Sending SMS Messages Via the ISS

Sending SMS Messages Via the ISS


On Sunday July, 12 2020 at 06: 00 UTC I sent myself three SMS messages thru the Worldwide House Position’s APRS digipeater. Here’s how I did it, nevertheless first reasonably of background on my motivation for this mission.

Confirmation of SMS messages forwarded by ISS.

Confirmation of SMS messages forwarded by ISS

Why Even Distress?

The ISS has carried an amateur radio payload since its early beginnings. Section of this payload involves a radio that serves as a digipeater for APRS. Hams all around the footprint ISS as it orbits can ship and ranking knowledge packets containing messages that will well well be feeble to produce contact with each and every assorted. There exists loads of assorted stations transmitting all over any given bolt. These fabricate of stations are right computerized beacons transmitting ever quick time and a few are genuinely assorted hams trying to produce contact thru the ISS. It’s been my experience in my space all around the US that there had been largely computerized stations clogging up the airwaves with there unimaginative beacon transmissions. Consequently trying to produce a contact with one other human thru the ISS has been fruitless. Consequently I wished to produce employ of the ISS’s digipeater as it traversed thru repute over my home. In the future I chanced on it’s doubtless you’ll well maybe ship SMS messages the usage of APRS to the SMSGTE residing. This residing used to be connected to the ranking and acted as a gateway for SMS messages onto the mobile networks. Odd I tried sending a message to myself with terrestrial stations receiving my transmission and routing my knowledge packets onto the SMS gateway. Honestly, this used to be bright for most efficient a minute or two since terrestrial stations are pretty usual and the job used to be no more subtle than sending a SMS the usage of my cell phone. One night while trying to connect a contact thru the ISS’s digipeater with one other human (Seriously, is there somebody within the Mountain West residence moreover me even trying ISS contacts?) I had the unprecedented notion of sending myself a SMS message thru the ISS. It’s laborious ample genuinely having your beacon APRS packets heard by the ISS, so I figured why no longer up the difficultly level by trying to ship myself a message. Moreover, I must fabricate something on those solitary nights when the ISS is flying over my residence.

APRS SMS Gateway

SMS message flow between ISS and mobile phone.

SMS message waft between ISS and cell phone.

The glue that preserve this total experiment together are APRS Satellite I-Gates and the SMSGTE APRS mobile gateway. Without these two an APRS packet might maybe well maybe no longer be relayed by the ISS and sent to my phone. APRS Satellite I-Gates hear on the 145.825 Mhz frequency for APRS packets which might maybe well well be relayed by the ISS as it flys over. These packets are then routed thru the APRS network to SMSGTE gateway, onto a SMS mobile gateway, and within the waste thru the mobile network to my phone. To make employ of the SMSGTE gateway, it’s pretty easy. All it might maybe most likely well well be well-known to fabricate is transmit a message to SMSGTE within the next format: @

@1235551234 Hey from repute!

When the message is delivered, this will seemingly be order on the cell phone cherish so:

@KJ7NZL-6 Hey from repute!

Here’s all you truly require fabricate to initiate the usage of the SMSGTE gateway, nevertheless within the event you exhaust to must conceal a person’s phone number internal your APRS packets it’s doubtless you’ll well be ready to be triumphant on this by the usage of an alias. You are going to be ready to residing these up by registering as user on

Sending A SMS Message Via the ISS

The significant to sending a SMS message thru the ISS is preparation. For me a Conventional ISS bolt for me is about six minutes and thirty seconds long. In that time I must uncover the ISS, queue up my message to the SMSGTE gateway, and transmit my message to the ISS. I don’t hang a admire setup with an azimuth and elevation rotor and circular polarized beam antennas; I’m merely working with my right Yaesu FT3D and handheld Arrow II antenna. Consequently it takes a minute or two ranking the ISS and it’s doubtless you’ll well be ready to with out express loose note of it while navigating thru the menus on the FT3D with one hand. To support shortcut one of the important crucial job I truly assign the message on the FT3D forward of the upcoming ISS bolt and transmit on 145.825 MHz right earlier than the ISS appears on the horizon. Since this message isn’t purchased by something else an acknowledgement isn’t sent to the FT3D. This provides the message to a queue of unsent messages the FT3D will try a resend after a minute or two. I’m ready to manually strive to resend these messages while they are within the queue. This allows me to focal level on monitoring the ISS while barely desiring to test the radio’s show cloak cloak, most efficient desiring to for just a few seconds at a time to make certain I click on the message transmit button. Once the ISS receives my APRS message a confirmation message from RS0ISS will order on my show cloak cloak and I’ll ranking the SMS message on my phone a 2d or two later. This sounds pretty easy, nevertheless in note it took me just a few weeks of trying to get the job down.

KJ7NZL using the Arrow II antenna.

KJ7NZL the usage of the Arrow II antenna.

Next Steps

Now that I’ve accomplished my aim of sending a SMS thru the Worldwide House Position’s APRS digipeater, I must exhaust a gape at something fresh. Once I sent my first messages I feeble 5 watts of strength. The bottom strength atmosphere on my FT3D is 300 milliwatts, and I’m enthralling to know if I will genuinely attain the ISS with that diminutive quantity of strength. I judge it’s that it’s doubtless you’ll well be ready to evaluate of, nevertheless I’m going to must make certain I’m aiming my antenna without delay as the object as it passes overhead. The following aim I hang is to truly reply to my SMS message once it’s purchased. This would well maybe be more subtle if no longer impossible. It’s that it’s doubtless you’ll well be ready to evaluate of to reply to an SMS message and ranking the response as an APRS packet out of your radio. On the other hand, I’m in doubt what digi course the SMSGTE gateway makes employ of, nevertheless I believe it’s no longer setup to relay packets to the ISS. Even though it had been, this is able to well maybe honest require me to be below the same ISS footprint as the SMSGTE gateway. I’ll must attain out to the owner of the gateway to search out out more knowledge.



Hey! look, i give tutorials to all my users and i help them!

you're currently offline