How to measure antenna tune | VNA, VSWR, S11

[@GhostRyderFPV]

While related, I have a left field question for you Sir. My fixed-wings are looking more and more like my quads - festooned with antennas, bristling like masts from sailing ships. My VTx typically has a pagoda, I use LFrSky 9R paddles, plus GPS sensors. My ELRS planes have a vertically oriented dipole, and of course all of them have FPV cameras, typically plopped up front and on top. I'll stick a Mobius mini under a wing sometimes, and run a Caddx Peanut behind the FPV camera on a short mount. How 'draggy' is all this tech we've added to our planes? Obviously there's a weight penalty, too, which must be, what... 50-100g for an FC and FPV? Should we be taking this more seriously? I know Lee over at Painless360 has a couple planes with a flush VTx antenna that seem to perform well, but I wonder if we should start thinking about efficiency in terms of drag, not just the size of our Li-Ions and motor/prop combos? Being worried about it, I've installed my L9R antennas internally in my newest build, a Dolphin, deep inside the foam fuselage in the plane's batter tunnel, but still perpendicular to each other. Along with the GPS sensor, it seems to be working fine tucked under the dense foam, but I wanted to know if you suggest against it?

[@porlockos]

No tak ale miernik VNA dla 5.2ghz to kosztuje fortunę, a jednak to by się przy FPV chciało mierzyć najbardziej.

[@biggfpv2721]

U should check out the nano vna. It is a complete vna for 120. I use it for my ham radio side of the hobby but a great tool it will do way more but great video

[@edivollgas719]

Is there a suggested device to reach above 5ghz for the fpv equipment ?

[@EnglishTurbines]

Very good, I doubt it works on 5.8G band though?....😏😏

[@53roger]

the specs say the range is : 34.375MHZ-2.7GHz

[@MrJT270567]

so I have this thing for a while now and make my own antennas for 868,915 and 2400mhz... always good antennas. but I still don't understand the s11 value... should it be as low as possible e.g. -20 or even -30??? how can I guess or calculate the db value of the antenna???

[@airhogfpv1283]

Cool, i wait so long for this video!

[@marioobermaier4406]

Just wanted to add that VSWR is calculated from the magnitude of S11 and for checking antennas both values can be used.

[@Onefgear]

Like always great video. I remember this one from some time ago. Good stuff.

[@MCsCreations]

Fascinating tool indeed! Thanks a bunch, Pawel! 😃 Stay safe there with your family! 🖖😊

[@adilsongoliveira]

Great video Pawel. I have this and the NanoVNA and took me quite a while to figure out how they work because, as you know, documentation goes from bad to non-existent. I would like to add one suggestion tough. Due to the simplicity of those devices, it's good practice to let it warm-up for a few minutes (say, 5) before using it.

[@SheltonDCruz]

very nice video

[@FPVUniversity]

Thanks

[@13FPV]

Take a look at the LiteVNA-64. Much more capable device for not a lot of money! It made me so much better in making and tuning my antennas!

[@CyberPilot360]

Only 30$ more and can measure up to 6ghz ! Very nice. Do you know if it can be used to measure tx transmission power?

[@13FPV]

@@CyberPilot360 No, it can't unfortunately.