Dividendo digital = Spectrum dividend, digital dividend
Hello, students. Today I’m going to show you this inexpensive—not cheap, but inexpensive—spectrum analyzer. This is a very popular ___________ (1) among radio enthusiasts. It’s an amateur device, but it has many ___________ (2) that I’m sure you will find very useful.
It comes with a USB cable to use with the companion app. It also has some buttons: power buttons, a cursor, …it has a stylus—oh, not here. Where is it? Oh, I lost it. I’m going to use this ___________ (SORRY NO WORD, MY MISTAKE)(3) because it has a resistive touch ___________ (4).
How do you use this? Well, you have to plug in an antenna and choose your ___________ (5) frequencies. For example, if you want to analyse broadcast FM signals, you need to go to the frequency settings and pick a ___________ (6):
And this is the broadcast FM band. I have a very bad signal here, but you can see here a radio channel. I cannot do demodulation it with this device because that would require additional software.
It does have an audio jack, which I find mysterious, but I haven’t been able to demodulate radio signals (with it).
(…) So let me choose 95 MHz. You can see that this small mountain has become ___________ (7). I’m going to show you now several other services that you will find in the radio spectrum
For example, TETRA is used as a police and emergency services system. You may find some carriers at 395 MHz, so let’s set the center frequency to 395 MHz.
There it is—beautiful signal! I’m going to choose a different span. What is the span? The span is the bandwidth that the display ___________ (8) up. Oh another emergency service signal!
So, another different service. This is a child analog radio (*for children). So… yeah yeah yeah quiet. These radios are usually in the PMR (Public Mobile Radio) range at 446 MHz. So I’m going to:
If I press the push-to-talk button …here it is! Whoa! I think we need a wider span, so I’ll set it to 2 MHz. Beautiful carrier!
What ___________ (11) when a signal is not always visible, like intermittent signals? You can monitor them with this display functionality called “waterfall”. This is the frequency and this is the time.
So if I rock the button, you can see this red dot here. If I push it longer, the red line becomes longer, which means the signal is has been ___________ (12) than the other one.
Let’s see some mobile phone ___________ (13). First, 5G (Rural 5G). You can see it:
So this, this is 5G. While the spectrum is not very used but, if I show you, (…) these are the bands, so you can see that here we only have activity in the blue carrier which is Movistar Spain. This is ___________ (14) bandwidth. Since I live in a small town, there isn’t much activity here, and the three carriers available, these two have no activity at all. And this has strong activity, as you can see here.
Let’s see the 4G rural band which goes:
OK, this is the 4G spectrum. Once again, you can see the frequency ___________ (15) here. Notice that we only see the downlink, not the uplink, because the uplink depends on less powerful devices. The cell phone ___________ (16) are much more powerful than the cellphones.
Now yes, you can see three different carriers, you can see three different stains (* manchas) in the waterfall which are the three different carriers.
OK, now television! The classic digital video ___________ (17) service. Terrestrial television (DVB-T).
We have here eight channels called “multiplex”. Well, they have more or less the ___________ (18) power, about -70 dBm (mili-watt decibels).
One last service to see here, I’m interested in is Wi-Fi, so I go 2.4 GHz (from) and to 2.48 GHz. So, not much to see here, I see carriers jumping here and ___________ (19). These carriers are very ___________ (20), which means they are not Wi-Fi. These carriers are not from Wi-Fi. These carriers are probably from Zigbee, Thread, Bluetooth, any other service, not Wi-Fi because Wi-Fi channels are much wider.
I don’t see any Wi-Fi here because that would take up a lot of bandwidth.
I don’t think these signals are Bluetooth either, because Bluetooth does a lot of frequency hopping (*salto). Bluetooth is not staying in one channel.
And that has been it. Thank you for watching.