I wasn't originally going to reply to this thread, simply because I haven't got any positive suggestions or experiences to help Getaway Turtle's attempts at using an SDR (Software Defined Radio) USB dongle. However, sometimes sharing even a negative experience can at least add a little to the discussion, so here I am.
First off, I acknowledge G0ULI's valid and polite comments on the legalities of a non licence holder listening in on airband transmissions, indeed there are other contributors here on PPRune who are so vociferous and vehemently opposed to any such activity that I imagine them frothing at the mouth as they type their opinions! They'll be along shortly to add their 'two-penn'orth' to this discussion. Anyway, thats for another day maybe.
A few months back, I got me one of
these gadgets (based on the R820T RTL2832U chip) for the same purpose as Getaway Turtle, and hoped furthermore to find software that would allow the thing to be used as a scanner type receiver working alongside an Icom IC-R5. Just for clarity, these dongles were designed and intended originally for digital television reception, but their extraordinary 'wideband' receiving performance makes them theoretically at least suitable for airband purposes. It was hooked up to an Icom AH7000 discone antenna, and despite being close to the flight paths of Heathrow, Gatwick, Southend, Luton and Stansted, I never picked up even one airband transmission!! G0ULI is probably right about FM broadcast stations swamping all other transmissions, although one of the pieces of software I used lets the user narrow the 'selectivity' which should filter out adjacent frequencies.
For the record, the following SDR programs were used:
HDSDR,
SDR Console, and
SDR Sharp.
Edit to add just for fun: One of my classmates from school 40 years ago is today flying BA 777's out of Heathrow apparently. I haven't seen nor heard him in all that time, but I think possibly... just possibly heard him as a BA 777 was in the Lambourne hold a year ago!!