website saying "Offline" but local page and systemd status saying all is ok.

[abcd567]

Well.. It may be fixed. As crazy as this sounds.... The dongles wouldn't sit side by side on the pi because they were too wide to do so. For the heck of it I pulled the plastic covers off the dongles and plugged them in side by side. Now things are working. Been streaming for over an hour now.

No idea why that made a difference though.

It is possible that one dongles is defective, while other is ok. When you plugged both, the healthy one took over.

To find out, try for an hour one dongle only. If it works ok, replace it by the other dongle and try again for an hour.

[abcd567]

Failure of dongle in about 4 minutes is obvious from telnet port 30003 results.

It seems overheating caused dongle temprature to rise high enough in about 4 minutes to make it wedge. Removing cover improved cooling, temprature no more rises to the point of wedging, and hence dongle stopped wedging.
.

First, I don't use Windows for anything. Mac or linux only. (I wouldn't be a good Unix Sys Admin if I used Windoze)

The key tip I gave you (and you used it) was "telnet to port 30003 and monitor ouput to find if dongle is working ok".

As you are a Unix Administrator and a user of Mac & Linux, you are aware how to telnet from your Mac/Linux computer, and did not need any instruction other than above tip. There was no need to get annoyed seeing telnet instructions for Windows (which will help so many Windows users). You should have simply ignored these.

Unlike Windows, the terminal in Linux (Ubuntu) is capable of SSH, Telnet and Netcat (nc) by default.
The terminal in Mac is capable of SSH and Netcat (nc) by default, which can be used in place of Telnet.

Screenshot from 2017-11-25 03-51-14.png

.
PuTTY is available for Linux also. I have installed it on Ubuntu 16.04
I have my PC with dual boot configuration. Either "Windows 8.1" OR "Ubuntu 16.04.3" can be chosen at boot through Grub boot loader.

Screenshot from 2017-11-25 03-27-22.png

.

Second, that method calls for you to go to port 30003. Previously you told me to set "Decoded Data (30003)" to "No" in the settings. Can't connect to a port if nothing is there.

I have tested and found that even with "Decoded Data: (port 30003): NO" in FR24 settings, one can get dump1090 output data on port 30003 by telnet. This is strange, but this is how it is.

Try it yourself.

Screenshot from 2017-11-25 03-24-17.png
.

[RunnerFL]

Still going strong here. Averaging 1600 aircraft a day.

Not 100% sure I'm buying the whole overheat thing though. The covers that were on the dongles were well vented and now that everything is working fine I've moved the Pi and dongles to a case and there was no change. I have no other explanation as to why it's now working though.

[abcd567]

May be one dongle is healthy, other one is defective.

Did you try both dogles one by one?

(1) Only dongle #1 plugged in and run for say half an hour, and check output of port 30003.
(2) Unplug dongle #1, and in its place plug in dongle #2.
(3) Restart fr24feed.

sudo systemctl restart fr24feed
#OR
sudo service fr24feed restart
#OR
sudo /etc/init.d/fr24feed restart

(4) Run dongle #2 for half an hour, check output of port 30003. 30003

[RunnerFL]

May be one dongle is healthy, other one is defective.

Did you try both dogles one by one?

(1) Only dongle #1 plugged in and run for say half an hour, and check output of port 30003.
(2) Unplug dongle #1, and in its place plug in dongle #2.
(3) Restart fr24feed.

sudo systemctl restart fr24feed
#OR
sudo service fr24feed restart
#OR
sudo /etc/init.d/fr24feed restart

(4) Run dongle #2 for half an hour, check output of port 30003. 30003

I'm pretty sure I posted before that I ran one dongle alone and then the other dongle alone and still had the same issue. Also, the dongles are separate frequencies, One is 1090MHz and and the other 978MHz.

[abcd567]

I think you believe that the two dongles have different preset frequencies of 1090 Mhz and 978 Mhz.

As far as I know, the dongles dont have any preset frequency. It is the receiver-decoder software which sets the frequency. The integral receiver-decoder software of FR24 feeder / Pi24.img is "dump1090 MR", which is preset to 1090 Mhz. You can plugin any of the two dongles in Pi, and the integral dump1090 will tune it to 1090Mhz

Please note that the dvb-t dongle hardware is SDR i.e. Software Defined Radio. All its parameters such as tuned frequency, bandwidth, demodulation, gain, and decoding is controlled by the software such as dump1090.

You can use any of the two dongle for 1090 mhz or 978 mhz perfectly well. It is the software which is different for the two i.e dump1090 which is integral in Pi24, and dump978, which you will have to install additionally, if you want to run any dongle on 978 mhz.

[RunnerFL]

I think you believe that the two dongles have different preset frequencies of 1090 Mhz and 978 Mhz.

wow, almost seems like an insult to my intelligence. I "believe that" because they are calibrated for 1090 and 978, marked as such and come with a certification to back that up. All the information was in the product description at the link I provided previously. Had you read it you would have seen that.

I don't just blindly buy products, I research them to get what I want.

[abcd567]

Following quote from Amazon:

Each SDR is lab-calibrated and serialized for easy 'plug-and-play' Stratux installation. Each comes with a calibration certificate with the calibration value & serial number..

The difference is not in dongles, but in antenna. It is therefore necessary that the 978 receiver software picks the dongle to which 978 antenna is connected, and 1090 receiver software picks the dongle to which 1090 antenna is connected.

To achieve this, the dongles are serialized with two different numbers in EEPROM. User has to set the same numbers in the Stratux software.

Please note that ALL dongles by default have serial # 00000001 stored in EEPROM, unless the serial is intentionally changed, as done by NooElec

Since you are NOT currently using Stratux, but only FR24 feeder with integral dump1090, with SINGLE dongle, it will use it irrespective of what its serial serial number is. The problem comes when 2 dongles are plugged in simultaneously, both having same serial # 00000001. In this case dump1090 randomly picks any one of the two.

If you dont belive me, just remove from Pi the dongle labelled 1090 and plug in the dongle labelled 978 (preferably with 1090 antenna if possible, otherwise for testing 978 antenna will also do), reboot Pi, and monitor output at port30003 and fr24feed status.

[abcd567]

I "believe that" because they are calibrated for 1090 and 978, marked as such and come with a certification to back that up.

The Calibration does NOT mean the dongles are "Tuned to a particular frequency" or "Optimized for a particular frequency".

Check the Calibration Certificate you got with the dongles. What are Calibration Values?

The Calibration is for frequency stability of TXCO in PPM (Part Per Million), and is equally applicable for 978 MHz AND 1090 MHz.
Therefore any of the two dongles can be used for 1090 MHz without loss of performance. The performance will drop if you use 978 MHz antenna for 1090 MHz.


TCXO specifications for NESDR nano 2+:
Frequency stability: 0.5PPM (max)
Phase noise @1kHz offset: -138dBc/Hz (or better)
Phase noise @10kHz: -150dBc/Hz (or better)
Phase noise @100kHz: -152dBc/Hz (or better)

[abcd567]

@RunnerFL:
Please see this Question & Answer page at Amazon:

https://www.amazon.com/ask/questions/Tx26SF9YGCEDYX8

Question:
Can both nano 2+ dongles in this bundle be used for 1090? i want to build two 1090 stations using "this bundle + 2 rpi + additional 1090 antenna"

Answer:
Yes. It comes with 2 Nano 2+ SDR's that can be used to receive either 1090 or 978 ADS-B signals. It also comes with a short and long 1090 antenna. So technically you have everything you need other than a second raspberry Pi to create 2 1090 stations. However, you may want to get a second long antenna for better reception.

[abcd567]

@RunnerFL: Reply from NooElec Support:

"Yes, both can be used for 1090MHz ADS-B."

Please see screenshot of their reply email below:

NESDR Nano 2+.png