I'm in Richmond, Virginia and I'm trying to noticeably improve my
reception of WWV's 10MHz signal from Fort Collins, Colorado. It all
seemed so simple, two weeks ago: wind some wire, solder a
connector, and Hey...presto! a clean WWV signal. grin!

It wasn't so simple, and I'm afraid I've let it become an "ego
thing" (see also: resource sink). I've outlined the problem below
in the hope that someone can either suggest something I haven't
already tried, or even point out something really dumb that I've
been doing and shouldn't keep doing. grin!


Background
----------

Several years back I inherited a Heathkit GCW-1001 Most Accurate
Clock II from my father. This is an update to it's predecessor,
Heath's GC-1000 Most Accurate Clock; its circuit, built around a
Philips TDA1072A AM receiver IC and an 87C52 microprocessor,
monitors WWV's 10MHz signal and decodes the BCD-coded 100Hz
subcarrier (details at http://tf.nist.gov/stations/wwv.html) to keep
the MAC-II accurate.

This MAC-II worked fine for my father: he had a 30 meter dipole of
some kind in the attic, above the second floor of a house on a hill.
For him, WWV's 10MHz signal from Fort Collins came in regular as...
well, "clockwork". igg!

For me, in a one-story-plus-basement, in a low spot in a river
valley, it's a different story. The GCW-1001 has a stack-o-LEDs
signal strength indicator driven by the TDA1072's AGC output; it
would wander between 2 and 4 LEDs with my 40" indoor dangling wire
antenna, and it could take weeks or months for atmospheric
conditions to randomly improve the signal to where the GCW-1001
could "lock in" a time.

Two weeks ago, in a fit of madness, I decided to try building a
better antenna, one which would let the clock lock onto WWV at
least, say, once a week. The tuned-loop antenna I've built _has_
increased the signal -- I'm seeing 4-5 LEDs lit on a regular basis,
and 6 on occasion -- but the clock still isn't sync'ing to WWV's
time signal. The clock face remains at a cute(?) 7-segment "not
SEt" display. And what seems to be louder is the carrier -- or _a_
carrier, at any rate -- but not the tones or the human voice time
callout coming out of the GCW-1001's speaker.

I seem to be up to my assets in alligators, and the swamp doesn't
seem to be draining much.


Problem
-------

My main problem is that, although the GCW-1001's LED "Signal" stack
_says_ it's getting a stronger signal, what I hear through the
speaker monitor isn't _clearer_. There are long periods when I
cannot hear any WWV tones through the GC-1001's speaker, the
tones/ticks are faint even when there are 5-6 LEDs lit, and the
voice is almost never audible/distinguishable. The clock _seems_ to
be sync-ing a little more often (it's done it four times in the past
two weeks), but I had hoped it might happen a _little_ more
frequently.

Am I asking too much? Is WWV's 10MHz signal from (say) 2,000 miles
away, simply too weak to pick up solidly without an outdoor antenna?


What I've tried
---------------

My (second) attempt at a 30m indoor loop antenna:

Main loop (tuned): A 36" near-circle of #12 insulated house wire
with an AM/FM tuning capacitor across it.

Pickup loop: One (36") turn of #27 magnet wire taped to the #12
loop with electrical tapegrin!. The ends (scraped and tinned)
are tied to the GCW-1001's 50ohm antenna input with a couple of
12" clip leads and a 3' section of coax.

The loops are mounted on (and held in shape by) a 1'x4'x0.5"
"backboard" made of "blue foam" house insulation that I found in my
basement; the loops are held in place by small plastic cable ties.
The foam backing is resting against a (roughly) N-S wall, which
_should_ orient the loop plane across the WWV wavefront for maximum
pickup.

Does this sound like a reasonable attempt at a tuned 10MHz loop?

Is there any reason to believe that the foam backing would affect
the loop inductance? I'm assuming it's a good insulator and nothing
more, but that's an assumption.

Is it possible that I'm picking up a non-WWV dignal so strong that
it's masking WWV? I tried tuning around 10MHz with a shortwave
radio; it didn't find WWV -- not a particularly hopeful sign -- but
it did pick up a station called (IIRC) WWCR. WWCR's 'web site
(www.wwcr.com) lists its transmitter #4 as using 9.985MHz and
9.975MHz between 0900 and 2100 CST.

Any advice or suggestions will be appreciated, up to and including
"You can't power a hedge trimmer from two AAA cells!".

Thanks...


Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all)
--
Physics is mathematical not because we know so much about the
physical world, but because we know so little; it is only its
mathematical properties that we can discover.
-- Bertrand Russell
--

On Oct 8, 9:16 pm, Frnak McKenney
wrote:


Is it possible that I'm picking up a non-WWV dignal so strong that
it's masking WWV? I tried tuning around 10MHz with a shortwave
radio; it didn't find WWV -- not a particularly hopeful sign -- but
it did pick up a station called (IIRC) WWCR. WWCR's 'web site
(www.wwcr.com) lists its transmitter #4 as using 9.985MHz and
9.975MHz between 0900 and 2100 CST.

Sounds like it's being masked by some type of noise,
but this could just be from the signal being very weak.
If you can hear other stations ok, it probably the propagation
more than anything. Being that you can barely hear it on a
regular receiver seems to bear this out.
Unless a noise is local, and you are trying to null it, I see no
real advantage to using a small loop vs whatever else.
I would make sure you don't have any local noise. IE:
powerline noise, etc. If you did, the loop would be a good
antenna to null that noise as long as you can turn it.
But if there is no local noise, and the noise you hear is
atmospheric, then it's not going to matter much what
you use.
I've got a hunch that the propagation is just the pits for
you right now.
I wouldn't be surprised if you tried it in a couple of months
and it worked ok.. If you hear it on the regular radio ok,
the clock should too. If you can't hear it on the regular
radio, the clock probably won't either, and there is
probably not much you can do about it.
There should be times that it comes in fairly decent though,
depending on time of day, etc..
I would use what you hear on the regular receiver as to
whether the signal is really there or not.
Propagation on most of the HF bands has been fairly
flaky the last few months. IE: I got on 40m in the daytime
the last time I was in OK, and it was like I was on 20m..
Band was real stretched out, and pretty long skip zones.
I'd miss the semi locals I'd usually talk to, and end up
hearing stations 1000 miles away instead.
MK

On Oct 9, 6:06 am, wrote:
On Oct 8, 9:16 pm, Frnak McKenney

wrote:

Is it possible that I'm picking up a non-WWV dignal so strong that
it's masking WWV? I tried tuning around 10MHz with a shortwave
radio; it didn't find WWV -- not a particularly hopeful sign -- but
it did pick up a station called (IIRC) WWCR. WWCR's 'web site
(www.wwcr.com) lists its transmitter #4 as using 9.985MHz and
9.975MHz between 0900 and 2100 CST.

Sounds like it's being masked by some type of noise,
but this could just be from the signal being very weak.
If you can hear other stations ok, it probably the propagation
more than anything. Being that you can barely hear it on a
regular receiver seems to bear this out.
Unless a noise is local, and you are trying to null it, I see no
real advantage to using a small loop vs whatever else.
I would make sure you don't have any local noise. IE:
powerline noise, etc. If you did, the loop would be a good
antenna to null that noise as long as you can turn it.
But if there is no local noise, and the noise you hear is
atmospheric, then it's not going to matter much what
you use.
I've got a hunch that the propagation is just the pits for
you right now.
I wouldn't be surprised if you tried it in a couple of months
and it worked ok.. If you hear it on the regular radio ok,
the clock should too. If you can't hear it on the regular
radio, the clock probably won't either, and there is
probably not much you can do about it.
There should be times that it comes in fairly decent though,
depending on time of day, etc..
I would use what you hear on the regular receiver as to
whether the signal is really there or not.
Propagation on most of the HF bands has been fairly
flaky the last few months. IE: I got on 40m in the daytime
the last time I was in OK, and it was like I was on 20m..
Band was real stretched out, and pretty long skip zones.
I'd miss the semi locals I'd usually talk to, and end up
hearing stations 1000 miles away instead.
MK

Even with my antennas on a 150 foot tower there are times of day when
WWV at 10 megacycles is not audible... This is just the way the daily
propagation cycle is at 30 meters.
My best advice is to put up a dipole for 30 meters, even if you have
to bend the ends to make it fit your space... A horizontal dipole
being balanced picks up less vertically polarized noise than vertical
antennas... Getting the wire outdoors will help also... You are
likely picking up lots of humm and buzz inside the building from
various electrical and electronic devices...

The other issue is whether your clock is actually able to synch with
the WWV signal... You may have a defect in the clock... It would seem
that 4 or 5 bars should have done the trick...

denny / k8do

Denny wrote in news:1191956444.157030.11580@
22g2000hsm.googlegroups.com:

The other issue is whether your clock is actually able to synch with
the WWV signal... You may have a defect in the clock... It would seem
that 4 or 5 bars should have done the trick...

Presumably the LED meter indicates recieved power, not signal to noise
ratio.

Owen

"Owen Duffy" wrote in message
...
Denny wrote in news:1191956444.157030.11580@
22g2000hsm.googlegroups.com:

The other issue is whether your clock is actually able to synch with
the WWV signal... You may have a defect in the clock... It would seem
that 4 or 5 bars should have done the trick...

Presumably the LED meter indicates recieved power, not signal to noise
ratio.

Owen


--------


That's good!

Polarization was one of my thoughts.

Also, how is the synch tone derived by the receiver? Maybe that part of the
radio needs tweaking? One would think that seven segments out of ten should
be sufficient. I'm assuming there are ten segments total.

Ed, NM2K

Since he said previously that he could hardly hear the tones/voice, isn't it
probable that the receiver is just seeing mostly noise?

As mentioned by someone else, propagation is currently "very ordinary" (aka
poor) at present, so maybe he's just out of range.

KeithM
VK1ZKM

"ecregger" wrote in message
...

"Owen Duffy" wrote in message
...
Denny wrote in news:1191956444.157030.11580@
22g2000hsm.googlegroups.com:

The other issue is whether your clock is actually able to synch with
the WWV signal... You may have a defect in the clock... It would seem
that 4 or 5 bars should have done the trick...

Presumably the LED meter indicates recieved power, not signal to noise
ratio.

Owen


--------


That's good!

Polarization was one of my thoughts.

Also, how is the synch tone derived by the receiver? Maybe that part of
the radio needs tweaking? One would think that seven segments out of ten
should be sufficient. I'm assuming there are ten segments total.

Ed, NM2K

Owen,

Thanks for the comments.

On Tue, 09 Oct 2007 19:58:10 GMT, Owen Duffy wrote:
Denny wrote in news:1191956444.157030.11580@
22g2000hsm.googlegroups.com:
The other issue is whether your clock is actually able to synch with
the WWV signal... You may have a defect in the clock... It would seem
that 4 or 5 bars should have done the trick...

Presumably the LED meter indicates recieved power, not signal to
noise ratio.

Exactly. It's an LED bargraph driven by pin 9 on the TDA1072A chip;
according to the data sheet that's the "Field strength indicator
output", a log-scale output driven by the internal AGC amplifier.

I got a clearer WWV signal the other day and was able to re-tune my
antenna. It turns out that the "loud signal" I was tuning to wasn't
WWV, just some random RF I was overloading my poor clock with. The
bargraph now sits down at 1-2 LEDs most of the time, although I did
see a "bursty" period this morning where it went up to 3-5 LEDs.

The WWV audio was coming and going on about a five-second interval:
louder (almost clear), then softer (almost to disappearing), then
louder again. "Wow", so to speak. grin!

Ah, well. Maybe in my Copious Free Time I'll replace the MAC-II's
87C52 with something I understand, like an AVR, and program it _my_
way. (Oh. Then _I_ get the support calls. ... Ack!)


Frank
--
"Curiosity is one of the permanent and certain characteristics
of a vigorous mind. -- Dr. Samuel Johnson
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all)

Denny,

Thanks for joining in.

On Tue, 09 Oct 2007 12:00:44 -0700, Denny wrote:
On Oct 9, 6:06 am, wrote:
On Oct 8, 9:16 pm, Frnak McKenney

wrote:

Is it possible that I'm picking up a non-WWV dignal so strong that
it's masking WWV? I tried tuning around 10MHz with a shortwave
radio; it didn't find WWV ...
--snip--
Sounds like it's being masked by some type of noise,
but this could just be from the signal being very weak.
If you can hear other stations ok, it probably the propagation
more than anything. Being that you can barely hear it on a
regular receiver seems to bear this out.
--snip--

Even with my antennas on a 150 foot tower there are times of day
when WWV at 10 megacycles is not audible... This is just the way
the daily propagation cycle is at 30 meters.

Grumph! (but the 150' tower impresses me! grin!)

My best advice is to put up a dipole for 30 meters, even if you have
to bend the ends to make it fit your space...

Well, a halfwave 30m dipole comes out to... 49 feet?

I went back and checked the NIST "Time and Frequency Services" PDF
file. According to this, WWV-10MHz comes off "half-wave vertical
antennas that radiate omnidirectional patterns."

Maybe I can wind my two 24.5' wires into vertical-axis helices?
grin!

... A horizontal dipole
being balanced picks up less vertically polarized noise than
vertical antennas... Getting the wire outdoors will help also...
You are likely picking up lots of humm and buzz inside the building
from various electrical and electronic devices...

Not sure what you could be referring to... other than the three
computers, 25" monitor, printer, Atmel AVR development board (8MHz
clock), flourescent desk lamp, and overhead I-look-like-an-
incandescent flourescent helix... all within 3 feet of the antenna
and clock. grin!

The other issue is whether your clock is actually able to synch with
the WWV signal... You may have a defect in the clock... It would
seem that 4 or 5 bars should have done the trick...

If it _never_ sync-ed I'd be strongly leaning toward your way of
thinking. In the past, with a "dangling wire" antenna, it has
occasionally taken months to get in sync; with my two loops I've
managed to get it in sync three times (IIRC) in the past two weeks.
(If I were still rational on the subject, I'd just admit that I
_have_ seen improvement -- all the way from "completely
undependable" to "approaching acceptable" -- even if it's not quite
as much as I'd hoped for.)

Thanks again.


Frank
--
The cure for boredom is curiosity. There is no cure for
curiosity. --Ellen Parr
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all)

Frnak McKenney wrote:
Not sure what you could be referring to... other than the three
computers, 25" monitor, printer, Atmel AVR development board (8MHz
clock), flourescent desk lamp, and overhead I-look-like-an-
incandescent flourescent helix... all within 3 feet of the antenna
and clock. grin!

With all that hardware, wouldn't NTP (internet time) be a better option? Or if
you are not too deep into steel and concrete a GPS receiver?

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

(Geoffrey S. Mendelson) writes:

Frnak McKenney wrote:
Not sure what you could be referring to... other than the three
computers, 25" monitor, printer, Atmel AVR development board (8MHz
clock), flourescent desk lamp, and overhead I-look-like-an-
incandescent flourescent helix... all within 3 feet of the antenna
and clock. grin!

With all that hardware, wouldn't NTP (internet time) be a better option? Or if
you are not too deep into steel and concrete a GPS receiver?

Sounds like OP is really interested in bringing his father's WWV clock
to life.

But if correct time is the objective, ntp is easy. Over the internet
it is supposed to be accurate to tens of milliseconds. On our network,
1 - 5 ms is typical, but I suppose it is quite well behaved.

A GPS intended for timing gives better than 100 ms accuracy off the
cable. It can discipline ntp on a computer to typically 1 - 10 us
accuracy.

It looks like the Garmin GPS 18lvc us the timing GPS of choice for
hobbyists. You need a pulse per second (PPS) signal. There are other
GPS dongles which don't have PPS on the plug, but you can find the signal on
the circuit board.

More info at TAPR: "http://www.tapr.org". See also the timekeepers
mailing list archive:
"http://fortytwo.ch/mailman/pipermail/timekeepers/".

John Ackerman N8UR is an authority on timing and ham radio.

But again - this is probably not what you're really after :-)

73
LA4RT Jon