Frnak McKenney wrote:
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 -
I am up in Maryland, not too far from you.

WWV on 10MHz is only usable for about a third or less of the day for
locking an electronic clock. Generally the late afternoons and
evenings are great, early afternoons and mornings are a little more
variable.

Overnight 5MHz works best. During the mid-day 15MHz or when
propogation permits 20MHz rules for WWV. I don't think your Heath has
any frequency diversity capability, right? Well, 10MHz is a pretty
good choice if you only have a choice of one, it is usually coming in
strong in the evenings there. Over wintertime 5MHz gets pretty good at
night.

You will, especially in the early morning, occasionally hear WWVH on
10MHz or 5MHz or 15MHz. Sometimes I hear both WWV and WWVH at the same
time. You can recognize WWVH by the woman's voice reading the time.

My best antenna for 10MHz WWV is my 40-meter dipole strung between
two trees. Mine mostly points broadside to the NE/SW but if you could
arrange it, it would be slightly preferable to have it broadside to be
sensitive to the W.

A dipole optimized for 10MHz would be even shorter - the formulas
put a half wave dipole at 47 feet long.

Tim.