Hi, I don't think that it is quite correct to say you could record in "any" format. Straight out old fashioned analogue (for example tape) or any other loss less recording system would work OK. For PC recording you need a system that does not compress the data stream to reduce file size (eg .wav ). You are unlikely to have much success with systems that throw away much of your data in order to reduce file size (eg .mp3). The down side of loss less recording systems is the huge file sizes that are quickly generated,as you can see by recording a favourite song with ..wav and then with .mp3... something has to give to reduce file size. Most of the sstv programs have the facility to record of air and then save the resulting decoded file in a much reduced "digital" format. (I know... this is a gross simplification and I apologise in advance to the experts!). My choice in a more esoteric professional field is to record our data using .wav files using laptops and large portable hard drives, mainly because it's a rare pc that can't handle .wav files! Just my 2 cents worth.
Cheers, Don ZL1THO.