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Updated Audio Receivers (markdown)
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@ -57,7 +57,7 @@ The next item is the setting of the bin sizes used for the waterfall (0-63) with
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And next right to that field ,while you are still in SPEC mode, you will see Rx_IQ_CAL field.It actually can improve (8 to 10 dB's from worse CAL point to the best one ) the receiver Image Reject Ratio only in the Receiver Applications that are using Zero IF-frequency tuning ,like this SPECTRUM mode. This calibrated value it is stored in the SD card , /settings/rx_audio.ini .
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To calibrate it , you will need to try to find some clean isolated continuous carrier , and try to tune it , (example , to the right of the positive frequencies ). Select properly the BW to try to isolate that air carrier signal (in below example , I selected BW = 2 Mhz).
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To calibrate it , you will need to try to find some clean air isolated continuous carrier signal (pls make sure that it is a real air signal, not internal harmonic residual interferent clock beats) , and try to tune it , (example , to the right of the positive frequencies ). Select properly the BW to try to isolate that air carrier signal (in below example , I selected BW = 2 Mhz).
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Then, to make visible the bare Image mirror frequency -that appears in the other symetric left part screen.-, you will need to start set up CAL to 0 (min). Then , you will need to adjust AMP , LNA and GAIN to receive strong enough signal to the right part (not so strong to not produce intermodulations , otherwise re-adjust again decreasing AMP, LNA, GAIN) , and not so weak , till just getting the carrier +freq. clean (desired carrier signal) , and its bare visible Image mirror Signal (in the other symetrical -xx mirror freq . (unwanted Image signal to be minimized) . Then, when you got similar situation as left below picture, you can start adjusting Rx IQ phase CAL till minimizing the received Image "mirror" signal (as in the middle below picture).
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That below example is calibrating H2+ old r6 version (max2837) that has 31 steps ,(Note , using Hackrf r9 (max2839 ,we will have 64 steps)
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