Here is a simple list of tools you’ll need to start searching for noise:
- a small DF loop, like this one
- for VHF and UHF, a Yagi or other directional antenna. Say something around 8db gain
- a simple wide band AM receiver or a 2/70 handheld for higher frequency work
- the new Nano VNA could be used for wideband viewing. Cost around $65 to $85. Depending on source.
- a field strength meter for close in work.
- the old analogue TV field strength meter tunes from 39 Mhz to 900 Mhz and are very useful for searching. Eg Sadelta TC402D or TEC MC661C 41 Mhz to 850 Mhz
- Lacy TV sell a small field strength meter for around $45 which will detect down to -90 dBm and is wideband.( 5 LEDS)
- The ultrasonic receiver I supplied the how to build article. For detecting corona on power lines.