4.23 - Native Recording
4.23.1 - System Requirements and Limitations
Please be aware that these functions take significant CPU power as well as require a fast storage device. Some machines may not be able to record. If you have problems, try a lower SDR bandwidth (e.g. 50 KHz) as this will reduce the data rate, and so the demands upon your computer's filesystem and CPU.
The maximum size of the file recorded in megabytes, and the directory where SdrDx looks for, and saves, recordings, can be set by right clicking on the o (record) control. If the recorded file size exceeds that size, the file will be closed and another one opened. The default max file size is 500 MB.
4.23.2 - Setting up to Record
First, set the SDR to the bandwidth you intend to record. Then, with Run on, press the o or "record" button, and record for the period of time you wish. Be aware that this uses up disk space extremely quickly. If you run out of disk space, the recording will stop automatically and you'll be left to move or delete the recording. To stop recording, just press o again.
4.23.3 - While Recording
The size of the file currently being recorded is indicated in two ways. First, in the topmost info black at the end, where the size is indicated as "X.XX GB"; second, in the scrub bar, which shows progress towards the maximum set file size.
During Record, the center frequency is locked.
Caution: The wider the
SDR bandwidth is (e.g., 50, 100, 500
KHz), the more disk space the recording will take.
4.23.4 - Record File Format
If you're interested in reading files saved by SdrDx, here is a description of the files it creates:
Wave Header:
------------
signed byte (4) - 4 ASCII characters = "RIFF"
unsigned 32bit (1) - file length
signed byte (8) - 8 ASCII characters = "WAVEfmt "
unsigned 32bit (1) - format length
unsigned 16bit (1) - format tag
unsigned 16bit (1) - number of channels
unsigned 32bit (1) - samples per second
unsigned 32bit (1) - Average bytes per second
unsigned 16bit (1) - block align
unsigned 16bit (1) - bits per sample = 16
signed byte (4) - 4 ASCII characters = "DATA"
unsigned 32bit (1) - data size
Interstitial Padding
--------------------
signed 8bit (2) - content not used
Auxiliary Information
---------------------
unsigned 16bit (1) - start year
unsigned 16bit (1) - start month
unsigned 16bit (1) - start day of week
unsigned 16bit (1) - start day of month
unsigned 16bit (1) - start hour
unsigned 16bit (1) - start minute
unsigned 16bit (1) - start second
unsigned 16bit (1) - start millisecond
unsigned 16bit (1) - stop year
unsigned 16bit (1) - stop month
unsigned 16bit (1) - stop day of week
unsigned 16bit (1) - stop day of month
unsigned 16bit (1) - stop hour
unsigned 16bit (1) - stop minute
unsigned 16bit (1) - stop second
unsigned 16bit (1) - stop millisecond
unsigned 32bit (1) - Center Frequency
unsigned 32bit (1) - A/D Frequency
unsigned 32bit (1) - IF Frequency
unsigned 32bit (1) - Bandwidth
unsigned 32bit (1) - I/Q Offset
unsigned 32bit (1) - dB Offset
unsigned 32bit (1) - Maximum Value
unsigned 32bit (1) - unused
unsigned 32bit (1) - unused
signed 16bit (n) - where n is the number of samples
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