From: (Mark Zenier) on Tues, Jan 24 2006 7:13 pm

xpyttl wrote:
"John S." wrote in message

Are you looking to decode the data transmissions or listen to the voice
signals. If the former it may take something more sophisticated
because you will have to feed a decoder.

Well, the 60 kHz WWVB transmissions were designed to be decoded, and there
are a fair number of projects out there to do just that. However, depending
on where you are, you can typically only hear WWVB for a small part of the
day.

For information on the WWV, WWVH, WWVB time codes and signal
strength, go to: http://tf.nist.gov/timefreq/index.html

From the coverage diagrams (every 2 hours), most of the
contiguous states of the USA get sufficient signal from
WWVB in any 24-hour period. That has been observed here
(Los Angeles County) using a 2 1/2 foot diameter loop;
distance to Ft. Collins is roughly 800 miles (?).

By actual test, my LaCrosse radio wris****ch was able to
sync on WWVB on an auto trip to Wisconsin and back over
September to October. Typically such radio watches only
begin checking/syncing after midnight local time. The
internal quartz timing oscillator remains stable (for
time indication) within one second in 24 hours.

Radio clocks are consumer electronics items that typically
cost $20 to $30 (depending on display size and extras such
as local temperator). If all that is wanted is automatic
time setting, it may not be a good return on time
investment to build one's own automatic-setting clock.
Those radio clocks aren't much good for zero-beating a
local frequency standard except: If the local standard
is counted down to 1-second pulses for comparison with
the radio clock (arduous process to check).

The same time code is in the WWV HF signals as a 100 Hz, One Baud, pulse
duration modulated subcarrier tone. If you've only got a communications
grade speaker in your receiver, you may not notice it.

There was once a KIT for a WWV time code receiver (Heathkit?).
As memory serves, it cost about $400 just for the kit! That
was in much older days before 25-cent 74LS00 chips.

The original requestor wanted a WWV receiver, presumably to
zero-beat a local crystal standard. ANY HF receiver will do
for that, but preferrably one whose S-Meter can show very
slow beats (well below 100 Hz). As another suggested, a
cheapo import SWL receiver can do that, adding only a
metering connection to the internal AGC line (for the slow
zero beat). Bandwidth of the IF is not of great importance
since the time-frequency bands are wider than the usual
cheapo receiver IF bandwidth.

In the northern Los Angeles area, I've never had a problem
picking up either WWV or WWVH on 5, 10, or 15 MHz, even with
a few feet of hook-up wire as an antenna. That's over a 42
year residence in this same house here. The time ticks are
good for checking progressive aging of local frequency
standards which are counted down to 1 second output...that
compared with the time tick in delay...and delay change (to
indicate very slow changes in the local frequency standard).

The time tick method was once the ONLY precise way to check
out local L.A. frequency standards when WWV was located
back east. That preciseness was to better than 1 part per
million.

A simple TRF arrangement tuned to 5 MHz will do the trick
for a receiver used solely for zero-beating and hearing the
voice announcements and time ticks. The interstage tuning
will be stable enough to pick up WWV or WWVH. To get 10
or 15 MHz carriers, add a mixer to the antenna input with
a local oscillator of 5 and 10 MHz. A local frequency
standard can supply that; no extra LO crystals required.
Four stages tuned to 5 MHz with Q = 100 will result in an
overall TRF/IF bandwidth of about 20 KHz, quite adequate
for WWV/WWVH.

On Mon, 23 Jan 2006, John S. wrote:

Are you looking to decode the data transmissions or listen to the voice
signals. If the former it may take something more sophisticated because
you will have to feed a decoder.

I'm interested in both. From the radio perspective, I'll certainly be
happy (but not satisfied) when I am able to hear the station's audio.
However, I was thinking this would be a good project in part because it
leads to the logical extension of decoding the time signals. My plan of
attack is to first try to get the audio, then try inputting it to the
audio input of a PC and writing a program to decode the time signal, and
finally implementing some kind of microprocessor-based decoder.

Tobin Fricke
--
http://web.pas.rochester.edu/~tobin/

On Mon, 23 Jan 2006 08:39:46 -0800, 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?

thank you,
Tobin
The 30 meter Vectronics direct conversion receiver kit can be tuned to
receive WWV. I built one, and before I moved the range up to the 30
meter ham band at 10.100MHz, I used it with WWV at 10.000 MHz to
calibrate my frequency counter.
Ted KX4OM

On Mon, 23 Jan 2006 08:39:46 -0800, 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?

thank you,
Tobin

How about a simple one to three transistor regenative reciever. There
are several on the net.

Here's a few:

w1.859.telia.com/~u85920178/rx/regenrx.htm
http://www.techlib.com/electronics/regen.html
http://www.tricountyi.net/~randerse/regen.htm

Try Google for more.

Allison
no spam, no uce!

wrote:
How about a simple one to three transistor regenative reciever.

In principle that's a great idea, but the gotcha is that very near
WWV's 10MHz frequency there are a lot of powerhouse SW broadcasters.
Here on the East Coast in the evenings, there are at least 10 SW
broadcasters each of which are 10x more powerful all within +/- 100kHz
of 10MHz, several of them within 10kHz of 10MHz.

If I fire up my regenerative receiver (my trusty old Space Spanner that
my Dad bought for me when I was in 2nd grade!) WWV 10MHz reception does
not work at all in the evenings due to those broadcasters, my
particular regen just does not deal well with all those stations packed
so tight together. The adjacent broadcasters block up the receiver or
sometimes the regen locks onto them instead!

On 5 or 15 or 20 MHz, or on the west coast, the regenerative may welll
work better. (There are SW broadcasters near 5 and 15 but not nearly so
close and not nearly so packed.)

If the OP is looking for a build-it-yourself SW receiver for picking up
the powerhouse SW broadcasters, then a regen is a fine choice. In fact
my complaint is that my regen doesn't pick up WWV because of all those
other broadcasters outgunning it here :-).

Ten-Tec and others sell really nice regenerative receiver kits for SW.

Tim.

On 24 Jan 2006 07:58:14 -0800, "Tim Shoppa"
wrote:

wrote:
How about a simple one to three transistor regenative reciever.

In principle that's a great idea, but the gotcha is that very near
WWV's 10MHz frequency there are a lot of powerhouse SW broadcasters.
Here on the East Coast in the evenings, there are at least 10 SW
broadcasters each of which are 10x more powerful all within +/- 100kHz
of 10MHz, several of them within 10kHz of 10MHz.

If I fire up my regenerative receiver (my trusty old Space Spanner that
my Dad bought for me when I was in 2nd grade!) WWV 10MHz reception does
not work at all in the evenings due to those broadcasters, my
particular regen just does not deal well with all those stations packed
so tight together. The adjacent broadcasters block up the receiver or
sometimes the regen locks onto them instead!

On 5 or 15 or 20 MHz, or on the west coast, the regenerative may welll
work better. (There are SW broadcasters near 5 and 15 but not nearly so
close and not nearly so packed.)

If the OP is looking for a build-it-yourself SW receiver for picking up
the powerhouse SW broadcasters, then a regen is a fine choice. In fact
my complaint is that my regen doesn't pick up WWV because of all those
other broadcasters outgunning it here :-).

Ten-Tec and others sell really nice regenerative receiver kits for SW.

Tim.

The trick with regens is to couple as loosely as possible. There is
enough gain in most regens that even a very loose coupling is enough
to overlaod and flatten out the selectivity.

At 5mhz I have no difficulty here is MA and at 10mhz it's still not a
problem. I've even heard WWVH from here when propagation was good.


Allison

On Tue, 24 Jan 2006, wrote:

The trick with regens is to couple as loosely as possible. There is
enough gain in most regens that even a very loose coupling is enough to
overlaod and flatten out the selectivity.

Could you recommend a good introduction to the theory of the regenerative
receiver (and superregen)?

thanks,
Tobin

Tobin Fricke wrote:

On Tue, 24 Jan 2006, wrote:

The trick with regens is to couple as loosely as possible. There is
enough gain in most regens that even a very loose coupling is enough
to overlaod and flatten out the selectivity.


Could you recommend a good introduction to the theory of the
regenerative receiver (and superregen)?

thanks,
Tobin


I'll recommend a little book that is readily available. "Secrets of
Homebuilt Regenerative Receivers" by C.F. "Rock" Rockey. Its a Lindsay
Publications book.
Rockey does a good job at simplifying the simple Basically the
concept of a regen is feeding the output back into the input for
reamplification. Theoretically its a somewhat infinite process in that
the reamplification continues repeating itself resulting in very high
gain at the particular frequency the set is tuned to and thats also
where the selectivity improvement comes from.
Its similar to oscillation in a tube.

The coupling issue mentioned by Allison is related in the sense that
heavy antenna loading will decrease the circuit Q and consequently
decrease its selectivity as the regenerative signal makes its round-trip
thru the circuit. That opens the window for strong stations that are
well off frequency to easily overload the circuit as a whole due to the
high magnitude of amplification. You'll see some circuits with direct
antenna connections to the tank circuit (bad)...some use a separate
antenna winding on the coil (better) some use capacitive coupling to
the tank...some use a combination of both.

Easy enough to build one for grins...might not be as stable as you would
want for your decoding project but would be a good, fun exercise just
the same.

GL,
Bill

On Tue, 24 Jan 2006 20:06:22 -0800, Tobin Fricke
wrote:

On Tue, 24 Jan 2006, wrote:

The trick with regens is to couple as loosely as possible. There is
enough gain in most regens that even a very loose coupling is enough to
overlaod and flatten out the selectivity.

Could you recommend a good introduction to the theory of the regenerative
receiver (and superregen)?

thanks,
Tobin
You may want to consider this little regen receiver project. The board
for it is available from Far Circuits for around $5, or you could make
your own board.
http://www.electronics-tutorials.com...o-receiver.htm

Mike

On Tue, 24 Jan 2006 20:06:22 -0800, Tobin Fricke
wrote:

On Tue, 24 Jan 2006, wrote:

The trick with regens is to couple as loosely as possible. There is
enough gain in most regens that even a very loose coupling is enough to
overlaod and flatten out the selectivity.

Could you recommend a good introduction to the theory of the regenerative
receiver (and superregen)?

thanks,
Tobin

I Don't have any but I'd look on the net as there are gobs of circuits
with explanation. However the best explaied ones may be the older
tube designs.

Allison