[Hackrf-dev] 1090 MHz

[Andrew Rich]

Thank you Kevin

The data rate of sampling is 2MHz

I have a full install of gnu radio here perhaps I can play with some scope sinks ? 

A 

Sent from my iPhone

> On 6 Aug 2017, at 10:14 am, Kevin Reid <kpreid at switchb.org> wrote:
> 
>> On Sat, Aug 5, 2017 at 4:45 PM, Andrew Rich <vk4tec at tech-software.net> wrote:
>> Question. I have a flightaware blue rtl dongle for adsb. It picks up aircraft some 100 kms away ok. But when I run it with a software defined radio I don't see great amplitudes . Why is that ? I would have expected to see quite large signal peaks on the sdr program . Is it because the signal is spread out over 2 MHz that I can see a distinct signal strength ? Does the signal need to be compressed down to a narrower bandwidth ? 
> 
> These signals are extremely short in duration. Most SDR software does not display all of the input signal in the waterfall, but samples it according to the chosen display frame rate / scrolling speed, so any signal between those samples will be missed. You need a rate much greater than 60 Hz to consistently see these signals. (This does not mean you need a super-fast monitor, just that the waterfall will scroll more than one row/pixel per display frame.)
> 
> If you have gr-osmosdr and gr-fosphor installed, try:
> 
> osmocom_fft -F
> 
> and enter 1090M for frequency and 2.4M for sample rate. You should see plenty of horizontal lines flying by, as gr-fosphor is designed to use and display 100% of the input signal.
> 
> My own ShinySDR can also do high enough FFT rates and includes ADS-B decoding.
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