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Where to bye a good quality and accurate 50 Ohm SMA Load ?

 

Hi All

Where to bye an accurate 50 Ohm +/- 0.1 Ohm SMA Load to ensure a good quality NanoVNA calibration ?

Indeed the most important capability of a nanoVNA is to be calibrated by an external reference 50 Ohm load, the firmware with it's float point computing will do the rest, all quality or default of NanoVNA will be affected by the quality of the calibration Load 50 Ohm , if it has a large band resistor behavior without resonnance or parasitic inductors or capacitors and if it has an accurate resistor value to be refered to, i am not so sure that the loads given by NanoVNA vendors are very accurate , ohmetre measurement gives 50 Ohm +/- 1 Ohm wich is no so good . i would like to bye a better 50 Ohm load reference to be sure to have a good wide band value calibration .

73's Nizar
 

Cheers,
I had the same issue, placed an order through our business to get SMA
calibration kit from kirkbymicrowave.
Money spent, nothing arrived, my advice is against. Can anyone post here
what happened to the old chap and business?
I can advise, what I did after:
Obtain very good SMA PCB edge connectors, highest quality you can afford.
Open and Close standards are straightforward, trim the pins, reuse offcuts
for making Close standard.
For 50 Ohm buy expensive Vishay RF resistors, e.g. Part: CH0402-50RGFTA
https://www.mouser.co.uk/ProductDetail/Vishay-Sfernice/CH0402-50RGFTA?qs=bZr6mbWTK5l8pl0WkFCzkw%3D%3D&mgh=1&vip=1

See also https://www.vishay.com/docs/60093/fcseries.pdf
Solder resistor directly on trimmed SMA, to get the same electrical length
as your newly created open and close standards.
In case of parts shortages, you can also use 100 Ohm resistors in parallel.
Please forget 0.1%. it does not matter on tool like NanoVNA and indeed any
VNA.
More important than DC accuracy is to have 'flat enough' characteristics in
the whole range of calibration frequency.
Cheers
TKa
73 de Mi6HQA

On Sun, 1 Dec 2024 at 08:42, Team-SIM SIM-Mode via groups.io <sim31_team=
yahoo.com@groups.io> wrote:

Hi All

Where to bye an accurate 50 Ohm +/- 0.1 Ohm SMA Load to ensure a good
quality NanoVNA calibration ?

Indeed the most important capability of a nanoVNA is to be calibrated by
an external reference 50 Ohm load, the firmware with it's float point
computing will do the rest, all quality or default of NanoVNA will be
affected by the quality of the calibration Load 50 Ohm , if it has a
large band resistor behavior without resonnance or parasitic inductors or
capacitors and if it has an accurate resistor value to be refered to, i am
not so sure that the loads given by NanoVNA vendors are very accurate ,
ohmetre measurement gives 50 Ohm +/- 1 Ohm wich is no so good . i would
like to bye a better 50 Ohm load reference to be sure to have a good wide
band value calibration .

73's Nizar
 

a sidenote.. best results are with using two 100 ohm resistors.. from centre pin to left and right .. better as using a single 50 ohm
Dg9bfc sigi

Am 01.12.2024 10:45 schrieb "tom Kawala via groups.io" <kawala.tomasz@...>:




Cheers,
I had the same issue, placed an order through our business to get SMA
calibration kit from kirkbymicrowave.
Money spent, nothing arrived, my advice is against. Can anyone post here
what happened to the old chap and business?
I can advise, what I did after:
Obtain very good SMA PCB edge connectors, highest quality you can afford.
Open and Close standards are straightforward, trim the pins, reuse offcuts

for making Close standard.
For 50 Ohm buy expensive Vishay RF resistors, e.g. Part:  CH0402-50RGFTA
https://www.mouser.co.uk/ProductDetail/Vishay-Sfernice/CH0402-50RGFTA?qs=bZr6mbWTK5l8pl0WkFCzkw%3D%3D&mgh=1&vip=1


See also https://www.vishay.com/docs/60093/fcseries.pdf
Solder resistor directly on trimmed SMA, to get the same electrical length

as your newly created open and close standards.
In case of parts shortages, you can also use 100 Ohm resistors in
parallel.
Please forget 0.1%. it does not matter on tool like NanoVNA and indeed any

VNA.
More important than DC accuracy is to have 'flat enough' characteristics
in
the whole range of calibration frequency.
Cheers
TKa
73 de Mi6HQA

On Sun, 1 Dec 2024 at 08:42, Team-SIM SIM-Mode via groups.io <sim31_team=
yahoo.com@groups.io> wrote:

Hi All

Where to bye an accurate  50 Ohm +/- 0.1 Ohm  SMA Load  to ensure a good
quality NanoVNA calibration ?

Indeed  the most important capability of a nanoVNA is to be calibrated
by
an external reference 50 Ohm load,  the firmware with  it's float point
computing will do the rest, all quality or default of NanoVNA will be
affected by the quality of the calibration  Load 50 Ohm ,  if it has a
large band resistor behavior without resonnance or parasitic inductors
or
capacitors and if it has an accurate resistor value to be refered to,  i
am
not so sure that the loads given by NanoVNA vendors are very accurate ,
ohmetre measurement  gives 50 Ohm +/- 1 Ohm wich is no so good . i would
like to bye a better 50 Ohm load reference to be sure to have a good
wide
band value calibration .

73's Nizar
 

I use a Mini-Circuits ANNE-50L+ good to 12 GHz. I think I got it off eBay but you can buy it direct from Mini-Circuits, Digi-Key or Mouser for about $9 US.
Gary
W9TD
 

I have about 100 50 ohm SMA loads that were used by Motorola on a Nextel receiver multi-coupler. They were used to terminate unused ports on the multi-coupler. A test with a network analyzer shows that they are comparable to the load supplied with the Nanovna I purchased from R&L.

I really do not have the time or ambition to sell them individually, but maybe someone would be interested in them all. Offers?

Private email to k1ike at snet dot net

73, Joe, K1ike

IMG_20241201_131637204.jpg

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