Antennengewinn dB dBi dBd einfach erklärt

Hello and welcome to this video. Yes, today I will present something to you: this antenna is two meters and 70 cm and this antenna has 28 dB of gain. 28 dB. This little antenna. How do I come to the conclusion that this antenna has 28 dB. gain you can find out in So stay tuned for this video, so of course it's not about this antenna, it's about the dB designation or gain of antennas in general, you read again and again about antennas from all kinds of manufacturers of antennas from all distributors. and especially from distributors that are not exactly the same here.

If you live in our area, I say now you are always reading dream values ​​from your hands, what is the information in dB, it's really cool, it corresponds approximately to 28 dB for this antenna, but are you even allowed to do that ? Yes, you are allowed to give DB information as you really want if it is true to the fact, but now we have the problem and that is something I am asked over and over again, often in my videos, what is the gain of the antenna , what is DB, what is DBI, what is DBD and that is exactly what I want to do.

I'm going to tackle it today, but in my usual, very relaxed, easy way, so that everyone can understand it without using mathematical formulas, without having any basic knowledge of physics, so let's start in the normal way with an antenna, a normal antenna, like a quarter lamp radiator or you can do that It's even easier a dipole a dipole you all know that an antenna that is fed in the middle and has a leg on the left and on the right, ideally of the same length, then we have a symmetrical dipole, this dipole already has an antenna gain of 2.15 DBI now we have the first term and that is exactly what I am going to get to now because the term DB always refers to a comparison, that is, compared to that and if now I say DBI, for example, then it refers to an isotropic spherical radiator.

Now we have a technical term, but simply an isotropic spherical radiator is a purely theoretical antenna, round, completely like an orange, like a tennis ball, like a soccer ball, just round, radiating evenly in all directions, up , down, right, left, forward, back, everywhere, and that is the isotropic spherical radiator and if I now build an antenna that has a greater output than this sphere, that is, than this isotropic spherical radiator, then of course , I can compare it. Now I take an example dipole and the dipole has a gain of 2.15 in comparison. to this sphere, i.e. 2.1 times or stay times and twice as strong, i.e. twice as strong as the isotropic spherical radiator, so the dipole has a gain of 2 dBi exactly 2.15 DBI, which means that the antenna is twice as strong as the DBI isotropic spherical radiator, which means that this All this information refers to the isotropic spherical socket, but there are also antennas that have a gain or a gain indication.

DBD, what does DBD mean? That is, once in relation to DB. DB always means in relation to and then at the back the designation. It is an i as in the isotropic spherical radiator or a D as with the dipole for example, if the dipole is also used as a comparison standard, it could well be that you see an antenna that has 2.1 DBI gain but at the same time it also gains 0 DBD, very logical because you probably have this 2.1. I hope it was not too complicated, so we start from the isotropic spherical radiator as i as the zero line, there is nothing that has the measure of all things and the other terms or profit information are based on this, everything I mean to DBI, so now you can see an antenna, for example it has one or one DPD gain or let's say two more DPD gains, that means that if now I express it in DBI I have to give this dividend the information refers to the dbd2dbd poles that means that The dipole already has two DBI, which would be four DBI.

I hope it is now somewhat clear what it is, so an antenna that is specified in dB can. See Google isotropic radiator, but may also refer to dipole. You don't know that, so try to find out what. If this gain is referred to DBD, then it will always have two more DBs than if it is referred to DBI. that is really the case or why, for example, an antenna has a gain of 7 DB or 7 DBI may simply be one of the isotropic spherical radiators. I just told you that the sphere radiates uniformly in all directions, so 0 0 the power that comes in goes out uniformly in all directions if now I use a directional antenna, for example a directional antenna that radiates in one direction, it is That is, everything that is in the sphere or when the ball radiates to the right, to the left, back, up and down, is grouped here and sent forward, that is, in a direction like a through a pipe, it is sent to Wallachia, that is, into the atmosphere here in the area.

So this power is sent there and therefore now all the power is directed to one point. Of course, you can also have all the power in one direction and in this direction, and only in this direction does this directional antenna have gain. I'll just say yes, 7 DBI, that means 7 DBI more than this ball, but like me. Said only in the direction it radiates, the dipole has two preferred directions once to the left once to the right, so if the dipole stretches from my nose to yours now like this, then it radiates from right to left of top to bottom, like a donut I put there and exactly in this direction it has 2.1 DBI that means it's twice as strong yeah why just because the direction towards you and the direction towards you It doesn't radiate as strong for me, it goes towards the right and left and that's why it wins, but now back to the point, why did I just say that this antenna has a gain of 28 dB? 28 dB, do you know how many levels that is?

I'll get to that. Also, stay tuned because that's Now the next topic, how much does this antenna really have? Attention, I estimate a gain of 28 dB. I just said that DB is always comparative information. I didn't say DBI, I didn't say DPD either. I am not referring to the spherical isopropyl radiator, nor am I referring to the dipole, I am simply saying that this antenna has, for example, 28 DB of gain compared to this cup of coffee, that may be the case. , then I can give this information, I have not decided with what or what I already have with what I compare this antenna with where I get this time in dB, I only said that it has a gain of 28 dB, it could well be that it has a gain of 28 dB compared to this cup of coffee, but now at least you know where that or other information about the antenna gain comes from, but if I already have the cup then I will just take a sip because my mouth won't be so dry from talking and I always talk a lot like that and now we will do one more thing and what does that mean for this gain if, for example, now I have an antenna, I have a completely normal one? antenna, it doesn't matter which one, and now with zero gain I just say the normal zero gain and now I take an antenna with six DB gains compared to this antenna So as I said, I need one antenna as a measure and I compare the other one and it has a gain of 6 dB compared to it.

Let's continue with the isotropic spherical radiator, yes zero, I have an antenna that has a gain of 6 DBI, what does that say now? I have a stronger s level so I have a stronger signal level on my other station's smeter when everything is going well and everything is normal and purely theoretically everything is just theory because there are a lot of things involved. It may be a. first and a half level But it could also be that you only have half a level, but in terms of the value of the signal, it would normally have to gain 6 dB, so to achieve this level with my original antenna, I would have to quadruple the power, which means that now we have three things next to each other and the s level is equal to four times the power, it is equal to 6 dB, that means that if someone tells you, just 6 dB less power, then you have to reduce the power. for a quarter or for three quarters, that's just a quarter.

That means it's exactly the same the other way around if I send with 25 watts from my normal transiver and I would like to have one more level S on my remote station, as always with one of you, then I have to regulate it from 25 watts to 100 watts I have this gain of 6 dB and now everything comes and that is why antennas that make a little more gain are so interesting because then you can keep the 25 watts if you can use an antenna that generates a gain of 4 dB four times greater than the winner 6 dB, so it's the same as quadrupling the performance and that's why these gain figures make a lot of sense if used correctly DBI is the measure of all things, that's what all the measurements generally refer to. antennas, but if your DBI is there then it could also be something else you are referring to and dealers and manufacturers are very flexible about what they are referring to, you can also refer to no antenna, so antenna is twice better than none, so three DB wins people, that's still 3 dB is just double, four times as much, it's 6 dB, so that's it, so it's all about.

I will repeat it. Again, very briefly, everything refers to the isotrophic spherical radiator as the measure of all things, everything that is stronger. As this isotropic trigger is calculated in the DBI ratio, the radiation is twice as strong, so if only half of the triggers did If you were blind, only half would be blind, so you would have twice the power here, so you would have gained two DBI here, more or less like. By the way, with the dipole there is also a table and I will show it to you. , but I'll open it up very briefly so you can see, that's something like that and there are the individual designs, for example, the isotropic spherical radiator here is minus 0.215 DBD, that's what I just explained, no.

DBD has yes, the dipole has 2.1 times more, so the isotropic spherical radiator of course has minus -2 DB, the dipole then has plus two DBI and and and then I will show you this table and since there are others, they are Moxon . antennas on the bottom, all kinds of things and there it says the antenna construction curtain, so the approximate shape of the belly and then on the back it says how many DB DBI DBD are accepted and how do you say, this is all purely mathematical in the theoretical sense. values ​​and but it helps if you see here that an antenna is a normal half dipole lamp of the heart dipole has much less but the lambd of the half dipole has a gain of 2.1 DBI and if for example if someone on the Internet wants to sell you a half lambda dipole for win with cntb, then you know something isn't that strange, it usually has the B in there and most likely refers to a broom handle or a car tire or something else, you know, well, like I said that was , generally speaking, DBI DBD db antenna gain power and s stage and I hope you understand it now, at least I could explain it in a way that everyone would understand.

I tried to do that if that doesn't work. Write it in the comments, then I will specifically address what was not understood in the comment and then we will get rid of the misunderstanding or lack of understanding. That's not as difficult as it seems. I hope it is useful for you. It was fun. If so, give me another thumbs up and I hope we see each other again in the next video in this spirit but the h73 here was Delta Lima 8 my hotel