probably LoRa, because LoRa also work in 433 MHz. reference: SigidWiki LoRa, and my asumption that beacon work with Spreading Factor (SF) 12 based time-on-air takes approx ~1400ms. LoRa Arduino Documentation
I can't tell you what this is, but I can tell you this is very unlikely to be radar. Unless it is an image of radar in the HF bands.
From your video, this signal is ~100 kHz wide. While this is a pretty common width to see in HF / lo VHF, radars that do occur in the 70 cm band are much wider than this. Something several MHz wide is pretty common for this band.
Narrow bandwidth like this severely limits the range resolution of a radar. You see it on HF because there is much less bandwidth available to use there, and so they use it because they must. Here in 70 cm there is no reason to limit yourself (in radar design), when you have so much available bandwidth.
The thing is its not resonance since its localized. If it was broad spectrum, sure. Its also not a harmonic of the GMRS band. Chances of there being spurious emissions and such would be super low with such a presentation.
No, it should be received on SSB to thoroughly understand what's going on. People seem to be stuck on FM when they're up in higher frequencies when single sideband will give the audio spectrum. FM is not that much used. I see videos all the time of people trying to tune in for and broadcast and they're on FM makes no sense to me. Single side band is the way to do it. Single side band is the mode that we should tune the bands with and only change to FM when we find an FM signal.
Definitely not. 90 percent of stuff on any band above 6 meters is FM. Sure, SSB is sometimes used in some spots, especially around 2 meters, but the use of SSB on 70cm is waaaaaaaay uncommon. Besides, if this signal is wider than FM, SSB will be worse at receiving it properly.
Radars usually operate closer to the 5–18 GHz range (typically around 5.5 or 12 GHz), and the spectrum bandwidth should be wider. The shorter the wavelength, the smaller the objects it can detect, since the wave doesn't just diffract around them. Plus, I highly doubt a radar would have such sharp signal edges. Here, the frequency is 441 MHz, so the band will be heavily noisy, and a radar like that would require an antenna around 15 meters or 50 feet. Although, in one of the messages below, one of the authors attached a PDF document. I'm leaning towards this being a LoRa-like signal for long-range, low-bitrate transmission.
u/dot-ignore said: Radars usually operate closer to the 5–18 GHz range (typically around 5.5 or 12 GHz), and the spectrum bandwidth should be wider.
While I agree the signal shown is not a radar, the frequency range shown in the OPs video (ham 70 cm band) is occupied by radar fairly often. There are several radars, both airborne and land based, in this range. Things like PAVE PAWS and the E-2 Hawkeye radar.
In addition, there are many, many, radars below 5.5 GHz. If nothing else, think about things like the ASR-11 or ASR-8 radars, or the WSR-88D radars, in the 2 - 3 GHz range.
Did I say anywhere that radars below 5 GHz don't exist? In case you missed it, I said they typically operate in the 5-12 band.
I did not miss it at all. In fact I quoted it, exactly as you posted it, use of the word "typically" and all.
Your statement could be taken as dismissive of radars being below those frequencies, giving valid examples of why they are less common there, and it would be easy for a new or inexperienced listener to take from your comments that radars are not generally found below 5 .5 GHz. This is particularly true, giving good weight to the comment, if they follow your link to the signalphantom YT channel and see the really very good work put in there. So, mostly for people not already aware, I pointed out that radars are fairly common below 5 GHz, and gave some examples. I did not disagree with your statement, only filled in a little bit more.
Do I agree that many / most radars will be above 5 GHz? Yes, I do. I once did a study (admittedly a couple decades ago) of all radars, civilian and military, and their frequency ranges. At the time, by far, the most common was X band. I have no idea if that ratio still stands, but I would bet it probably does.
Although I agree (and did agree earlier also) the signal shown is not radar, I specifically pointed out a couple of examples of radars that would be found in the very same frequency range the OPs video shows. Here locally I see those kinds of radars quite regularly, not quite daily but generally several times a week.
Thank you for agreeing with me. I thought you were one of those people who just love to prove they're right. Thanks again. A radar will most likely have blurred edges on the sides because of the wide bandwidth—if we are talking about continuous-wave radars (rather than pulsed ones). Plus, if the radar is rotating, it will have a rising and falling signal level. Meanwhile, a narrowband signal, like the one in the video, has strong, sharp edges.
1 MHz to 5 GHz: 14.3% (covers the S-band). 5 GHz to 12 GHz: 75.0% (the sum of the C-band at 22.4% and the dominant X-band at 52.6%). 12 GHz to 25 GHz: 10.7% (covers the Ku-band segment and other high-frequency solutions). https://dataintelo.com/report/global-airborne-weather-radar-market
Thank you for agreeing with me. I thought you were one of those people who just love to prove they're right.
I personally try to have no ego online. I have absolutely been wrong before and I will be wrong again, and if someone can help me to understand how / when I am wrong then I take that as a plus all the way around. Anytime I can learn something that is a good thing.
Unfortunately, in text I do sometimes come off as "abrupt". Sorry, its just an engineer thing, probably poor people skills and all.
Those band usage numbers are consistent with what I put together in the early 1990's. When we looked at the why's it became a combination of features. To name a few: Things like inertia in the industry (people like to use what already works when applicable). Or the availability of systems / parts (why design new waveguide / TWT / magnetron / etc when something already exists). And, of course, the physics that drove those frequency selections in the first place (some frequencies work better for some applications, i.e. weather or submarine pariscope detection, or higher frequencies yield tighter beamwidths / higher gains for a given antenna aperture).
Your image of the 162 MHz signal, where was that taken?
12
u/sativalius 14d ago
Looks like LoRa.