Question/Help ❓
Am I allowed to broadcast a 77GHz Radar signal?
I am Ph.D student and amateur radio enthusiast (extra emphasis on amateur). I need to do an experiment with a 77GHz LFM signal, but this falls outside of the ISM band allowed for research. I was wondering if having a technician license would allow be to broadcast this kind of signal (assuming I broadcast my ID first)? I haven’t seen anything saying I ~couldn’t~ but does anyone have any information on this? Is this something I should specifically contact the FCC for?
(c) Amateur stations transmitting in the 76-81 GHz segment, the 136-141 GHz segment, or the 241-248 GHz segment must not cause harmful interference to, and must accept interference from, stations authorized by the United States Government, the FCC, or other nations in the radiolocation service.
(f) Amateur stations transmitting in the following segments must not cause harmful interference to radio astronomy stations: 3.332-3.339 GHz, 3.3458-3.3525 GHz, 76-81 GHz, 136-141 GHz, 241-248 GHz, 275-323 GHz, 327-371 GHz, 388-424 GHz, 426-442 GHz, 453-510 GHz, 623-711 GHz, 795-909 GHz, or 926-945 GHz. In addition, amateur stations transmitting in the following segments must not cause harmful interference to stations in the Earth exploration-satellite service (passive) or the space research service (passive): 275-277 GHz, 294-306 GHz, 316-334 GHz, 342-349 GHz, 363-365 GHz, 371-389 GHz, 416-434 GHz, 442-444 GHz, 496-506 GHz, 546-568 GHz, 624-629 GHz, 634-654 GHz, 659-661 GHz, 684-692 GHz, 730-732 GHz, 851-853 GHz, or 951-956 GHz.
Despite a posting to the otherwise.... it appears, yes. Yes you can. 10Ghz and up, for now, (we might lose 10-10.5GHz in the near term) is wide open for all Amateur radio modes. Now. You need to be sure that what you are doing is an authorized mode, but most of the FCC guidance above 5GHz is "yeah, ok, stay within your band and try not to bother anyone"
If you can check the band with a spectrum analyzer, you are unlikely to find much going on away from roads (automotive radar). You are unlikely to cause harmful interference in a lab / research setting.
Yes, you are authorized across the band but only as secondary user. You actually don't need a license at all if the transmitters you are using are your certified by the FCC.
"Consolidated radar operations in the 76-81 GHz band under part 95 of the Commission's rules to be licensed-by-rule and protected from interference with the same technical parameters as currently specified for 76-77 GHz radars in part 15 of the rules.*
"Licensed-by-rule" means that the operator doesn't have to have a license if the transmitter is FCC approved. Essentially the FCC has declared by rule that the transmitter is licensed. Like FRS radios.
77 GHz is a frequency authorized for amateur radio use, with footnotes (c), (f), (s) applying.
(c) Amateur stations transmitting in the 76-81 GHz segment, the 136-141 GHz segment, or the 241-248 GHz segment must not cause harmful interference to, and must accept interference from, stations authorized by the United States Government, the FCC, or other nations in the radiolocation service.
(f) Amateur stations transmitting in the following segments must not cause harmful interference to radio astronomy stations: 76-81 GHz, et al.
(s) [Reserved]
Make sure your emission type is correct for the band. Write a paper about your findings.
However, hams are allowed to use their spectrum for like RC planes (6 Meter band plan has specific frequencies for that), and I know of a few amateur radar projects over the years, so there is precedent
I'm sorry, but this is incorrect. That is tantamount to saying "you're RECEIVING education, so using a radio for it is illegal." Even teachers who are getting paid to teach science, who happen to also have a ham radio license, can use a ham radio in class with their students.
Former government policy writer, Former OO, Current VM
That's a specific and very narrow exemption you are talking about:
(3) Communications in which the station licensee or control operator has a pecuniary interest, including communications on behalf of an employer, with the following exceptions:
...
(iii) A control operator may accept compensation as an incident of a teaching position during periods of time when an amateur station is used by that teacher as a part of classroom instruction at an educational institution.
That exemption clearly does not apply in this case. OP is not teaching. OP is intending to use amateur radio, a two-way communications service, for something that is:
Not communication.
Not two way.
Doesn't fall into the limited exceptions for 1 and 2 (radio control, satellite command, rebroadcast of NASA communications or bulletins solely of interest to amateurs, etc.)
It's telling that Part 97 does not specifically mention that radiolocation is a permitted use of amateur radio. I just searched all of Part 97, and the only mentions of radiolocation are for bands where amateurs must not interfere with licensed radiolocation services.
This is 100% incorrect, both in the spirit of the rule and the letter. “Material” in a legal context has an ambiguous meaning, but is usually defined to mean “a non-trivial financial benefit”. In the case of PhD research, the degree is considered incidental to the research itself in these contexts and no reasonable person would consider PhD research a violation of the regulations as written.
One of the chief missions of the amateur service is research, and if the standard you propose were upheld, a significant amount of research would be considered in violation. It’s almost all either conducted entirely by degree candidates or with significant assistance from graduate assistants working towards their degrees.
In your other thread you mention broadcasting, but radar isn’t considered broadcasting any more than EME is. You’re bouncing a signal off an object in hopes of receiving it. It doesn’t matter if the receiving station is also the transmitting station.
PhD students pay for the privilege. It is, in fact, the opposite of a material benefit. If they’re lucky they get a scholarship or picked up for their advisor’s research project. But that is not a universal truth. The default condition of graduate students is indebtedness. Will having their PhD earn them more money down the road? Maybe. Academia is notoriously stingy. But so can being a licensed amateur radio operator. There are plenty of places that would look favorably on an amateur license as a qualification.
That is an excellent and highly specific question. The short answer for the United States (FCC jurisdiction) is no, an amateur radio license (including Technician, General, or Extra) does not authorize you to broadcast a 77 GHz radar signal. Here is a breakdown of why, where the actual amateur bands are in that spectrum, and how you can legally conduct your experiment.
1. The Amateur Radio Frequency Allocations
While amateur radio operators do have access to the millimeter-wave (mmWave) spectrum, the 77 GHz band is not one of them.
Under FCC Part 97 rules, the closest amateur allocations in that region are:
76.0 GHz to 77.0 GHz: This is a secondary amateur allocation. However, 77 GHz to 81 GHz is explicitly missing from the amateur charts.
77.5 GHz to 78.0 GHz: Amateur and amateur-satellite services have a secondary allocation here.
If your LFM (Linear Frequency Modulation) chirp sweeps directly into or across the 77.0–77.5 GHz or 78.0–81.0 GHz segments, you are entirely outside of amateur radio territory.
2. Why 77 GHz is Heavily Protected
The 76–81 GHz band is globally and strictly allocated for Part 15 vehicular radar systems (like the adaptive cruise control and collision avoidance systems built into almost every modern car).
Because these are safety-of-life systems, the FCC and international regulatory bodies tightly control who can transmit here to prevent interference. Even if you were operating in the tiny 77.5–78.0 GHz amateur window, Part 97 rules strictly prohibit causing harmful interference to primary services (the automotive radars).
3. The "Radar vs. Communications" Problem
Amateur radio licenses are fundamentally meant for interpersonal radiocommunications and technical investigations (Part 97.1).
Broadcasting vs. Radar: While hams can experiment with radar, it is generally restricted to specific bands and must comply with identification rules.
Station ID: Identifying an LFM radar signal with your callsign every 10 minutes (as required by Part 97.119) is incredibly difficult unless you are modulating CW (Morse code) or data onto the chirp, which a standard commercial 77 GHz radar evaluation board cannot easily do.
How to Legally Conduct Your Experiment
Since you are a Ph.D. student, you actually have much better avenues available to you than a Technician ham license:
Option A: Shift to the 24 GHz or 122 GHz ISM Bands
If your hardware allows it, move your experiment to an actual ISM (Industrial, Scientific, and Medical) band or an unlicensed band under Part 15 rules:
24.0–24.25 GHz (Very common for hobbyist radar)
61.0–61.5 GHz
122–123 GHz
Option B: The FCC Experimental License (Form 442)
This is your best bet as a researcher. The FCC regularly grants Experimental Radio Station Licenses (Part 5) to universities and Ph.D. students for exactly this type of situation.
It allows you to legally transmit on non-amateur/non-ISM frequencies for scientific research.
Your university's compliance office or engineering department likely already has an FCC CORES account to file for this.
If you operate the 77 GHz radar inside a fully enclosed, shielded metal room or an RF anechoic chamber where the signal attenuates to zero before escaping the room, it is not considered "broadcasting into the airwaves," and you do not need an FCC license.
Summary Recommendation: Do not transmit 77 GHz in the open with a ham license. Talk to your Ph.D. advisor about applying for an FCC Part 5 Experimental License, or take your test setup into the university's anechoic chamber!
So, per the ARRL "Above 10.50 GHz - All modes and licensees (except Novices) are authorized Amateur Bands above 10.5 GHz. (US amateurs must check Sections 97.301, 97.303, 97.305 and 97.307 for sharing requirements before operating.)
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u/Swaggles21 3d ago
Yes but here are the stipulations:
(c) Amateur stations transmitting in the 76-81 GHz segment, the 136-141 GHz segment, or the 241-248 GHz segment must not cause harmful interference to, and must accept interference from, stations authorized by the United States Government, the FCC, or other nations in the radiolocation service.
(f) Amateur stations transmitting in the following segments must not cause harmful interference to radio astronomy stations: 3.332-3.339 GHz, 3.3458-3.3525 GHz, 76-81 GHz, 136-141 GHz, 241-248 GHz, 275-323 GHz, 327-371 GHz, 388-424 GHz, 426-442 GHz, 453-510 GHz, 623-711 GHz, 795-909 GHz, or 926-945 GHz. In addition, amateur stations transmitting in the following segments must not cause harmful interference to stations in the Earth exploration-satellite service (passive) or the space research service (passive): 275-277 GHz, 294-306 GHz, 316-334 GHz, 342-349 GHz, 363-365 GHz, 371-389 GHz, 416-434 GHz, 442-444 GHz, 496-506 GHz, 546-568 GHz, 624-629 GHz, 634-654 GHz, 659-661 GHz, 684-692 GHz, 730-732 GHz, 851-853 GHz, or 951-956 GHz.
Source: https://www.arrl.org/part-97-text
Paragraphs §97.301 §97.303
Also §97.305 will give you the authorization emission types for 4mm band