Re: VNA calibration kit to 50 GHz
OK, with further thought, if you did do some software mods for a waveguide cal system, you wouldn't actually need to make the the precision offset short, you just need to know how long they actually are and use that mechanical distance in the software to calculate from. Really anything close would work, because, as Ed (Hi Ed!) pointed out, really only 1/8 wave at one frequency, you just have to know THAT freq!. So to that end, short sections of flanged waveguide with shorting plates would work. If you use the standard 4 hole flange (UG-52?) a purist might argue that the surface contact was not good enough to insure REALLY low ohmage connection, so drill more holes in the flange and use more screws, like WE did on the CMRR flange, or if you can find guide with CMR? standard 8 hole comm flanges (you get more screw pressure and even contact force). Now you dont need to EDM anything, as you as you start with standard pieces of rectangular guide!? You can add the standard 4 hole cover flange to cut off section to make your connection point. If a purist, a little silver soldering for the new flange ( a jeweler can be bribed to do it, I know first hand, as I got some MMW horns repaired!) Then if you plan to make a habit of this stuff, you can get the waveguide pieces silver plated, shorting plates, screws and all (although you can buy silver plated screws for $1 each, thanks W1GHZ!)! There was a company in Cincinnati that would do a basket silver plating of many items for me for $200, beautiful work and was a few years back but should be about the same price at other shops. Then you could paint the stuff and have a "professional" custom waveguide cal set.
Regards, Jeff Kruth
In a message dated 7/13/2024 11:54:16 AM Eastern Standard Time, edr10000@... writes:
?
All of this is somewhat academic as choosing something to be at 1/8 or 3/8 guide wavelength only fits at a single frequency with a short or no add line section.
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Re: VNA calibration kit to 50 GHz
I have been away and just noticed this. I am from the old era of the original automated VNA measurements. As I am sure you know, what we used the sliding loads for was to help the AVNA determine the locus to the return loss couplers directivity vector, as part of the 12 term error terms for the cal. The new ecal boxes do this automatically, I guess, by using a load on an electrically controllable phase shifter. The load doesnt even have to be that good as the rotation of the return loss vector over the whole phase shift interval will determine to center of the directivity circle and therefore the directivity vector. A lot simpler as I used to have to move the load under computer prompt at each cal freq and it was tedious to do a full up cal.
A blast from the past.
IF you wanted to perform a cal on waveguide hardware, I am sure a routine could be written that operated on the same way. In this case, a sliding load (also a sliding short) could be usefully. The problem would be to set the load or short at exactly the same distances each time. We had dial indicators on some of the waveguide pieces to permit setting to .001 inch (yes, I know about wear and slop, but we would approach the position from the same direction each time, and this helped).
Of course, tedious, but if narrowband and not too many measurement points (freq's) it could be done.
Regards, Jeff Kruth
In a message dated 7/13/2024 2:29:04 PM Eastern Standard Time, rfconsulting.fr@... writes:
?
For the X band, I can confirm that coaxial systems don't require sliding loads (see my previous post). I never use them on my 8720ES. In N I use an 85054D and in APC 3.5 I use an 85052B or D.
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Whow! Superb!
Thank you, Gianni!
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Re: VNA calibration kit to 50 GHz
Hello Dr. Kirkby,
Thanks for the details. I have a question and maybe you can make me
understand the offset shorts calculation or maybe you can give me a link
to some article or paper to read.
I was looking on eBay for waveguide calibration kits and I saw the
Anritsu ones for the WR90 waveguide size. There are different sizes but
let's take this one as an example.
Anritsu delivers 2 offset sorts:
- 1/8 Offset short and it writes 4.89mm
- 3/8 Offset short and it writes 14.68mm
WR90 frequency range is 8.20 to 12.40 GHz. Center frequency would be
10.3GHz and ¦Ë would calculate as 29.118mm considering relative
permittivity of air to be 1.00058986.
If ¦Ë is 29.118mm, ¦Ë/8 would be 3.63975mm.
I also calculated using the cut off frequency range for the WR90
waveguide size and it still doesn't match the 4.89mm value for the 1/8
or 3/8 written on the Anritsu offset shorts.
Thank you!
Razvan
The wavelength in a waveguide is nothing like the value in free space. In fact, the wavelength tends to infinity as the frequency tends to cut off frequency of the waveguide.
Dave
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Re: E4411B forgotten its option(s)
Hi,
I can confirm that your 16MB ROM is correct volume for B72 option
and A.14.06 firmware can fit in including power suite package. And
32MB RAM is correct too. On my E4402B after A14.06 and power suite
being installed I still had like 7MB out of 16MB free.
You can check in system view if power suite is installed. If you
just tried to reinstall firmware without formatting flash (ROM),
power suites was still in ROM and therefore its reinstallation was
not initiated after firmware reinstallation attempt.
Vladimir
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Dne 14.07.2024 v 14:25 vee-dub565 via
groups.io napsal(a):
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Show quoted text
Sorry for the duplicate posting all, I didn't see Vladimir had
already posted about this.
I think the backup battery has died, which has probably upset it.
It comes up with a data out of range error at boot, plus time
& date is lost.
Regards option B72 expanded memory. Can someone check their system
for me and confirm. I have ROM: 16777216 and RAM: 33554432
Just want to double check that is correct, because when I loaded
FW: A14.06 the firmware went on ok, but power suite utilities
wouldnt install. And it should have done with B72 memory upgrade.
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Re: E4411B forgotten its option(s)
Sorry for the duplicate posting all, I didn't see Vladimir had already posted about this.
I think the backup battery has died, which has probably upset it. It comes up with a data out of range error at boot, plus time & date is lost.
Regards option B72 expanded memory. Can someone check their system for me and confirm. I have ROM: 16777216 and RAM: 33554432
Just want to double check that is correct, because when I loaded FW: A14.06 the firmware went on ok, but power suite utilities wouldnt install. And it should have done with B72 memory upgrade.
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Re: E4411B forgotten its option(s)
Thanks I'll give that a go. It was already working for me, thats the strange thing.
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Re: VNA calibration kit to 50 GHz
thanks very much for all that great information; i'm moving up the learning curve now.
50 Ohms? Well actually i did mean a match load, but in waveguide, for the SOLT calibration.
As for the TRL (Thru, Reflet, Line) calibration in waveguide, i see the value of having the lambda/4 (90 degrees) Line. Clearly, difficult to make unless you have the spark eroder. I found an interesting report online about making these from NPL ? indicating the thickness of the line needs to be lambda/4 in the waveguide, which of course is longer than the free space wavelength, but the report is more about problems of TRL calibration at higher frequencies, from 26 GHz all the way up to 300 GHz.
Right now i'm interested in a calibration for WR42(WG-20) 18-26.5 GHz, probably in waveguide as that would be easier than coax. However, on longer timescales an interest all the way up to 50 GHz
Having the NI USB/GPIB interface adapter compensates someway for the lack modern electronics in the 30-year plus year old kit. However, one of the problems with this is the slow triggering of the sweeps if you want to do multiple sweeps quickly. I was wondering if if could replace the ASCII (GPIB 'FORM4')data transfer with the GPIB 'FORM1' binary data, which according to the 8510C manual allows for a faster data transfer. However, i tried this but it failed, so i have to get back to that to figure why, and if there is a route there to get more speed from the 8510C, but that's a whole new area for investigation.
Cheers, Neil
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Re: E4411B forgotten its option(s)
Hello Ben,
I have made the post about the same problem just few days ago on
eevblog forum, you can check it here:
Description of all available options for ESA-L spectrum analyzers
(e.g. your 4411B) are described here:
Vladimir
Dne 14.07.2024 v 8:58 vee-dub565 via
groups.io napsal(a):
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Show quoted text
I have a HP branded E4411B, if I press system-more-shiw system it
correctly identifies the following options
1DR
049
B72
If I then press system-more-more-licensing-show License then
there's nothing there.
I can confirm the color screen (option 049) is working, but the
narrow bandwidth (1DR) isn't, its still pegged at 1khz (@1MHz
span).
I tried re-entering the license code for 1DR, and it said it was
activated, and it then appeared in the show license screen... but
still didn't actually work.
I'm thinking I might have to reinstall the firmware, re-enter the
license codes and see if that works. Unless there's something else
I can try?
Ben
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Re: E4411B forgotten its option(s)
Hi Ben, ? When checking for the 1DR option, did you meet the following condition: 'Only available in spans ¡Ü5 MHz, sweep times ¡Ý 4 ms, and not usable with tracking generator on (Option 1DN)' ? With option B72 you could have the latest firmware version: A.14.06. ? Option 049 is a hardware option, it should be automatically detected and therefore work on power up...this is what you noticed as you described ? Yves ? I have a HP branded E4411B, if I press system-more-shiw system it correctly identifies the following options
1DR
049
B72
If I then press system-more-more-licensing-show License then there's nothing there.
I can confirm the color screen (option 049) is working, but the narrow bandwidth (1DR) isn't, its still pegged at 1khz (@1MHz span).
I tried re-entering the license code for 1DR, and it said it was activated, and it then appeared in the show license screen... but still didn't actually work.
I'm thinking I might have to reinstall the firmware, re-enter the license codes and see if that works. Unless there's something else I can try?
Ben
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E4411B forgotten its option(s)
I have a HP branded E4411B, if I press system-more-shiw system it correctly identifies the following options
1DR
049
B72
If I then press system-more-more-licensing-show License then there's nothing there.
I can confirm the color screen (option 049) is working, but the narrow bandwidth (1DR) isn't, its still pegged at 1khz (@1MHz span).
I tried re-entering the license code for 1DR, and it said it was activated, and it then appeared in the show license screen... but still didn't actually work.
I'm thinking I might have to reinstall the firmware, re-enter the license codes and see if that works. Unless there's something else I can try?
Ben
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Thank you for another excellent book!
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Re: How to remove the output cable of the isolator in the 8672A
I forgot to add that Kendon Park has nice little connector torque wrenches for a wide variety of connectors. Prices are reasonable, too. (I¡¯m not associated with them, just use their wrenches)
Greg
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Re: How to remove the output cable of the isolator in the 8672A
Was anyone lucky enough to get one of these little SMA torque wrenches when Keysight was handing them out for free some years ago?? It even came with a certificate of calibration indicating it is set to 5 in-lb.
Greg
 
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Simply fabulous.
?
Available energy is the main object at stake in the struggle for
existence and the evolution of the world. Ludwig Boltzmann
(1844-1906)
Illegitimi Non Carborundum
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Re: VNA calibration kit to 50 GHz
Hello Dr. Kirkby, Thanks for the details. I have a question and maybe you can make me understand the offset shorts calculation or maybe you can give me a link to some article or paper to read. I was looking on eBay for waveguide calibration kits and I saw the Anritsu ones for the WR90 waveguide size. There are different sizes but let's take this one as an example. Anritsu delivers 2 offset sorts: - 1/8 Offset short and it writes 4.89mm - 3/8 Offset short and it writes 14.68mm WR90 frequency range is 8.20 to 12.40 GHz. Center frequency would be 10.3GHz and ¦Ë would calculate as 29.118mm considering relative permittivity of air to be 1.00058986. If ¦Ë is 29.118mm, ¦Ë/8 would be 3.63975mm. I also calculated using the cut off frequency range for the WR90 waveguide size and it still doesn't match the 4.89mm value for the 1/8 or 3/8 written on the Anritsu offset shorts. Thank you! Razvan On 13/07/2024 16:24, Dr. David Kirkby, Kirkby Microwave Ltd via groups.io wrote: On Sat, 13 Jul 2024 at 13:50, Razvan Popescu via groups.io
<> <yo8ryr@... <mailto:[email protected]>>
wrote:
Hello Neil,
/I have had some reading about waveguide and calibration of the 8510C and
I can say that there are no 50ohms waveguide terminations.
?From what I saw the waveguide calibration kits have the following parts:
- waveguide load (termination)
- short (I saw flush ones, 1/8 wavelength ones, 3/8 wavelength ones (you
need to look on a Smith chart to see how they show up))
- shim/
As a minimum for SOLT calibration of waveguide you need
1) Load
2) Either of the following 3 sets of shorts
* ¦Ë/8 and 3¦Ë/8 offset shorts
* Flush short and ¦Ë/4 offset short
* Flush short and ¦Ë/4 spacer.
A theoretical advantage of the ¦Ë/8 and 3¦Ë/8 offset shorts is supposed to
be that the connection is made at a low current point. Despite looking I
have found no evidence that this is actually an issue, st least at
X-band. In fact, I can not even find a scientific paper where this is
claimed.
You can¡¯t make decent spacers or offset shorts with just a milling
machine as the internal radius is limited by the diameter of the cutter.
A spark eroder is needed too. If you use rounded corners then all the
waveguide calibration goes out the window.
If anyone wants a flush short and quarter wave spacer I have some like these
<>
I am not aware of any advantage of a sliding load for X-band as fixed
loads with a VSWR of around 1.02 are available. There might be
advantages in sliding loads at higher frequencies.
Regards,
Razvan
Dr. David Kirkby
Kirkby Microwave Ltd
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Re: VNA calibration kit to 50 GHz
Hi Ed,
Did you try METAS VNA Tools software? It is supporting many VNAs
including the 8510C.
You can save different traces and compare them later. I used it to
compare different coaxial calibration kits but never used it for waveguides.
Regards,
Razvan
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Show quoted text
On 13/07/2024 20:43, Ed Marciniak via groups.io wrote: Considering I can have a PC that¡¯s one rack unit high and half width or
less, if I wanted¡or use a NUC plus a thunderbolt to PCIe cage and a
PCIe to pci adapter with an NI PCI-GPIB card, and then to bridge the gap
in hardware too new if I need an older OS, direct the virtual machine to
own the pci device(s) behind the adapter¡it¡¯s completely practical to
use a PC and hide it behind the instruments.
if someone had a specific piece of software in mind, I might even be
interested in trying to make some one or two page cheat sheets with
steps to install for not so computer focused people or even attempt to
create images that just require you provide windows license keys¡or
something in between like installer scripts.
Alternatively, if someone wanted to collaborate on a MAME/MESS HPIB
interface that would work with an emulated 9000/360 or 9000/382 or
similar. While the emulators are interesting for someone trying to list
code, they¡¯re not really useful if you can¡¯t talk to outside world where
physical instruments live.
Either require more time than I have to spend right now without knowing
there¡¯s at least a few people interested enough to devote some time of
their own to an open source solution.
_._,_._,_
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Re: VNA calibration kit to 50 GHz
Considering I can have a PC that¡¯s one rack unit high and half width or less, if I wanted¡or use a NUC plus a thunderbolt to PCIe cage and a PCIe to pci adapter with an NI PCI-GPIB card, and then to bridge the gap in hardware too new if I need an older OS, direct the virtual machine to own the pci device(s) behind the adapter¡it¡¯s completely practical to use a PC and hide it behind the instruments.
if someone had a specific piece of software in mind, I might even be interested in trying to make some one or two page cheat sheets with steps to install for not so computer focused people or even attempt to create images that just require you provide windows license keys¡or something in between like installer scripts.
Alternatively, if someone wanted to collaborate on a MAME/MESS HPIB interface that would work with an emulated 9000/360 or 9000/382 or similar. While the emulators are interesting for someone trying to list code, they¡¯re not really useful if you can¡¯t talk to outside world where physical instruments live.
Either require more time than I have to spend right now without knowing there¡¯s at least a few people interested enough to devote some time of their own to an open source solution.
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Re: VNA calibration kit to 50 GHz
Neil will tell us which band he wants to test in, but we can assume it's not the X-band but the Q-band, since he talks from 50 GHz right from the start.
For the X band, I can confirm that coaxial systems don't require sliding loads (see my previous post). I never use them on my 8720ES. In N I use an 85054D and in APC 3.5 I use an 85052B or D.
I've only once had the opportunity to work with a 34 GHz guide on an Anritsu VNA, a recent racing beast for an aeronautical customer some 5 years ago. I don't like the Anritsu philosophy, but it was nevertheless a very high-performance device: 70 kHz to 40 GHz!!!! With guide, it's extremely difficult to know what you're really doing, and it takes a long time to set up the standards. In coaxial today, if you don't need to quantify very low S21 or S12 values, it's so easy with Ecal kits! But if you need to measure insertion losses of less than 1 dB, it's still essential to use mechanical kits, because with Ecal kits you get uncertainties of a few tenths of a dB. So, when it comes to qualifying connector insertion losses, you'll do just about anything with Ecals.
Now, the suggestion of using an external PC to drive an 8510C is indeed conceivable, but we already have a cabinet as an instrument, and if we add a PC to it, we get a "gas factory" (a purely French expression). In any case, I declare myself unable to create the software for interpolation and, above all, to feed the results back into the analyzer.
However, you can simply use the floppy disk to store configurations, or an external HPIB disk.
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Re: VNA calibration kit to 50 GHz
In principle placing something at a low current point would require (in the limiting case of a lossless or nearly lossless section) well known absolute positions of an interface.
In a minimal length section (a resonating cavity essentially) you¡¯d have a single frequency and its odd harmonics.
With a longer nearly perfect line section attached to a broadband transition with a reflectionless interface, you could have peaks or nulls spaced at intervals that correspond to something like say 10,9.5,9,8.5,8¡.wavelengths. In reality the transition and mode conversion won¡¯t be perfect.
All of this is somewhat academic as choosing something to be at 1/8 or 3/8 guide wavelength only fits at a single frequency with a short or no add line section.
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LB6B Ingebrigt
Dr. David Kirkby, Kirkby Microwave Ltd
Dick Benson