number of the
control cable says RS232 and there are 4 lines connected in the
testset BUT the doubler control uses a PAL as a decoder so I think
it¡¯s a parallel interface and having a 20ft cable could be a bit
much
Sent from Mail<>
for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:21 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Does the IF error occur below 20 GHz ?? If not, the doubler is
suspect - if so, look at the switching or the test set.
Nexg step would be to try and look at the test set VTO. It is
difficult because they pipe it directly into the samplers.
Cheers!
Bruce
Quoting ratn9ne@...:
Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has
something to do with the doubler I assume. Any span or frequency in
this range has this error. I have seen >20GHz work for a little
while but only randomly. My next idea is a shorter DB25 cable as
mine is about 20 feet long. Tried turning up the LO power coming in
on the sweeper with no luck. I can't find a replacement doubler on
ebay to test with. These must be very rare. Can they be serviced?
This display/sweeper/control box setup has been tested with an 8515
and no errors at all.
|
Thanks - Excellent, now he can test his cable.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
Pin 4
Pin 10
Pin 11
Pin 17
Wired straight through !
I am using a DB25 cable from Amazon 3ft works flawless
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 9:57 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
If you know the cable connections please POST it to the board. That
way, he can check his cable and "fix" it if necessary.
BTW - IS the cable straight through? If so, which conductors are needed?
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
I bought mine on ebay for $800 , spend quite a bit of time trying to
figure out the cable
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 7:13 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Seems like the wrong wearing due to a cross over or some other
"defect" could cause intermittent operation.
How about using a break out box to look at the signals. I've never
owned an 8516 (owned most of the others). Just looked in my 8510
service manual set and have no 8516 schematic - do have for most of
the others - He could look at the output from the doubler to see if it
is working - possible connector damage is a risk.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
There is no schematic for the 8516 only a few block diagrams , the
switching isn¡¯t done by relays but rather with pin diodes inside the
brick , the doubler control board is buttoned up on the Doubler ,
the only information to be gathered from the service manual is that
there are 4 control lines that go to a PAL that acts as adress
decoder , from there are 5 lines one goes to the doubler to switch
it in and out the other 4 lines go to a block labeled filter control
which outputs 5 lines that go to the actual doubler block so there
is quite a bit of switching going on but there is no info on the
switch points or details on the filters .
Having a crossover cable definatly might be a concern but he also
mentioned that it used to work ¡°intermittent¡± so that¡¯s also
something to think about
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:48 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Sure but it is comparatively slow - Normal 8510C sweep is relatively
slow, and the problem can be avoided by only weeping 50-20 and say
25-40GHz.
I think the best first step is to look at the doubler switching module
to see if the relay is actually switching the doubler in. I don't
seem to have a schematic diagram for the 8516, but hopefully, HP
included a LED on the module?
In any case need to check the cable connections and determine whether
the doubler is being energized - actually, maybe just watching the +
supply to the doubler itself might work.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Disagree with you on this, dont forget that the synthesizer is swept
so if you do a 45MHz to 40GHz sweep the doubler is switched in and
out constantly so your DC now becomes a squarewave , also the
control signal not only switches the doubler but also switches in
and out filters to clean up the signal so there is some activity
going on those control lines !
One way to find out would be to tack a scope probe on the control
lines and look at the shape of the control signals
On Mar 2, 2022, at 18:30, Bruce via groups.io
<bruce@...> wrote:
?Missed that - the 20 ft cable seems NOT likely to be a problem -
these ar DC control signals. I recall some discussion that it is a
straight through cable without cross over based on looking at 8341
and 8516 schematic diagrams - I think that I'd focus on
investigating the wiring of the cable.
1) Determine which conductors are used and be certain that the
cable has those conductors 1-1 without cross over.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
He mentioned earlier in this thread that its only 20-40GHz but he
also mentioned using a 20ft cable ? which could be the problem, I
am not sure what the control interface is , the part number of the
control cable says RS232 and there are 4 lines connected in the
testset BUT the doubler control uses a PAL as a decoder so I think
it¡¯s a parallel interface and having a 20ft cable could be a bit
much
Sent from Mail<>
for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:21 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Does the IF error occur below 20 GHz ?? If not, the doubler is
suspect - if so, look at the switching or the test set.
Nexg step would be to try and look at the test set VTO. It is
difficult because they pipe it directly into the samplers.
Cheers!
Bruce
Quoting ratn9ne@...:
Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has
something to do with the doubler I assume. Any span or frequency in
this range has this error. I have seen >20GHz work for a little
while but only randomly. My next idea is a shorter DB25 cable as
mine is about 20 feet long. Tried turning up the LO power coming in
on the sweeper with no luck. I can't find a replacement doubler on
ebay to test with. These must be very rare. Can they be serviced?
This display/sweeper/control box setup has been tested with an 8515
and no errors at all.
|
Pin 4
Pin 10
Pin 11
Pin 17
?
Wired straight through !
I am using a DB25 cable from Amazon 3ft works flawless
?
Sent from for Windows
?
toggle quoted message
Show quoted text
From: Bruce via groups.io
Sent: Wednesday, March 2, 2022 9:57 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
?
If you know the cable connections please POST it to the board.? That?
way, he can check his cable and "fix" it if necessary.
BTW - IS the cable straight through? If so, which conductors are needed?
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
> I bought mine on ebay for $800 , spend quite a bit of time trying to?
> figure out the cable
>
> Sent from Mail<> for Windows
>
> From: Bruce via groups.io<mailto:bruce@...>
> Sent: Wednesday, March 2, 2022 7:13 PM
> To:?
> [email protected]<mailto:[email protected]>
> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>
> Seems like the wrong wearing due to a cross over or some other
> "defect" could cause intermittent operation.
>
> How about using a break out box to look at the signals.? I've never
> owned an 8516 (owned most of the others).? Just looked in my 8510
> service manual set and have no 8516 schematic - do have for most of
> the others - He could look at the output from the doubler to see if it
> is working - possible connector damage is a risk.
>
> Cheers!
>
> Bruce
>
>
>
> Quoting Lothar baier <Lothar@...>:
>
>> There is no schematic for the 8516 only a few block diagrams , the
>> switching isn¡¯t done by relays but rather with pin diodes inside the
>> brick , the doubler control board is buttoned up on the Doubler ,
>> the only information to be gathered from the service manual is that
>> there are 4 control lines that go to a PAL that acts as adress
>> decoder , from there are 5 lines one goes to the doubler to switch
>> it in and out the other 4 lines go to a block labeled filter control
>> which outputs 5 lines that go to the actual doubler block so there
>> is quite a bit of switching going on but there is no info on the
>> switch points or details on the filters .
>> Having a crossover cable definatly might be a concern but he also
>> mentioned that it used to work ¡°intermittent¡±? so that¡¯s also
>> something to think about
>>
>>
>> Sent from Mail<> for Windows
>>
>> From: Bruce via groups.io<mailto:bruce@...>
>> Sent: Wednesday, March 2, 2022 6:48 PM
>> To:
>> [email protected]<mailto:[email protected]>
>> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>>
>> Sure but it is comparatively slow - Normal 8510C sweep is relatively
>> slow, and the problem can be avoided by only weeping 50-20 and say
>> 25-40GHz.
>>
>> I think the best first step is to look at the doubler switching module
>> to see if the relay is actually switching the doubler in.? I don't
>> seem to have a schematic diagram for the 8516, but hopefully, HP
>> included a LED on the module?
>>
>> In any case need to check the cable connections and determine whether
>> the doubler is being energized - actually, maybe just watching the +
>> supply to the doubler itself might work.
>>
>> Cheers!
>>
>> Bruce
>>
>>
>>
>> Quoting Lothar baier <Lothar@...>:
>>
>>> Disagree with you on this, dont forget that the synthesizer is swept
>>> so if you do a 45MHz to 40GHz sweep the doubler is switched in and
>>> out constantly so your DC now becomes a squarewave , also the
>>> control signal not only switches the doubler but also switches in
>>> and out filters to clean up the signal so there is some activity
>>> going on those control lines !
>>> One way to find out would be to tack a scope probe on the control
>>> lines and look at the shape of the control signals
>>>> On Mar 2, 2022, at 18:30, Bruce via groups.io
>>>> <bruce@...> wrote:
>>>>
>>>> ?Missed that - the 20 ft cable seems NOT likely to be a problem -
>>>> these ar DC control signals.? I recall some discussion that it is a
>>>> straight through cable without cross over based on looking at 8341
>>>> and 8516 schematic diagrams - I think that I'd focus on
>>>> investigating the wiring of the cable.
>>>>
>>>> 1) Determine which conductors are used and be certain that the
>>>> cable has those conductors 1-1 without cross over.
>>>>
>>>> Cheers!
>>>>
>>>> Bruce
>>>>
>>>> Quoting Lothar baier <Lothar@...>:
>>>>
>>>>> He mentioned earlier in this thread that its only 20-40GHz but he
>>>>> also mentioned using a 20ft cable
? which could be the problem, I
>>>>> am not sure what the control interface is , the part number of the
>>>>> control cable says RS232 and there are 4 lines connected in the
>>>>> testset BUT the doubler control uses a PAL as a decoder so I think
>>>>> it¡¯s a parallel interface and having a 20ft cable could be a bit
>>>>> much
>>>>>
>>>>> Sent from Mail<>?
>>>>> for Windows
>>>>>
>>>>> From: Bruce via groups.io<mailto:bruce@...>
>>>>> Sent: Wednesday, March 2, 2022 6:21 PM
>>>>> To:
>>>>> [email protected]<mailto:[email protected]>
>>>>> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>>>>>
>>>>> Does the IF error occur below 20 GHz ??? If not, the doubler is
>>>>> suspect - if so, look at the switching or the test set.
>>>>> Nexg step would be to try and look at the test set VTO.? It is
>>>>> difficult because they pipe it directly into the samplers.
>>>>>
>>>>> Cheers!
>>>>>
>>>>> Bruce
>>>>>
>>>>> Quoting ratn9ne@...:
>>>>>
>>>>>> Wow you guys are fast to help!
>>>>>> Here is some more info: error is only from 20-40GHz, so it has
>>>>>> something to do with the doubler I assume. Any span or frequency in
>>>>>> this range has this error. I have seen >20GHz work for a little
>>>>>> while but only randomly. My next idea is a shorter DB25 cable as
>>>>>> mine is about 20 feet long. Tried turning up the LO power coming in
>>>>>> on the sweeper with no luck. I can't find a replacement doubler on
>>>>>> ebay to test with. These must be very rare. Can they be serviced?
>>>>>> This display/sweeper/control box setup has been tested with an 8515
>>>>>> and no errors at all.
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
>
>
>
>
>
>
>
>
?
|
If you know the cable connections please POST it to the board. That way, he can check his cable and "fix" it if necessary.
BTW - IS the cable straight through? If so, which conductors are needed?
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
I bought mine on ebay for $800 , spend quite a bit of time trying to figure out the cable
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 7:13 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Seems like the wrong wearing due to a cross over or some other
"defect" could cause intermittent operation.
How about using a break out box to look at the signals. I've never
owned an 8516 (owned most of the others). Just looked in my 8510
service manual set and have no 8516 schematic - do have for most of
the others - He could look at the output from the doubler to see if it
is working - possible connector damage is a risk.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
There is no schematic for the 8516 only a few block diagrams , the
switching isn¡¯t done by relays but rather with pin diodes inside the
brick , the doubler control board is buttoned up on the Doubler ,
the only information to be gathered from the service manual is that
there are 4 control lines that go to a PAL that acts as adress
decoder , from there are 5 lines one goes to the doubler to switch
it in and out the other 4 lines go to a block labeled filter control
which outputs 5 lines that go to the actual doubler block so there
is quite a bit of switching going on but there is no info on the
switch points or details on the filters .
Having a crossover cable definatly might be a concern but he also
mentioned that it used to work ¡°intermittent¡± so that¡¯s also
something to think about
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:48 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Sure but it is comparatively slow - Normal 8510C sweep is relatively
slow, and the problem can be avoided by only weeping 50-20 and say
25-40GHz.
I think the best first step is to look at the doubler switching module
to see if the relay is actually switching the doubler in. I don't
seem to have a schematic diagram for the 8516, but hopefully, HP
included a LED on the module?
In any case need to check the cable connections and determine whether
the doubler is being energized - actually, maybe just watching the +
supply to the doubler itself might work.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Disagree with you on this, dont forget that the synthesizer is swept
so if you do a 45MHz to 40GHz sweep the doubler is switched in and
out constantly so your DC now becomes a squarewave , also the
control signal not only switches the doubler but also switches in
and out filters to clean up the signal so there is some activity
going on those control lines !
One way to find out would be to tack a scope probe on the control
lines and look at the shape of the control signals
On Mar 2, 2022, at 18:30, Bruce via groups.io
<bruce@...> wrote:
?Missed that - the 20 ft cable seems NOT likely to be a problem -
these ar DC control signals. I recall some discussion that it is a
straight through cable without cross over based on looking at 8341
and 8516 schematic diagrams - I think that I'd focus on
investigating the wiring of the cable.
1) Determine which conductors are used and be certain that the
cable has those conductors 1-1 without cross over.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
He mentioned earlier in this thread that its only 20-40GHz but he
also mentioned using a 20ft cable ? which could be the problem, I
am not sure what the control interface is , the part number of the
control cable says RS232 and there are 4 lines connected in the
testset BUT the doubler control uses a PAL as a decoder so I think
it¡¯s a parallel interface and having a 20ft cable could be a bit
much
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:21 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Does the IF error occur below 20 GHz ?? If not, the doubler is
suspect - if so, look at the switching or the test set.
Nexg step would be to try and look at the test set VTO. It is
difficult because they pipe it directly into the samplers.
Cheers!
Bruce
Quoting ratn9ne@...:
Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has
something to do with the doubler I assume. Any span or frequency in
this range has this error. I have seen >20GHz work for a little
while but only randomly. My next idea is a shorter DB25 cable as
mine is about 20 feet long. Tried turning up the LO power coming in
on the sweeper with no luck. I can't find a replacement doubler on
ebay to test with. These must be very rare. Can they be serviced?
This display/sweeper/control box setup has been tested with an 8515
and no errors at all.
|
I bought mine on ebay for $800 , spend quite a bit of time trying to figure out the cable
?
Sent from for Windows
?
toggle quoted message
Show quoted text
From: Bruce via groups.io
Sent: Wednesday, March 2, 2022 7:13 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
?
Seems like the wrong wearing due to a cross over or some other?
"defect" could cause intermittent operation.
How about using a break out box to look at the signals.? I've never?
owned an 8516 (owned most of the others).? Just looked in my 8510?
service manual set and have no 8516 schematic - do have for most of?
the others - He could look at the output from the doubler to see if it?
is working - possible connector damage is a risk.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
> There is no schematic for the 8516 only a few block diagrams , the?
> switching isn¡¯t done by relays but rather with pin diodes inside the?
> brick , the doubler control board is buttoned up on the Doubler ,?
> the only information to be gathered from the service manual is that?
> there are 4 control lines that go to a PAL that acts as adress?
> decoder , from there are 5 lines one goes to the doubler to switch?
> it in and out the other 4 lines go to a block labeled filter control?
> which outputs 5 lines that go to the actual doubler block so there?
> is quite a bit of switching going on but there is no info on the?
> switch points or details on the filters .
> Having a crossover cable definatly might be a concern but he also?
> mentioned that it used to work ¡°intermittent¡±? so that¡¯s also?
> something to think about
>
>
> Sent from Mail<> for Windows
>
> From: Bruce via groups.io<mailto:bruce@...>
> Sent: Wednesday, March 2, 2022 6:48 PM
> To:?
> [email protected]<mailto:[email protected]>
> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>
> Sure but it is comparatively slow - Normal 8510C sweep is relatively
> slow, and the problem can be avoided by only weeping 50-20 and say
> 25-40GHz.
>
> I think the best first step is to look at the doubler switching module
> to see if the relay is actually switching the doubler in.? I don't
> seem to have a schematic diagram for the 8516, but hopefully, HP
> included a LED on the module?
>
> In any case need to check the cable connections and determine whether
> the doubler is being energized - actually, maybe just watching the +
> supply to the doubler itself might work.
>
> Cheers!
>
> Bruce
>
>
>
> Quoting Lothar baier <Lothar@...>:
>
>> Disagree with you on this, dont forget that the synthesizer is swept
>> so if you do a 45MHz to 40GHz sweep the doubler is switched in and
>> out constantly so your DC now becomes a squarewave , also the
>> control signal not only switches the doubler but also switches in
>> and out filters to clean up the signal so there is some activity
>> going on those control lines !
>> One way to find out would be to tack a scope probe on the control
>> lines and look at the shape of the control signals
>>> On Mar 2, 2022, at 18:30, Bruce via groups.io
>>> <bruce@...> wrote:
>>>
>>> ?Missed that - the 20 ft cable seems NOT likely to be a problem -
>>> these ar DC control signals.? I recall some discussion that it is a
>>> straight through cable without cross over based on looking at 8341
>>> and 8516 schematic diagrams - I think that I'd focus on
>>> investigating the wiring of the cable.
>>>
>>> 1) Determine which conductors are used and be certain that the
>>> cable has those conductors 1-1 without cross over.
>>>
>>> Cheers!
>>>
>>> Bruce
>>>
>>> Quoting Lothar baier <Lothar@...>:
>>>
>>>> He mentioned earlier in this thread that its only 20-40GHz but he
>>>> also mentioned using a 20ft cable
? which could be the problem, I
>>>> am not sure what the control interface is , the part number of the
>>>> control cable says RS232 and there are 4 lines connected in the
>>>> testset BUT the doubler control uses a PAL as a decoder so I think
>>>> it¡¯s a parallel interface and having a 20ft cable could be a bit
>>>> much
>>>>
>>>> Sent from Mail<> for Windows
>>>>
>>>> From: Bruce via groups.io<mailto:bruce@...>
>>>> Sent: Wednesday, March 2, 2022 6:21 PM
>>>> To:
>>>> [email protected]<mailto:[email protected]>
>>>> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>>>>
>>>> Does the IF error occur below 20 GHz ??? If not, the doubler is
>>>> suspect - if so, look at the switching or the test set.
>>>> Nexg step would be to try and look at the test set VTO.? It is
>>>> difficult because they pipe it directly into the samplers.
>>>>
>>>> Cheers!
>>>>
>>>> Bruce
>>>>
>>>> Quoting ratn9ne@...:
>>>>
>>>>> Wow you guys are fast to help!
>>>>> Here is some more info: error is only from 20-40GHz, so it has
>>>>> something to do with the doubler I assume. Any span or frequency in
>>>>> this range has this error. I have seen >20GHz work for a little
>>>>> while but only randomly. My next idea is a shorter DB25 cable as
>>>>> mine is about 20 feet long. Tried turning up the LO power coming in
>>>>> on the sweeper with no luck. I can't find a replacement doubler on
>>>>> ebay to test with. These must be very rare. Can they be serviced?
>>>>> This display/sweeper/control box setup has been tested with an 8515
>>>>> and no errors at all.
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
>
>
>
>
>
>
>
>
>
?
|
Seems like the wrong wearing due to a cross over or some other "defect" could cause intermittent operation.
How about using a break out box to look at the signals. I've never owned an 8516 (owned most of the others). Just looked in my 8510 service manual set and have no 8516 schematic - do have for most of the others - He could look at the output from the doubler to see if it is working - possible connector damage is a risk.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
There is no schematic for the 8516 only a few block diagrams , the switching isn¡¯t done by relays but rather with pin diodes inside the brick , the doubler control board is buttoned up on the Doubler , the only information to be gathered from the service manual is that there are 4 control lines that go to a PAL that acts as adress decoder , from there are 5 lines one goes to the doubler to switch it in and out the other 4 lines go to a block labeled filter control which outputs 5 lines that go to the actual doubler block so there is quite a bit of switching going on but there is no info on the switch points or details on the filters .
Having a crossover cable definatly might be a concern but he also mentioned that it used to work ¡°intermittent¡± so that¡¯s also something to think about
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:48 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Sure but it is comparatively slow - Normal 8510C sweep is relatively
slow, and the problem can be avoided by only weeping 50-20 and say
25-40GHz.
I think the best first step is to look at the doubler switching module
to see if the relay is actually switching the doubler in. I don't
seem to have a schematic diagram for the 8516, but hopefully, HP
included a LED on the module?
In any case need to check the cable connections and determine whether
the doubler is being energized - actually, maybe just watching the +
supply to the doubler itself might work.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Disagree with you on this, dont forget that the synthesizer is swept
so if you do a 45MHz to 40GHz sweep the doubler is switched in and
out constantly so your DC now becomes a squarewave , also the
control signal not only switches the doubler but also switches in
and out filters to clean up the signal so there is some activity
going on those control lines !
One way to find out would be to tack a scope probe on the control
lines and look at the shape of the control signals
On Mar 2, 2022, at 18:30, Bruce via groups.io
<bruce@...> wrote:
?Missed that - the 20 ft cable seems NOT likely to be a problem -
these ar DC control signals. I recall some discussion that it is a
straight through cable without cross over based on looking at 8341
and 8516 schematic diagrams - I think that I'd focus on
investigating the wiring of the cable.
1) Determine which conductors are used and be certain that the
cable has those conductors 1-1 without cross over.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
He mentioned earlier in this thread that its only 20-40GHz but he
also mentioned using a 20ft cable ? which could be the problem, I
am not sure what the control interface is , the part number of the
control cable says RS232 and there are 4 lines connected in the
testset BUT the doubler control uses a PAL as a decoder so I think
it¡¯s a parallel interface and having a 20ft cable could be a bit
much
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:21 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Does the IF error occur below 20 GHz ?? If not, the doubler is
suspect - if so, look at the switching or the test set.
Nexg step would be to try and look at the test set VTO. It is
difficult because they pipe it directly into the samplers.
Cheers!
Bruce
Quoting ratn9ne@...:
Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has
something to do with the doubler I assume. Any span or frequency in
this range has this error. I have seen >20GHz work for a little
while but only randomly. My next idea is a shorter DB25 cable as
mine is about 20 feet long. Tried turning up the LO power coming in
on the sweeper with no luck. I can't find a replacement doubler on
ebay to test with. These must be very rare. Can they be serviced?
This display/sweeper/control box setup has been tested with an 8515
and no errors at all.
|
Re: Spectrum analyser in a high traffic strong signal environment
In case anyone is interested, there is some amazing new technology that came out using some interesting magnetic materials that automatically filters out any frequencies above a certain threshold power level.? Imagine automatic notch filters that zero in on whatever signal are the highest.? You end up with all spikes in the frequency domain at or below the threshold.? I heard about this a few years ago; the company is called Metamagnetics.
Maybe not relevant here, but it sure is interesting!
Jim Ford
------ Original Message ------
Sent: 3/2/2022 6:15:24 PM
Subject: Re: [HP-Agilent-Keysight-equipment] Spectrum analyser in a high traffic strong signal environment
Good pojnt and actually one that is often not considered , spectrum analyzers ARE wideband and as a result signals that fall within the bandwidth of anything before the mixer WILL affect the mixer even if they are outside of the selected
center frequency and span !
There is HOWEVER one caveat to this , if you are using a microwave analyzer above 2.9GHz than things become less severe , this is because the MW path of your analyzer incorporates a YIG filter which not only suppresses signals outside the
useable BW but also acts a limiter, granted the rejection is not as good as with a tuneable mechanical or cavity filter but its better than nothing
?
Sent from for Windows
?
DW,
?
You can confirm what the expected total power of multiple signals is by the usual formula:? Ptotal
?= ?P of one signal + 10Log N ?where N = number of identical powered signals.?
In your example, 10 signals of -30dBm each produce a total combined power of -20dBm.?
However, there¡¯s a ¡®gotcha¡¯ lurking here for the unwary.? As @nj902 indirectly alluded, there may be other (larger) signals present outside the frequency band that your instrument is observing.? Observing off-the-air signals, this is
likely the case.? The only way to be sure is to use a broadband power meter and then tuneable filters to only pass the signal band of interest to your SpecAn¡¯s input.
?
A quick and ¡®accurate¡¯ way to confirm ?that your instrument¡¯s front-end is not suffering from overload (and IM issues) is to increase the input attenuation 10dB and observe that ALL signals reduce by 10dB. (You should insert another 10dB
attenuation to be sure.)? If some, or all of the signals drop by more that 10dB ¨C you¡¯ve got IM and overload present !
?
As an aside, measuring the total power of the 3-30MHz HF spectrum ?with even a half-decent antenna is very instructive.?? With some Asian HF broadcast stations having ERP¡¯s in the order of many megawatts using directional arrays, it¡¯s
no wonder many receivers suffer overload and image problems. ?
?
Cheers,
?
Kit
|
There is no schematic for the 8516 only a few block diagrams , the switching isn¡¯t done by relays but rather with pin diodes inside the brick , the doubler control board is buttoned up on the Doubler , the only information to be gathered
from the service manual is that there are 4 control lines that go to a PAL that acts as adress decoder , from there are 5 lines one goes to the doubler to switch it in and out the other 4 lines go to a block labeled filter control which outputs 5 lines that
go to the actual doubler block so there is quite a bit of switching going on but there is no info on the switch points or details on the filters .
Having a crossover cable definatly might be a concern but he also mentioned that it used to work ¡°intermittent¡±? so that¡¯s also something to think about
?
?
Sent from for Windows
?
toggle quoted message
Show quoted text
From: Bruce via groups.io
Sent: Wednesday, March 2, 2022 6:48 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
?
Sure but it is comparatively slow - Normal 8510C sweep is relatively?
slow, and the problem can be avoided by only weeping 50-20 and say?
25-40GHz.
I think the best first step is to look at the doubler switching module?
to see if the relay is actually switching the doubler in.? I don't?
seem to have a schematic diagram for the 8516, but hopefully, HP?
included a LED on the module?
In any case need to check the cable connections and determine whether?
the doubler is being energized - actually, maybe just watching the +?
supply to the doubler itself might work.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
> Disagree with you on this, dont forget that the synthesizer is swept?
> so if you do a 45MHz to 40GHz sweep the doubler is switched in and?
> out constantly so your DC now becomes a squarewave , also the?
> control signal not only switches the doubler but also switches in?
> and out filters to clean up the signal so there is some activity?
> going on those control lines !
> One way to find out would be to tack a scope probe on the control?
> lines and look at the shape of the control signals
>> On Mar 2, 2022, at 18:30, Bruce via groups.io?
>> <bruce@...> wrote:
>>
>> ?Missed that - the 20 ft cable seems NOT likely to be a problem -?
>> these ar DC control signals.? I recall some discussion that it is a?
>> straight through cable without cross over based on looking at 8341?
>> and 8516 schematic diagrams - I think that I'd focus on?
>> investigating the wiring of the cable.
>>
>> 1) Determine which conductors are used and be certain that the?
>> cable has those conductors 1-1 without cross over.
>>
>> Cheers!
>>
>> Bruce
>>
>> Quoting Lothar baier <Lothar@...>:
>>
>>> He mentioned earlier in this thread that its only 20-40GHz but he?
>>> also mentioned using a 20ft cable
? which could be the problem, I?
>>> am not sure what the control interface is , the part number of the?
>>> control cable says RS232 and there are 4 lines connected in the?
>>> testset BUT the doubler control uses a PAL as a decoder so I think?
>>> it¡¯s a parallel interface and having a 20ft cable could be a bit?
>>> much
>>>
>>> Sent from Mail<> for Windows
>>>
>>> From: Bruce via groups.io<mailto:bruce@...>
>>> Sent: Wednesday, March 2, 2022 6:21 PM
>>> To:?
>>> [email protected]<mailto:[email protected]>
>>> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>>>
>>> Does the IF error occur below 20 GHz ??? If not, the doubler is
>>> suspect - if so, look at the switching or the test set.
>>> Nexg step would be to try and look at the test set VTO.? It is
>>> difficult because they pipe it directly into the samplers.
>>>
>>> Cheers!
>>>
>>> Bruce
>>>
>>> Quoting ratn9ne@...:
>>>
>>>> Wow you guys are fast to help!
>>>> Here is some more info: error is only from 20-40GHz, so it has
>>>> something to do with the doubler I assume. Any span or frequency in
>>>> this range has this error. I have seen >20GHz work for a little
>>>> while but only randomly. My next idea is a shorter DB25 cable as
>>>> mine is about 20 feet long. Tried turning up the LO power coming in
>>>> on the sweeper with no luck. I can't find a replacement doubler on
>>>> ebay to test with. These must be very rare. Can they be serviced?
>>>> This display/sweeper/control box setup has been tested with an 8515
>>>> and no errors at all.
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
?
|
Sure but it is comparatively slow - Normal 8510C sweep is relatively slow, and the problem can be avoided by only weeping 50-20 and say 25-40GHz.
I think the best first step is to look at the doubler switching module to see if the relay is actually switching the doubler in. I don't seem to have a schematic diagram for the 8516, but hopefully, HP included a LED on the module?
In any case need to check the cable connections and determine whether the doubler is being energized - actually, maybe just watching the + supply to the doubler itself might work.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
Disagree with you on this, dont forget that the synthesizer is swept so if you do a 45MHz to 40GHz sweep the doubler is switched in and out constantly so your DC now becomes a squarewave , also the control signal not only switches the doubler but also switches in and out filters to clean up the signal so there is some activity going on those control lines !
One way to find out would be to tack a scope probe on the control lines and look at the shape of the control signals
On Mar 2, 2022, at 18:30, Bruce via groups.io <bruce@...> wrote:
?Missed that - the 20 ft cable seems NOT likely to be a problem - these ar DC control signals. I recall some discussion that it is a straight through cable without cross over based on looking at 8341 and 8516 schematic diagrams - I think that I'd focus on investigating the wiring of the cable.
1) Determine which conductors are used and be certain that the cable has those conductors 1-1 without cross over.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
He mentioned earlier in this thread that its only 20-40GHz but he also mentioned using a 20ft cable ? which could be the problem, I am not sure what the control interface is , the part number of the control cable says RS232 and there are 4 lines connected in the testset BUT the doubler control uses a PAL as a decoder so I think it¡¯s a parallel interface and having a 20ft cable could be a bit much
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:21 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Does the IF error occur below 20 GHz ?? If not, the doubler is
suspect - if so, look at the switching or the test set.
Nexg step would be to try and look at the test set VTO. It is
difficult because they pipe it directly into the samplers.
Cheers!
Bruce
Quoting ratn9ne@...:
Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has
something to do with the doubler I assume. Any span or frequency in
this range has this error. I have seen >20GHz work for a little
while but only randomly. My next idea is a shorter DB25 cable as
mine is about 20 feet long. Tried turning up the LO power coming in
on the sweeper with no luck. I can't find a replacement doubler on
ebay to test with. These must be very rare. Can they be serviced?
This display/sweeper/control box setup has been tested with an 8515
and no errors at all.
|
Disagree with you on this, dont forget that the synthesizer is swept so if you do a 45MHz to 40GHz sweep the doubler is switched in and out constantly so your DC now becomes a squarewave , also the control signal not only switches the doubler but also switches in and out filters to clean up the signal so there is some activity going on those control lines !
One way to find out would be to tack a scope probe on the control lines and look at the shape of the control signals
toggle quoted message
Show quoted text
On Mar 2, 2022, at 18:30, Bruce via groups.io <bruce@...> wrote:
?Missed that - the 20 ft cable seems NOT likely to be a problem - these ar DC control signals. I recall some discussion that it is a straight through cable without cross over based on looking at 8341 and 8516 schematic diagrams - I think that I'd focus on investigating the wiring of the cable.
1) Determine which conductors are used and be certain that the cable has those conductors 1-1 without cross over.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
He mentioned earlier in this thread that its only 20-40GHz but he also mentioned using a 20ft cable ? which could be the problem, I am not sure what the control interface is , the part number of the control cable says RS232 and there are 4 lines connected in the testset BUT the doubler control uses a PAL as a decoder so I think it¡¯s a parallel interface and having a 20ft cable could be a bit much
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 6:21 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Does the IF error occur below 20 GHz ?? If not, the doubler is
suspect - if so, look at the switching or the test set.
Nexg step would be to try and look at the test set VTO. It is
difficult because they pipe it directly into the samplers.
Cheers!
Bruce
Quoting ratn9ne@...:
Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has
something to do with the doubler I assume. Any span or frequency in
this range has this error. I have seen >20GHz work for a little
while but only randomly. My next idea is a shorter DB25 cable as
mine is about 20 feet long. Tried turning up the LO power coming in
on the sweeper with no luck. I can't find a replacement doubler on
ebay to test with. These must be very rare. Can they be serviced?
This display/sweeper/control box setup has been tested with an 8515
and no errors at all.
|
Willy
Alex_03
RubenRubio