Very cool project! The company I work for is building a similar sat/cell GPS tracker for civil aviation. In fact we're using the same GPS and Iridium modules.
The costs for satellite SBD messages is definitely eye-watering though. Our device transmits position data every 2 minutes while relying on satellite connections, which we definitely notice the costs of during development. We'd like to look at other providers, but for various reasons (excluding costs) they end up being less ideal than Iridium.
If you have an amateur radio license, a small HF transmitter would probably successfully send a signal to a receiver on land most of the time, and of course wouldn't cost anything.
HF propagation does vary over time, but you could send a signal far more often to make up for it.
Ah, that's cool. We built a similar system using Iridium SBD and LTE for controlling drones a few years back. SBD isn't the fastest comms around, and it can get rough if you don't have clear sky view, but it works pretty much everywhere, with a small antenna. If you don't have line of sight or LTE, it's a solid fallback.
For anyone else wondering, the satellite transceiver is a RockBoard, which charges:
- $302 for the hardware
- $17/month for a “line fee”
- $0.20/message (50 characters)
Would be nice if there was an actually affordable, programmable Iridium device.
The keyword of the problem there is Iridium. Their SBD (short burst data) and in fact all their services are just extremely expensive. This reseller doesn't really seem to put much margin on it.
When I had a sat phone (needed to travel sometimes to questionable places for work) I used Thuraya which is much cheaper for airtime. 40€ gets you a whole year's worth of inbound service (airtime) and about 15 mins of call credit for outbound. With iridium that gets you about one month.
But Thuraya only had 2 active sats. One geostationary over the middle east and one over the far east. No service over the Americas. The Asian one failed early this year and the coverage for the region which can't be met by the other one is now inoperable.
The middle east sat is actually beyond its planned service life and if it goes down there's no immediate backup. Though a replacement is ready for launch according to Wikipedia. You also need visibility of the southern horizon (or northern, if you're in the southern hemisphere). So for hiking in valleys it's not a good bet. The same goes for Inmarsat for that matter. But they do have more sats.
Iridium in contrast is fully worldwide, has a robust constellation of many low earth orbit sats that move across the sky so you don't need to see a fixed point. It's more robust for emergencies. But the price is much higher. It's a trade-off. You get what you pay for.
As I no longer travel for work but do hike, I ditched the Thuraya and got a Garmin InReach which runs on iridium. But that costs more than Thuraya even though it can only send messages. Though with their latest cost increase I might just drop it and find something cheaper. Maybe Starlink direct to cell.
I've been wondering how Iridium costs are tallied.
Recently had two calls with an Iridium phone, one sent and one received, about 1 minute each. T-Mobile charged me $50 for those.
I found it very odd - it seemed like Iridium was somehow passing the call fees onto me, but I can't be sure because the T-Mobile rep I chatted with was unable to comprehend the situation (I suspect I was talking to an LLM, but it ultimately gave me a $30 rebate at least).
Receiving calls from Iridium should be free – the caller usually pays for the satellite portion of the call.
That usually makes Iridium -> terrestrial calls much more economical than the other way around, as telcos usually use the opportunity of terrestrial -> satcom calls to add on ridiculous margins. Conversely, satellite -> terrestrial calling is usually around a dollar per minute or less, these days.
In your situation, that would come out to a $50 (or maybe $25) charge per minute. Hefty, but that indeed seems to be at least in the ballpark of their listed rates (for prepaid here, for example: https://prepaid.t-mobile.com/connect/international-calling-r...).
Nice - thanks for digging. I'm guessing you're right, iirc it rounded up the number of minutes.
I’ve had to make and pay for an unfortunate number of Iridium calls. They can be crazy expensive depending on carrier, who all bill them as a call to an international line in the country of “Satellite”. Usually you pay your carrier’s fee for outgoing and it’s cheaper/free to receive the calls.
It seems like cell carriers always charge more per minute for satellite calls than any satellite provider does, so I’m guessing they just set their rates conservatively to always make a profit on their end. And the demand for satellite calls seems like it would be pretty inelastic.
This is why iridium supports calling their regular PSTN gateway and then dialing the satellite number recipient, then the satellite recipient pays a more palatable $1.50/minute:
I've always assumed that answering a phone call would be free for me (excepting the dawn of cell phones when they had a limited number of minutes per month). If answering a sat-phone call is "cheaper" rather than free, does anything warn me that I'm incurring extra charges?
Paying to receive a call seems to a mostly American phenomenon. In most (all?) of Europe, receiving calls is always free, no matter where or how they originate.
Indeed - a Garmin InReach is about US $500 and already ruggedized and tested. I understand the DIY aspect of this project is the fun part, but it definitely isn't a way to save money.
With a robust used market, as well. I laughed at the battery life goals for this - the inreach mini I use lasts _days_.
You can actually achieve this even with Iridium Go. I tried it years ago and it worked.
It isn't too documented, or let me say it isn't documented at all but you can write AT commands and start raw TCP connections and read and write to that socket.
And it is actually reasonably priced. I tried to open SSH connections and it was barely usable. You get a very small number of bits per second.
Edit: Found the private repo I had created back then in case anyone has any interest. It looks like I did something like this:
func (sess *IridiumGoSession) ActivateDataWithCustomSettings() (*PerformTaskResponse, error) {
return sess.PerformTask("2",
MakeOption("set state", "true", "bool"),
MakeOption("Firewall allow all traffic", "false", "bool"),
MakeOption("Firewall exceptions", "XXX.XXX.XXX.XXX-all-tcp", "bool"),
MakeOption("Enable DNS forwarding", "false", "bool"),
MakeOption("Dial number", "0088160000330", "bool"),
)
}
Depending on how you look at it, Starlink can be incredibly cheap compared to Iridium. It’s still not cheap from where I’m sitting in my clapped out Honda Civic, though.
Edit: I think $250 for 50GB of truly global data. I can’t do the math right now, but it seems like a better deal at face value.
$50/month, these days, if I'm not mistaken. (You can only use it abroad for two months at a time, but you can update your location as as far as I'm aware, and it's $/€ 50 in most places.)
Price wise, it's no comparison, but the two don't directly compete yet – power usage and antenna size of Iridium and Starlink are orders of magnitude apart (largely due to the L-band spectrum available to Iridium globally).
> Depending on how you look at it, Starlink can be incredibly cheap compared to Iridium.
They don't have sat-to-sat communications deployed yet, so they can work only near the ground stations.
Hmm? Starlink has had sat-to-sat active for a while now. They've been making a killing selling services to ships and planes lately.
> Would be nice if there was an actually affordable, programmable Iridium device.
I remember reading about this a while back, but doesn’t SpaceX offer some kind of IoT modem for a low cost (not the Starlink dishes)
Where did you buy Iridium access for $17/month?
This is a very cool project, happy to see the costs of this stuff coming down a little bit.
When I was an intern 15 years ago I worked on a software library for this https://www.embeddedts.com/products/TS-IRIDIUM Board that does a similar thing (though you would need to stack on a cellular board if you wanted cell modems).
We used them to help Arizona Department of Transportation collect traffic data in remote locations.
We had big plans at that company to make a much smaller, much cheaper 9602 transceiver replacement, but the company got bought out before that could launch.
Hearing about Iridium reminded me of how excited I was to take on a job managing 5 engineers for them, until they offered me a base salary of $135,000 in Phoenix. They work on incredibly cool technology—I'm bummed I had to pass it up to work for some garbage web-focused tech company becayse Iridium pays pennies on the dollar to their engineering department.
Is it just me, or does the wording of this comment imply that you passed up the Iridium job to work somewhere else that underpays their engineers? Seems like you meant to imply the opposite.
I think it's clear he has to work for the "garbage" company because it paid more than Iridium did
The opposite. Op would have preferred to work at Iridium, if only they offered higher pay compared to where they are currently.
Why not trying using something like WSPR? It really depends from the propagation conditions, but it would be interesting IMHO
>The ultimate motivator for building this project was the opportunity to join the crew of the S/Y Southern Star yacht, which sails in the Arctic.
Anyone know how he got this opportunity? I'd love to join something like this if all I had to do was make a cool Iridium transmitter!
Fun project! Did you look into NTN (Non-Terrestrial Networks) capable modules as an alternative to Iridium? I haven't played with NTN myself, but it seems modules such as SIM7070G-HP-S support LTE-M/NB-IoT as well as NTN networks, and could in theory serve the purpose of your Iridium tranceiver as well as your LTE module. This technology hasn't matured yet, and I suspect the roaming tarriffs are expensive, but I don't know how it compares to Iridium.
NTN seems to be only offered by geostationary satellite operators at this point, which unfortunately puts the use case from TFA out of coverage. See for example Inmarsat's coverage: https://www.inmarsat.com/content/dam/inmarsat/corporate/core...
I'm not even sure if Skylo is live with Inmarsat at this point, or if there are any other NTN providers covering oceans.
saveitforparts on youtube recently setup an old satellite terminal and went through the pricing of doing so, its expensive.
This is so cool! Thanks for sharing and creating something like this :) BTW do you use Iridium handsets? Do you have recommendations?
OP is using Iridium SBD according to the article, specifically this modem: https://www.groundcontrol.com/product/rockblock-9603-compact...