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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.
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.
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.
Re: Checking HP 8672A output level: are these drops normal?

 

I worked at the HP/Agilent Midwest Sales, Rolling Meadows, IL / repair/cal center from 1974-1992, then the onsite cal team from 1992-2003 (laid off), then Northrop Grumman from 2003-2015 ATE Engineering. With them I did 8566B's for a sum total of 36 yrs. At HPA, I did all of the Spectrum Analyzers, Phase Noise, later the sweepers 8620's, 8350's, 8340,'s, MMS systems, distance meters, tape recorders, plotters, x-y plotters, and a lot of other stuff. I strongly suspect we were on combined Cal campaigns, New York, New Jersey, Mexico, etc.?
The name Pete strikes a familiar memory, but you will have to give me your last name to complete the memory.
Don Bitters
Re: VNA calibration kit to 50 GHz

 

On Sat, 13 Jul 2024 at 13:50, Razvan Popescu via <yo8ryr=[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
Re: HP free e-book

 

Thanks for another great edition Gianni.
I am amazed at the magnitude of your publication output.
Cheers,
Tom
8510C + linux laptop setup

 

On 7/13/24 04:44, neil via groups.io wrote:
I know the 8510C is limited in storage, but in principle using the HPIB all configurations can be storing in a driving PC, even
perhaps making the calibration corrections in the PC, if you write the DUT uncalibrated data and the calibration data to the PC?
I'm gathering parts to become an 8510C + linux laptop setup with that style in mind. By that I mean using pyvisa-py commands to do most everything.
Re: HP 8566B - Can my high voltage transformer be faulty?

 

Hi Don,

Wouldn't a shrunken display usually indicate that the HV was
too high, speeding up the electrons, and reducing how much the
electrostatic deflection system can deflect them?

That's how it works on conventional scopes...

-Chuck Harris


On Sat, 13 Jul 2024 00:31:43 -0500 "Don Bitters via groups.io"
<donbitters@...> wrote:
I have replaced several in the 85662A many, many years ago. There are
2 types depending whether you have a long CRT (PN 5083-5791, IIRC),
or a shorter CRT newer type dot raster scan CRT (Panasonic). The HV
transformer is inside the metal box at the rear, left of the CRT
(A1A6 circuit). They usually fail open. You should see a shrunk
image on the CRT when the HV transformer fails, both horizontally and
vertically, or a dim dot. You will still have a good display if you
check the video and horizontal outputs on an oscilloscope.

Don Bitters
Re: wanted clip for E4432B output board E4400-60188

 

¿ªÔÆÌåÓý

Hi Peter,


I don't have a CLIP for that board, but where is the problem in the circuit?

The block diagram for the E4400-60188 might help.

See:


Tom
N3AJA



On 7/13/2024 3:53 AM, Peter Hansen wrote:

Hello Can anyone help me with that. I have a Fet fault where bias circuit is not working correct either. I must the version that uses the H1 Fet (SHF-189)
Best regards Peter OZ1LPR
Re: VNA calibration kit to 50 GHz

 

Hello Neil,

I followed this subject because I am also interested exactly the same
scenario like yours.

I have had some reading about waveguide and calibration of the 8510C and
I can say that there are no 50ohms waveguide terminations. Waveguides
have a "wave impedance" which can fluctuate a lot. For rectangular
waveguides as a rule of thumb you can say they have 500 ohms from what I
was reading in some articles but there are some excel sheets with
formulas that can calculate the wave impedance for your waveguide more
precisely.

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
- standard section (used for system verification only)
- straight section (used as port 1 and 2)

Waveguide load you can find on eBay. Look for the ones that have a label
on them and buy the ones that have the lowest VSWR. I saw a Narda one
for example with 1.035. You can get a sliding load which I understood it
is better but I need to read more to understand why and how it is used
during calibration procedure...

If you know someone with a milling machine maybe he can make the "short"
one for you and also different sizes.

Standard section and straight section you can also find on eBay. Some
are cheap some are not cheap. Try to buy the well known brands and not
the "no name" ones.

Regards,
Razvan

On 13/07/2024 12:44, neil via groups.io wrote:
Just for starters with no calibration kit i'm just wondering how far i
can get if i operate in waveguide. So at the end of the two coaxial
cables connected to the 8510C there are transmissions to fundamental
waveguide. I can then connect my DUT between the fundamental waveguide
flanges. So in making a SOLT calibration, for Short i just measure S11
and S22 when there are conducting metal plates over the ends of the
waveguide transision exits, for Open i just leave the ends of the
waveguides open, making sure they point in the direction of empty space
so there are no reflections from object outside the waveguide exits, for
Load i just connect 50 Ohm waveguide terminations to the waveguide
exits, and for Thru i just connect the ends of the waveguides together.
I know this is rather crude, but might this work as a first shot at
making a full 2-port calibration?

I know the 8510C is limited in storage, but in principle using the HPIB
all configurations can be storing in a driving PC, even perhaps making
the calibration corrections in the PC, if you write the DUT uncalibrated
data and the calibration data to the PC?

many thanks, Neil
Re: VNA calibration kit to 50 GHz

 

Just for starters with no calibration kit i'm just wondering how far i can get if i operate in waveguide. So at the end of the two coaxial cables connected to the 8510C there are transmissions to fundamental waveguide. I can then connect my DUT between the fundamental waveguide flanges. So in making a SOLT calibration, for Short i just measure S11 and S22 when there are conducting metal plates over the ends of the waveguide transision exits, for Open i just leave the ends of the waveguides open, making sure they point in the direction of empty space so there are no reflections from object outside the waveguide exits, for Load i just connect 50 Ohm waveguide terminations to the waveguide exits, and for Thru i just connect the ends of the waveguides together. I know this is rather crude, but might this work as a first shot at making a full 2-port calibration?

I know the 8510C is limited in storage, but in principle using the HPIB all configurations can be storing in a driving PC, even perhaps making the calibration corrections in the PC, if you write the DUT uncalibrated data and the calibration data to the PC?

many thanks, Neil
wanted clip for E4432B output board E4400-60188

 

¿ªÔÆÌåÓý

Hello Can anyone help me with that. I have a Fet fault where bias circuit is not working correct either. I must the version that uses the H1 Fet (SHF-189)
Best regards Peter OZ1LPR
Re: HP 8566B - Can my high voltage transformer be faulty?

 

I have replaced several in the 85662A many, many years ago. There are 2 types depending whether you have a long CRT (PN 5083-5791, IIRC), or a shorter CRT newer type dot raster scan CRT (Panasonic). The HV transformer is inside the metal box at the rear, left of the CRT (A1A6 circuit). They usually fail open. You should see a shrunk image on the CRT when the HV transformer fails, both horizontally and vertically, or a dim dot. You will still have a good display if you check the video and horizontal outputs on an oscilloscope.

Don Bitters
Re: HP free e-book

 

Gianni, this is a work of art.? Very nicely done!

Peter

On 7/12/2024 5:23 PM, Gianni Becattini via groups.io wrote:
A new edition of the e-book "The Great HP" has been released and can be freely downloaded from my page www.k100.biz <>. I removed the Advantest R3132 (now in a separate ebook) and added various instruments. It has now more than 1,000 pages.

To make easier the download, I split the file in three parts which can be downloaded separately.

Tell me if you have problems - any suggestion welcome.
Re: Made one out of workshop scrap to enable the correct tightening of SMA 's

 

On July 12, 2024 9:35:13 PM "Steve Hendrix" <SteveHx@...> wrote:
That is what happens when you try to use the incorrect word for a spanner.
...or was that spammer? <couldn't resist>
You're a mean, bad man Steve. ;)

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: Made one out of workshop scrap to enable the correct tightening of SMA 's

 

On 2024-07-12 6:09 PM, george edmonds via groups.io wrote:
That is what happens when you try to use the incorrect word for a spanner.
...or was that spammer? <couldn't resist>
Re: Bubble Memory Reseed

 

Thanks for the responses. I did see the Hackaday project to build a Bubble Seed Module, but it was for a SBC-85 board. Evidently, HP built or had built their own module. Volume I of the service manual shows a (grainy on my copy) photo of the device. You plug it in and run Test Routine 169.

Ed, the Boot Loop routine you referred to can be run with loading a program from the manual with a HP-1B controller. Maybe, that is all I need. The program would have to be hand typed in, and I'd have to find a way to emulate the controller. I have a Prologix USP Controller. I'll have to figure out how to use it.

The history of Bubble Memory is interesting. Turned out to be a blind alley, but it was a creative idea.

Thanks again,
John
Re: Made one out of workshop scrap to enable the correct tightening of SMA 's

 

That is what happens when you try to use the incorrect word for a spanner.

G Edmonds
On Friday 12 July 2024 at 22:06:05 BST, Tom Lee <tomlee@...> wrote:


She must've been very strong...

(sorry, couldn't resist)


On 7/12/2024 10:10 AM, george edmonds via groups.io wrote:
> Hi John
>
> Used a wench of Chinese origin
HP free e-book

 

A new edition of the e-book "The Great HP" has been released and can be freely downloaded from my page . I removed the Advantest R3132 (now in a separate ebook) and added various instruments. It has now more than 1,000 pages.

To make easier the download, I split the file in three parts which can be downloaded separately.

Tell me if you have problems - any suggestion welcome.
Re: Made one out of workshop scrap to enable the correct tightening of SMA 's

 

soda -> keyboard

On July 12, 2024 5:06:11 PM "Tom Lee" <tomlee@...> wrote:
She must've been very strong...

(sorry, couldn't resist)

On 7/12/2024 10:10 AM, george edmonds via groups.io wrote:
Hi John

Used a wench of Chinese origin


--
Dave McGuire, AK4HZ
New Kensington, PA
6581 - 6600 of 151621