FlightAware Discussions

Uat / tis-b

#1

I’ve had my UAT receiver up for roughly a week now and recently changed over to the orange flightaware dongle. Doing so my range doubled and at times can see aircraft on UAT anywhere to 75-100 miles in each direction. I’ve noticed i’m picking up a lot of “TIS-B” traffic and wondering how this is different then UAT. From my research I’m less than 10 miles (as the crow flies) from a TIS-B Tower located in Kenly, NC. Can I assume i’m seeing traffic being rebroadcasted by this tower since the TIS-B traffic comes and go’s throughout the day?

FWIW I’ve also been picking up F15e Fighter Jets from Seymour Johnson AFB on TIS-B

Screenshot_2019-04-15%20PiAware%20UAT978%20Site%20-%204%204

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#2

Yes, TIS-B is from a ground station. This is traffic data sent for conspicuity reasons so that 1090MHz aircraft are visible to aircraft that only have 978MHz in. You’ll typically see two types of TIS-B:

  • data from an aircraft with 1090MHz ADS-B out, e.g. N22593 in your screenshot, being rebroadcast by the ground station on 978MHz (i.e. ADS-R)
  • radar tracks e.g. all the 278xxx addresses (note the italics - these are not ICAO addresses)

In theory Mode S radar tracks could turn up as TIS-B with an ICAO address, but in practice this doesn’t seem to happen, they turn up without the ICAO address.

TIS-B is usually only sent when there’s something around to hear it (i.e. something nearby with 978 in + out).

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#3

It is weird, every now and then I get TIS-B with proper ICAO addresses.

I saw some JetBlue or DHL today on UAT as TIS-B.

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#4

OK Thanks, The italic codes were confirmed F15’s from SJAFB, so that would make since.

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#5

Yes I get “big” aircraft showing up with proper data on UAT, I’ve identified several helicopters and a few smaller commercial aircraft that are running dual ADS-B and UAT out. What is interesting is I usually pick up the UAT beacon at a lower altitude then I do 1090 ADS-B.

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#6

UAT does have a slightly longer wavelength. It would allow for better low level range(it bends better).
It could also be antenna design or placement.

I caught a few big ones in UAT a minute ago
image

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#7

I know I’m an old goat in this hanger but can someone please direct me to the link to download the new UAT version of PiAware?

Thanks guys.

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#8
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#9

Thank you sir. I guess it was the format of this message board that was making it hard to find.

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