Inmarsat Aero Changes

[Dark_sky]

Ok I think mystery solved. I just moved my spare 1m antenna around and was able to find the C1/C5 carriers all the way around East. So looks to me like they migrated to 62E or 64E, maybe I5-F1 or I4-F2. Can't get more accurate than that at the moment. I have a very poor look angle in that direction ( low elevation and through tree line) hence why they disappeared from my main antenna. I guess this maybe in preparation for the I6-F1 and I6-F2 satellites coming on line ? Maybe someone with a better look angle and higher elevation could confirm ?

Hutch

Looking at the Psmc channel I guess this must be 64.5E ( (SAT ID =3)which would fit with the Azimuth angle I have the antenna at.

Good work Hutch. Think that would confirm I4-F2 is now in use for C1/C5. If i'm not mistaken I4-F2 was the previous sat to carry the C1/C5 channels before the switch to Alphasat. I would imagine I-6 F1 will be the replacement for I4-F2.

In terms terms of aircraft positions i would say it's the same as before. Pretty much all European USAF aircraft using C1/C5 from mid Atlantic to the Middle East. As before some be will using 54W. I also have a tree directly at 64E so likely why i'm also seeing reduced signal strength.

 

[Hutchp]

Good work Hutch. Think that would confirm I4-F2 is now in use for C1/C5. If i'm not mistaken I4-F2 was the previous sat to carry the C1/C5 channels before the switch to Alphasat. I would imagine I-6 F1 will be the replacement for I4-F2.

In terms terms of aircraft positions i would say it's the same as before. Pretty much all European USAF aircraft using C1/C5 from mid Atlantic to the Middle East. As before some be will using 54W. I also have a tree directly at 64E so likely why i'm also seeing reduced signal strength.

Thanks. I-6F1 is at 84E so will be pretty much below the horizon for UK reception. I think I saw that I-6F2 will be going into 28W. Hopefully once they finish IOT all the C1/C5 traffic will then migrate to 28W. In the interim will be spending the weekend trying to find at better position for the second dish to get I4-F2.

Hutch

 

[JamesWest]

when will Inmarsat F6-1 be operational? Anybody know?

 

[Hutchp]

when will Inmarsat F6-1 be operational? Anybody know?

They should be transitioning services to it now. Its been on station at 84E for almost a year. I know they have been using Perth as one of the ground Earth Stations. Satellite won't be visible from the UK but anyone further East should start looking for it.

Hutch

 

[JamesWest]

I just pointed my 7 turn Inmarsat helix (thanks Bald Geek pizza pan version) at 84E and I have what I think is a beautiful signal from F6-1.
No time to decode anything, just did a screen grab.
I have been away from monitoring sats for a while and always looked at POR and I can say for almost maybe for sure this was not there before.

 

[JamesWest]

OK I have decoded three 600 baud JAREO channel. Looks the same as JAREO 4 F1 at 143E.

 

[batdude]

this is just an observation on my end.... I am most certainly just a novice on INMARSAT, etc.

but.

When I last monkey'd around with JAERO ... back in February or so ---- the 1200bd ACARS would drop about 5 messages a minute or so.

Today....

I am getting.... just minimal traffic.... a polar express flight dinged.... that was pretty much it. signals appear to be VERY strong (-35db on SDR#) and Jaero seems happy "green green green" ---- so ....

did all these planes magically shift somewhere else for their ACARS?

(sub screen shown on Jaero .... good data ... just no messages on ACARS!)

 

[open-sky]

Hello,
had also missed the channels C1 and C5 for some time,after reading your posts the channels can be found on 64°E, I aligned my antenna there and I am receiving data, thank you....my location is Austria.
25°E I receive 600/1200/10500 bps....64°E only 10500 bps 4-7 db with jaero...use the helix from thebaldgeek / patch from SDR-RTL / patch from Outhernet / patch from Nooelec ...dongle V3 and Nooelec...

best regards Gerhard

 

[open-sky]

now 64°E also runs with 600/1200 bps ...15db RTL-SDR patch antenna....

regards Gerhard

 

[Hutchp]

Viasat reporting that the new Inmarsat I6-F2 that was scheduled to go to 28W could be a complete loss. It seems to have suffered a power supply fault during orbit raising. Not sure if that will result in more traffic being shuffled across the remaining fleet.

Regards
Hutch

 

[open-sky]

Missing C1 / C5 on 64° E today

 

[Hutchp]

Looks like I4-F2 has been drifted to 68E... so not visible from my location anymore. Maybe someone with better look angles could confirm if its still in use or has all traffic moved to I6-F1. Can't quite understand how C1/C5 traffic could be using a satellite so far East though.

Hutch

 

[open-sky]

Unfortunately I didn't take a screenshot! It should be noted that the message came from planes from the area Asia to Australia!

 

[Sadeepa]

Please share if there are updated frequency plans available for 4F1, 4F4 and 6F1. I am interested in Aero as well as STD-C.
Thank you.

 

[Hutchp]

I recall that Inmarsat were due to cease the AERO H services in Dec 2023. This is the Global beam services using high gain antenna systems .
Will be interested to see if it actually happens and if the 21000 bps voice traffic switches to the jaero decodable 8400 bps service. Should see an increase in Mil A-400M voice traffic if it does. They are very active users on the 1545.35Mhz band on 25E and 1542.82-98MHz on 54W.
I note its still active as of today. Also note AERO H+ services are set to continue for the foreseeable future.

Hutch

 

[BackHive67]

I see short data bursts around 1647 to 1648 MHz... I think from Alphasat-25E. Does anybody know what they are... perhaps related to an AERO service ?

 

[Hutchp]

I see short data bursts around 1647 to 1648 MHz. I think from Alphasat-25E. Does anybody know what they are... perhaps related to an AERO service ?

1646.5-1656.5MHz is the Inmarsat aero, aircraft to satellite uplink band. If you are line of sight with an aircraft during a transmission or close to an airport you may well see activity in this band. I have decoded data and voice call calls in the band before but only briefly when aircraft are close.

Hutch

 

[BackHive67]

1646.5-1656.5MHz is the Inmarsat aero, aircraft to satellite uplink band. If you are line of sight with an aircraft during a transmission or close to an airport you may well see activity in this band. I have decoded data and voice call calls in the band before but only briefly when aircraft are close.

Hutch

Many thanks Hutch.
I expect the voice is the same as that which can be decoded in JAERO from 1.5 GHz, but what about the data bursts ? Can they be decoded in JAERO too ? If so, what settings ?

I'd appreciate any further info.

B/H

 

[Hutchp]

Yes voice channel can be decoded in JAERO same as normal. The data bursts will likely be the 10500bps burst ACARS data that would be downlinked normally at C Band. You can try and decode them.

Hutch

 

[BackHive67]

Many thanks again Hutch.. I will try and see if I can decode the bursts.

B/H