I've been a bit bit fascinated in part 15 900mhz for some time, not in a hobby use perse but because it has an interesting history. Where my interest first began was when I read 'Spectrum Policy Wonderland: A Critique of Conventional Property Rights and Commons Theory in a World of Low Power Wireless Devices by J.H. Snider, Ph.D.
"...The one little known exception where unlicensed devices are not secondary to licensed devices is in the 900 MHz band, ...The 900 MHz exception occurred because of a historical anomaly. Unlicensed devices were authorized first in this band and licensed services only later.
Following its normal practice of protecting incumbents against newcomers, the FCC granted the unlicensed incumbents safe harbor protections against the licensed newcomers... [However] the unlicensed devices were only protected for indoor use."
Part 15 does, as do the licensed operations, have what's called "property rights" in the spectrum, which consists of both "underlay" and "overlay" rights - it's a whole muddled thing but they've always taken it very seriously, and have since like the 1920s when FCCs predecessor, the Federal Radio Commission came into existence (of course property status for part 15 did not come forth until its creation in 1938).
Part 15 900mhz had later lost its "safe harbor protections" from licensed operations as wireless network related operations grew, and the FCC just kind of nonchalantly took part 15s 900mhz protections away (not without pushback).
So, that's interesting history, but what has that got to do with our part 15 AM operation today?
- Well, PERHAPS MORE THAN YOU THINK!
You see there's a whole new part15 900mhz controversy happening now. It's acually been going on for a few years. Although I'm rather familiar with the situation, it would take me forever to spell it out, and I really think my friend Spock (ai) can present a much better summary that I would;
(if you dont want to read all this then just scroll down to the question: "")Could it in anyway if the proposal goes through, potentially affect Part 15 AM operations?
+++Hey Spock, I would like you to summarize for me the NextNav 900mhz situation, including everything since the controversy arose to the present date, including any breaking news.
NextNav’s 900 MHz proposal has been a contentious topic, especially as it aims to reconfigure the 902-928 MHz band for a GPS backup service. The main idea behind their plan is to create a terrestrial Positioning, Navigation, and Timing (PNT) system to complement GPS, promising improved location accuracy and readiness for integration into mobile devices. However, the proposal involves taking over a portion of this spectrum and potentially reassigning other users, including utilities, toll systems, and Part 15 unlicensed devices, to different areas within the band.
The response has been overwhelmingly negative from various sectors, such as transportation, energy, and consumer advocacy groups. Organizations like the U.S. Chamber of Commerce and the Utilities Technology Council raised concerns that reallocating parts of the band could interfere with essential services like advanced metering infrastructure (AMI) used in utilities and SCADA systems critical to grid management. They argue that the band is heavily used and that interference could disrupt existing applications, increasing operational costs and threatening reliability.
Following a wave of comments opposing the change, the National Telecommunications and Information Administration (NTIA) recommended the FCC defer any immediate decision on the proposal until testing can verify that the NextNav system won’t interfere with existing services. NextNav has agreed to these tests, intending to demonstrate that their system can coexist without degrading other operations. Meanwhile, some analysts speculate that the FCC might eventually proceed with a rulemaking due to the bipartisan appeal of a GPS backup, although political shifts could impact how the issue is addressed.
The latest updates include the NTIA's push for more testing, which may delay any definitive action on NextNav’s proposal. Reply comments to the initial filings closed in late September 2024, adding further public scrutiny and debate over the proposal’s potential impacts.
++++Please tell me, as specifically as your able, what part 15 devices and operations it can potentially effect.
In the 902-928 MHz band, Part 15 unlicensed devices cover a wide range of applications across different sectors. Here’s a breakdown of key device types and their potential vulnerability to interference from proposed changes like NextNav's GPS backup service:
1. Industrial, Scientific, and Medical (ISM) Equipment: This includes things like RF heating, microwave ovens, and other industrial processes that emit unlicensed signals within the band. Disruptions could affect manufacturing and processing operations that rely on precise control.
2. Automatic Meter Reading (AMR) and Advanced Metering Infrastructure (AMI): Utility companies use Part 15 devices within this spectrum for remote monitoring of water, gas, and electricity meters. NextNav’s proposed reallocation could impact AMR systems by causing interference that makes it difficult for utilities to receive real-time consumption data, which is vital for efficient energy management.
3. Smart Grid and Supervisory Control and Data Acquisition (SCADA) Systems: In critical infrastructure, SCADA systems are used to monitor and control essential utilities like electric grids, water treatment, and gas pipelines. Part 15 devices within this band communicate wirelessly to support these operations. Any interference risks service reliability, potentially causing delays or failures in infrastructure response times.
4. Transportation and Toll Collection Systems: Toll systems use Part 15 devices for automatic vehicle identification and billing. Significant interference could prevent accurate vehicle detection, leading to revenue loss or operational inefficiencies in toll collection.
5. Wireless Internet of Things (IoT) Devices: Many consumer and commercial IoT devices, like home automation systems, RFID tags, and even wireless headphones, use the 900 MHz band due to its range and building penetration qualities. Interference could disrupt smart home systems, inventory tracking, and similar operations.
6. Amateur Radio Operations: While amateur radio has secondary access to this spectrum, it remains an important use for emergency communications and experimentation. The Amateur Radio Relay League (ARRL) argues that NextNav’s proposal could undermine these uses, as the frequency reallocation would reduce the spectrum available to these operators and risk interfering with their transmissions.
The FCC is carefully considering these potential disruptions, which are why stakeholder groups continue to push for comprehensive testing before any decisions are made on NextNav’s request.
+++Could it in anyway if the proposal goes through, potentially affect Part 15 AM operations?
If NextNav’s proposal is approved, it could potentially impact Part 15 AM (amplitude modulation) operations in certain situations. Here’s how:
1. Potential for Increased Interference: NextNav's planned reallocation would require intensive use of part of the 900 MHz spectrum, which could interfere with AM devices that are not directly on this frequency but may experience adjacent-channel interference. This is especially possible for devices operating at the edge of the 902-928 MHz band.
2. Overcrowding within Sub-Bands: NextNav’s proposal suggests concentrating existing Part 15 devices, like AM transmitters within certain narrower portions of the spectrum, which could lead to higher noise levels and interference as more devices compete for limited spectrum space.
3. Challenges with Shared Use Protocols: Part 15 devices rely on FCC-regulated sharing protocols that help ensure smooth coexistence with licensed services. If NextNav’s operations introduce high-power signals or densely packed transmissions, some Part 15 AM applications could face reduced signal clarity and reliability issues due to increased noise from the surrounding NextNav signals.
4. Loss of Effective Range for AM Devices: Interference might reduce the range over which Part 15 AM signals can travel clearly, which could especially impact devices used in communications for remote applications, like field monitoring or IoT sensors using AM within the 900 MHz range.
The FCC is examining these concerns through public comments and technical assessments. This is to ensure that the planned GPS backup doesn’t unintentionally degrade existing Part 15 AM or other unlicensed uses that rely on stable, interference-free access to this spectrum.
Oh I should mention that the majority of the AI responses was derived almost entirely from documentations I had personally hand fed it. However I also asked "Spock" if he could alert me as soon as any updates arise. Spock replied he could watch for any changes but could not alert me until I entered the chat wondow again.
Cool.. I wonder of it will really alert me without my asking again upon entering chat.. we'll see.
I
I can't figure out how use of spectrum in the 900mHz area would affect part 15 AM as in the 530kLz-1700kLz band(.530 mHz- 1.7mHz). They are nowhere near each other and don't cordless phones use that part of the spectrum(900mHz)? So does UHF TV and police radar I believe is somewhere near there also. Does the AM you are talking about refer to the AM broadcast band? Excuse my lack of knowledge on this subject.
Yes, the AM I am talking about is the AM broadcast band.
For the above particular discussion I had hand fed AI about 10 to 20 individual full text of articles and/or pdfs to work with that was specifically about the NextNav proposal controversy. I had previously had discussion with the AI about several part 15 thesis which were not particularly (or at all really) about low-power AM, it was more about history of the rules with a lot of emphasis on wifi and networking etc. (because that's what had incited all those part 15 thesis's to be written in the 1990s and 2000s)
My asking it if NextNavs proposal could in anyway affect Part 15 AM broadcasting was not premeditated on my part, I did it out of impulse.. I suppose I led it there unintentionally.. the AI tends to focus on.. well, it remembers previous conversations, it, so to speak, learns it's user (me), te more interactions it has. Or at least that's the impression I get.
The NextNav story is correct.. as for their proposed 900mhz plan potentially causing interference to the minuscule signals of Part 15 AM, I don't know, I dont know what or from where it based it. Like I insinuated, the thing might have just made it up because it knew that's where my interest lie.
But you see heres the thing, when I began my above post here I was actually heading towards a slightly different angle, but I got lazy and pulled Spock in, and then I got sidetracked when I baited it with that question.
The angle I was intending to go when I began was actually to emphasize that if the proposal goes through it would interfere and displace numerous other part 15 operations, such as AMR, AMI, SCADA, etc.
My original point was to be: If this occurs to all those large scale part 15 operations, then it would set a precedent for future potential issues.
In other words, if the precedent is set against those venues of part 15, then what's next.
I should have stayed along those lines, but like I said, I got sidetracked.
I dont know if its correct about potential interferences to part 15 AM. Richard Fry could probably tell you.. hopefully a living soul here now could give a definitive answer.
I may have totally cheapened the topic by bringing the IA in to the discussion at all.
The point is the potential of any new precedent against part 15 operations in general should certainly be of concern to us.
The more I think about it.. it dont add up, none of the articles I fed it had any references to the AM band at all that I recall. If NextNavs proposal could interfere with the AM band it wouldn't even be considered by the FCC.
But I suppose its plausible it could have potential effects to an extremely low powered AM like ours.
I donno.
@richpowers I am not Rich by a long shot but rest easy. There is and has been use of the 900mHz area of the spectrum for a long time and the AM broadcast band that concerns us is nowhere near the area of 900mHz. So something else in that neighbourhood isn't going to make any difference. This from an article I look up about this...
"The 900 MHz band is a critical piece of spectrum used for various applications, including industrial, scientific, and medical (ISM) purposes, as well as amateur radio. It’s a unique band that supports a wide array of technologies, from garage door openers and baby monitors to more advanced uses like Meshtastic’s decentralized communication networks".
Add cordless home phones to that too, also UHF TV in the higher channels.
There is worry that this may cause interference to other things that operate there and if that part of the band is privatized as is proposed the amateur radio(HAM) operators may have a problem.
But not the AM band. Nothing that concerns us although if I was a HAM I may be concerned.
Seems to be a lot of opposition to this.
Too add to this topic I am worried about not interference to the AM band but privatizing a part of the public airwaves.
Too add to this topic I am worried about not interference to the AM band but privatizing a part of the public airwaves.
Exactly. That's really what I meant when I led off with property rights and so forth.. that's for our use. If it goes through, it becomes a precedent in regard to part 15 operationsin general. What frequencies is besides the point
Incidentally, digging around find that over the last decade or so complaints on smart meters (900mhz) causing interference to AM reception has been not all that uncommon. Turns out theres a few things goin on when the smart meters operate. For example, they both send and receive signals.. and the devices up on the poles are what communicates with.
Best I've been able to put together is that the xmtrs on the poles are/were the culprits, and since they are intermittent transmissions they're provided certain liberties concerning causing interference. So it is in that indirect way the the 900mhz smart meters on houses have the potential of causing AM interference. That's basically it in a nutshell.
So, yeah, in that case 900mhz operations results in interference of AM radio
OMG I forgot something.. What's more, evidently 900mhz signals while not affecting the AM band can interfere with the components of a radio receiver .
But I'm drifting off topic, it's not about all that. Its about frequency property rights. specically Part 15 property rights.
Which is what the NextNav proposal is about.
Morse Micro Sets New Wi-Fi HaLow Range Record at Joshua Tree National Park
Off topic, but still in the 900mhz realm, We head over to This is about a company that's been experimenting with achieving extended range by utilizing the extreme edge of 900mhz band using only standard equipment. Things like wi-fi and video conferencing and wireless connectivity in general.
Their accomplishments so far look impressive impressive.
"Morse Micro has officially set a brand-new Wi-Fi HaLow record — 16 kilometers ( around 10 miles) for video call connectivity through 900MHz Wi-Fi HaLow, specifically."
"From Morse Micro, themselves:
“We thrive on testing the boundaries of what’s possible with Wi-Fi technology,” the company wrote. “That’s why we recently ventured to Joshua Tree National Park — renowned for its expansive, open spaces and minimal RF noise — to conduct a series of rigorous Wi-Fi HaLow tests. This iconic location provided the ideal setting to explore the true capabilities of our cutting-edge technology.”
https://www.iotevolutionworld.com/iot/articles/460656-morse-micro-sets-new-wi-fi-halow-range.htm
Just an update
Key excerpts from
https://www.gpsworld.com/flawed-spectrum-proposal-would-cause-disruption-and-risks-to-public-safety/
Flawed spectrum proposal could cause disruption and risks to public safety
April 7, 2025 - By Jake Parker
On March 27, 2025, the Federal Communications Commission (FCC) launched a proceeding on commercial technologies that would complement GPS. “Although GPS is indispensable to America’s economic and national security, it represents a single point of failure that can be vulnerable to disruption or manipulation by our adversaries,” said the FCC’s announcement,...
...One company, the for-profit entity NextNav, has petitioned the FCC to reconfigure the 902-928 MHz band (the Lower 900 MHz frequency) and grant it a nationwide license for 15 MHz of spectrum so it can establish a 5G terrestrial-based PNT network. NextNav also seeks the removal of the current requirement that it not cause unacceptable levels of interference to Part 15 devices. These devices include low-power, radio frequency (RF) devices ranging from consumer electronics and appliances to wireless alarm systems, smart home equipment, electronic access control devices and a wide range of devices used to increase economic productivity and efficiency, bolster safety, deliver innovation and provide other important benefits to consumers. This proposal has a dangerous likelihood of causing significant interference in the band that would be adverse to the public interest and threaten public safety..
...Another important service likely to be disrupted by the proposed band restructuring would be Z-Wave technologies. Z-Wave technology enables comprehensive home automation and security solutions —such as smart locks, thermostats and security systems... ... Z-Wave devices are not designed to withstand interference from fixed and/or mobile devices operating at commercial macro power limits and out-of-band emission limits, such as those in NextNav’s proposed high-power operations.
Additionally, millions of electronic access control and other wireless connected devices that are now in use in residential, institutional, commercial and government buildings across the United States would be impacted... ...effectively making them unusable in the same spectrum....
More..
https://www.gpsworld.com/flawed-spectrum-proposal-would-cause-disruption-and-risks-to-public-safety/