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diff --git a/md/notes/sdr/gnu_radio_receive_am.md b/md/notes/sdr/gnu_radio_receive_am.md index e193e1a..5a29214 100644 --- a/md/notes/sdr/gnu_radio_receive_am.md +++ b/md/notes/sdr/gnu_radio_receive_am.md @@ -3,3 +3,39 @@ keywords:sdr,am,demodulation,gnuradio # +Lets listen to AM radio stations with AirSpyHF + +## Frequencies + +For frequencies search at http://websdr.org/ find the nearset receiver +on the map that support AM broadcast frequencies as it will give a clue +if propogation of time of the day is ok around your location. + +In this example I found only few AM station in 17Mhz range at day time +to test receiver. + +## GNU Radio blocks + +Base blocks for the AM receiver. This blocks have 2 channels and those +are to test switch between two radio stations. + +![AM receiver blocks](/img/sdr/airspyhf_am_receiver_blocks.png) + +| Name | Value | Note | +| --- | --- | --- | +| band | 192000 | AirSpy samplerate, closely follows the bandwidth | +| freq | 1749000 | The channel0 stations frequency | +| f_channel0 | 0 | If the stations is there, no need to change main frequency | +| f_channel1 | 10000 | offset from the channel1 find offset from waterfall | +| fir_dec | 4 | nicely match 48kHz for audio | +| fir_bw | band/(2*fir_dec) | auto filter calculations for Xlate FIR blocks | + +![AM receiver block params](/img/sdr/airspyhf_am_receiver_params.png) + +Example when the blocks are running, with arranged GUI's + +![AM receiver block params](/img/sdr/airspyhf_am_receiver_gui_.png) + +## Links + +1. [http://websdr.org/](http://websdr.org/)
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