I've been watching these older videos about the VNA's, and this is a good one. Someone mentioned having BNC connectors, but BNC don't work well up into the high frequencies the SMA connectors reach, so use adapters to get the type connectors you need. There are many kits for SMA to about any other connector you need, or make your own! I have my first home brew male SMA to female BNC connector adapters still in use! Many times I will use the small through cables supplied with the VNA to make using the adapters easier, all you need to do is calibrate the setup before use!
Can't calibration be done by fitting the adaptor, and then using the VNA menu's port extension/electrical delay setting, to move the measurement plane from the VNA connector out to the end of the adaptor?
Challenge: 1) Cal with the normal SOL loads, 2) In S11 note the phase angle with Short connected 3) Attach SMA barrel, attach your Short 4) look at phase again. 5) Repeat but use YOUR SOL fixture for cal and *then* attach the factory Short, measure phase change. What/how many degrees? Option: Do at only say 30 MHz. Repeat at 500 MHz for giggles (phase diff will be larger, of course).
re: "phase angle change is as expected" Well, yes; to be expected. The assembled multitude might like to know what that value is for, say 30 MHz for starters ... I mean, what is the phase change for a centimeter's worth of length at a frequency whose wavelength is 10 meters? Small ... and, of course, that is my point ... the phase change at 500 MHz (Lambda being 60 cm) would be proportionally larger, +- instrument accuracy.
Let's not get ahead of ourselves; I've got TWO perfectly good HP 8405's, TWO HP 8410's (-18 option; good to 18 Ghz) with various display plug-ins, a couple Transmission-Reflection Test sets, one S-Parameter Test Set, a RigExpert AA-55 Zoom (only does up to 55 MHz otherwise like the Nano) .. I'm VNA poor here!!!
@IMSAI Guy re: " It's only $50 buy one. " Ha. You risk "winding me up." You know, they are US$35 (and they are THE genuine article) each in lots of 10 from Alibaba? Thinking I will make a bulk purchase and show up at our monthly 'sidewalk sale' in Dallas and make it work my while.
yes, I do that for many measurements. it relies on the accuracy of the cal standards used. I'm highly suspicious of the reference plane between the open/short/load SMA cal 'standards' supplied with the NanoVNA. I trust the reference plane of my female standard I show here.
@@IMSAIGuy Especially when as you point out the calibration standards can cost thousands. The whole idea of a 50 dollar VNA serms suspicious lol. Thanks and keep the good stuff coming. Im really enjoying the series on the old kenwood !
@@clems6989Its because there are various capacitance and inductance correction factors added in to opens and shorts. I would be skeptical of this basic standard as opens and shorts are not just straight shorts to ground and open circuits. If it was this easy to make an accurate standard, most professional standards wouldnt cost hundreds of dollars.
You Can Calibrate With Like 6 Meter Coax Even, Just Take Off The ANtenna And WHen You Done Calibrating Just Add The ANtenna To The End Of That 6 Meter Coax ANd It Will Show Only The Antennas Results :) THATS HOW VNA SHOULD BE WORKED ON In My Opinion
If You Have A problem Like This, Just Calibrate WITH The Addapter And Save 1. Or Save2, SAVE1 Could Be Calibrated Without Anything On, Right? SAVE2 Can Be Calibrated With The Addapter, SAVE3 Could Be Calibrated With The Extention Wire, Thats Why We Have Planty of SAVE States On The VNA So We Can Do That, There Is No Problem With That My Dear Friend. :) Just Save The Presets Wich Are Calibrated Diferently- Problem Solved
Why don't you use the "Electrical delay" function in the "Scale" menu to compensate the delay introduced by the adapter?
I've been watching these older videos about the VNA's, and this is a good one.
Someone mentioned having BNC connectors, but BNC don't work well up into the high frequencies the SMA connectors reach, so use adapters to get the type connectors you need. There are many kits for SMA to about any other connector you need, or make your own!
I have my first home brew male SMA to female BNC connector adapters still in use!
Many times I will use the small through cables supplied with the VNA to make using the adapters easier, all you need to do is calibrate the setup before use!
BNCs are good to 3 GHz
Great idea! Saves having to look for all three when it comes time to calibrate too! ;-)
Can't calibration be done by fitting the adaptor, and then using the VNA menu's port extension/electrical delay setting, to move the measurement plane from the VNA connector out to the end of the adaptor?
yes. that is ok but your reference plane will be about 1cm off due to the female/female adapter.
Challenge: 1) Cal with the normal SOL loads, 2) In S11 note the phase angle with Short connected 3) Attach SMA barrel, attach your Short 4) look at phase again. 5) Repeat but use YOUR SOL fixture for cal and *then* attach the factory Short, measure phase change. What/how many degrees? Option: Do at only say 30 MHz. Repeat at 500 MHz for giggles (phase diff will be larger, of course).
I"ve already done that. phase angle change is as expected. I show a little of that in video th-cam.com/video/fVzT23onCxI/w-d-xo.html
re: "phase angle change is as expected"
Well, yes; to be expected. The assembled multitude might like to know what that value is for, say 30 MHz for starters ...
I mean, what is the phase change for a centimeter's worth of length at a frequency whose wavelength is 10 meters? Small ... and, of course, that is my point ... the phase change at 500 MHz (Lambda being 60 cm) would be proportionally larger, +- instrument accuracy.
@@uploadJ It's only $50 buy one
Let's not get ahead of ourselves; I've got TWO perfectly good HP 8405's, TWO HP 8410's (-18 option; good to 18 Ghz) with various display plug-ins, a couple Transmission-Reflection Test sets, one S-Parameter Test Set, a RigExpert AA-55 Zoom (only does up to 55 MHz otherwise like the Nano) .. I'm VNA poor here!!!
@IMSAI Guy re: " It's only $50 buy one. "
Ha. You risk "winding me up." You know, they are US$35 (and they are THE genuine article) each in lots of 10 from Alibaba? Thinking I will make a bulk purchase and show up at our monthly 'sidewalk sale' in Dallas and make it work my while.
You could add second piece of board to the top to stiffen up the three way load connectors.
thought about that. I'll add it when it breaks :)
Love your videos keep up the good work, very helpful information.
You could use tge "electrical delay" funtion to 0-out the connectors, without disturbing your base calibration...
yes, I do that for many measurements. it relies on the accuracy of the cal standards used. I'm highly suspicious of the reference plane between the open/short/load SMA cal 'standards' supplied with the NanoVNA. I trust the reference plane of my female standard I show here.
@@IMSAIGuy Especially when as you point out the calibration standards can cost thousands. The whole idea of a 50 dollar VNA serms suspicious lol. Thanks and keep the good stuff coming. Im really enjoying the series on the old kenwood !
@@clems6989Its because there are various capacitance and inductance correction factors added in to opens and shorts. I would be skeptical of this basic standard as opens and shorts are not just straight shorts to ground and open circuits. If it was this easy to make an accurate standard, most professional standards wouldnt cost hundreds of dollars.
For me it would be best to use male and female BNC's to test antennas.
You Can Calibrate With Like 6 Meter Coax Even, Just Take Off The ANtenna And WHen You Done Calibrating Just Add The ANtenna To The End Of That 6 Meter Coax ANd It Will Show Only The Antennas Results :) THATS HOW VNA SHOULD BE WORKED ON In My Opinion
certainly that would work
If You Have A problem Like This, Just Calibrate WITH The Addapter And Save 1. Or Save2, SAVE1 Could Be Calibrated Without Anything On, Right?
SAVE2 Can Be Calibrated With The Addapter, SAVE3 Could Be Calibrated With The Extention Wire, Thats Why We Have Planty of SAVE States On The VNA So We Can Do That, There Is No Problem With That My Dear Friend. :)
Just Save The Presets Wich Are Calibrated Diferently- Problem Solved
yes, I do that all the time
What about doing the same with sma to so239 and sma to bnc connectors?
sure!
Calibrate without the adapter. Then add the adapter and adjust the e-delay
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