Re: HP 8566A/B Noise Floor
higher conversion loss of the mixer translates into a increase in system noise figure , since there is no gain prior to the mixer the IF gain will also play into it , you can go online and find a cascaded noise figure calculator to get a feel for it
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Re: HP 8566A/B Noise Floor
a spectrum analyzer in essence a receiver therefore the noise floor is determined by several factors , system Noise figure , System bandwidth and noise contribution ( phase noise ) from local oscillators being the main ones .
System NF on a spectrum analyzer will be poor as you have no gain before the 1st mixer , the mixer used for the high band of the 8566 is a harmonic mixer , the conversion loss increases the higher the order of the used harmonic is so your noise floor increases accordingly resulting in the "stepped" response you see .
the frequency range below 2.5GHz is fundamental mixed hence your noise floor is flat !
as far as comparing the noise floor of 2 units there will always be differences, YTO and other semiconductor components have lot variations so one unit may have a "better " yig than the other and of course there are always degradations that depend on how much the unit was used , as long as your unit meets specs there is nothing to worry about
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Re: HP 8566A/B Noise Floor
"Samudra" <samudra.haque@...> writes: Interesting. I saw the stepped noise floor also on the recently acquired
8566b I setup recently, and would like to know mire what you find out. It
does look strange. Will do Samudra. FYI the "stepped" nature of the noise floor is expected and present in all 8566's. It occurs because the gain is stepped up about 6 dB for each frequency band above the fundamental frequency band of the YIG. My question is really about why the level is so high. In a previous message from Don Bitters /g/HP-Agilent-Keysight-equipment/message/112070?p=%2C%2C%2C20%2C0%2C0%2C0%3A%3Arecentpostdate%2Fsticky%2C%2C8566+noise+floor%2C20%2C2%2C0%2C78770386he described the typical noise floor levels and also the reason for the stepped nature: the top of the noise floor from 2-5.8GHz should be flat and about 65dB down from the top graticule, from 5.8-12.5GHz almost flat and about 60dB down from the top graticule, from 12.5-18.6GHz - tilted up about 4dB and about 54dB down from the top graticule, from 18.6-22GHz - tilted up about 6dB and about 48dB down from top graticule. The gain is stepped up about 6dB for each band from 2-22GHz, which causes the noise floor steps Mine seems to be about 5+ dB above those levels. Matt
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Re: HP 8566A/B Noise Floor
These analyzers use several bands to cover their operating frequency range. The stepped noise floor is due to the increased mixer conversion loss in the higher bands. The higher the band, the greater the conversion loss, and so the IF gain is increased to compensate for it, to correct the amplitude. This higher IF gain raises the noise floor.
Vladan, please correct me if I'm wrong on any details here.
-Dave
toggle quoted message
Show quoted text
On 6/6/22 21:32, Samudra wrote: Interesting. I saw the stepped noise floor also on the recently acquired 8566b I setup recently, and would like to know mire what you find out. It does look strange.
On Mon, Jun 6, 2022, 20:58 Matt Huszagh <huszaghmatt@... <mailto:huszaghmatt@...>> wrote:
I have 2 HP 8566's: an A and B unit. The noise floor on the A unit is
noticeably better than the noise on the B unit. I've attached 2 images
of my B unit corresponding to the 0-2.5 GHz and 2-22 GHz ranges.
A few things stand out to me in comparison with the A unit. The noise
floor in the lower range slopes up slightly, which I don't notice at all
in the A unit.
In the higher frequency range, the noise floor is just overall higher.
What causes this and is there anything I can do to improve it?
I'm currently going through the performance tests and doing the
corresponding adjustments where necessary. I'm hoping this will improve
the situation, maybe someone has a proper understanding of this.
Matt
--
Dave McGuire, AK4HZ
New Kensington, PA
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Re: HP 8566A/B Noise Floor
Interesting. I saw the stepped noise floor also on the recently acquired 8566b I setup recently, and would like to know mire what you find out. It does look strange.?
I have 2 HP 8566's: an A and B unit. The noise floor on the A unit is
noticeably better than the noise on the B unit. I've attached 2 images
of my B unit corresponding to the 0-2.5 GHz and 2-22 GHz ranges.
A few things stand out to me in comparison with the A unit. The noise
floor in the lower range slopes up slightly, which I don't notice at all
in the A unit.
In the higher frequency range, the noise floor is just overall higher.
What causes this and is there anything I can do to improve it?
I'm currently going through the performance tests and doing the
corresponding adjustments where necessary. I'm hoping this will improve
the situation, maybe someone has a proper understanding of this.
Matt
|
85662A CRT raster shifting position
Has anyone noticed this before? I did not make any adjustments, the display raster seems to have moved further to the top the CRT all by itself. It doesn't appear to? wonder around that I can see. Could something be on its way out?
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Re: HP 8566A/B Noise Floor
Performance test 14 is the "Average Noise Level Test", which looks
applicable and mentions the "Last Converter Adjustments". I'll give
those a shot, but still curious to hear thoughts on this.
Matt
|
I have 2 HP 8566's: an A and B unit. The noise floor on the A unit is
noticeably better than the noise on the B unit. I've attached 2 images
of my B unit corresponding to the 0-2.5 GHz and 2-22 GHz ranges.
A few things stand out to me in comparison with the A unit. The noise
floor in the lower range slopes up slightly, which I don't notice at all
in the A unit.
In the higher frequency range, the noise floor is just overall higher.
What causes this and is there anything I can do to improve it?
I'm currently going through the performance tests and doing the
corresponding adjustments where necessary. I'm hoping this will improve
the situation, maybe someone has a proper understanding of this.
Matt
|
Re: HP 8566B YTO Main Coil Driver Adjustments Difficulty
Think you may be a bit too critical. IMO, they are talking about rapid drift - it generally is not stable equivalent to lock. The 6.15 end is always a bit more difficult. Generally, I switch back and forth between 2.3 and 6.15 and if the first 5 digits agree, I'm good.
If you think there is a problem, once you get it reasonably adjusted, close the PLL and watch the control voltage - if it is significantly unstable, maybe you do have a problem.
Also, I'd take a look at the voltages to see if the remain on target. If they do and you can get the frequency to remain relatively closse, you should be OK.
Cheers!
Bruce
Quoting Matt Huszagh <huszaghmatt@...>:
toggle quoted message
Show quoted text
I'm currently performing the YTO Main Coil driver adjustments (preferred
procedure) for my HP 8566B. This apparently sets the frequency endpoints
of the YIG. Leaving out some details, the procedure basically has you
key in zero spans centered at 2.3 and 6.15 GHz, disconnect the YTO loop
phase detector output and check the frequency of the 1st LO output.
I've performed this procedure probably 2 or 3 times in the past, and
each time I've found it difficult. The documentation says to wait for
the 1st LO output frequency to stabilize when adjusting the trimpots to
get the 2.3 and 6.15 GHz frequencies on mark (within 100 kHz). However,
I've always found the frequency to slowly drift in one direction. This
time I was able to get a pretty stable reading on the 2.3 GHz endpoint,
but the 6.15 GHz endpoint has been steadily drifting up over the last
10+ minutes. This long drift period obviously makes the procedure
difficult because you can't just adjust and check, you have to try to
predict where it will go.
Does anyone have any advice for how to perform this adjustment
effectively? There's an alternate procedure which I'm tempted to try.
Thanks
Matt
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Re: HP 8566B YTO Main Coil Driver Adjustments Difficulty
To add a bit more detail:
The drift is on the order of 100 kHz or so every few minutes and in one
direction. That's a rough estimate; I haven't actually measured it.
I should also mention that I'm using the 10 MHz reference provided by my
counter (an HP 5350B) as the external reference to the HP 8566B. I don't
think that will have much of an effect, but I figured it could only
help.
Matt
|
HP 8566B YTO Main Coil Driver Adjustments Difficulty
I'm currently performing the YTO Main Coil driver adjustments (preferred
procedure) for my HP 8566B. This apparently sets the frequency endpoints
of the YIG. Leaving out some details, the procedure basically has you
key in zero spans centered at 2.3 and 6.15 GHz, disconnect the YTO loop
phase detector output and check the frequency of the 1st LO output.
I've performed this procedure probably 2 or 3 times in the past, and
each time I've found it difficult. The documentation says to wait for
the 1st LO output frequency to stabilize when adjusting the trimpots to
get the 2.3 and 6.15 GHz frequencies on mark (within 100 kHz). However,
I've always found the frequency to slowly drift in one direction. This
time I was able to get a pretty stable reading on the 2.3 GHz endpoint,
but the 6.15 GHz endpoint has been steadily drifting up over the last
10+ minutes. This long drift period obviously makes the procedure
difficult because you can't just adjust and check, you have to try to
predict where it will go.
Does anyone have any advice for how to perform this adjustment
effectively? There's an alternate procedure which I'm tempted to try.
Thanks
Matt
|
Re: The time-bomb in the HP 70700A digitizer
Replacement battery:?? { Thank you Dave M. !! }
Tadiran TL5104/P
SUFFIX- /P AXIAL PINS 15-5104-41000
~ $7.75us @ ?? { less, if one buys Qty: 50?? ,? $5.67us? @ }
Data Sheet:?
Perhaps obvious to develop a "hot" install procedure to solder the new battery "in parallel" with the old, via alligator clips or soldered wires to the PCB,
to prevent Ram memory loss when removing the old.
Don't know if HP published a service procedure for this ?
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Re: ESA instrument adjustments - reverse engineering
I agree with Sandra, there is a huge amount of collaboration on EEVBlog, following a thread is easy once you click on "notify" While there is not a dedicated storage space, files are attached to the poster's reply so it keeps the uploaded file in context with the reply.
Just my thoughts.........
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Re: ESA instrument adjustments - reverse engineering
interesting,? we've done some rather complex stuff there without any issues and posting a message in a thread automatically subscribes you.? or you can manually subscribe to a thread.
Everything is stored in the thread and images/files can be uploaded locally or shared from any of the online storage sites.
I use my google drive personally unless I want it to remain in the thread
Once a solution is found it can be posted here of course with all related materials
here's a thread we worked that I mentioned
I just find the collaboration that goes on there extremely good
but whatever the OP wants
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Re: 53181A 3 GHz prescaler from China
Hello Hardy,
Thank you for? the information.? I have a 53181A, which is the 1.5GHz counter.? There is another digit in the counter that never lights up.? That was probably used in the 12GHz model.
I wonder if it can be converted to the 3GHz model by changing the firmware?
Tom
toggle quoted message
Show quoted text
On 6/6/2022 11:23 AM, hardyhansendk via groups.io wrote: Tom
I have also bought an prescaler from china-12 Ghz-works great.
But the guy mention that one should be carefull about the counter(mine 53132A)--some are only 1.5Ghz versions and other 3Ghz!--will try to dig out the info.
Regards
Hardy
-----Oprindelig meddelelse-----
Fra: [email protected] [mailto:[email protected]] P? vegne af Tom B
Sendt: 6. juni 2022 16:39
Til: [email protected]
Emne: Re: [HP-Agilent-Keysight-equipment] 53181A 3 GHz prescaler from China
I received the 3GHz prescaler board from China. It arrived quicker than
I expected. I installed it in my 53181A but it does not count above
1.69999 GHz. I think this is a limitation of the counter, not the
prescaler. The board looks well made and works fine.
Aside from that, I had to find the correct spacers to mount the board.
The kit came with 2 but they were just the right length to interfere
with the interface connector. I put in longer spacers and that solved
that problem. The other minor issue was that the kit came with an SMA
to SMA cable. It should be an SMA to BNC so it will mount correctly in
the front panel. Fortunately, I had an SMA to BNC cable available.
Tom
On 5/24/2022 6:31 PM, Jeremy B wrote:
I¡¯ve upgraded my 53181 with an eBay prescaler and oven timebase. I
believe I got them from a fellow in Poland. No problems at all. For
the timebase I calibrated it to a rubidium standard as described in
the manual.
--
Denne mail er kontrolleret for vira af AVG.
;!!KfGNmQmE!gzWP-BSwicEw-0ypzF-ePgTwHztjKXzvJhCmhQOfeWxq0nt3rfGatOS5mU9Xp-u381iBJkn3dBKsJsUtwsHoD7iZ1Q$
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Re: New file: Sprague capacitor types in files
Thank you!? I need (but, of course, have not yet) to start making notes on issues, or the lack of, with different series - hopefully others here will start that ball rolling.?
Hal
|
While the process may seem daunting when you first do one of these cal's, once done, it's basically setting the offsets and gains of each band, setting the YTM bias at the beginning and the end of each band, and then adjusting the delay needed at the various
sweep speeds so that the amplitude of the output doesn't change with sweep speed.? You have a few adjustments that affect all the bands and then you adjust the items that are specific to each band.? When you go at it that way, it starts to make sense.? Of
course the first thing you do is to check the power supplies to make sure that they haven't shifted much off their nominal values.? There are only a few power supply voltages that can actually cause problems everywhere, like the -10V & 40V supplies (if I remember?correctly,
I have been known to be wrong).
The 8360 series is actually just an 8340 that uses D/As instead of physical adjustments.? Once you've done a few 8340Bs, the adjustments on the 8360's make much more sense.
Richard Parrish
toggle quoted message
Show quoted text
Thanks for the help? and the fact that is someway usual to perform the calibration procedure.
Gianni
IW1EPY
?
?
It appears that you need to adjust your SRD Bias (along with the complete unleveled RF adjustment procedure) which is spelled out in the adjustment portion of the service manual.?
The problem you're seeing is not all that unusual considering the age of the unit.? I'm doing the same thing with 3 8340/41's that are sitting on my bench at the moment.? The procedure is not that difficult and the equipment required is fairly common, a decent
DVM,? a power meter & sensor, a Xtal detector & a scope that is capable of XY operation.? If the frequencies are in spec, you don't even need a counter although a spectrum analyzer would be handy for confirmation once you've finished the adjustment procedure.
My HP8340B , even if the level indicator say the right level end no unleveled annunciator appear , the real RF output is unstable.
Sweeping at some frequencies the power out goes unleveled , it happens in the 3 High band .
Only some point and small range in the first high band increasing in second high band finally large portion of band in 3rd high band.
The internal power detector and all its circuit works ok ,the out voltage that goes to the error amplifier and its corresponding reference level are ok.
The ALC level sims working according to the specs.
At a certain point of the ALC loop A26 Board a signal is taken out SDR BIAS CONT? using an OP Amp ( way the designer have set a test point at the inverting input and not to the output is a mystery¡.but
this is useful for my investigation).
This signal goes to board A24 and shaped using frequency info ( 2 times ) plus an exponential generator drives the SRD in order to allow a linear operation in the power range.
What happens is that to SDR is driven in non linear zone ( reverse power vs SRD voltage increase) this leads what HP manual call SQEGGING , the output power become to be modulated ,the average
continue to be ok so the equipment do not detect any malfunction and no unleveled light appears .
Focusing at 22.5 GHz where this problem is more evident breaking the SRD line and driving externally the correct operation can be obtained increasing the SRD voltage ?at high power output ( see
PDF Misure a 22 5 GHz) .
Using this info I placed a circuit offset using the test point located at the inverting input of the OP Amp located in A26 board ( a pot using -10V one side and + 5.2V other side and 1 Mohm from
the cursor to the inverting input ).
Inserting the offset first ?disappear the instability in high band 1 then increasing the offset the problem of high band 2 at the end setting an offset at the out of the OP amp of 0.3 V all the
band are ok . This could be a work around because at the end the equipment works .
Due to this need of offset ( small in first High band medium in second high band and finally 0.3 V in 3rd band ) push me to think that is not a general ?offset? the problem but a shaping
problem or an offset linked with the frequency .
The A24 board makes this kind of job but looks a mess al potentiometers , can someone help me because that in the past entered in similar problem?
Turning pots in random mode is not what I like !!!
Regards
Gianni
IW1EPY
?
?
?
It would be desirable to catalog those commands so they can be analyzed and further documented and eventually be used in creating some calibration routines that can be used by people !
Let me however render some words of caution :?
Keysight/agilent has chosen the path of not to provide service software any longer for a very good reason and to put it simple its all about MONEY !
Used to service was purely auxiliary now it¡¯s a profit center , keysight wants to keep their service centers busy and they want to control end of life of their equipment , if the analyzer requires software to do adjustments
and you don¡¯t have the software than you cant fix the unit period !? when it was still available the N7800A software was very expensive , If I remember correctly the framework was $7500 and then you had to pay for the different support modules separately ,
once you shilled out the $? you needed very specific test equipment which set you back another 100-200K depending on what you wanted to run ¡¡..? after a little while they stopped issuing licenses altogether and only made them available to big corporate self
supporters !
Having said this keysight may not take kindly to the information becoming public and may undertake measures to deter the effort , therefore I strongly suggest not to use any techniques to extract the information that
could be interpreted as reverse engineering or hacking
?
?
Hi Kalle.
This is fantastic work.? ?
When I was working on hacking the E4407B one thing I was looking for was the SCPI commands but could never find them.
Did you find these on the E4407B or did you find them in the looking at N7800?files?
I really hope we can find a way to be able to do a cal.? personally I'd like to cal my TG as I think that it needs it?
If I can help on this I'm more than will.
Sandra
|
Thanks for the help? and the fact that is someway usual to perform the calibration procedure. Gianni IW1EPY ? ? It appears that you need to adjust your SRD Bias (along with the complete unleveled RF adjustment procedure) which is spelled out in the adjustment portion of the service manual.? The problem you're seeing is not all that unusual considering the age of the unit.? I'm doing the same thing with 3 8340/41's that are sitting on my bench at the moment.? The procedure is not that difficult and the equipment required is fairly common, a decent DVM,? a power meter & sensor, a Xtal detector & a scope that is capable of XY operation.? If the frequencies are in spec, you don't even need a counter although a spectrum analyzer would be handy for confirmation once you've finished the adjustment procedure.
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> on behalf of Gianni via groups.io <gianni.chiodo@...>
Sent: Monday, June 6, 2022 5:36 AM
To: [email protected] <[email protected]>
Subject: [HP-Agilent-Keysight-equipment] HP8340B SQUEGGING My HP8340B , even if the level indicator say the right level end no unleveled annunciator appear , the real RF output is unstable. Sweeping at some frequencies the power out goes unleveled , it happens in the 3 High band . Only some point and small range in the first high band increasing in second high band finally large portion of band in 3rd high band. The internal power detector and all its circuit works ok ,the out voltage that goes to the error amplifier and its corresponding reference level are ok. The ALC level sims working according to the specs. At a certain point of the ALC loop A26 Board a signal is taken out SDR BIAS CONT? using an OP Amp ( way the designer have set a test point at the inverting input and not to the output is a mystery¡.but this is useful for my investigation). This signal goes to board A24 and shaped using frequency info ( 2 times ) plus an exponential generator drives the SRD in order to allow a linear operation in the power range. What happens is that to SDR is driven in non linear zone ( reverse power vs SRD voltage increase) this leads what HP manual call SQEGGING , the output power become to be modulated ,the average continue to be ok so the equipment do not detect any malfunction and no unleveled light appears . Focusing at 22.5 GHz where this problem is more evident breaking the SRD line and driving externally the correct operation can be obtained increasing the SRD voltage ?at high power output ( see PDF Misure a 22 5 GHz) . Using this info I placed a circuit offset using the test point located at the inverting input of the OP Amp located in A26 board ( a pot using -10V one side and + 5.2V other side and 1 Mohm from the cursor to the inverting input ). Inserting the offset first ?disappear the instability in high band 1 then increasing the offset the problem of high band 2 at the end setting an offset at the out of the OP amp of 0.3 V all the band are ok . This could be a work around because at the end the equipment works . Due to this need of offset ( small in first High band medium in second high band and finally 0.3 V in 3rd band ) push me to think that is not a general ?offset? the problem but a shaping problem or an offset linked with the frequency . The A24 board makes this kind of job but looks a mess al potentiometers , can someone help me because that in the past entered in similar problem? Turning pots in random mode is not what I like !!! Regards Gianni IW1EPY ? ? ? It would be desirable to catalog those commands so they can be analyzed and further documented and eventually be used in creating some calibration routines that can be used by people ! Let me however render some words of caution :? Keysight/agilent has chosen the path of not to provide service software any longer for a very good reason and to put it simple its all about MONEY ! Used to service was purely auxiliary now it¡¯s a profit center , keysight wants to keep their service centers busy and they want to control end of life of their equipment , if the analyzer requires software to do adjustments and you don¡¯t have the software than you cant fix the unit period !? when it was still available the N7800A software was very expensive , If I remember correctly the framework was $7500 and then you had to pay for the different support modules separately , once you shilled out the $? you needed very specific test equipment which set you back another 100-200K depending on what you wanted to run ¡¡..? after a little while they stopped issuing licenses altogether and only made them available to big corporate self supporters ! Having said this keysight may not take kindly to the information becoming public and may undertake measures to deter the effort , therefore I strongly suggest not to use any techniques to extract the information that could be interpreted as reverse engineering or hacking ? ? Hi Kalle.
This is fantastic work.? ?
When I was working on hacking the E4407B one thing I was looking for was the SCPI commands but could never find them.
Did you find these on the E4407B or did you find them in the looking at N7800?files?
I really hope we can find a way to be able to do a cal.? personally I'd like to cal my TG as I think that it needs it?
If I can help on this I'm more than will.
Sandra
|
Re: New file: Sprague capacitor types in files
Thank you for posting this information Hal.
Very handy to have available.
Cheers,
Tom
|
Re: 53181A 3 GHz prescaler from China
Here it comes -----Oprindelig meddelelse----- Fra: [email protected] [mailto: [email protected]] P? vegne af Tom B Sendt: 6. juni 2022 16:39 Til: [email protected]Emne: Re: [HP-Agilent-Keysight-equipment] 53181A 3 GHz prescaler from China I received the 3GHz prescaler board from China. It arrived quicker than I expected. I installed it in my 53181A but it does not count above 1.69999 GHz. I think this is a limitation of the counter, not the prescaler. The board looks well made and works fine. Aside from that, I had to find the correct spacers to mount the board. The kit came with 2 but they were just the right length to interfere with the interface connector. I put in longer spacers and that solved that problem. The other minor issue was that the kit came with an SMA to SMA cable. It should be an SMA to BNC so it will mount correctly in the front panel. Fortunately, I had an SMA to BNC cable available. Tom On 5/24/2022 6:31 PM, Jeremy B wrote: I¡¯ve upgraded my 53181 with an eBay prescaler and oven timebase. I
believe I got them from a fellow in Poland. No problems at all. For
the timebase I calibrated it to a rubidium standard as described in
the manual. -- Denne mail er kontrolleret for vira af AVG.
|
Dave McGuire
Harold Foster
Tom Phillips