The Owon XSA1036TG Spectrum Analyzer, 9KHz-3.6GHz, with Tracking Generator Kit offers a minimum bandwidth of 10Hz, allowing excellent signal resolution when separation of closely spaced signals is required. This model also offers a DANL (displayed average noise level) down to -130 dBm, which is able to measure smaller signals.
Reference: EX15131455EG
Brand: Extech
4-Wire Earth Ground Resistance Tester 4 Ranges from 2 to 2000 Ohm
Reference: BE67478936BB
Brand: Besantek
Dual Channel Wireless Temperature Data Logger with External Probes
Reference: BE76227234BB
Brand: Besantek
Ground Resistance Clamp Tester, 30A, 65mm X 32mm Clamp
9 kHz-3.6 GHz, Spectrum Analyzer, with Tracking Generator Kit