Tobin Fricke wrote:

As a project to learn more about building radio receivers, I'd like to
build a WWV receiver (or maybe a receiver for the Canadian station CHU,
since it's nearby and the format sounds easier to decode). I'm looking
for suggestions for how to design such a radio, reading material, etc.

I was thinking it might be easier to design a fixed-frequency receiver
(rather than a tunable one) because I could just select the L and C in the
resonant circuit to give the right frequency. Or, since WWV is at such
"round number" frequencies, maybe I could somehow use a crystal
oscillator?

Tobin-

A couple other ideas:

1. Try your hand at building a crystal set! Just an antenna, a tuned
circuit, a diode and earphones. There could be more sophistication such
as using an amplified speaker and higher-Q tuned circuits.

2. Try a direct-conversion receiver. It may be just a more sophisticated
crystal set with RF preamplifier and on-frequency crystal filter. A
product detector could be included to convert to audio, but a diode
detector should work and wouldn't change the audio tone frequencies.

I considered using this direct-conversion approach to obtain an accurate
10 MHz signal. I wanted to use it to synchronize my oscilloscope so I
could adjust a counter's timebase (or vice-versa). However, I never built
it after finding a Rubidium controlled oscillator on eBay.

Fred

Fred McKenzie wrote:

Tobin Fricke wrote:

As a project to learn more about building radio receivers, I'd like to
build a WWV receiver (or maybe a receiver for the Canadian station CHU,
since it's nearby and the format sounds easier to decode). I'm looking
for suggestions for how to design such a radio, reading material, etc.

I was thinking it might be easier to design a fixed-frequency receiver
(rather than a tunable one) because I could just select the L and C in the
resonant circuit to give the right frequency. Or, since WWV is at such
"round number" frequencies, maybe I could somehow use a crystal
oscillator?

Tobin-

A couple other ideas:

1. Try your hand at building a crystal set! Just an antenna, a tuned
circuit, a diode and earphones. There could be more sophistication such
as using an amplified speaker and higher-Q tuned circuits.

2. Try a direct-conversion receiver. It may be just a more sophisticated
crystal set with RF preamplifier and on-frequency crystal filter. A
product detector could be included to convert to audio, but a diode
detector should work and wouldn't change the audio tone frequencies.

I considered using this direct-conversion approach to obtain an accurate
10 MHz signal. I wanted to use it to synchronize my oscilloscope so I
could adjust a counter's timebase (or vice-versa). However, I never built
it after finding a Rubidium controlled oscillator on eBay.

Fred

I know that there are several plans on the internet for building a radio
controlled clock. These involve building a fixed frequency rx and then
hooking it up to a clock. How feasible would it be to hook the same
circuit up to an amp and speaker instead of a clock? I suspect that the
clock radios listen in on 60khz, but it should be simple to insert a
crystal or change it to get 10Mhz. Also, you could build a radio with
three frequencies-5Mhz, 10Mhz, and 15Mhz in order to take advantage of
day vs night propagation.

On Sat, 04 Feb 2006 19:12:18 -0800, running dogg wrote:



I know that there are several plans on the internet for building a radio
controlled clock. These involve building a fixed frequency rx and then
hooking it up to a clock. How feasible would it be to hook the same
circuit up to an amp and speaker instead of a clock?

I haven't looked at any of these circuits, but I'd expect it to be
quire easy to connect and audio amplifier and speaker to the output of
the detector.

I suspect that the
clock radios listen in on 60khz, but it should be simple to insert a
crystal or change it to get 10Mhz. Also, you could build a radio with
three frequencies-5Mhz, 10Mhz, and 15Mhz in order to take advantage of
day vs night propagation.

Converting a 60 KHz receiver to 10 MHz is likely impossible -
construction techniques and tuned circuits will be quite different -
you can almost use audio techniques and iron-core coils at 60 KHz, but
are well into RF territory at 10 MHz, and will likely have to use
air-core coils in the tuned circuits.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

Hello Peter,


Converting a 60 KHz receiver to 10 MHz is likely impossible -
construction techniques and tuned circuits will be quite different -
you can almost use audio techniques and iron-core coils at 60 KHz, but
are well into RF territory at 10 MHz, and will likely have to use
air-core coils in the tuned circuits.


Not just that. The transmitted code is also different.

Regards, Joerg

http://www.analogconsultants.com

"Joerg" wrote in message
news:TwmFf.27179

Not just that. The transmitted code is also different.

He wants to listen, and at least at 10 MHz there's something to listen TO.
The 60Khz signal is pretty strange.

...

xpyttl wrote:

"Joerg" wrote in message
news:TwmFf.27179

Not just that. The transmitted code is also different.

He wants to listen, and at least at 10 MHz there's something to listen TO.
The 60Khz signal is pretty strange.

..


No, its not. It was never intended to be listened to. It has a 1 BPS
data rate encoded time signal that has always been used to carry time
code.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

In Europe,namely,England,they have the ten notches.
cuhulin

In other words,,, he wants to experiment? Nothing wrong with that!
cuhulin

xpyttl wrote:


Not just that. The transmitted code is also different.

He wants to listen, and at least at 10 MHz there's something to listen TO.
The 60Khz signal is pretty strange.


Tobin wrote "... easier to decode". So I guess he is after decoding and
not so much after listening.

Regards, Joerg

http://www.analogconsultants.com

"Peter Bennett" wrote in message

are well into RF territory at 10 MHz, and will likely have to use
air-core coils in the tuned circuits.

Huh? Yes, he is well into RF and construction techniques will be different.
But while there are advantages to air-coil cores, their use in recievers
went out with hollow state detectors. Even in transmitters they tend to be
only used in the KW neighborhood anymore. I can't imagine that even in the
wilds of BC people are winding air coils and building on heavy steel
chassis.

...