[time-nuts] David Welch's 3 block signal

[David Welch]

Yes ,I am looking into a better receiver to test or a spectrum analyzer to
find the source of the noise..I can receive wwv on 5 and 15 with no problem
at the right times but have a lot of noise(just at 10 mhz.) the radio shack
radio is a pll digital model and shows highest signal level at exactly 10mhz
if I tune up or down the signal fades away..I did take the clock driver
output (which is connected to unshielded cable out to the clocks)using smpte
time code over two 22awg unshielded conductors..the signal is much less with
this "antenna" disconnected.I just wonder why the 10 mhz generated in the
cesium hp5071a is leaking through into the sempte out of the leitch clock
driver which in turn radiates out through the clock lines..you think they
would have better isolation in this (2003) very high end unit..BTW the
driver is based on the leitch neo platform with two, main and backup cards
installed..model CSD-3901..----- Original Message ----- 
From: "WB6BNQ" <wb6bnq at cox.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Wednesday, February 13, 2008 7:14 PM
Subject: [time-nuts] David Welch's 3 block signal


> Hi David,
>
> I am not sure where you are at, but your mail server appears to be on the
East
> Coast of the US.  I seriously doubt that it is your "in house" 10 MHz that
is
> traveling 3 blocks.  If it is then there are some serious issues to
contend
> with.  The first being, if you are in the US, that you are exceeding the
FCC
> limits for unintentional radiators as defined under Part 15 of the FCC
rules.
> For what would be considered a more or less sealed system (i.e., your
> equipment/cables), it is NOT normal to hear "the" signal beyond the first
> neighbor in any direction from the equipment location.
>
> Are you sure your "old Radio Shack" receiver is working properly ?  I can
still
> copy 10 MHz WWV mixed in with the local house standards at my location in
the San
> Diego, California area.  Of course I am using much higher quality receiver
> designed for the Amateur radio market.
>
> First I would turn everything off and then see what you hear.  Then i
would turn
> on & off each individual item and see how much (if any) contribution the
item
> makes to noise floor in the receiver.  After that I would turn on, in
succession,
> the most important to the least significant and see who might be
generating the
> strong signal.  Something in that process should give you a clue as to
which item
> may have a serious problem.
>
> In the end, if you have a real need to receive WWV on the HF frequencies,
I would
> consider a much better receiver and, of course, an outside antenna.  If I
may
> suggest, the is a software defined receiver that appears to be of quality
design
> covering from 500 Hz to 30 MHz for $499.99 that may interest you.  Go to
> http://www.rfspace.com and look at the SDR-IQ model.  I talked to someone
who has
> one to test and he thought quite highly of it.  It is of a very
interesting
> design and includes software to run it.  It plugs into the computer via a
USB
> cable and is powered from that USB cable.  The software includes bandwidth
> settings, a FFT spectrum and a waterfall type display as well.  In
addition, it
> handles CW, AM, LSB, USB, wide and narrow FM and perhaps other modes.
>
> Don't forget that WWV also transmits on 2.5, 5 and 15 MHz.  15 MHz is good
during
> mid day and 5 MHz is quite good at night time.  2.5 MHz is only good at
night and
> a little tough to copy unless you have a good antenna or are living quite
close
> to it.
>
> Bill....WB6BNQ
>
> David Welch wrote:
>
> > I was wondering with so many 10 mhz sources running.or even a single
cesium
> > and gps receiver running, as I have now..and the 10 mhz is also routed
to a
> > clock driver system (leitch).I cannot receive 10mhz wwv broadcasts at
all
> > anytime,I am using a old radio shack sw radio on batt power..I tried
even
> > almost 3 blocks away and all I get is my 10 mhz carrier..so even a
rooftop
> > ant will not work ..I must have a lot of leakage somewhere to travel for
the
> > signal to peg the radios meter blocks away..
> >
> > ----- Original Message -----
> > From: "Matt Ettus" <boyscout at gmail.com>
> > To: "Tom Van Baak" <tvb at leapsecond.com>; "Discussion of precise time and
> > frequency measurement" <time-nuts at febo.com>
> > Sent: Wednesday, February 13, 2008 3:17 AM
> > Subject: Re: [time-nuts] GPS Locked and Unlocked Performance Comparison
> >
> > > On Feb 13, 2008 1:03 AM, Tom Van Baak <tvb at leapsecond.com> wrote:
> > > > To prevent, or at least detect, this effect I allow my 10 MHz
> > > > house reference to drift off-frequency by quite a bit (last
> > > > month it was 1.7e-12 off). That way there are no on-time
> > > > or on-frequency sources near the test setup.
> > >
> > > Tom,
> > >
> > > I think you might be the only person in the world who would consider
> > > 1.7 parts per trillion to be "quite a bit off" :)
> > >
> > > Matt
> > >
> > > _______________________________________________
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