Re: Frequency Standard Crystal filters


Geoff Blake <geoff@...>
 

On Fri, 16 Dec 2005, David Wrigley wrote:

Hi Malcolm,

£67 + VAT is outrageous. If you wanted a 60KHz crystal it would be less than
£10.

We had this problem a few years ago and Mike Scott designed a trf receiver
using several TOKO tuned ccts instead of the crystal. I can let you have
this cct if you haven't seen it.

However since that time and after playing with such a receiver I have
reached the conclusion that a better design would be a superhet. Now I
realise that a superhet would require a super stable LO but this could be
derived form the 10MHz freq std......
David,

A large part of a lifetime ago, I had the dubious priviledge of
maintaining the distributed standard frequency system of a (then) large
research labs near here.

The prime mover was two Marconi RD101 crystal bridge standards and the MSF
off-air receiver used 50kHz (derived from one RD101) as the local osc and
a 10kHz phase comparator. This worked quite well and plotted on a 10"
Foster recorder.

The whole system was valve (several 100's of CV4014's including the
distribution rack) and the RD101 was the frequency standard part on the
Marconi TME02 system.

The off air comparitor was replaced with a Hewlett Packard 117A standard
frequency receiver sometime in the mid '70's. and the RD101's with a Rhode
& Schwarz Rb87 standard in the '80's - long after I had moved on.

Happy Crimbletide.

Geoff
--
Geoff Blake G8GNZ located near Chelmsford, Essex, U.K.
Please reply to: geoff (at) palaemon (dot) co (dot) uk
Using Linux on Intel & Linux or NetBSD on Sun Sparc platforms

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