APRS Tracker wish list - Page 4

RV8RIVETER · #31 05-07-2008, 06:30 AM

Allen

Agree that the best bang for your buck would be to use the protocol most supported, either Garmin or Zaon.

Call Todd at GRT, they have always been very helpful and honest when communicating with them. They should be able to help you with a protocol recommendation and how to do it.
PH (616) 245-7700

I take it by your comments that the new unit will be TT4 and transmitter in one package. Sounds great.

MacNab · #32 05-07-2008, 07:23 AM

Quote:

Originally Posted by VHS

...We will certainly explore supporting other devices, but if you can let me know the best one to work on first, it would be a great help.

Allen
VHS

Allen,

It seems to me that a whole lot of folks are using the Garmin 296, 396, and 496/495. I think starting here would definitely give you the most bang for your buck... also the most bang for the users buck.

VHS · #33 05-07-2008, 02:45 PM

I downloaded the manual for the 496 ( Geez, do you guys actually change things on that while you are flying!!!? Talks about multi-tasking!) It already supports NMEA input/output, so marrying it to the TT4 should be more or less plug-and-play! Spoofing TIS and other workarounds "should" not have to be a consideration. When I get back from the big Ham convention in Dayton, Ohio ( Those hams know how to pick a party atmosphere, don't they?) I will try to get my hands on one and see if it does what it should, vis a vis, displaying airplanes as airplanes. Does anybody in the Northern California area have one of these?

Allen
VHS

Ron Lee · #34 05-07-2008, 03:08 PM

http://www.zaon.aero/content/view/81/1/

http://www.zaon.aero/content/view/29/47/

Davepar · #35 05-07-2008, 03:58 PM

License a protocol? I'm sure if that was possible, Hayes would have done it for modems a zillion years ago and still be in business today. If the protocol is proprietary, that just means it has to be reverse-engineered instead of being able to read a nice public spec. I wasn't able to pull up the Zaon site, but I'll try again tonight. Our current products here don't display traffic, so I don't have any specs on hand.

I'm willing to lend some help to the effort, if needed. It would be cool to be able to see other APRS targets on a screen.

Although a much more ambitious product, an all-in-one traffic tracker like Bill mentioned would be killer. Something that listens for TIS packets, ADS-B, and APRS and spits them out to a screen (EFIS or GPS) would be a hot seller. Garmin currently charges a $1500 premium just for TIS. I have no idea what ADS-B costs, but I'm sure it's much more than that.

kevinh · #36 05-07-2008, 06:36 PM

Quote:

Originally Posted by VHS

I downloaded the manual for the 496 ( Geez, do you guys actually change things on that while you are flying!!!? Talks about multi-tasking!) It already supports NMEA input/output, so marrying it to the TT4 should be more or less plug-and-play! Spoofing TIS and other workarounds "should" not have to be a consideration. When I get back from the big Ham convention in Dayton, Ohio ( Those hams know how to pick a party atmosphere, don't they?) I will try to get my hands on one and see if it does what it should, vis a vis, displaying airplanes as airplanes. Does anybody in the Northern California area have one of these?

Hi Allen - I'm an embedded software geek at San Carlos. I have a 496 you can play with a bit. We might be able to even capture the existing TIS stream from my transponder to look at it.

Btw - the following patent describes the TIS packets when sent over the air to the transponder. I wouldn't be surprised if they are passed unmolested over the serial link to the 496:

http://www.freepatentsonline.com/6512975.html

I couldn't find a web reference that actually documents the over the wire protocol (though this patent does give the name of that document)

Ron Lee · #37 05-07-2008, 07:03 PM

About $17,000 for just OUT (does not receive anything) per the FAA.

VHS · #38 05-07-2008, 08:44 PM

Is the uplink frequency for ADS-B , 978 Mhz? If the data is receivable, it may be possible to use the TT4 and display the info on a GPS. Any idea what format the data-flavor it comes in? Is there any advantage to a receive only system for ADS-B? ( yes, I know, you would like a transmitter too, but FCC approval for transmitters is a whole different world!) Looking at the info online, it looks like the system is similar in many respect to APRS.

Allen
VHS

Davepar · #39 05-07-2008, 10:08 PM

I believe UAT is being used in the U.S., which Wikipedia says is 978 MHz.

There is a benefit to receive-only. Near large airports, ground stations transmit all traffic (ADS-B equipped or not) out over ADS-B.

Being able to transmit would be handy in the hinter-land, but traffic is much less of an issue anyway. At some point, it sounds like the FAA will mandate ADS-B transmitters for aircraft in certain areas, but that is likely a long way away and will be fought by the various airplane owner lobbying groups.

I have no idea about the format of the messages, but it must be online somewhere. Too bad it doesn't just use the compressed APRS format. Guess they wanted to re-invent the wheel.

kevinh · #40 05-07-2008, 10:14 PM

Quote:

Originally Posted by VHS

Is the uplink frequency for ADS-B , 978 Mhz? If the data is receivable, it may be possible to use the TT4 and display the info on a GPS. Any idea what format the data-flavor it comes in? Is there any advantage to a receive only system for ADS-B? ( yes, I know, you would like a transmitter too, but FCC approval for transmitters is a whole different world!) Looking at the info online, it looks like the system is similar in many respect to APRS.

A reasonably priced receive only ADS-B decoder would sell like hotcakes I suspect.