> In 2007, the SOSS was retired for the newest and current system of the PRSS, the ContentDepot. The ContentDepot no longer uses linear feeds of SCPC-based digital audio bitstreams like the SOSS. Instead, it uses a dedicated TCP/IP-based one-way connection uplinked via satellite from PRSS, which is received by a storage receiver (a combination satellite data receiver & file server) manufactured by International Datacasting [5]. Program feeds are requested and set up at a special internet-accessible web site (known as the ContentDepot Portal) that member stations can log on to, where they can subscribe to specific programs and live feeds. The subscribed programs are then delivered via satellite as a file transfer to the storage receiver in the form of MP2-encoded ACM-based WAV files, which then can be imported into a station's automation and/or playback system.
> Live feeds are sent in the ContentDepot system as streaming MP2 audio, sent over the same satellite transponder, but as an IP multicast stream (as opposed to a file transfer for pre-recorded programs) which is decoded by a special streaming audio receiver (called a stream decoder) set to the IP multicast addresses assigned for live audio streams on the satellite transponder used by ContentDepot.
> The newest generation of ContentDepot hardware for the PRSS, as of 2014 and also manufactured by International Datacasting, is a special version custom-manufactured for PRSS of their commercially available "Superflex Pro Audio" receiver. It combines both the stream decoder for live programming and storage receiver for pre-recorded programming in one rack-mounted system, in previous comparison to separate units for live decoding and program storage respectively with the introduction of ContentDepot.
> Some components of the previous SOSS still are in use in the ContentDepot era: one of the ABR-700 demods (as well as the downconverter) is still used by NPR as a "squawk box" for verbal announcements regarding programming to NPR stations
In the case where you don't expect a response, you can still rely on the rudimentary error checking of TCP (checksum and sequence numbers) to detect when damaged or dropped - but this smells like a custom implementation of the protocol.
Good catch, I think the article needs a fix. As I read it, at the edges, everything is TCP/IP. Over satellite, IP multicast (UDP) is used for live audio, and unidirectional file broadcast (using a proprietary protocol with inline forward error correction) for program files.
Note that the CPB probably won't exist anymore in three years, for next renewal.
And because of congressional action not executive, so probably legal.
> The Corporation for Public Broadcasting, the conduit for federal funds to NPR and PBS, announced on Friday that it is beginning to wind down its operations given President Trump has signed a law clawing back $1.1 billion in funding for public broadcasting through fiscal year 2027.
> The announcement follows a largely party-line vote last month that approved the cuts to public broadcasting as part of a $9 billion rescissions package requested by the White House that also included cuts to foreign aid. While public media officials had held a glimmer of hope that lawmakers would restore some of the money for the following budget year, the Senate Appropriations Committee declined to do that on Thursday.
Call me ignorant but isn't it drastically cheaper to run an internet radio station? Then let others, including other radio stations repeat your internet stream over radio. I'm genuinely curious.
A major reason for the enduring use of satellite in radio distribution is that, for live events like sports or (more common in NPR's case) political events, the satellite system provides appreciably lower latency than distribution over the internet. Reduced jitter also allows for generally higher reliability, you never hear the radio station buffering. There are options for low-latency land-based connectivity but at the scale of PRSS, the satellite system is cheaper to operate.
Most stations can also receive this programming over the internet, another reason for the satellite system is that it provides a completely redundant path for programming delivery. This is important for general reliability but especially so in an emergency.
Historically, radio networks distributed their programming over leased telephone lines. Satellite took over because it was cheaper. That gap has probably narrowed as terrestrial communications infrastructure continues to expand, but the internet struggles with low-latency real-time media, and an arrangement like leased fiber wavelengths to member stations would still be more expensive than the satellite system. There's a lot of member stations in a lot of places, satellite reaches all of them at once.
> the satellite system provides appreciably lower latency than distribution over the internet
Is that true? Round trip to/from geostationary satellites is about 240ms.
And, with most stations using HD encoding, which adds 8 seconds to the transmission delay, any network latency isn't going to be that important anyway.
It’s not about the latency between when words are spoken and when they’re heard, it’s snot when a packet is sent and when it’s received. There’s a lot of jitter and you really don’t want intermittent drops to cause people to miss parts of your programming.
The justification for many of these stations is emergency preparedness. They're maintained for the ability to receive and transmit emergency alerts despite power outages or transmission line cuts. The daily programming is mostly incidental beyond maintaining listenership
Same reason communities still maintain HAM radio clubs and rely on them for emergency communications in a grid down situation - it's an interesting (though expensive) hobby that has some merit for isolated communities.
People don't maintain HAM clubs for the potential use in an emergency, any more than people learn to fly in the hope of being able to rescue a commercial aircraft when both pilots are incapacitated.
They enjoy HAM radio as a hobby in and of it's self. It's doesn't come free to the government either, I'm sure some HFT organisation would pay handsomely for some of the bands currently used by HAM radio.
The cost is having the satellite systems in place, working, and available. You don't save money by not using the tiny amount of bandwidth when it isn't "an emergency"
The burden on taxpayers would be significantly less if the government simply paid to run the system rather than additionally funding two sets of attorneys to duke it out in court to make an out of control executive actually execute the law. It's getting harder and harder to believe that this fascist movement was ever earnestly about saving money.
It doesn't look like the Federal Government is being erased. In fact, it and its debt are rapidly growing. I'd say the motte is autocratic authoritarianism (ie fascism).
The US is pretty large, and has large areas without reliable cellular or wired Internet connections. Public radio ensures accessibility in those areas.
I wonder if we should just pass a bill that requires Starlink or Amazon Leo to use 0.5% of their bandwidth for low quality (but higher than radio) free access to Inet Radio streams in some special way. Then start building out the infra in vehicles.
There are plenty of places in the US that don't have reliable satellite access either (not because of orbital coverage, but because of geographic features like mountains/deep valleys).
(And these aren't remote/unpopulated areas: you can find plenty of satellite dead zones 2-3 hours outside of NYC in the Catskills.)
> because of geographic features like mountains/deep valleys
I remember this being quite an issue trying to target geosync broadcast satellites like DirectTV/Dish. Even being in the shadow of a relatively small hill could block access if your location and local topology happened to create an unfortunate alignment. I've naively assumed Starlink's rotating constellation of thousands of LEO satellites reduces how often this is an issue - but maybe it doesn't?
Starlink has other issues. I have locations in London I can get to specific geostationary satellites, but can't use starlink there as there isn't much sky coverage
Honestly curious: how many of those satellite dead-zones have good radio coverage? In my various times driving places, I've often lost radio signal in a sufficiently remote place where I 100% would have had satellite coverage. Those same features that can block satellite will also block (some kinds of) radio, if you don't have a broadcast tower at the top of the ridge or something.
Yes, I agree that satellite coverage is not 100%. But neither is radio.
I think the idea is that the sats relay a signal to radio stations including remote ones.
It's the radio stations who are in charge of situating their reception equipment where it can see the sat, and also for figuring out how to best broadcast to their served area (e.g. AM and/or FM? Tower height, power, setting up some translator stations on a different frequency to serve outlying areas, giving the feed to local cable systems to be sent with TV service, etc.)
It's definitely a mixed bag, but the areas I'm thinking of have decent FM radio coverage (from local stations that affiliate with public radio). AM coverage tends to be good regardless.
I've had the same experience as you around remote places, but those places were generally the flat-and-desolate kind :-)
What happens when a major CDN goes out? Or, god forbid, a major datacenter region has a DNS blip that apparently 1/3 of the internet depends on?
Or, what if a hurricane or ice storm knocks out some internet connectivity? That would be a time when you really want to broadcast a message to anyone with a cheap fm/am radio.
Is affected by? No idea, but I'm sure there's some cloudflare rep convincing you that you need cloudflare to make sure your high-availability stream stays highly available when just yesterday azure got a ddos measured with Tbs. Just not today... today those cloudflare reps happen to be busy.
Point is, radio comms serve a public utility that often is a Plan-B if internet links go down. Multicast it onto your podcatcher of choice, sure, but don't make that your backbone.
The stations that rely on CPB funding as a main source of income are the "others" who repeat the NPR content over the radio. They're tiny stations (typically 1-2 full-time employees) that mainly serve communities where internet streaming is not a viable option due to spotty cell coverage.
Also, receiving internet service requires some kind of paid monthly plan. The cheapest plans have very low data caps. Streaming audio over them is much less practical for the end users than having a simple radio receiver. Radio waves also propagate further than cell broadcasts.
The OP here, in their defense, wasn't talking about just operating an internet radio to replace public broadcasting and telling listeners to just get a data planpay for Internet and go online to listen. They were suggesting TCP/IP backhaul to get the signals to the remote radio stations, and rebroadcasting on the radio.
Presumably this would be feasible for most populated areas, but broadband availability is so crap outside of urban/suburban, I bet half of those really remote stations are already getting their Internet over Starlink or Hughesnet.
Now, I think there are plenty of reasons that the satellites (which are already in the sky, presumably) are probably more robust in the face of emergencies than the entire Internet infrastructure.
If I may steelman a good counterargument: "The Internet itself is supposed to be resilient to nuclear war!"
True, but that doesn't mean outages of critical pinch points like AWS, Azure and Cloudflare don't constantly affect even services like GitHub that have huge budgets. A fully robust Internet solution with a ton of high-uptime redundancy in many POPs nationwide would likely cost more than maintaining the satellite systems.
I'm curious too. As a complete outsider to that problem space, it seems like a lot of the tech was designed/created in an era before wide-spread broadband and internet-based content distribution. I'm sure a lot of it is simply that new hardware from that vendor is largely a drop-in replacement for each station, so there's no need to re-engineer their broadcast booth.
...
I guess HN is the new Reddit. Downvotes, not a single response. You can do better, HN.
Some equipment is drop in - hooking up an audio output to a keyed radio is only occasionally difficult. You see a lot of these solutions in the HAM radio space.
The actual radio equipment is a tad more sophisticated - and in poor areas (where it's barely hanging on) is held together with spit, glue, and prayers (exaggeration, joke, but aspects of it are true).
Believe it or not, the RF cables are (in many cases) more expensive than the radios themselves.
Background: Computer systems, radio systems, General class HAM, but certainly not an expert.
As someone who grew up hearing pledge drives every few months on (ad-free) Christian radio: Would that be an option to fund NPR? Surely those who want to listen/watch/support would donate regularly.
Half of NPR's revenue comes from payments from stations to run their programs, and most of the rest comes from individuals, businesses, and foundations. Those public radio stations are also mostly funded by listeners and donors.
Also, this isn't relevant anyway, because the article is about a dispute about a particular program that NPR was running.
The system in question is actually pretty interesting from a tech standpoint;
https://en.wikipedia.org/wiki/Public_Radio_Satellite_System
> In 2007, the SOSS was retired for the newest and current system of the PRSS, the ContentDepot. The ContentDepot no longer uses linear feeds of SCPC-based digital audio bitstreams like the SOSS. Instead, it uses a dedicated TCP/IP-based one-way connection uplinked via satellite from PRSS, which is received by a storage receiver (a combination satellite data receiver & file server) manufactured by International Datacasting [5]. Program feeds are requested and set up at a special internet-accessible web site (known as the ContentDepot Portal) that member stations can log on to, where they can subscribe to specific programs and live feeds. The subscribed programs are then delivered via satellite as a file transfer to the storage receiver in the form of MP2-encoded ACM-based WAV files, which then can be imported into a station's automation and/or playback system.
> Live feeds are sent in the ContentDepot system as streaming MP2 audio, sent over the same satellite transponder, but as an IP multicast stream (as opposed to a file transfer for pre-recorded programs) which is decoded by a special streaming audio receiver (called a stream decoder) set to the IP multicast addresses assigned for live audio streams on the satellite transponder used by ContentDepot.
> The newest generation of ContentDepot hardware for the PRSS, as of 2014 and also manufactured by International Datacasting, is a special version custom-manufactured for PRSS of their commercially available "Superflex Pro Audio" receiver. It combines both the stream decoder for live programming and storage receiver for pre-recorded programming in one rack-mounted system, in previous comparison to separate units for live decoding and program storage respectively with the introduction of ContentDepot.
> Some components of the previous SOSS still are in use in the ContentDepot era: one of the ABR-700 demods (as well as the downconverter) is still used by NPR as a "squawk box" for verbal announcements regarding programming to NPR stations
> TCP/IP-based one-way
What would it mean to have one-way communication over TCP? Don't you need to send the acknowledgements back?
Normally, yes.
In the case where you don't expect a response, you can still rely on the rudimentary error checking of TCP (checksum and sequence numbers) to detect when damaged or dropped - but this smells like a custom implementation of the protocol.
But this is a scientific wild ass guess.
> What would it mean to have one-way communication over TCP? Don't you need to send the acknowledgements back?
https://en.wikipedia.org/wiki/Multicast ?
https://en.wikipedia.org/wiki/Broadcasting_(networking)
IP multicast/broadcast does not use TCP.
Good catch, I think the article needs a fix. As I read it, at the edges, everything is TCP/IP. Over satellite, IP multicast (UDP) is used for live audio, and unidirectional file broadcast (using a proprietary protocol with inline forward error correction) for program files.
Note that the CPB probably won't exist anymore in three years, for next renewal.
And because of congressional action not executive, so probably legal.
> The Corporation for Public Broadcasting, the conduit for federal funds to NPR and PBS, announced on Friday that it is beginning to wind down its operations given President Trump has signed a law clawing back $1.1 billion in funding for public broadcasting through fiscal year 2027.
> The announcement follows a largely party-line vote last month that approved the cuts to public broadcasting as part of a $9 billion rescissions package requested by the White House that also included cuts to foreign aid. While public media officials had held a glimmer of hope that lawmakers would restore some of the money for the following budget year, the Senate Appropriations Committee declined to do that on Thursday.
https://www.npr.org/2025/08/01/nx-s1-5489808/cpb-shut-down-p...
Let’s hope the midterms changes enough of Congress to make it more sensible.
Call me ignorant but isn't it drastically cheaper to run an internet radio station? Then let others, including other radio stations repeat your internet stream over radio. I'm genuinely curious.
A major reason for the enduring use of satellite in radio distribution is that, for live events like sports or (more common in NPR's case) political events, the satellite system provides appreciably lower latency than distribution over the internet. Reduced jitter also allows for generally higher reliability, you never hear the radio station buffering. There are options for low-latency land-based connectivity but at the scale of PRSS, the satellite system is cheaper to operate.
Most stations can also receive this programming over the internet, another reason for the satellite system is that it provides a completely redundant path for programming delivery. This is important for general reliability but especially so in an emergency.
Historically, radio networks distributed their programming over leased telephone lines. Satellite took over because it was cheaper. That gap has probably narrowed as terrestrial communications infrastructure continues to expand, but the internet struggles with low-latency real-time media, and an arrangement like leased fiber wavelengths to member stations would still be more expensive than the satellite system. There's a lot of member stations in a lot of places, satellite reaches all of them at once.
> the satellite system provides appreciably lower latency than distribution over the internet
Is that true? Round trip to/from geostationary satellites is about 240ms.
And, with most stations using HD encoding, which adds 8 seconds to the transmission delay, any network latency isn't going to be that important anyway.
It’s not about the latency between when words are spoken and when they’re heard, it’s snot when a packet is sent and when it’s received. There’s a lot of jitter and you really don’t want intermittent drops to cause people to miss parts of your programming.
The justification for many of these stations is emergency preparedness. They're maintained for the ability to receive and transmit emergency alerts despite power outages or transmission line cuts. The daily programming is mostly incidental beyond maintaining listenership
The burden on taxpayers would be significantly less if it was strictly satellite coverage for use during emergencies.
What reason would people have for maintaining equipment capable of receiving radio though?
Same reason communities still maintain HAM radio clubs and rely on them for emergency communications in a grid down situation - it's an interesting (though expensive) hobby that has some merit for isolated communities.
People don't maintain HAM clubs for the potential use in an emergency, any more than people learn to fly in the hope of being able to rescue a commercial aircraft when both pilots are incapacitated.
They enjoy HAM radio as a hobby in and of it's self. It's doesn't come free to the government either, I'm sure some HFT organisation would pay handsomely for some of the bands currently used by HAM radio.
The cost is having the satellite systems in place, working, and available. You don't save money by not using the tiny amount of bandwidth when it isn't "an emergency"
The burden on taxpayers would be significantly less if the government simply paid to run the system rather than additionally funding two sets of attorneys to duke it out in court to make an out of control executive actually execute the law. It's getting harder and harder to believe that this fascist movement was ever earnestly about saving money.
Erasing the Federal Government is the motte and saving money is the bailey.
It doesn't look like the Federal Government is being erased. In fact, it and its debt are rapidly growing. I'd say the motte is autocratic authoritarianism (ie fascism).
The US is pretty large, and has large areas without reliable cellular or wired Internet connections. Public radio ensures accessibility in those areas.
This doesn't answer the question. Why not use the internet to get the radio to those stations?
Isn't that what they do now? They describe a lot of the IP-based transmission stuff in the link.
I don't think the distribution of the signal to the transmitters is the problem here.
This is ironic because it may be radios delivering internet to those stations.
I wonder if we should just pass a bill that requires Starlink or Amazon Leo to use 0.5% of their bandwidth for low quality (but higher than radio) free access to Inet Radio streams in some special way. Then start building out the infra in vehicles.
There are plenty of places in the US that don't have reliable satellite access either (not because of orbital coverage, but because of geographic features like mountains/deep valleys).
(And these aren't remote/unpopulated areas: you can find plenty of satellite dead zones 2-3 hours outside of NYC in the Catskills.)
> because of geographic features like mountains/deep valleys
I remember this being quite an issue trying to target geosync broadcast satellites like DirectTV/Dish. Even being in the shadow of a relatively small hill could block access if your location and local topology happened to create an unfortunate alignment. I've naively assumed Starlink's rotating constellation of thousands of LEO satellites reduces how often this is an issue - but maybe it doesn't?
Starlink has other issues. I have locations in London I can get to specific geostationary satellites, but can't use starlink there as there isn't much sky coverage
Honestly curious: how many of those satellite dead-zones have good radio coverage? In my various times driving places, I've often lost radio signal in a sufficiently remote place where I 100% would have had satellite coverage. Those same features that can block satellite will also block (some kinds of) radio, if you don't have a broadcast tower at the top of the ridge or something.
Yes, I agree that satellite coverage is not 100%. But neither is radio.
I think the idea is that the sats relay a signal to radio stations including remote ones.
It's the radio stations who are in charge of situating their reception equipment where it can see the sat, and also for figuring out how to best broadcast to their served area (e.g. AM and/or FM? Tower height, power, setting up some translator stations on a different frequency to serve outlying areas, giving the feed to local cable systems to be sent with TV service, etc.)
It's definitely a mixed bag, but the areas I'm thinking of have decent FM radio coverage (from local stations that affiliate with public radio). AM coverage tends to be good regardless.
I've had the same experience as you around remote places, but those places were generally the flat-and-desolate kind :-)
Most towns have the repeater(s). They are cheap and easy to maintain.
Or we just continue to use the infrastructure that we already have and works?
Because... it does not work, I want 100% access to any audio stream. I get garbled crap on terrestrial.
Seems like a really expensive solution to an already-solved problem.
What happens when a major CDN goes out? Or, god forbid, a major datacenter region has a DNS blip that apparently 1/3 of the internet depends on?
Or, what if a hurricane or ice storm knocks out some internet connectivity? That would be a time when you really want to broadcast a message to anyone with a cheap fm/am radio.
Cheaper isn't always the metric here.
CDN? for internet radio? Internet radio predates all that.
Predates, sure.
Is affected by? No idea, but I'm sure there's some cloudflare rep convincing you that you need cloudflare to make sure your high-availability stream stays highly available when just yesterday azure got a ddos measured with Tbs. Just not today... today those cloudflare reps happen to be busy.
Point is, radio comms serve a public utility that often is a Plan-B if internet links go down. Multicast it onto your podcatcher of choice, sure, but don't make that your backbone.
The stations that rely on CPB funding as a main source of income are the "others" who repeat the NPR content over the radio. They're tiny stations (typically 1-2 full-time employees) that mainly serve communities where internet streaming is not a viable option due to spotty cell coverage.
Also, receiving internet service requires some kind of paid monthly plan. The cheapest plans have very low data caps. Streaming audio over them is much less practical for the end users than having a simple radio receiver. Radio waves also propagate further than cell broadcasts.
The OP here, in their defense, wasn't talking about just operating an internet radio to replace public broadcasting and telling listeners to just get a data planpay for Internet and go online to listen. They were suggesting TCP/IP backhaul to get the signals to the remote radio stations, and rebroadcasting on the radio.
Presumably this would be feasible for most populated areas, but broadband availability is so crap outside of urban/suburban, I bet half of those really remote stations are already getting their Internet over Starlink or Hughesnet.
Now, I think there are plenty of reasons that the satellites (which are already in the sky, presumably) are probably more robust in the face of emergencies than the entire Internet infrastructure.
If I may steelman a good counterargument: "The Internet itself is supposed to be resilient to nuclear war!"
True, but that doesn't mean outages of critical pinch points like AWS, Azure and Cloudflare don't constantly affect even services like GitHub that have huge budgets. A fully robust Internet solution with a ton of high-uptime redundancy in many POPs nationwide would likely cost more than maintaining the satellite systems.
What ISP still has data caps that isn't a LTE carrier?
Comcast.
Not on new plans as of earlier this year: https://www.pcmag.com/news/comcasts-new-plans-dump-the-data-...
But Cox still has data caps.
Not during a major earthquake or hurricane.
I'm curious too. As a complete outsider to that problem space, it seems like a lot of the tech was designed/created in an era before wide-spread broadband and internet-based content distribution. I'm sure a lot of it is simply that new hardware from that vendor is largely a drop-in replacement for each station, so there's no need to re-engineer their broadcast booth.
...
I guess HN is the new Reddit. Downvotes, not a single response. You can do better, HN.
Some equipment is drop in - hooking up an audio output to a keyed radio is only occasionally difficult. You see a lot of these solutions in the HAM radio space.
The actual radio equipment is a tad more sophisticated - and in poor areas (where it's barely hanging on) is held together with spit, glue, and prayers (exaggeration, joke, but aspects of it are true).
Believe it or not, the RF cables are (in many cases) more expensive than the radios themselves.
Background: Computer systems, radio systems, General class HAM, but certainly not an expert.
Please don't comment about the voting on comments. It never does any good, and it makes boring reading.
Please don't post comments saying that HN is turning into Reddit. It's a semi-noob illusion, as old as the hills.
https://news.ycombinator.com/newsguidelines.html
How on earth does it cost this much?? This could be done for like $5k/month on even the most expensive of AWS setups if you weren't pinching pennies.
Do it, then? I'm sure you could convince NPR to save a lot of money.
As someone who grew up hearing pledge drives every few months on (ad-free) Christian radio: Would that be an option to fund NPR? Surely those who want to listen/watch/support would donate regularly.
Half of NPR's revenue comes from payments from stations to run their programs, and most of the rest comes from individuals, businesses, and foundations. Those public radio stations are also mostly funded by listeners and donors.
Also, this isn't relevant anyway, because the article is about a dispute about a particular program that NPR was running.
Public Radio is already famous for their pledge drives with their tote bags.
Every local public radio affiliate station already does this.