Well, in fact this is just a very good but "short" video scratching the surface of antenna and RF theories. If you are interested in that stuff, you can buy a lot of books dealing with details of one or few antenna types or some aspects of antennas, and there is a whole engineering branch of study, just dealing with antennas and RF. I would recommend books (or even sets of books) like the "ARRL Antenna Book for Radio Communications" or alike (depending on your preferred language). It is a very interesting and fascinating subject, that was much more interesting (and understandable) when radios were just analog devices with coils, capacitors and a few transistors, as you easily and directly could *hear* and *see* the direct resulting differences inbetween different solutions. Computerization of radio receivers and it's complexity did make that whole stuff a lot more "black-box"-like and unfortunately makes it much harder to understand what is going on. So for the start I would recommend you to first go for radio stations on AM bands (long wave, up to short wave radio stations) or FM Radio stations, as there you get direct feedback on how good your antenna is working. Absoluteley not like with digital signal types like DVB, DAB, phones (GSM and later), WiFi and so on, where your usual receiver in best case will have some sort of very rough signal quality indicator. A good accesory for a HackRF also might be the Portapack case/display, that will give you the tool of "waterfall diagrams" showing the signal strength (as opposed to the "signal quality" which only shows some informations about the signal-to-noise ratio).
This is probably the best video I've seen on this topic. The storytelling, videomaking and information is top notch, congrats I'd just like to give my 2c on the topic of powering stuff without antennas. Sure, it is not ideal, but most modern systems will have some kind of protection to the backfeed or won't have enough power to cause significant damage, but I'd say it is a pretty hot debatable topic. Hope to see more from you!
Even if you do have a fair understanding of antenna and transmission line theory, your video still makes interesting viewing. I think you have made a very straightforward description of basic antenna types for anyone new to the subject.
Perfect explanation of the need for the proper antenna. I eventually found this out the hard way through a lot of trial and error and research online. Makes our radio hobby all the more exciting. Very good video. Thank you!
Yes. Many people today don't have the life skills of how to formulate what's in their head into written language and search engine-optimized query. Many don't know what they even want lol
Sn0ren deserves so many more subscribers. The quality of these videos are through the roof and the information is amazing. Also I love my NanoVNA, and I probably only use about 10% of its features.
This is a truly excellent video! It explains a lot of theory with RF communication that is often overlooked or assumed but is rarely explicitly taught! Thank you for such an informative video! :)
i knew nothing about rf and antennas now I know quite a bit! great explanation very well constructed video. thank you! now I will know which antenna to use with my UV K5(8)'s !
Sn0ren you always make the best videoes 🙂 Quick question, i use the Harris AN/PRC 152 in the Danish army, the same antenna is used from 30-512MHz, how is that possible?
There are many ways to make an antenna multi band. One way is to have more than one antenna in one, compacting several dipoles together. Another way is to have "traps" along the antenna, small passive filter circuits that cut off the antenna for signals of certain frequencies. Another way is to use bands that are multiples of each other, the ham radio bands are like this 2m, 4m, 6m, 10m, 20m, 40m - this way one antenna can be resonant on multiple bands. Another way, which is mostly common on the HF bands below 30 MHz, is to use an antenna matching circuit or antenna tuner. On HF there is more leeway to use non resonant antennas, as long as they are long antennas, but their impedance still needs to be matched to the radio. An antenna is like a load (think resistor) to the radio, and that load needs to be 50 ohms. If you have an end fed long wire or whip antenna, the impedance will be very high. A matching circuit such as a balun/unun, can bring down the impedance closer to the required 50 ohms. However even if you match the impedance with a tuner, it doesn't necessarily make the antenna good radiator - but it might be good enough. An antenna tuner can also do this, or work together with a matching circuit. Many radios for HF have built in antenna tuners. Also military radios are typically built to withstand high impedance mismatches, and can survive high SWR - unlike hobby radios. For every point I make in this video, there is a longer "well, actually.." answer ;)
Please 🙏🏻 make a step by step tutorial for the rabbit labs hack rf , I received mine a week ago I am a beginner please do a step by step out of the box tutorial for the rabbit lab hackrf 🙏🏻🙏🏻🙏🏻
0:33 I hate to be pedantic, but Iron actually makes for a poor antenna, especially at high frequencies, due to the conductor skin effect. Great video though!
Thanks!🙏 There are plenty of options for being pedantic as I’ve had to cut out a lot of details to not make the video too long for the beginners. I’m happy to have lots of great input as yours in the comments though 🙌
Thank you so much for making this video, I’m new to SDR and found this incredibly informative. I will be ordering a HackRF portable soon and will be scanning 1.4ghz to 1.8ghz. Can you recommend an Antenna that i can research please, i would be very grateful.
Amazing video as always. Thanks for sharing. Couple of questions: 1. How useful is to get a nanovna if I just want to receive. I was thinking to get one and design my own antenna for different frequencies reception 2. For receiving, can I just use a dipole (with lengths adjusted) for any frequency?
For receiving you can get away with eyeballing a dipole or ground plane in some approximate area of a frequency. If you want to build more complicated antennas like a yagi, it’s beneficial to have the NanoVNA even just for receiving to check that your design is working out correctly.
Some do and will throttle down the output if they detect a bad SWR. Some are just built more robustly and can take even a high amount of reflected power. But a lot aren't. It's all down to cost and most hobby radios expect you to know to check your SWR before transmitting 50-100 watts into an antenna. You get to buy the radio for a little less money or get other features instead.
Great all around explanation of the subject of antennas. Such a fascinating subject. 1/4 length antennas seem to be the most common, but wouldn't a full length antenna be the best option (at least for reception)? I'll have to look into the 5/8th approach to understand why it actually "flattens/strengthens the donut" rather than just degrade the transmission power from reflections. Now I want to make a measuring tape for my portapak telescopic antenna which shows the frequencies (instead of cm/inches) as that would be handy :-)
For some reason a full wave antenna is a really poor radiator when used for transmitting. I'm not sure of it's receiving capabilities. The mysterious theory of antennas crosses into physics which is a weird place.
@@sn0ren That's why I find it so fascinating, we think we have it all figured out and then the universe says "not so fast, I've got some more puzzles for you!"
Always a good idea to have the amp turned until you actually are in a situation where you need it. I haven't had a situation where I would need the transmit amp yet.
only had my flipper and this for a 2 weeks think I'm going to sell them find it hard getting any info on how to get the software even on mayhem site etc I know how to extract files all that but its a bit to much for me even with getting the dev board working on flipper 😢
I've built a Pwnagotchi. I've put an antenna on it that was 5dBi. I took off the 5dBi antenna & put on a 10dBi antenna. Both antenna are the same size but the 10dBi antenna appear to get a better signal. You explained that the same size antenna are the same. I don't understand then why I get a more powerful signal then. I'm new to this so I'm clueless.
If these antennas have a plastic shroud over them you don't really know what's inside without disassembling them. A lot of antennas use the same default plastic shroud, but have very different lengths of metal inside them. Some can be coiled, some can be stacked dipoles for increased gain... and some can just be marketing adding a few extra dBi's in the text and hoping that no one is the wiser.
Try as I might I cannot find a listing of what the frequency range is for the shipped antennas anywhere. I came here looking for that. Disappointed you didn't run through them.
@@sn0ren The authentic ones come with a set of antennas. Even the knock off clones come with almost identical ones. It's okay I found a guy who tested the knock off ones (watch?v=QZSs7vfO5cg) I don't have a VNA so I can't test mine but I can at least know what general area the antennas are in, I'm a noob so knowing which one to put on for what was kinda what I was after, yet sadly HackRF content is either for the painfully new beginner or the pro, there's nothing in the middle for the little finnicky things. :D Thank you for the reply though, I appreciate it!
There is no such thing as a set of authentic antennas. Every seller has their own idea of what antennas to include and the listing says what frequencies they are suitable for - but as I said in the video they are, at best, only for listening in these frequency areas. For transmitting always use a known resonant antenna.
Another excellent video! That lesson was not only concise and informative, it was well produced and interesting to boot! Love and appreciate all your content. Looking forward to more! Thanks!!
A little life hack for antennas that need a metal surface: I use cheap fan grills for PC cabinets. They also give some stability to the antenna, if you place them near a open window or outside. To begin with in my early SDR journey, I did not knew, that these antennas need a metal surface for ground plane. I was very happy when I found out, that a metal surface helped improving the signal just by using a left over fan grill.
I see some antennas have different frequency ranges for tx and rx. Does a nanovna show you ideal tx and rx frequencies for an antenna or just rx? Is it same to tx on any frequency registering below a 3 on the vna?
If they have a different rx range it’s usually just a guesstimated range that extends a bit beyond the tx range. NanoVNA shows you where you can tx with the antenna. You can also rx in the same range and beyond. It’s best to have an swr below 1.5 for tx.
@@sn0ren wow I wasn’t expecting a reply from you. Thanks. I do have a bit of a silly question in addition to my last one though. The numbers on the right hand side of the graph (like the 1.5 you mention) don’t seem to be shown in official documentation. Are they only available in certain firmware, and if not, do you know where the option to make the visible is? Thanks again.
@@sn0renNot anymore unfortunately. I just bought one of these because I'm interested in learning more, and there's a lot to learn here. I thought that SDR was able to receive digital broadcasts such as that.
