VNA Compact Cal Kit from Rosenberger

[sixtimesseven]

I'm looking around for a Cal Kit to ultimatly replace my DIY attempt (which is pretty bad at 6GHz).
So far all the used HP/Agilent options seem really expensive to me.

I looked at the Kirkby cal kits but I'm a bit reluctant to get SMA connectors at that price point.

However, I stumbled on an offering from Rosenberger's Compact Cal Kits: https://www.rosenberger.com/0_documents/de/catalogs/ba_tm/TM_Compact_CalKits.pdf
In particular: 03K30R-MSOS3
Datasheet: https://catalog.rosenberger.com/images/documents/db/03K30R-MSOS3-RMS.pdf

They are not cheap, 1250USD 850USD (Rosenberger quote) for 3.5mm SOL or 1450USD 1025USD (Rosenberger quote) for SOLT, but still a far way from Keysight Kits and pretty close to used HP/Agilent 3.5mm kits in dubious condition and they go up to 26GHz...
Specs look pretty good. But I'm still interested if sombody uses them already?

Andreas


EDIT:
Updated pricing with actual quoted prices from local Rosenberger distributor. Prices are significantly lower then Mouser/Digikey prices so ask!

EDIT II:
Received kit after about a month. I'm pretty impressed by it so far. I used VNA Cal Kit Manager http://www.vnahelp.com/ckman_new2.html to send the cal via GPIB.
A little quirk in Windows is that, if you see comma seperated values in the CKM, you have to change them to point seperated values.
Control Panel\Clock and Region -> Change date, time or number formats -> Additional Settings -> Decimal Symbol -> Change from "," to "."
I have attached the .ckm file to load directly via CKM.

[rastro]

That's a good find.  Rosenberger is a good brand/reputation.

I wonder if anyone knows who makes HP/Agilent/KS calibration kits?  I suspect they are re-badged.

rastro

[TheSteve]

Keysight makes there own 3.5mm kits such as the 85052x. Years ago and possibly still today they have rebranded Maury Microwave kits. I believe the all in one kits like the 85521a are rebranded.

Rosenberger should be good stuff. I've never used them though. Cal kit deals pop up on eBay all the time, but they usually sell pretty quick.

[sixtimesseven]

Cal kit deals pop up on eBay all the time, but they usually sell pretty quick.

But the prices are ... Rather high I found. I mean a as-is kit with how knows connector health for 600+ Euros 
https://www.ebay.de/itm/HP-Agilent-Keysight-85033D-3-5mm-Calibration-Kit/202660980808?hash=item2f2f892848:g:YUQAAOSwok9cwB9Y

[TheSteve]

Keysight makes there own 3.5mm kits such as the 85052x. Years ago and possibly still today they have rebranded Maury Microwave kits. I believe the all in one kits like the 85521a are rebranded.

Do you happen to know who makes 85521A? If it's below 1/2 Keysight's price I will get one to replace mine with crooked connector, just so I can sleep well.

No idea - but all of the 3.5mm stuff they make is PSC (precision slotless). Those cal kits look pretty generic, there seem to be quite a few companies who make them at the moment.

[cloidnerux]

Do you happen to know who makes 85521A? If it's below 1/2 Keysight's price I will get one to replace mine with crooked connector, just so I can sleep well.

Some of those cal kits are made by "Spinner GmbH":
https://www.spinner-group.com/de/produkte/messmittel/vna-messmittel
I think they are rebranded by R&S, Keysight and a few others.

[rastro]

Rosenberger 3.5mm female connector do not appear to be PSC (precision slotless).

The 03K30R-MSOTS3 (female 26GHz) kit uses there PRC-3.50 connector and their datasheet shows a slot on the female interface.

The concern with buying used PSC hardware is the delicate internal fingers inside the female connector can be damaged.  This can be hard to detect without close inspection under magnification. 

I think the slotted 3.5mm connectors are a little more mechanically forgiving/robust when compared to the slot-less. 

[OwO]

I don't get all the effort to make an "ideal" connector in a cal kit because the best accuracy is achieved when the cal kit connector closely matches the DUT's connector in characteristics.

[Bud]

Honestly I can't recall seeing anywhere in VNA books a requirement to match the DUT connector characteristics. This would simply be unreslistic to cover all use cases. Connectors in calibration kits are made with tight tolerances because they need to be precisely characterized for calibration coefficients and have repeatability when made. Nobody wants to individually characterize every single kit produced. In some cases cal coefficients are derived from simulation for which it is needed to know precise geometry of the connector parts.

[sixtimesseven]

Do you happen to know who makes 85521A? If it's below 1/2 Keysight's price I will get one to replace mine with crooked connector, just so I can sleep well.

Some of those cal kits are made by "Spinner GmbH":
https://www.spinner-group.com/de/produkte/messmittel/vna-messmittel
I think they are rebranded by R&S, Keysight and a few others.

I agree, R&S cal kits look exactly the same.
Contacted them and got the attached product catalog. Still waiting on the quote for the DC-13 and DC-26 OSLT cal kit from them(product nr: 533828 / 533882).

[sixtimesseven]

I got the offer from Spinner (Keysight / R&S OEM):

Spinner 533828 -- 950USD + Tax etc. --Datasheet Attached
OSLT 3.5mm female (IEC 60169-23) connector, 0-13Ghz

Phase match open:
0 - 4 GHz / 1,5° max.
>4 - 8 GHz / 3,0° max.
>8 - 13 GHz / 4,5° max.

Phase match short:
0 - 4 GHz / 1,0° max.
>4 - 8 GHz / 2,0° max.
>8 - 13 GHz / 3,5° max

Load, return loss
0 - 4 GHz / 40 dB min.
>4 - 8 GHz / 34 dB min.
>8 - 13 GHz / 28 dB min.

Thru, return loss
0 - 4 GHz / 34 dB min.
>4 - 8 GHz / 28 dB min.
>8 - 13 GHz / 25 dB min.


Spinner 533882 -- 2100USD + tax (Out of my league) --Datasheet Attached
OSLT 3.5mm female (IEC 60169-23) connector, 0-26.5Ghz

Phase match open:
0 - 5 GHz / 1,5° max.
5 - 15 GHz / 3° max.
15 - 26,5 GHz / 4,5° max.

Phase match short:
0 - 5 GHz / 1° max.
5 - 15 GHz / 2,5° max.
15 - 26,5 GHz / 4° max.

Load, return loss
0 - 5 GHz / 42 dB min.
5 - 15 GHz / 36 dB min.
15 - 26,5 GHz / 32 dB min.

Thru, return loss
0 - 5 GHz / 34 dB min.
5 - 26,5 GHz / 30 dB min.


Rosenbergs 03K30R-MSOS3 850USD (quote)
26.6GHz 3.5mm female (IEC 61169-23) connector
Specs for comparison:

Open
Error from nominal phase
1 ≤ 1.0°, DC to 4 GHz
 ≤ 2.0°, 4 GHz to 8 GHz
≤ 3.0°, 8 GHz to 26.5 GHz

Short
Error from nominal phase
≤ 1.0°, DC to 4 GHz
≤ 2.0°, 4 GHz to 8 GHz
≤ 3.0°, 8 GHz to 26.5 GHz

Load
Return loss ≥ 40.0 dB, DC to 4 GHz
≥ 35.0 dB, 4 GHz to 8 GHz
≥ 30.0 dB, 8 GHz to 26.5 GHz



In conclusion:
The Rosenberger OSL costs slightly less then the Spinner 0-13GHz version. It lacks the throu standard (which seems likt the easiest-to-replace standard to me), goes to 26GHz and has better phase specs for the open and short but a significantly better return loss for the load. Only bummer is 12-13 weeks of indicated delivery time

So far I lean towards the Rosenberger. Any objections?


EDIT: Mixed up Short and Thru for Spinner kits. Fixed.

[rastro]

I got the offer from Spinner (Keysight / R&S OEM):
...
So far I lean towards the Rosenberger. Any objections?

Thanks for sharing that information.  Unless I missed something the Rosenberger 26.5GHz looks like it has specifications still very close to the Spinner 26.5GHz standard.  I suspect that any random production Rosenberger unit would meet the Spinner 26.5GHz specification.  The specification gap may be attributed to how much margin each manufacture is comfortable with.

Dam it, now you got me thinking about purchasing a Rosenberger 26.5GHz cal standard.  Gonna have to wait for a few months for finances.  I like the case and coefficient card that is included.

Some other thoughts:
1. I wonder how easy it is to remove the standards from the holder?  I didn't see anything in the data sheet.
2. Out of curiosity I wonder how the Coefficients compare between the Rosenberger 26.5GHz and Spinner 26.5GHz.  Probably meaningless...
3. Outer conductor is different Rosenberger = Stainless steel Passivated; Spinner = CuBe / gold-plated.  Don't know this affects performance/longevity?

rastro

[sixtimesseven]

Dam it, now you got me thinking about purchasing a Rosenberger 26.5GHz cal standard.  Gonna have to wait for a few months for finances.  I like the case and coefficient card that is included.

Rosenbergs delivery time seems to match your financing requirements pretty well.

1. I wonder how easy it is to remove the standards from the holder?  I didn't see anything in the data sheet

I would suspect it to be very easy. The OSL part looks identical. I suspect one screw on the back.

2. Out of curiosity I wonder how the Coefficients compare between the Rosenberger 26.5GHz and Spinner 26.5GHz.  Probably meaningless...

Coefficents are in the datasheets. See atachments. They are also freely available on the net.

[rastro]

Sorry just realized I had the information at hand.  Was editing prior message when you replied...

[Bud]

@sixtimesseven are you sure you read the specs for the Short correctly?   
Seems it is absorbing energy, not reflecting it. 

[sixtimesseven]

@sixtimesseven are you sure you read the specs for the Short correctly?   
Seems it is absorbing energy, not reflecting it. 

You are correct. I mixed up Short and Thru specs while translating from German. Sorry!

[TheUnnamedNewbie]

I don't get all the effort to make an "ideal" connector in a cal kit because the best accuracy is achieved when the cal kit connector closely matches the DUT's connector in characteristics.

Could you care to explain/clarify? The best accuracy should be achieved when the error on the calkit with respect to the stored values used in the VNA are lowest, shouldn't they? The advantage of an ideal connector in a calkit is because an ideal connector means you need less precise compensation values to cancel out the non-ideal connector. After all, that is why sliding-loads are a thing - they wouldn't work with near-perfect connectors.

OP, getting a through that can match the performance of that rosenberger kit might not be as straight-forwards as you think. 3.5mm air-dielectric through are not exactly cheap.

[Bud]

@sixtimesseven are you sure you read the specs for the Short correctly?   
Seems it is absorbing energy, not reflecting it. 

You are correct. I mixed up Short and Thru specs while translating from German. Sorry!

Ah, that RL figure was for the Thru, makes sence.

[OwO]

Could you care to explain/clarify? The best accuracy should be achieved when the error on the calkit with respect to the stored values used in the VNA are lowest, shouldn't they? The advantage of an ideal connector in a calkit is because an ideal connector means you need less precise compensation values to cancel out the non-ideal connector. After all, that is why sliding-loads are a thing - they wouldn't work with near-perfect connectors.

The point was that when you are measuring the DUT you are going through its non-ideal connectors, which for example may have a nominal characteristic impedance different from 50 ohms due to physical design. No matter how good your cal kit is, this error gets added to the measurement, and conversely if you construct a cal kit out of a connector that closely resembles the DUT's connectors, the error of the connector gets calibrated out.

[OwO]

In general I think people pay way too much for anything related to a network analyzer, and never realize the instrument or even cal kit is usually not the performance bottleneck, but rather measurement technique and the DUT itself.

[dcarr]

In the spirit of OwO’s comment— if you really want to characterize a PCB mounted device, you should be using on board TRL or similar fixtures.  These will calibrate out your connectors, PCB transitions, and your transmission line geometry.  Best of all, it’s cheap!  You don’t necessarily have to have a traditional cal kit to do it.

[sixtimesseven]

In the spirit of OwO’s comment— if you really want to characterize a PCB mounted device, you should be using on board TRL or similar fixtures.  These will calibrate out your connectors, PCB transitions, and your transmission line geometry.  Best of all, it’s cheap!  You don’t necessarily have to have a traditional cal kit to do it.

Well this is true if you use <10$ SMA edge launch connectors which will vary by quiet a bit but is pretty cheap. And arguably this precision is all you need for most application which use SMA edge launch connectors in the real product anyway. However, if you want to get rid of connector variations, they won't do. Have a look at the 3.5mm/2.92mm edge launch connector prices! And you will need 6+ for the TRL kit (depending on frequency range) and 2 for each DUT!

[rastro]

...
OP, getting a through that can match the performance of that rosenberger kit might not be as straight-forwards as you think. 3.5mm air-dielectric through are not exactly cheap.

I didn't see any indication on the 3.5mm(f) MSOT (03K30R-MSOTS3) data sheet that the "Through" is an airline. 
It looks like both use the same short/open/load on the data sheet.

Both mouser and digikey have prices between $1200USD and $1600USD for these kits.  The 850USD looks like good deal in comparison.

[dcarr]

Great point about the connector repeatability.  I can recommend Rosenberg 32K243-40ML5 as a high performance yet moderately priced option.  It clamps on to the edge of the board and if you bend down the center PCB contact slightly, it acts like one of the expensive Southwest Microwave connectors.  (ie: You clamp it on to the PCB in one place and then when finished you can unclamp it and move it to a new location.)

David

[TheUnnamedNewbie]

Could you care to explain/clarify? The best accuracy should be achieved when the error on the calkit with respect to the stored values used in the VNA are lowest, shouldn't they? The advantage of an ideal connector in a calkit is because an ideal connector means you need less precise compensation values to cancel out the non-ideal connector. After all, that is why sliding-loads are a thing - they wouldn't work with near-perfect connectors.

The point was that when you are measuring the DUT you are going through its non-ideal connectors, which for example may have a nominal characteristic impedance different from 50 ohms due to physical design. No matter how good your cal kit is, this error gets added to the measurement, and conversely if you construct a cal kit out of a connector that closely resembles the DUT's connectors, the error of the connector gets calibrated out.

If you want to measure only the DUT on a test-board, you need to calibrate on the test board with TRL (ideally even TRLL). I don't know about the math and I never do this, since I tend to either use GSG probes or waveguide stuff, but I have once been told that you can get better performance if you first calibrate up to the ports of your expensive VNA cables, then calibrate the TRL, instead of going straight for the TRL (this can also give you an idea about the repeatability of the TRL, since you can see the difference between connectors if you look at the time-domain).

In the spirit of OwO’s comment— if you really want to characterize a PCB mounted device, you should be using on board TRL or similar fixtures.  These will calibrate out your connectors, PCB transitions, and your transmission line geometry.  Best of all, it’s cheap!  You don’t necessarily have to have a traditional cal kit to do it.

Well this is true if you use <10$ SMA edge launch connectors which will vary by quiet a bit but is pretty cheap. And arguably this precision is all you need for most application which use SMA edge launch connectors in the real product anyway. However, if you want to get rid of connector variations, they won't do. Have a look at the 3.5mm/2.92mm edge launch connector prices! And you will need 6+ for the TRL kit (depending on frequency range) and 2 for each DUT!

The thing is that you want your connectors to be as ideal as possible. After all, any variability in the connectors (both between different connectors and the repeatability of the connector itself) will translate into larger errors and uncertainty on the device performance. Just because it will be used with cheap connectors does not mean it is okay to measure it with cheap connectors - you want as precise measurement as possible, since errors tend to compound in simulations and when you start cascading things. And while you might not get big amplitude variations, phase variations can be very important - after all, you need to 'un-rotate' the transmission lines you use.

...
OP, getting a through that can match the performance of that rosenberger kit might not be as straight-forwards as you think. 3.5mm air-dielectric through are not exactly cheap.

I didn't see any indication on the 3.5mm(f) MSOT (03K30R-MSOTS3) data sheet that the "Through" is an airline. 
It looks like both use the same short/open/load on the data sheet.

To be a APC3.5 mm connector that adheres to the standard, it has to be a airline connector. There is no such thing as a non-airline APC3.5 mm connector.