Thank you for your kind comment ! Those things annoy me in other peoples videos. That and music which is too loud and irrelevant...

Hehe - you spotted my joke :-)

Glad it was helpful!

I agree with you. Antennas are very sensitive to surrounding objects ! I normally avoid using the 90 degree bend function. Problem also is that on a node in a bag, the antenna SMA connector comes unscrewed far too easily !

why? because you add 4dBm of inline loss most likely, VSWR does not equal efficiency, a good dummy load will have an VSWR of 1:1, and yet 0% efficiency as a radiator.

Thanks for the good advice. 73 !

Glad it helped. Meshtastic is certainly rekindling enthusiasm for experimentation and home brewing. Don't put it in the bin ! Cut it open and repurpose the parts or use it for experiments like I am doing with my rubbish antennas :-)

@@fotografm only the rubbish antenna bit went in the bin 😉 I kept the mount etc. The other thing was that the supplied coax was made with aluminium wire and so is unsolderable..(I needed to solder) . So was honestly awful. It was very cheap though! I usually make my own...that's the next job.

@@neilbchilton goodness me. Aluminium wire. That is really unpractical ! I extended a USB cable and discovered the same problem...

Have fun

That is a very good point. I calibrate my VNA before every test run just in case.

A video on calibrating a Nano-VNA for Meshtastic would be great 👍

well, the nano VNA is a toy compared a real VNA, it is enough to check if an antenna is badly detuned though. But the calibration is certainly not a "cheat" that is how any VNA works, it is only good for the range you calibrated it on, and calibration should always be done prior to the measurement and with the same setup, which is the most important point, that is, you use any extension cable out of the port, it must be calibrated at the end of this extension (and the cable should be compensated for), and if you use SMA to uFL then you need a calibration kit for uFL as well, because it would make zero sense to calibrate at the SMA connector and then do the mesurements with an SMA to uFL pigtail. There is also totally no point "saving" the calibration, it should be redone each time you change the connetion setup or power off. Anyway one point these DIY peoples really do not understand is that VSWR is only 1/3 of the picture, you can have an antenna with an extremely low VSWR and perfectly tuned, which is a terrible radiator and has very bad efficiency, which will make it worst than an mistuned antenna with high VSWR. And the only way to test correctly the efficiency of an antenna is with a proper VNA and an anechoic room, or at the very least a large shielded box.

Buying antennas has been a real lottery for me. Some of them seem to have really slack quality control with characteristics all over the place. Also some premade cables are better than others and I don't know how reproducibly accurate my VNA is. All this adds up to a wild goose chase bit it's fun !

LOL

Thank you for the info. I noticed that some antennas perform completely differently when hanging upside down ! There is also no groundplane of course apart from the coax feeder. Also, some antennas are manufactured as monopoles and some as dipoles or co-linear elements. It's a bit like antennas for handhelds. You can never guarantee how the user will hold the radio (if at all) and this has a huge effect on performance. I am also really hooked on Meshtastic as it reawakens that pioneering spirit of experimentation and being at the forefront of something new !

It's all a learning curve for me.

That is exactly what I planned to do next. I obtained a cable of reasonable quality to connect the distant antenna to vna port 2.

mmh, no, because this is not an appropriate tool nor setup to test an antenna efficiency.

@@lo2740 Oh you are right. He should just buy an anechoic chamber for a couple million dollars so he can do far-field tests like the pros... In the meanwhile, he can get a sense of near-field gain with a reasonable cable length. duh.

Exactly. It is a bit of a jungle at the moment. The only trend I can confirm is that the more money you pay for it, the more likely it is that the antenna will perform properly as expected.

Which unit are you referring to ?

@@fotografm the nanovna

At the moment I am not sure of anything as there seems to be a fair amount of misrepresentation with labelling and/or shipping of wrong products. The Amazon antenna I bought was coloured black on their webpage and was black when it arrived. There may be other versions however. I just ordered some more antennas that were only available in white !

@@fotografm I know where you're coming from. It's the only headache I am having over here in Portugal. I am looking for something like that one of yours on the wooden stand. I feel like taking the VNA with me to test them in the shops, but I can just imagine the faces of the shop owners lolol.

@@PortugalCarp I am surprised that walk in shops stock things like this. If so, I would definitely walk in there with my VNA and choose one that worked. Don't be shy - just do it !!! Here in the UK I only found them online so far which means you have no idea what you are buying until it arrives in the post....watch my next video where I measure some "identical" antennas 🙂

@@fotografm Thanks for the reply. Looking forwards to seeing your upcoming video.

Yes it is a 4.3 inch NanoVNA. I got it from Amazon (link below). I see that on Aliexpress they are available for around half the price if you don't mind waiting and risking that it could be a cheap fake version. www.amazon.co.uk/gp/product/B085CFHTBM

Deary me... ripoff Britain LOL