NanoVNA for Antenna Analysis

A short video showing a basic ability of a nanoVNA to display standing wave ratio (SWR) as measured through the reflection port CH0. Two antennas are analyzed, an 80m EFHW (end fed half wave) and a 40m dipole. There is a short discussion of the calibration procedure steps for an SWR measurement.

[@wild-radio7373]

Thank you for explaining this ♡ I am building an antenna and the price of the rig expert was really discouraging... I will have to try this nano VNA for sure!♡ 🤜🏻👍🤛🏻

[@RabbitHoleAdventures]

Thanks for the video!

[@Inkling777]

You passing mention of the Smith chart help me begin to understand that. You might want to do a video on it.

[@thom3124]

What about static charge on the antenna and feedline? I hope you took care of that before connecting your Nano VNA. It could be fried.

[@SergeantExtreme]

^^^^^ This. For those who are wondering what Thom is talking about, I highly suggest you watch this video here: kzbin.info/www/bejne/qqDXqKhqfseUrKc

[@Radiogenes]

Hello! When you travel across the swr curve with the left and right keys… is it to adjust the steps? For instance, i find that mine goes from 7050 to 7150 or so… Thank you

[@CaptainRadioAdventures]

The distance between steps depends upon the stimulus bandwidth. If you want small steps set the bandwidth to be small.

[@victorb22622]

You said to cut the length but it is not true,when you go left to tune there is rise and not dip ,so you have to increase the the lengh

[@CaptainRadioAdventures]

What I mean is you start out long - dip is the low side and start pruning (cutting) until the dip in the SWR is in the region desired.

[@barrywells9486]

Great explanation.. Thanks

[@stevegooch2356]

Question: Should I measure AT (+/- 10' away) from the antenna or where the transceiver connects? I get GREAT readings AT the antenna, and MUCH worse at end of coax where the transceiver connects. What am I doing wrong?

[@CaptainRadioAdventures]

The readings should not be that much different between "at" the antenna and 10-15 feet away. You could have a bad coax. Check your coax against a dummy load. It should read 50 ohms.

[@stevegooch2356]

@@CaptainRadioAdventures -Thanks! for closure, I found an issue with the remote antenna switch that was causing the difference!

[@brcisna]

Captain Radio Adventures, Thank You for this VNA explanation. Question. I am trying to increase the range of FPV on a new drone that was purchased. As it is now,,the FPV stops at only 125 meters. The drone itself have flown out to 1300 meters several times,,albeit line of sight,,,not good! Am wanting to piggback an rtlduino on back of drone to create a bridged wifi setup to the drones wifi,setup,,then another rtlduino on ground station,connecting to drone rtlduino,,to connect smartphone to,,with the drones proprietary app. The PROBLEM: From what i can understand these VNA will only go to a little over 3ghz. The drones fpv broadcasts on wifi 5.8 ghz,,,so if i bought one of these it really wouldnt do me any good for troubleshooting would it. Am very dumb on this stuff,,it goes without saying. Thanks again

[@CaptainRadioAdventures]

NanoVNA version 2 only goes up to 3 GHz so until the programmers increase the dynamic range to that which will cover the drone frequencies you don’t really have a choice that is affordable.

[@brcisna]

@@CaptainRadioAdventures Thank You much. .. May I ask,,,do you think if i was to piggyback an rtlduino,,which is essentially a 5.8 ghz repeater on top of drone,, with the pcb antenna built it,,it would mostly reflect back into the drone,,and not gain much,,or may be worse output (to ground) for smartphone receive? These arduinos do have pads to solder uaw?,,,for external antennas connect also. Thanks

[@CaptainRadioAdventures]

I am not a drone expert. I think your idea will work though at least in principle.

[@danidatasystemsindiapvt.lt9251]

How to measure/ calibrate SWR of a patch RFID antenna with frequency of 865 -867 Mhz

[@CaptainRadioAdventures]

Sorry I am not familiar enough with how RFID antennas are configured in terms of whether it has a port that a nanoVNA can connect to.

[@danidatasystemsindiapvt.lt9251]

@@CaptainRadioAdventures yes, a sms port is there to connect to nanovna. Can I send pictures of measurements to discuss the problem I am facing.

[@patrickdemeyer2210]

change the stimulus , you have to recalibrate.

[@chrisharmon1667]

Changed band and it was clearly out of calibration

[@SergeantExtreme]

Correct. Every single time you change a band on a NanoVNA, you need to recalibrate it. With NanoVNAs, remember this simple advice: calibrate early, calibrate often.

[@MrSabram07]

That's not true. You can just save calibrations