Cubesats on PSLV/EmiSAT launch

A PSLV launch is scheduled for April 1st, 03:47UTC. Besides the primary payload and a bunch of Doves and Lemurs, 5 cubesats are included.

BlueWalker 1 (BW 1)
Astrocast 0.2
AISTECHSAT 3 (Danu Pathfinder)

The last object is interesting, as they are experiments which remain attached on the PSLV upper stage.

Let’s report in this thread any VHF or UHF frequencies that these objects transmit at.


Astrocast 0.2

Aistechsat 3 (Sort of?) Mentions the thrid sat that is on this launch


Haven’t found anything on the AIS/APRS/ARIS or BlueWalker 1


BlueWalker 1 most likely won’t be transmitting in UHF or VHF (Or if it is we may not want to listen to it)

Based off "The first satellite, “BlueWalker 1,” is the first of a series of satellites for AST & Science, to be used for testing the company’s patented technologies in space. "

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Interested in the aprs :

Yea but I can’t find any information on it.


An APRS payload from AMSAT INDIA will be flown on PSLV C45. The launch is scheduled on April 1st 2019 at 09:27 IST / 03:57 UTC. The payload will be powered on approximately over Sweden,Norway,Denmark, Finland, Poland and Moscow.We request stations at these locations to report the first signals (145.825 Mhz) from the payload.We also request the Amateur Radio fraternity worldwide to use the payload and Satgates to feed the traffic. More details about this unique project is available at
The prelaunch TLE are also available for download on
Nitin [VU3TYG]Secretary, AMSAT INDIA


Aha, another APRS digi-peater.

They’ve also provided preliminary TLEs:

1 99999U          19091.29152269  .00000000  00000-0  00000-0 0 00004
2 99999 097.4979 151.8159 0004334 104.9050 359.4795 15.22377597000038
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Satellites and transmitters added in db:

  • 99990 - Astrocast 0.2
  • 99991 - AISTECHSAT-3
  • 99992 - M6P
  • 99993 - AISAT

For the transmitter data I used the links from the previous posts, IARU and DK3WN sites.

Let me know if you spot anything that needs fix. In the next hours I’ll add TLE in network and I’ll schedule a couple of observations for these satellites.

This reddit post has more details about the launch, it has also links for live streaming.

EDIT: Schedule is done until 1st April 13:00 UTC.


Any infos on downlink data format?

For Astrocast 0.2 and AISTECHSAT-3 there are “telemetry forwarders” so I guess that their downlink format is known but haven’t found anything.

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A quick update:
All, except M6P, have successfully received but not decoded. The TLE above are very accurate, all received signals where almost in a straight line.

Yep, just had an overhead pass here in Lancaster County (my SatNogs stations are about 50 miles east of here) and I could hear the APRS packets on my D72, but none decode. Looking at the Satnogs observation at my house - the TLE is pretty good (not perfect), but the packets are very weak (maybe comparable to NO-84).

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First TLE are out, from them some estimations, with bold the ones chosen for the network to follow:
AISAT-1: either 44104 or 44105
Astrocast-0.2: 44082, 44083, 44084, 44085, 44086 (less possible 44079-44081 and 44087-44090)

EDIT: By the way I want to thank all the station owners around the globe that observe these satellites and help me to estimate the right TLEs by using ikhnos


I’ve got ~96 Hz residual (using STRF) on 44081 and 44082 for AstroCast-0.2, on 437.176 kHz. Need to bulk that up a bit with more observations though, I only get ~8 packets per pass.

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From a couple more estimations, I moved Astrocast-0.2 to 44083.
44082 is also a good candidate.