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dump1090 - 2 vs. 8MHz and RSSI

Posted: Mon Jan 16, 2017 2:44 pm
by rack201
Hi All,

Been building some antennas and playing with my RSP2 and dump1090 to plot aircraft using VRS. Am able to decode signals from aircraft >350km away so all seems to be working well.

Can someone explain to me (novice) how to understand the difference between running dump1090 in 2MHz vs 8MHz mode? I understood this was the 'bandwidth' of RF spectrum you would sample at a given time, so for a fixed frequency like ADS-B it wouldn't seem to apply. Or is it more like a 'sample rate' i.e. how often in a given time period the RSP looks at the RF?

Also, when I run Dump1090 in 8MHz mode, all tracked aircraft report an RSSI of "-50.0" whereas if I run in 2MHz mode is seems to return meaningful data.

Any ideas?

Re: dump1090 - 2 vs. 8MHz and RSSI

Posted: Tue Jan 17, 2017 8:20 am
by sdrplay
The 8MHz mode is a experimental demodulation mode that we added to take advantage of the RSP. It should provide better long range results (not sure about close in though)

If anyone has any data on the difference of the 2 modes I'd be interested to see it (

Thanks and best regards,

SDRplay Support

Re: dump1090 - 2 vs. 8MHz and RSSI

Posted: Tue Jan 17, 2017 8:57 pm
by F1BJB
If you use more than 2 MHz bandwidth you will pick up interference
Mainly DME signals.