----- Original Message -----

Sent: Monday, June 10, 2002 12:35 AM

Subject: Re: LF: DJ

In a message dated 6/9/02 7:02:29 PM GMT Daylight Time, g3kev.ham@virgin.net writes:

Re: Decca

Using the original coils the inductance when measured in the case and out of the case varies by several Uh and therefore difficult to resonate/align properly

Not really.
The coils have about 3 turns at the top of the former that are not fixed other than with a tywrap.
These turns can be fully or partially wound in-phase or out of phase in order to precisely resonate the tank circuits where you need them.

Only applicable to the A model on 127 khz and even then is not the best approach for optimum alignment on 137 khz. The methods that I recommend in my previous message will give the best results with a mimimum of trouble, and by adjusting the core the resonant frequency is easily changed to cover the whole band, any frequency between 135.7 - 137.8 khz.

Using the ferrite core method just select the appropriate tap to resonate on the desired frequency.

Adjust each of the 3 coils.

All models except A need turns removing from the coils for optimum LC using the BCB capacitor boards on 137 khz. Capacitor boards BCA need modification as well as the coils for 137 khz.

Others in the UK have published information on their WEB sites about Decca mods, so take your pick.

G3KEV

73

David G0MRF