I see a lot of questions about whether the stock antenna that comes with many of the RTLSDR dongles is any good. The answer is dependent on many variables, including how high you have the antenna placed.
Today I did a test and took a dongle, the stock antenna and my laptop to Toronto Pearson airport. I sat just east of the threshold of runway 23 and stuck the antenna on the roof of my truck, providing a decent ground plane for it. Here’s where I was parked (within a few meters):
I then ran SBSplotter for about an hour to get a rough idea of the range I was getting. Being near the airport, I expected to pick up a large number of aircraft in all directions, given that the area around the airport is fairly flat and has no large obstructions like buildings or trees around its border. Here’s the result:
This image was created using the steps I describe in my blog post on how to Superimpose Your Polar Plot in Google Earth.
The results aren’t surprising to me. The red plot, from ground level, reaches 150 nautical miles, with just a few points beyond that range. The yellow plot is my original plot from home, where I live on the seventh floor of an apartment building. Both plots were made using the same kind of dongle and stock antenna.
Moral of the story: get that antenna up as high as you can and it’ll serve you just fine.