Introduction

Durham Bat Group

Events and surveys

Bats in Durham

Bat calls

Bat maps

About maps

Bat Records

Bat Helpline

Feeding bats

Bat detectors:

How they work

DSP

Frequency division

Heterodyne

Time expansion

Calibration

Recording calls

Call Analysis

Torches, LED's

More about torches

Batteries and chargers

Bat boxes

Bat links

Detector links

Detector reviews