Improving Cheap SDR Antennas | Hackaday
[VK3YE] knows that at least two things are wrong with the cheap antennas you get with most SDR switches. First, they are too short. You would like to have enough to download a quarter wavelength of the longest frequency you want to work. The second problem is that there is no real basis. He fix both problemsas you can see in the video below.
The result can be called an ugly duckling rather than a rubber duck. But it seems to work. You could probably come up with something better to re-seal the base, but the tape works. A nice 3D printed case would also work and could improve the look. We also thought about the hoop you use on the tool handles.
In fact, we just cut off those antennas and reused the cable and connector to connect a better antenna. You can get more mileage from this approach. On the other hand, the magnetic base and the relatively small form factor are quite attractive.
If you want to do before and after testing, we would suggest using Python. Or just bite the bullet and build something that looks like it belongs in a movie.