I use a battery operated portable radio that covers the broadcast band, 540 to 1610 kHz. Tune to the low end of the band where there are no stations, then try the high end. The ferrite stick antenna in the portable radio has a directional effect.
I have a VHF-Hi channel that is marginal. I can receive it sometimes when the SNR is 15-16 dB. When the noise level is higher, I can't receive it because the SNR is less than 15 dB. I am able to measure the signal and the noise in an adjacent unused channel, and my Sony TV gives me the SNR in the Diagnostics Screen. My old SLM (signal level meter) has an AM detector for the audio so I can hear the signal and the noise. It's the meter on the left; the newer meter on the right can also measure noise and signal.
A car radio also covers the broadcast band. When I drive around town with the radio tuned to a frequency where there are no stations, I can hear the noise get louder when I get near power lines, especially the big high tension lines. This test doesn't work with the FM band on the radio, because FM is designed to reject noise.
The broadcast band is much lower in frequency than the VHF aircraft band (118-137 MHz) or the VHF TV band but often if you hear the noise on the broadcast band it is also on VHF TV frequencies. It is worse on VHF-Low than VHF-High.
http://www.arrl.org/files/file/Technology/HANDSON.pdf