The table below show the badges listed in the 1937 Coronation Review of the Fleet at Spithead by HM King George VI on the 20th May 1937, but are known to have been in use earlier in the 1930's.
Wireless Telegraphy
Alma Mater - HMS Mercury, Leydene, Nr Petersfield, Hampshire
The 1953 Review programme showed the Wireless Telegraphy badge like this. The badge represents the WINGS of MERCURY with a streak of lightning through the centre representing a spark of electricity. Easy to see where the polite colloquialism of SPARKER or SPARKS came from. However, in other organisations, the Mercantile Marine for example, a sparker is an electrician! There was one other less polite colloquialism used, which suggested the badge was "flying bullshit struck by lightning"! Well, as you saw, the badges with wings FLEW in and onto their respective holes.
The badges below belong to the Gunnery Branch, the rules below are relevant to the Wireless Telegraphy branch. By substituting the Gunnery badge with the W/T badge, you can see what the badges looked like.
This is our badge, dating from the 1st World War, and is the badge we rally to. Whilst always subservient to the famous flag hoist of Lord Nelson at Trafalgar, it is nevertheless very famous and very important. The flags shown comprise the actual signal which was hoisted to deploy the Grand Fleet into action at Jutland at 1817 on the 31st May 1916. The translation of the motto is "Wisdom by Signs". Historically, the outcome of this battle is still (2003) argued about, unlike Trafalgar, but the symbolism of the badge is in no doubt.
The signal school was in the RN Barracks in Portsmouth before the second world war, in what we now called HMS Nelson, but for many years of my career HMS Victory. Because of the bombing targeted at that city and in particular that of the night of the 10th March 1941 when near total destruction of the dockyard and HMS Vernon occurred, it was moved to Leydene House [owned by and lived in by Lady Peel] near Petersfield Hampshire led by its commanding officer Captain Cunningham Graham. Lord Mountbattens influence had some bearing on this acquisition!