How much HD space does a night of recording with the sdr-iq take up?
You can calculate the amount of storage:
First, what is the bandwidth? In my case 200 kHz. Note that the actual data rate is typically about 25% higher (check your SDR setup), it's 250 kHz for mine. So that means there's 256k sets of data written per second. The recording files are I/Q data, so there's two values written, and they are 16 bits, or two bytes each, so that's 4 bytes total. (Again, check your SDR setup, some write 24 bit data, which means 6 bytes per second). So doing the math, 256k * 4 = 1024k or 1 MB per second.
There's 3,600 seconds in an hour, so that's 3600MB or 3.6 GB an hour. A 12 hour recording is 43.2 GB, on weekends and holidays I usually run all day long.
The maximum data rate of the SDR-IQ is a little less (around 192 kHz from memory). Also, you can record a smaller segment of the band.
After buying an SDR, the next step is to buy another hard drive :-) In my case I have an external 3 TB firewire drive. I keep recording files for a few weeks (in case I need to go back to check something), then start deleting them.