WWV receiver
 

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

WWV receiver
 

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

You could build a direct conversion receiver with a crystal oscillator.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

WWV receiver
 

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?

You might look at the Ramsey electronics 10 MHz WWV receiver kit. It's
a pretty basic crystal controlled superhet/ceramic filter/AM detector
with AGC.

Tim.

WWV receiver
 

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?

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.

WWV receiver
 

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

WWV receiver
 

"John S." wrote in message
ups.com...

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.

...

WWV receiver
 

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!

WWV receiver
 

xpyttl wrote:
"John S." wrote in message
ups.com...

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.

..

True, but his message did not make that clear. A receiver that tunes
to the HF voice signals won't work well on the LF band.

WWV receiver
 

WWV receiver
 

"xpyttl" wrote in message
...
However, depending on where you are, you can typically only hear WWVB for a
small part of the day.

Does a bigger antenna help? Or is there just so much more background noise
than signal that it's a lost cause?

Hmm... isn't the data rate something like 1bps? Maybe they could do some
direct sequence spreading at 100Hz or so and improve the link margin a handful
of dB... :-)

WWV receiver
 

Joel Kolstad wrote:

"xpyttl" wrote in message
...
However, depending on where you are, you can typically only hear WWVB for a
small part of the day.

Does a bigger antenna help? Or is there just so much more background noise
than signal that it's a lost cause?

Hmm... isn't the data rate something like 1bps? Maybe they could do some
direct sequence spreading at 100Hz or so and improve the link margin a handful
of dB... :-)

And lose the ability to be used as a frequency standard?


--
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

WWV receiver
 

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

WWV receiver
 

In article ,
xpyttl wrote:
"John S." wrote in message
oups.com...

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.

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.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

WWV receiver
 

"Tim Shoppa" wrote in message
oups.com...
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.

Well, I suppose it depends on where OP is. Here in the middle, 10 MHz isn't
much of a problem but 15 is.

*HOWEVER*, 10 has one huge advantage -- there are very low cost uP crystals
for 10 MHz, so building even a simple reciever with a brick wall front end
isn't such a big deal, if the only frequency you care about is 10 MHz.
Personally, I'd go with a DC rather than a regen - a lot simpler and these
days, a simple SA612 will give you way more sensitivity than you can
possibly use on 10 MHz for a couple bucks. Well, with a crystal filter in
front maybe you will need a little amp, not so sure. But still quite a bit
simpler than a regen. Heck, if the local QRM isn't too strong, I bet a 10
MHz uP crystal, a 612 and an audio amp (like a 386 or so) is all you would
need.

A friend of mine did an article on a simple WWV reciever for QRP Homebrewer
recently, issue #5 I think. He was more interested in the frequency
standard than hearing the sounds, so his contribution was recognizing the
zero beat, but still an interesting article if you can find a copy.

...

WWV receiver
 

On Tue, 24 Jan 2006 17:43:07 -0500, "xpyttl"
wrote:

"Tim Shoppa" wrote in message
roups.com...
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.

Well, I suppose it depends on where OP is. Here in the middle, 10 MHz isn't
much of a problem but 15 is.

*HOWEVER*, 10 has one huge advantage -- there are very low cost uP crystals
for 10 MHz, so building even a simple reciever with a brick wall front end
isn't such a big deal, if the only frequency you care about is 10 MHz.
Personally, I'd go with a DC rather than a regen - a lot simpler and these
days, a simple SA612 will give you way more sensitivity than you can
possibly use on 10 MHz for a couple bucks. Well, with a crystal filter in
front maybe you will need a little amp, not so sure. But still quite a bit
simpler than a regen. Heck, if the local QRM isn't too strong, I bet a 10
MHz uP crystal, a 612 and an audio amp (like a 386 or so) is all you would
need.

A friend of mine did an article on a simple WWV reciever for QRP Homebrewer
recently, issue #5 I think. He was more interested in the frequency
standard than hearing the sounds, so his contribution was recognizing the
zero beat, but still an interesting article if you can find a copy.


For wwv I consider DC the least useful. One approach I've also tried
is 9.6mhz crystal LO and use 455khz if can retuned to 400khz. that
works and uses fairly easy to get parts. That allows a diode
detector for zero beat against external sources and copy of the audio
without beats.

Allison

WWV receiver
 

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/

shortwave
 

On Tue, 24 Jan 2006, Tim Shoppa wrote:

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.

What are these high-power shortwave stations on the east coast? I often
wonder what is "out there" these days to tune in.

Tobin

WWV receiver
 

On Tue, 24 Jan 2006, xpyttl wrote:

Well, I suppose it depends on where OP is. Here in the middle, 10 MHz isn't
much of a problem but 15 is.

I am in Rochester, NY.

*HOWEVER*, 10 has one huge advantage -- there are very low cost uP crystals
for 10 MHz, so building even a simple reciever with a brick wall front end
isn't such a big deal, if the only frequency you care about is 10 MHz.

Yes, that is what I was thinking. Is there a simple way to do frequency
multiplication (or division) to get 2.5, 5, 15, and 20 MHz additionally,
and thus be able to switch between all of the WWV frequencies?

"Brick wall front end"?

Personally, I'd go with a DC rather than a regen - a lot simpler and these
days, a simple SA612 will give you way more sensitivity than you can
possibly use on 10 MHz for a couple bucks.

Heck, if the local QRM isn't too strong, I bet a 10 MHz uP crystal, a
612 and an audio amp (like a 386 or so) is all you would need.

That sounds great.

A friend of mine did an article on a simple WWV reciever for QRP Homebrewer
recently, issue #5 I think. He was more interested in the frequency
standard than hearing the sounds, so his contribution was recognizing the
zero beat, but still an interesting article if you can find a copy.

I don't see any articles on WWV receivers there... Does anything look
familiar: http://www.njqrp.org/data/qrp_homebrewer.html

thanks,
Tobin Fricke

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

WWV receiver
 

On Tue, 24 Jan 2006, wrote:

For wwv I consider DC the least useful. One approach I've also tried

What do yo umean by "least useful"?

is 9.6mhz crystal LO and use 455khz if can retuned to 400khz. that
works and uses fairly easy to get parts. That allows a diode
detector for zero beat against external sources and copy of the audio
without beats.

What is the 400 kHz used for?

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

WWV receiver
 

Tobin Fricke wrote:


is 9.6mhz crystal LO and use 455khz if can retuned to 400khz. that
works and uses fairly easy to get parts. That allows a diode
detector for zero beat against external sources and copy of the audio
without beats.


What is the 400 kHz used for?

Tobin Fricke

Incoming 10.000 MHz signal with a 9.600 xtal heterodyne oscillator will
create at .400 IF frequency. If you had a 9.545 xtal then a .455 IF
would add up to the 10.000 incoming freq. Six of one, half dozen of the
other. Thats based on an easy to find crystal.

You asked in another reply about the other nearby signals to 10.000.
There's plenty! The 9900-10000 freqs are in common use these days and
there's a few powerhouses. I recall a strong BBC outlet on 9985 I think
it is?

That said, on any receiver worth its salt they should not be an issue.
I have no trouble at all with WWV on 10 Mhz on even simple 1-2 tube
regen rcvrs at my location (KP4). Thats not a recommendation for simple
1-2 tube receivers in as much as to say that overloading is something to
be considered. You might oughta try listening on a real receiver first
to get a feel for the band and general reception capabilities at 10 MHz.
You can get one of those cheapo Chinese digital shortwave radios
nowadays for under $50, non digital for about $15-20. Not only will
they reveal how well WWV/10 is received at your location but you may get
a real-time example of overloading effects as well!


-Bill

WWV receiver
 

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

WWV receiver
 

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

WWV receiver
 

On Tue, 24 Jan 2006 17:20:35 GMT, "Michael A. Terrell"
wrote:

Joel Kolstad wrote:

"xpyttl" wrote in message
...
However, depending on where you are, you can typically only hear WWVB for a
small part of the day.

Does a bigger antenna help? Or is there just so much more background noise
than signal that it's a lost cause?

Hmm... isn't the data rate something like 1bps? Maybe they could do some
direct sequence spreading at 100Hz or so and improve the link margin a handful
of dB... :-)

If the problem is more or less random noise, what is the point of
spreading the transmit signal, since the same noise density would
appear in a specific bandwidth after despreading.

And lose the ability to be used as a frequency standard?

The GPS signal is DSSS and it can be used as a time and/or frequency
standard.

Paul

WWV receiver
 

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

WWV receiver
 

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

WWV receiver
 

On Tue, 24 Jan 2006 19:43:45 -0800, Tobin Fricke
wrote:

On Tue, 24 Jan 2006, wrote:

For wwv I consider DC the least useful. One approach I've also tried

What do yo umean by "least useful"?

I consider recieving AM transmissions with a system more optimum a
less than desireable thing unless the LO is locked (PLL) to the source
and thats a lot of complication.


is 9.6mhz crystal LO and use 455khz if can retuned to 400khz. that
works and uses fairly easy to get parts. That allows a diode
detector for zero beat against external sources and copy of the audio
without beats.

What is the 400 kHz used for?

IF amplifer as in superhet style of reciever.

Allison

WWV receiver
 

"Tobin Fricke" wrote in message
F.Berkeley.EDU...

I don't see any articles on WWV receivers there... Does anything look
familiar: http://www.njqrp.org/data/qrp_homebrewer.html

Sorry, I meant "Homebrewer" rather than "QRP Home brewer". The AmQRP rag
rather than the now-defunct NJQRP mag.

...

WWV receiver
 

Paul Keinanen wrote:

The GPS signal is DSSS and it can be used as a time and/or frequency
standard.

So, you want everyone still using WWVB for a frequency standard to
spend wads of cash to convert?

--
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

WWV receiver
 

Allison wrote:
[Regens]
The trick with regens is to couple as loosely as possible.

And, to the original poster (Tobin), don't take anything I wrote as
being bad about regeneratives being a great first receiver project.
They are a wonderful first receiver project. Just don't do it to
receive one particular station, do it instead to receive all the
interesting stuff going on.

Tim.

WWV receiver
 

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.

WWV receiver
 

"Tobin Fricke" wrote in message
F.Berkeley.EDU
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

You might try and find a user manual for the old Heathkit GC-1000 Most
Accurate Clock.
It synchonizes the clock and local oscillator to the WWV transmissions
at 5, 10 or 15 MHz. The kit came with a preassembled and prealigned RF
board but you still had to assemble the data recovery and other parts of
the unit. The manual includes full schematics (including RF board) and
a good theory of operation section. The only thing missing are
instructions on aligning the RF board. The silly thing works pretty but
I had to build an antenna and install it in by attic to get it to
sychronize reliably.

--
James T. White

WWV receiver, CHU proposal...http://cbc.am/CHU.htm
 

CHU Time Station : Western Canada Coverage Proposal

The CHU time station is Canada's domestic shortwave time signal station.
CHU existed long before the Internet and sattilite navigation systems like
(GPS, GLONASS, Gallaeo).
CHU provides most of the functionality of the US WWV & WWVB (Bolder,
Colorado) and WWVH (Kauai, Hawaii).

Problems with CHU's configuation that this proposal addresses

The 3.3µs per km of path that makes CHU's signals problamatic for users in
Western Canada. Even the NRC realizes this: "for all distant users of CHU,
the dominant source of time error comes from the radio wave path reflecting
off the ionosphere as the radio signal travels from the transmitter".
The poor quality of CHU reception in Western Canada and the Artic, North of
55º Latitude.
It is suggested that the 7335 kHz frequecny be reused, but it may be
advisable to find alternate frequences.
The CHU signal fomat may need to be tweaked so as to take into consideration
2 transmitter sites.
A new set of atomic clocks will be needed, as well as equipement to sync
them to NRC's atomic clocks. It may be possible to obtain secondhand atomic
clocks from UBC (Vancouver) or other universities in Western Canada.
This proposal could be replicated in Newfoundland using another existing CHU
frequency, as Eastern Canada has CHU coverage problems as well.
Universally upgrading CHU's Ottawa transmitters to 10 kw may not fix CHU
coverage problems in Western or Eastern Canada.
[...]

http://cbc.am/CHU.htm


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?
--
http://web.pas.rochester.edu/~tobin/

WWV receiver
 

you HAVE to use a crystal oscillator. due to the nature of the tuned
resonant circuits, mistuning can change the propagation delay of the
signal through the receiver by incredible amounts. soooo, you have to
be on frequency. i think I still have some where a schematic of such a
receiver from Popular Elactronics but it may take a while for me to
find it.
Saandy 4Z5KS


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

WWV receiver
 

From: Tobin Fricke on Jan 24, 7:41 pm

On Tue, 24 Jan 2006, xpyttl wrote:

Well, I suppose it depends on where OP is. Here in the middle, 10 MHz isn't
much of a problem but 15 is.

I am in Rochester, NY.

There should be no real problem in receiving WWV in NY state unless
you want to do it with a few feet of hook-up wire dangling inside
the room. For just WWV on HF, use whatever is handy for a long-
wire OUTSIDE...some #26 or #28 coil wire would work and be near-
invisible on the outside.

The sensitivity needed by your receiver depends ENTIRELY on how
much signal arrives in your area and how much of that the antenna
intercepts.


*HOWEVER*, 10 has one huge advantage -- there are very low cost uP crystals
for 10 MHz, so building even a simple reciever with a brick wall front end
isn't such a big deal, if the only frequency you care about is 10 MHz.

Yes, that is what I was thinking. Is there a simple way to do frequency
multiplication (or division) to get 2.5, 5, 15, and 20 MHz additionally,
and thus be able to switch between all of the WWV frequencies?

To make a simple superheterodyne receiver, even if just single-
conversion using a legacy 455 KHz IF, capitalize on some simple
tuning arrangements using an RF Amp, Mixer, 1 or 2 stages of IF:

1. A single set of front-end inductors, tune RF and LO with Cap.

2. Capacitor tuning using fixed+trimmers. Frequency range of
5, 10, 15 MHz selected by rotary switch has a total frequency
range of 3:1 high to low. The capacitance change ratio for
this is the square of the frequency change ratio or 9:1.

Note: In the old "communications receiver" designs, it was
typical to cover a 3:1 frequency change ratio with a "365 pFd"
variable capacitor (typically 40 to 360 pFd min. to max.).

3. If there are temperature-drift problems in the LO, just make
use of a small front-panel control to a parallel trimmer cap
on the LO tuning (added to the cap. of the LO resonant ckts).

4. In most cases, the temperature drift is negligible and one
can make do with behind-the-front-panel trimmer cap. settings
for three switch-selected frequencies. Some simple experiments
with an oven termometer and a frequency counter would let you
check out the drift versus temperature and compensate. Begin
with mostly NPO caps fixed for the LO tuning, expect a towards-
low-frequency drift, compensate with negative-temp coefficient
fixed capacitors for the NPOs. Temperature drift is highly
dependent on WHAT you build and HOW you build it.

"Brick wall front end"?

No need. WWV time-frequency service frequency allocations have a
protected 10 KHz bandwidth, protected from other modes in other
radio services. Given a typical Q of about 40 and two tuned
stages (ant to RF amp, RF amp to Mixer), the bandwidth would be
about 80 KHz (5 MHz) to 250 KHz (15 MHz) in the front-end. With
an IF of 455 KHz, the image frequency would be 910 KHz away.

WWV is AM, not SSB, and most probably will be used to zero-beat
external CW frequency sources that are going to be calibrated.

For those who want "extreme accuracy" in time, just compare the
time-ticks to a 1 Hz (divided down from standard to be checked)
local tick. That was the way things were done with the old
General Radio primary standards equipment circa 1950-1960, good
to 1 part per million accuracy without sweat.


Personally, I'd go with a DC rather than a regen - a lot simpler and these
days, a simple SA612 will give you way more sensitivity than you can
possibly use on 10 MHz for a couple bucks.
Heck, if the local QRM isn't too strong, I bet a 10 MHz uP crystal, a
612 and an audio amp (like a 386 or so) is all you would need.

That sounds great.

If all that is wanted is SIMPLICITY, just use any old SW BC or
wide-tuning-range HF receiver. [suggested by another]

You can convert an old "All-American-Five" AM BC receiver to
receive 5 to 15 MHz just by substituting the "coils" (inductors
is the proper word now). Substitute an inductor for the old
loop or loopstick...with a primary link for an external antenna.
[I did this many, many years ago...it works] It won't be "top
of the line" in performance, but then a regen isn't that either.
The IF can be aligned easily and the new front-end alignment
is fairly easy.

The old Hallicrafters S-38 four-band "starter" receiver that
many used was really a simple "All-American-Five" Mixer-Single IF-
AM detector-Audio Output arrangement with an added BFO. A BFO
isn't needed to beat a local frequency standard with WWV.

Assuming an original 45 pFd, 101 pFd, 405 pFd capacitance (which
includes the stray circuit capacity) to tune 15, 10, 5 MHz, a
2.5 uHy inductance will do the job. A trimmable inductor would
be best there. The first task is to check the inductor
substitutions with the existing variable capacitor. If that works,
the variable can be substituted by a switched trimmable capacitor
to avoid the knob-twisting for three HF selections...or two, or
none at all assuming fixed tuning to 10 MHz.

An old tube AM BC receiver relegated to the basement/garage
junkpile is a good candidate for this kind of thing. Tube type
radios are a bit easier to work with if you aren't acquainted
with newer solid-state circuitry. Those are certainly cheap. :-)

A converted "All-American-Five" will NOT have great sensitivity.
But, since tubes' stage gains are essentially transconductance x
load impedance, the individual gain stages can be optimized by
going for minimum-C in resonant circuits. Not that easy with
old transistor radios having individual transistor stages...those
needing fussing about with matching input-output impedances.

A friend of mine did an article on a simple WWV reciever for QRP Homebrewer
recently, issue #5 I think. He was more interested in the frequency
standard than hearing the sounds, so his contribution was recognizing the
zero beat, but still an interesting article if you can find a copy.

I don't see any articles on WWV receivers there... Does anything look
familiar: http://www.njqrp.org/data/qrp_homebrewer.html

Depends on WHAT EXACTLY you are striving for and your own
experience-knowledge. If you are a relative beginner (we all
were once), then I'd suggest converting an old tube type BC
receiver. That avoids the construction hassle and concentrates
on individual theory areas during conversion. It's the least
expensive route if using an old BC junker receiver. Individual-
area concentration can teach more about those areas than building
a pre-designed kit or magazine article project.

WWV receiver
 

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

WWV receiver
 

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.

WWV receiver
 

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

WWV receiver
 

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

WWV receiver
 

"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.

...

WWV receiver
 

"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.

...