DVB-T dongle not suitable for ADS-B


#1

Hi, I received my dvb-t dongle this morning (order number PI178461), thanks. Problem is it doesn’t work for ADS-B. The dongle is recognised OK, the led is lit, When going through the instructions listed for dump1090 (the software recommended on the dongle’s web page) it passes all the tests. It can pick up (using kalibrate) some of the lower frequencies on the GSM900 bands and it picks up a couple on the GSM1800 and GSM1900 bands so I know the receiver is working OK.

The error shown is:
[FC0012] no valis PLL combination found for 1090000000 Hz!

The problem seems to be the onboard tuner in the device, this is shown as being a “Fitipower FC0012” which unfortunately has a gap in the receive frequencies between 948.6 Mhz and approximately 1400Mhz. The frequency needed for ADS-B is 1090 Mhz - right in the gap!

Google “Fitipower FC0012” for plenty of results which give the specs of this tuner.

Bottom line is, this dongle is simply incapable of receiving the required frequency for ADS-B.

Now what?

Mudcruzr


#2

Great detective work, we’re looking into this ourselves to see what might be awry. I’ll keep you posted.


#3

Just pulled a couple from stock both reporting via lsusb as “Realtek Semiconductor Corp. RTL3828 DVB-T”, which is what they should be.

What process did you use to identify yours as a “Fitipower FC0012”? Could you post the results from lsusb and possibly send us a photo of the device to see if there are any visual differences we could look for?

I’ll confirm the ones I’ve checked actually work, and get a replacement sent your way ASAP.

Thanks.


#4

Progressing further, and to keep you in the loop, in the output from rtl_test -t I see:

pi@raspberrypi:~ $ rtl_test -t
Found 1 device(s):
  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Found Fitipower FC0012 tuner
Supported gain values (5): -9.9 -4.0 7.1 17.9 19.2
Sampling at 2048000 S/s.
No E4000 tuner found, aborting.

#5

Cheers @gadgetoid, that’s exactly how I identified the tuner. try rtl_test again without the -t as that parameter is only for the E4000 tuner.

As far as a photo is concerned, I don’t think there’s any need now as it’s identical to the one on the product web page and, based on your output from rtl_test above, also identical to the one on your bench lol.

lsusb output is the same as yours.

The main error which demonstrates the dump1090 doesn’t work is shown immediately in the program’s startup messages before it clears the screen. That’s where I found the error message:

[FC0012] no valid PLL combination found for 1090000000 Hz!

Once you stop dump1090 you must scroll up quite a few pages to see the startup messages. Also if you force dump1090 to use a different frequency which is within the FC0012’s frequency range (but no use for ADS-B e.g. 940Mhz) with the --freq 940000000 switch, there is no error, Then change that command to select a frequency in the FC0012’s “gap” e.g. 960Mhz (–freq 960000000) it’ll fail. This is how I found the min & max values of the “gap” (948.6Mhz to approx 1400Mhz).

cheers,

mudcruzr


#6

Thanks for your feedback. I, too, have found that dump1090 doesn’t appear to work. I have somewhat sub-optimal conditions for testing this- what with being in a warehouse with a metal roof- but we’ve had it up and running before in a BilgeTank episode so I know roughly what to expect- and “nothing” ain’t it.

You’re right, if I run and exit dump1090 quickly, I see the [FC0012] no valid PLL combination found for 1090000000 Hz! error.

I’m trying to rescue an old DVB-T dongle from somewhere around the warehouse for comparison.

You’re right, photos and other details are moot at this point, I’m pretty sure that what we have here matches what you received.


#7

Yeah, I’ll get this one bundled back up and returned to you now, I don’t think there’s any point in hanging on to it.

mudcruzr


#8

Okay I’ve finally snagged an old DVB-T dongle buried in the warehouse and it’s identified as having a:

“Rafael Micro R820T tuner”

And, lo and behold, it gets plane tracking results almost immediately, even in my sub-optimal desk-bound conditions.

This is obviously quite starkly different to the new ones. It looks like the tuner part of the chipset has been switched out without us knowing. Presumably for perfectly sensible reasons; if you consider that it’s supposed to be a DVB-T dongle and still functions as such, it’s hardly surprising.

However, since we sell it expressly for plane tracking, and advertise it as such, we’ll obviously find some way to put this right.

As for your return, would you like a refund for now, or a replacement? I can’t make any promises when we’ll get any compatible dongles in, but I could have a quick dive through our remaining stock to see if I can locate any with the old tuner part and verify that they will work.

Edit: I’ve found and tested another dongle if you go the replacement route.


#9

@gadgetoid I’ll go for the replacement please if I may.

Many thanks for your perseverance.

mudcruzr


#10

@gadgetoid Many thanks, postie has just been with the replacement dongle and it works straight out of the box.

mudcruzr


#11

Whew! That’s great to hear, thanks.


#12

Is this now resolved for future orders? (am tempted).


#13

Unfortunately not. Securing the DVB-T dongles with a specific tuner- a feature totally unrelated to them performing the function they’re originally designed for- might be more trouble than it’s worth :( We’ll certainly look into it, though.


#14

Just to update you on this… we’ve updated the product page now with details of the change in the tuner, and have samples of a new plane-tracking-capable dongle (with the R820T2 tuner) coming early next week. It has an extendable antenna and better range. Assuming the samples are pukka then they should be on sale within a month or so. :-)


#15

So I bought one of these without realising that the spec had changed. No point in returning it but does anyone know if there’s an Android app that will work with it for digital TV?


#16

I bought a tuner on eBay that claimed to be a “R820T2” - turned not to be. Anyway I ended up on this thread via Google :-)

Looking forward to seeing the new product - don’t mind paying slightly more to know it will work.


#17

Reviving an oooooold thread, but our new flight-tracking-capable USB DVB-T dongles have just gone on sale. These new dongles use the R820T2 and have an extendable antenna. Also good for digital TV, DAB and FM radio, of course.


#18

Was about to order but I see it is marked as Out Of Stock.
Will it or a replacement be coming back soon?


#19

I’m also interested in one of these. Have registered for a notification when they do come back in stock but a estimate of arrival would be useful.