Would you use SARSAT info if it were still there???

[Nomex Maximus]

Hello All,

A friend and CAP member tells me that the SARSAT satellites are not "switched off" but just that the 121.5 MHz signals are no longer being monitored on the ground. My friend is an electrical engineer and thinks he could build a receiver that could monitor and interpret the 121.5 data still coming down from the SARSATS. In other words, we could still have satellite hits from 121.5 ELTs if we wanted.

My question is for those in ES leadership - if individual CAP members took on monitoring 121.5 SARSAT signals, if we heard something would CAP leadership  or the AFRCC be willing to use the information ?

Regards,

Nomex

[Al Sayre]

Absolutely, especially if they can get me 15-20 mile resolution.  I'm dreading the mission that comes with a ELT reported to Center from 37,000 feet 20 miles north of Nowhere VOR with no other pireps available...

[Phil Hirons, Jr.]

+10,000

[es_g0d]

It certainly would be valuable information to have.

I see two insurmountable obstacles, however.  The first is cost.  Just making a wild guess, I'd say that the cost of the equipment for a SARSAT-COSPAS Local User Terminal (LUT) is at least $50,000.  That includes using the most economical functional equipment.

Secondly, it is my understanding (which could be entirely incorrect) that the 121.5 / 243.0 processors have been shut down on the satellites themselves.  Power conservation on a satellite is very important, so any transmitter that doesn't need to radiate will save amps.  Even if the processors/transmitters aren't shut down, as the NOAA constellation is replaced they won't include a 121.5 / 243.0 processor.  Therefore, the investment made in a LUT will still be doomed from the outset; it will only be a matter of time.

[Al Sayre]

Scott, never under estimate an Electrial Engineer with time on his hands.

BTW, Mike H. at GTR said Hi

[N Harmon]

Absolutely, especially if they can get me 15-20 mile resolution.  I'm dreading the mission that comes with a ELT reported to Center from 37,000 feet 20 miles north of Nowhere VOR with no other pireps available...

Would AFRCC even dispatch on one pirep at FL370 with no other aircraft reporting hearing anything?

[JoeTomasone]

Absolutely, especially if they can get me 15-20 mile resolution.  I'm dreading the mission that comes with a ELT reported to Center from 37,000 feet 20 miles north of Nowhere VOR with no other pireps available...

Been there, done that, got the all-expenses-paid drive to find nothing already.   The other issue, of course, is that finding one ELT under such conditions doesn't mean you've silenced the one in the pirep.

We had one (break out Google Maps for this) with two pireps at 9,000 and 13,000 feet saying it was 20 miles south of Inverness, FL.   That makes it around Brooksville, FL.    We searched all night -- nada.

The next day, an air sortie was about to fly out of Charlotte County airport when they heard an ELT on the field, and silenced it.    Charlotte County is 120mi or so south of the pirep location.

So you tell me... Did we get it?

Without 121.5 being monitored via SARSAT, we have no idea if that was the one that was heard, or if it was a second ELT (or third, fourth, etc...).

It occurs to me that you really are taking your life in your hands if you don't upgrade to 406.

[Angus]

It certainly would be valuable information to have.


Secondly, it is my understanding (which could be entirely incorrect) that the 121.5 / 243.0 processors have been shut down on the satellites themselves.  Power conservation on a satellite is very important, so any transmitter that doesn't need to radiate will save amps.  Even if the processors/transmitters aren't shut down, as the NOAA constellation is replaced they won't include a 121.5 / 243.0 processor.  Therefore, the investment made in a LUT will still be doomed from the outset; it will only be a matter of time.

That's what I've heard myself.  It would probably cost more than the corporation has to get that up and running again.

[Al Sayre]

Absolutely, especially if they can get me 15-20 mile resolution.  I'm dreading the mission that comes with a ELT reported to Center from 37,000 feet 20 miles north of Nowhere VOR with no other pireps available...

Would AFRCC even dispatch on one pirep at FL370 with no other aircraft reporting hearing anything?

I honestly don't know, but they would have to take some kind of action.  I'm sure that Center would try and get additional info, but I'm thinking of say 0200 with low crappy IFR weather when the only ones flying are the big freight haulers like Fed-Ex and UPS at high altitudes...

[Nomex Maximus]

I am not the EE, just a software engineer and a ham operator. He says,

- The two Russion satellites have been turned off.
- The other 5 (3 US and two French) are currently on line and
  sending data.
- The SARSATS uses a "bent pipe approach" to the problem,
  the audio from 121.5 and 243.0 is directly send down via
  L-Band, thus the equipment needed to decode the data is
  all on the ground
- The processing problem need the audio from the ELT, and
  information on the satellites ground track to calculate the
  location of the ELT. Two passes by any given set of satellites
  are required to provide a location of the the ELT.

So, it seems to me that we are just talking about an L-Band (1 GHz - 2GHz) downconverter and either an audio demod of the retransmitted ELT audio OR some signal processing of the (digital?) signal. Either way, this is not a $50,000 task - more like $300 - $500 and a PC to do the signal processing. Not a big investment to be able to have some extra info about the 121.5 ELT signal your wing might be trying to track... Keep in mind we are talking CAP member / hobbyist / technical challenge / volunteer type interest here.

Now, the real question is for how long will the satellites leave this equipment running? My friend seems to think the stuff is still on, just not monitored. I have a feeling that 121.5 MHz ELTs are going to be around for quite some time to come and I suspect we will keep trying to track them.

Keep in mind the cost of building things in America - you can go to Wal-Mart and buy a Garmin Nuvi GPS device for $100. Or, if you are in the Air Force, you can go to Rockwell-Collins and buy a PLGR for about, oh I don't know, about $20,000 ? - and then find that the Nuvi does a better job and is a whole lot lighter...

[es_g0d]

If its a $500 project, build and share!  One important aspect of the bent-pipe is that both the LUT and the ELT need to be within the same footprint (which ought not be a problem at the state level).

Side note: try using your Garmin Nuvi when GPS is shut down by the folks at Schriever AFB.    The PLuGgeR will still be working, and hence the need for the more expensive equipment.  Its all to what standard you need!  Good example, though. 

Second Side Note: Hi Al, please give my best to the GTR airport manager! 

[Nomex Maximus]

If my Garmin Nuvi gets shut down by the AF then I suspect that our GX-55s and G-1000s will be shut down too.

[Senior]

Nomex,  could explain the... downconverter....what what to us laymen .
It sounds like an interesting squadron project.
Are we talking about radio signals or plumbing???

[♠SARKID♠]

I'm not sure its the best idea, but recognize its merits.  General aviation has been beating the horse that is "upgrade" pretty hard for the last few years.  If word got out that "CAP was still using SARSAT", however small of an operation it may be, it might undermine the campaigning that has been done to get pilots to switch.  "Why get an expensive 406 if those Silver Air Patrol* people are still monitoring the 121.5 satellites?"  We're volunteers so I doubt there would be someone to monitor the system 24/7 like at RCC so pilots relying on "CAP SARSAT" would be SOL when they may have otherwise been convinced to get a 406.  Just my two cents, take it or put it in the coin tray.

*I heard the newest misinterpretation while buying a truck last night when the auto dealer was getting my license plate info.