New to the site and just came across this thread. I think the suggestions on portable receivers that include SW etc are a good idea. I have a similar unit in my kit. An external antenna will add tremendous improvement on what you can receive. Antennas used on receivers are not as wavelength dependent as they are for transmitting. A long wire strung to a tree 100 ft away will do a fantastic job. (Assuming the radio has an external antenna connection.) Just be sure to disconnect if lightning is a possibility.
For those that are a little more technical a low cost SDR (software defined radio) might be an option. Using a SDR dongle, wire antenna, and a laptop with the appropriate drivers and software can allow you to tune a wide range of frequencies and modulation types. Even tell if there is transmitted energy in the area. Including digital transmissions that you might not be able to demodulate. (Hear the content.)
This book is a good primer on SDRs and explains how to load the driver used for many of the cheap dongles.
https://www.amazon.com/SDR-Beginners...4&keywords=SDR