I Hear You Knocking

Second in the Relics Series this one marks the anniversary of start of Radio Essex transmissions with echoes from the Knock John Fort

Testing began on 27th October with a programme schedule introduced on 7th November 1965

Audio: Listen to David Sinclair on the Big Band Show from 21st October 1966

Harry Putnam writes & later leaves his visiting card below

Pictured the last BBMS 813 transmitter output valve was discovered on the fort & retrieved in 1967

Finally gaining an RCA ET4336 transmitter some reliability was achieved but power output & quality was variable largely due to the haphazard antenna system used on the fort

Here's our technical consults analogy ......

The Navy Forts Harry Putnam Radio Essex Business Cardweren't big enough to erect a decent sized antenna even for frequencies near the 1500 kc/s part of the band. So a compromise had to be made by using a smaller than technically-necessary antenna. On Knock John it never got any better than scaffold poles so 40% top efficiency. Even with an RCA ET4336 output in pairs of 813's, the homemade mods etc didn't help, so it’s absolute max tx rf output 250W, those antenna deficiencies hammed it such that even with a good tx output the actual rf radiated could have been as low as 50W emrp as an example of this, Radio Essex / BBMS on 222m

N.B. EMRP = Effective Monopole Radiated Power, essentially compares an antenna with a reference antenna that radiates 300mV/m at 1km with 1000W power applied to it

One important point worth mentioning is that the offshore stations had a trump card in their favour, that was the efficiency of the earth system. There is no better conductor than salt water both for the actual rf installation & for the rf to flow over before it hits land. The absorption of the field over sea water is minimal compared to the best path over the earth. The BBC used this property to their advantage in the stations at Washford, Somerset, to cover South Wales. Start Point Devon, to cover the entire south coast eastwards & Burghead, Scotland

David Porter G4OYX, ex BBC Transmitter Engineer

Criticised for being "off beat" much Radio Essex music came courtesy of Harry Putnam's own collection that he'd brought over from the States

The American collection comprised R&B by the likes of John Lee Hooker, Black Artists, US Radio hits & LP's by then mostly artists unbroken in Britain

The stations format varied enormously originally 30'- 60' strip shows were demanded by roy Bates but with a small crew this was untenable

So a loose MoR & niche daytime programming began with Pop, R&B the Essex Beat Club after 7pm & a DX style programme late at night

Lost until rediscovered by chance in the Medway Towns a 3.7" Gun operation plate from Knock John fitted when the gun was made, this one was removed in 1966 the plate has subsequently been preserved

The schedule did gain popularity mainly across South East Essex & parts of Kent

It wasn't to last, Roy Bates was summons on 28th September 1966 under of Section 1 of the Wireless Telegraphy Act of 1949

Thinking big Bates changed the stations name to Britain's Better Music Station, or BBMS as it was better known

On the 30th November 1966 Bates pleaded guilty of the charge & was fined £100

Who ever told him it would be 25KW!

Even though new datum lines to so called drying sandbanks had been drawn bringing Knock John a mile & a half within inshore waters, Bates stated that he believed the Fort was outside territorial limits

But with the anti-pirate law pending advertisers deserted the station, with revenue below a sustainable level Radio Essex ran out of money & closed down at 4.30pm on Christmas Day 1966

One of the Knock Johns 3.7" guns in 1979

The equipment was dismantled & taken to Roughs Fort of Felixtowe & whilst there are rumors of Radio Essex being heard up to 3rd January 1967 these are unfounded

The Knock John Fort looking South towards the Kent Coast & East towards Margate in Summer 2003

No visual sign of the flimsy war-time Dolphin but various odd bits of debris, detectable by echo-sounder litter the sea bed

Even when calm note the swirl of the ebbing tide

Radar top House & guns gone Knock John looks a sorry state

So famous in these parts they named a Fish & Chip shop after it at Greenhill Herne Bay Kent

But these premises ceased trading under the Knock John name

Three dimensional model images of the Knock John Naval Fort

Produced by Mark Wesley

These have been made for a film

To illustrate life on the Radio Essex/BBMS Radio Fort

We will keep you posted!

Grateful thanks to David Porter, Jon Myer, Steve Norris, Chris Stewart, Mark Wesley & Terry Vacani for their help in producing this feature

To commemorate the 40th anniversary we've published a book written by David Sinclair & Bob Le-Roi called Making Waves the Radio Essex story available from the Offshore Shop

For Radio from Knock John navigate from Radio Essex 222 & for Radio Essex on Roughs Fort navigate from Sealand One

For a brief history of all the Thames Estuary Forts see Fort Fax

We a range of documentary CD's, the Sealand VCD, books, & a video on the Army & Naval Forts available from the Offshore Shop