NanoVNA V2: An Inexpensive and Effective Vector Network Analyser
I recently found that I was able to purchase a Vector Network Analyser (VNA) or the princely sum of only around $86, thanks to the wonders of modern electronics. Brand new, functioning and virtually ready to go out of the box. Putting this in perspective we have a couple where I work. We have a small portable unit (FIeldFox) that performs reasonably well and costs around $7200. We have another bench unit that will cost you $42k new, and we have a third one that is even more expensive. So, to get something that is reasonable for around $86 is amazing. Bottom and top frequencies don’t quite make it to where the more expensive units are but they are still very useful, especially in the area of the spectrum where we like to work with telemetry and GPS.
What is a VNA?
A Vector Network Analyser is basically an instrument that can be used to analyse networks of radio frequency (RF) components. When we say networks it is nothing like a computer network. We are essentially talking about a black box (unknown components inside) that might have connections in and out. The VNA is able to analyse how the network behaves at various RF frequencies and provide information on how much power is transmitted through, or reflected back from the connections, without knowing exactly what is inside the network. So even though we don’t know what is in the network exactly, we can measure how it affects signals we pass through it. In our case we could be testing a cable, a filter or perhaps an antenna.
This ability makes it very useful measuring the performance of antennas to some degree and also checking our antenna cables are behaving nicely.
How does a VNA do this? It is essentially a transmitter and two receivers that allow the comparison of the transmitted signal and the received signal. There are some clever devices called directional couplers in it which allow it to measure the power in each direction, forward and reflected. Both amplitude and phase are measured, hence the “vector” in the name. There are other scalar network analysers that just look at the amplitudes but the VNA is more versatile and at this price why wouldn’t you?
The frequency range of this device is from 50kHz to 3GHz. Very good for a bargain-priced unit.
Note that I have the V2 (version 2) of the NanoVNA. The original did not have as wide a frequency range and was technically inferior to this later version.
Here is where you can purchase the NanoVNA V2 and support the developers. There are clones available on some websites that may be cheaper but quality and performance can vary.
https://nanorfe.com/nanovna-v2.html
https://www.tindie.com/products/hcxqsgroup/nanovna-v2/
When ordering make sure you get the cable and calibration kits with the unit. It is pretty useless without those. The unit does need to be calibrated whenever you change the frequency settings, but the process is quite painless.
I would also recommend getting some “connector savers” that screw onto the VNA ports. The SMA connectors used (in fact all connectors) have a finite life and each insertion/removal takes it a step closer to its limit. By fitting the connector saver adapters you can replace them when the connectors wear out, as replacing the VNA connectors which are soldered on is a much more serious task.
https://www.ebay.com.au/itm/5-x-SMA-fem ... 3094372441
These connectors are fitted permanently to the existing SMA connectors on the unit and left there until they are worn out.
There are some video tutorials for the NanoVNA on this site:
https://www.rtl-sdr.com/tag/nanovna-v2/
Here is a pic of the cables and calibration kit. There are short, open, through and load (50ohm) connectors in the cal kit.
The VNA comes with two PCAs. One is the main board and the other the touch-screen display. Note that as supplied you can run it off a USB cable directly, but if you want to use it without external power you need to provide a suitable battery. They don't ship batteries to keep the hassle of DG shipping LiPos out of the transaction. There is a connector for the battery and charging circuitry is inbuilt. Note that this unit can run standalone with a battery, or it can be run off a PC with the VNA controlled from there as well, and results are able to be exported.
It comes with a fairly basic plastic case (if you order it). It is a bit agricultural but it will protect the unit so I would suggest you get some sort of case from somewhere. It is convenient to order it when ordering the VNA.
I had a friend print a case on a FormLab 2 SLA printer. It came out very nice.
Note that there are a couple of LEDs that you need to be able to see somewhat. The translucent case makes that possible without having to drill holes in the case. The red LEDs indicate battery capacity.
When I get some more time I will do a demonstration of how it can be useful around the workshop in general and rocketry in particular.
Disclosure: I am posting this on both the US and Australian rocketry forums. This is sometimes considered bad manners, but I think everyone needs to find out about this device. Very useful if you do anything with RF.
I recently found that I was able to purchase a Vector Network Analyser (VNA) or the princely sum of only around $86, thanks to the wonders of modern electronics. Brand new, functioning and virtually ready to go out of the box. Putting this in perspective we have a couple where I work. We have a small portable unit (FIeldFox) that performs reasonably well and costs around $7200. We have another bench unit that will cost you $42k new, and we have a third one that is even more expensive. So, to get something that is reasonable for around $86 is amazing. Bottom and top frequencies don’t quite make it to where the more expensive units are but they are still very useful, especially in the area of the spectrum where we like to work with telemetry and GPS.
What is a VNA?
A Vector Network Analyser is basically an instrument that can be used to analyse networks of radio frequency (RF) components. When we say networks it is nothing like a computer network. We are essentially talking about a black box (unknown components inside) that might have connections in and out. The VNA is able to analyse how the network behaves at various RF frequencies and provide information on how much power is transmitted through, or reflected back from the connections, without knowing exactly what is inside the network. So even though we don’t know what is in the network exactly, we can measure how it affects signals we pass through it. In our case we could be testing a cable, a filter or perhaps an antenna.
This ability makes it very useful measuring the performance of antennas to some degree and also checking our antenna cables are behaving nicely.
How does a VNA do this? It is essentially a transmitter and two receivers that allow the comparison of the transmitted signal and the received signal. There are some clever devices called directional couplers in it which allow it to measure the power in each direction, forward and reflected. Both amplitude and phase are measured, hence the “vector” in the name. There are other scalar network analysers that just look at the amplitudes but the VNA is more versatile and at this price why wouldn’t you?
The frequency range of this device is from 50kHz to 3GHz. Very good for a bargain-priced unit.
Note that I have the V2 (version 2) of the NanoVNA. The original did not have as wide a frequency range and was technically inferior to this later version.
Here is where you can purchase the NanoVNA V2 and support the developers. There are clones available on some websites that may be cheaper but quality and performance can vary.
https://nanorfe.com/nanovna-v2.html
https://www.tindie.com/products/hcxqsgroup/nanovna-v2/
When ordering make sure you get the cable and calibration kits with the unit. It is pretty useless without those. The unit does need to be calibrated whenever you change the frequency settings, but the process is quite painless.
I would also recommend getting some “connector savers” that screw onto the VNA ports. The SMA connectors used (in fact all connectors) have a finite life and each insertion/removal takes it a step closer to its limit. By fitting the connector saver adapters you can replace them when the connectors wear out, as replacing the VNA connectors which are soldered on is a much more serious task.
https://www.ebay.com.au/itm/5-x-SMA-fem ... 3094372441
These connectors are fitted permanently to the existing SMA connectors on the unit and left there until they are worn out.
There are some video tutorials for the NanoVNA on this site:
https://www.rtl-sdr.com/tag/nanovna-v2/
Here is a pic of the cables and calibration kit. There are short, open, through and load (50ohm) connectors in the cal kit.
The VNA comes with two PCAs. One is the main board and the other the touch-screen display. Note that as supplied you can run it off a USB cable directly, but if you want to use it without external power you need to provide a suitable battery. They don't ship batteries to keep the hassle of DG shipping LiPos out of the transaction. There is a connector for the battery and charging circuitry is inbuilt. Note that this unit can run standalone with a battery, or it can be run off a PC with the VNA controlled from there as well, and results are able to be exported.
It comes with a fairly basic plastic case (if you order it). It is a bit agricultural but it will protect the unit so I would suggest you get some sort of case from somewhere. It is convenient to order it when ordering the VNA.
I had a friend print a case on a FormLab 2 SLA printer. It came out very nice.
Note that there are a couple of LEDs that you need to be able to see somewhat. The translucent case makes that possible without having to drill holes in the case. The red LEDs indicate battery capacity.
When I get some more time I will do a demonstration of how it can be useful around the workshop in general and rocketry in particular.
Disclosure: I am posting this on both the US and Australian rocketry forums. This is sometimes considered bad manners, but I think everyone needs to find out about this device. Very useful if you do anything with RF.
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