[sunthaiboy]

Thank you for the reminder about unauthorised emissions and duly noted. Fortunately it is not yet illegal to own such "emitting devices" of which I have several much larger, although I will not hold my breath on this point.

Criggion MW Radio Station and the VLF site 50m away broadcast field strengths high enough to burnt out the tops of trees and support posts that held the ground counterpoints in place. The stray emissions from the pantry transmitter tank coils inside a blast proof building are suitably attenuated and don't even false trigger my cardiac pacemaker. The same cannot be said from modern switch mode PSU's which radiate wonderfully at LF through mains wiring, which makes a super antenna. Criggion LF/MW prior to de-commissioning had a Marconi HS51 (30KW) and as everybody in the know knows the VLF Tx had a custom built PA stage that fed 600KW at 250KV into the hill mounted antenna and was initially used in CW and as such modulated the main 11KV EAS before the 33KV upgrade.

I have not yet studied the Xtal in detail which sits in a tobacco tin on the lower deck. I doubt it has drifted that far off. I don't think David was a Amateur Radio man, so that's why it has "Pantry" classification. David did work at Daventry in the late 50's and went on to work in Ascension so probably knew a thing or to about emissions. The mode of operation is A3E. There is magic eye indicator which monitors the modulation levels (alas not visible in my photo). IP's are suitably low as there is a 3 tap band pass filter between the lower deck and the upper (PA stage).

I am currently building a much larger one with a similar layout.......