AirNav Comstation Teardown

[GregoryGHarding]

Gregory,

can you post a closer-in photo of the RF part of the upper PCB, too, please?

This is the area just behind the SMA connector.

It seems there are no SAW filters in this area and the whole setup reminds me of this small silver box that was on the market for some time, but disappeared 3 years ago or so, which name I forgot (but Anmer will remember)

Andy

http://imgur.com/a/8vSuF

[junglejet]

Hi Gregroy,

great pictures and VERY helpful ... and surprising ...

What this is, is (more or less) a remake of an Rpi plus 2 Dongles and a GPS receiver.

The front end is an exact replication of two Dongles (you can see the R820T and RTL2832 right behind the SMA connector). What is disturbing is the complete absence of any frontend filtering. As the antenna is broadband (there is no input splitter) this may create a lot of overload problems as they are known from the Dongles.

The two dongles are combined by a USB Hub (CY... chip) and then fed to the A20 CPU. This CPU is about the same class as the original Rpi CPU, but not as powerful as a Rpi 2 setup.

Except for the GPS I do not see any benefit in this design over an Rpi + 2 Dongles.

Knowing Brandao I would bet, that the software is an unauthorized branch of dump1090 with a mandatory uploader to Radarbox servers.

Andy

[Anmer]

Thanks Gregory for sharing the new photos and to Andy for his quick assessment.

I think Brandao knows he can't increase RadarBox24 app sales without massively improved global coverage.  And he knows this can't be achieved by the dwindling population of disgruntled RadarBox receivers.  So he needs to distribute a cheap alternative.

In my opinion, Brandao's misunderstood the motivation of hosts and the need to supply a robust device that can deliver quality data with minimum support.  Flightradar24, Plane Finder, FlightAware and others understand this and have invested heavily in receiver design and host support.

As I mentioned earlier, the "proof will be in the pudding".  Especially MLAT plots.

It will be interesting to compare coverage in a few months time.

[GregoryGHarding]

Great report Andy, I did notice the basic layout of the two dongles apon taking the closer images. This hasn't been powered up yet because I'm waiting on an sma extension. But I will keep thread updated on progress and testing once she's online. There's gotta be something with the serial connection at least.

[tarbat]

Have you tried connecting to the Ethernet port?  Presumably it gets an IP address assigned locally from DHCP.  If you can telnet in to it, try commands like - "shcfg,enter" or "shsys,ident".  You could also try these commands on the serial port.

[Anmer]

Hasn't Brandao sent you one Chris?

I'd have expected you to be high on the list of suitable hosts?

[tarbat]

Hasn't Brandao sent you one Chris?

No - I wasn't even aware of the new box

I'd have expected you to be high on the list of suitable hosts?

I would have tested it.  I'm guessing that the firmware may have been developed similar to that in other Airnav products.  I certainly wouldn't be posting photos of the circuit boards!!

[mhm]

I certainly wouldn't be posting photos of the circuit boards

Why not

[IanH]

Have you tried connecting to the Ethernet port?  Presumably it gets an IP address assigned locally from DHCP.  If you can telnet in to it, try commands like - "shcfg,enter" or "shsys,ident".  You could also try these commands on the serial port.

If it is anything like the security on the FR24 box, telnet won't work.

But opening a browser with the IP address might show some status information - the FR24 box generates useful information.

[Anmer]

If it is anything like the security on the FR24 box, telnet won't work.

But unlike the AirNav ComStation, the FR24 Radarcape outputs decoded data on port 30003 and, I think, PP raw data on port 10002.  Making it usable by the host.

[IanH]

That's what I meant by useful data on its internal web page. It shows:

STATUS:

RECEIVER SOFTWARE: ON [stop, display log]
  RAW FEED [30334]: UP, NUM CONNECTED: 0
  BS  FEED [30003]: UP, NUM CONNECTED: 0

[GregoryGHarding]

That's what I meant by useful data on its internal web page. It shows:

STATUS:

RECEIVER SOFTWARE: ON [stop, display log]
  RAW FEED [30334]: UP, NUM CONNECTED: 0
  BS  FEED [30003]: UP, NUM CONNECTED: 0

yes, this box does not have that. its only web interface allows DHCP/static. thats it

[GregoryGHarding]

haha,

got an email today from Alan telling me I've been naughty on radarspotting :p

all's good though. i think.. he hasnt asked for me to pack up and get lost yet anyway.

[Anmer]

got an email today from Alan telling me I've been naughty on radarspotting :p

Which Alan is that?

[GregoryGHarding]

got an email today from Alan telling me I've been naughty on radarspotting :p

Which Alan is that?

Alan McKnight from radarbox