| Year | 1921 |
| Date | 23-Jun |
| Volume | 44 |
| Issue | 1,052 |
| Page | 490 |
| Category | Electronic |
| Part | 11 |
| Title | Wireless Notes |
| Author | A.V.Ballhatchet |
| Notes | Earth Signalling. Diagram showing moethod of tapping earth conduction, adjustment to earth pins, induction "loop", "power buzzer" connections, amplifier for T.S.F. or wireless reception |