[sdiy] A Frequency Standard for Poor People?

[Brice D. Hornback]

Calibrated TCXO Frequency Standard
http://www.aade.com/freqstd/freqstd.html

"Consists of a 20 MHz TCXO module calibrated against a Rubidium frequency
standard to about
0.1ppm (1Hz accuracy at 10MHz).  Long term accuracy approximately 1ppm (1Hz
accuracy at 1MHz).
This drives a divide by 2 to produce 10MHz output, then by three stages of
divide by 10 to produce
additional 1MHz, 100KHz and 10KHz outputs. "

$39.95

I hope this helps.

- Brice
http://www.SynthModules.com

----- Original Message ----- 
From: "Magnus Danielson" <cfmd at bredband.net>
To: <mclilith at charter.net>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, December 15, 2003 9:49 AM
Subject: Re: [sdiy] A Frequency Standard for Poor People?


> From: Glen <mclilith at charter.net>
> Subject: [sdiy] A Frequency Standard for Poor People?
> Date: Mon, 15 Dec 2003 08:32:17 -0500
> Message-ID: <4.1.20031215081602.009582f0 at mail.charter.net>
>
> Dear Glen,
>
> > In the past, I've seen DIY articles about building inexpensive,
precision
> > frequency references. Unfortunately, I don't have any of these articles
> > handy at the moment. In concept, I think they all relied on extracting
> > precision reference signals from "someone else's" existing reference
signal.
> >
> > Such as, extracting a reference signal from:
> >
> > "time and frequency" SW radio stations
>
> In the US/North America you can sniff up a load of usefull signals from
NIST.
> There are many different projects for it. Further, you can sniff the
LORAN-C
> chains and there is a there is a full-featured project for that from Dave
> Mills. Beyond that there is the Rugby 60 kHz and DCF77 at 77.5 kHz here in
> Europe in addition to the LORAN-C chains.
>
> > signals derived from color television broadcasts
>
> Can be tricky if you are not sure about the traceability of the signal,
i.e.
> if you know that it actually derives from a stable enought source. Both
PAL
> and NTSC allow for single digit PPM deviations and speed of deviations can
be
> quite severe.
>
> > GPS receivers
>
> I am not sure that I've seen a good project for it, but have considered
doing
> one myself.
>
> > Anything else?
> >
> > Does anyone on the list know about any of these methods?
>
> Yes. ;O)
>
> > I could really use a reliable frequency reference, to check the
calibration
> > of a frequency counter. I want something that is very accurate, but also
very
> > cheap. Is it possible?
>
> Define cheap.
>
> > Which method gives the best results, and which is the least expensive
system
> > to construct? Unfortunately, I can't afford to spend much money.
>
> My bet would be a GPS receiver. Many if not all have PPS outputs. You then
use
> a VCXO and lock this to the PPS through a suitable PLL/FLL method. The
details
> of this locking determines the accuracy and ability to trace the
frequency, but
> you can get *really* good results with it, but a fairly quick and dirty
> solution should be sufficiently good for most amateur uses anyway.
>
> I've made a rought estimate of about 300-350 USD for such a receiver
(including
> antenna). That included a rather good VCXO (about as much money as the GPS
> receiver module itself).
>
> Cheers,
> Magnus
>