With the new 5G hardware, we are seeing all manner of new interference,
some of it quite broad-band. A good antenna with sharp SAW filter may
help, but not if the emmisions are in-band. Besides broad-band, there
also can be 2nd harmonic emissions that cause interference. We had this
problem
The part number has been garbled a bit, but the members of the family
are 74HC/HCT4046, 74HC/HCT7046 and 74HCT9046, the last one having a
significantly better phase detector. The on-board oscillator should not
be a issue, but on the '4046 and '7046, pin 5 held low disables the
oscillator. On
I have a number of Garmin GPS35s which are the same engine in a mouse
package. They are still working and do not have the roll-over problem
because they can be programmed with the current date and time if need be
(I wish Trimble had done this with the Thunderbolts). The NVRAM can get
I have a couple of Trimble UCCMs. They would not come ready unless pin
39 of the 50 pin ribbon connector is grounded. This selects the 1PPS
sync source. Ground is internal, open is external.
73,
David N1HAC
On 12/24/21 7:39 AM, Wilko Bulte wrote:
hi Francois,
That EEVblog thread
But not in a chronometer. They usually use something in the MHz range.
32kHz crystals are not very stable over temperature. Watches rely on
you wearing it for much of the day, keeping it at a nearly constant
temperature and putting it on your bed stand at night, also presumably
fairly
I have been using several versions of the UCCM units (Trimble,
Symmetricom and Samsung) with mostly good results, both bare and
packaged, as well as having several Thunderbolts. The one thing that
the Bodinar unit has which is nice is the synthesizer built in. The
Thunderbolts and UCCMs do
Speaking of aspirational, for those interested in time travel (that
comes under "time nuts", no? ;-) ) there is this:
https://www.oreillyauto.com/flux-500.html
David N1HAC
On 4/3/21 11:10 AM, David Witten wrote:
It seems to be aspirational.
It has been on the SparkX page for a long time
Stamp on the top is 1000 kHz in Russian.
David N1HAC
On 2/28/21 6:35 PM, Dan Kemppainen wrote:
Hi All,
I've picked up a couple of old crystals. Mostly because they look
neat. They are 1Mhz, in a glass tube. The quartz is ~25mm dia, at
about 1 mm thick. Was able to get them to oscillate
A clock that uses an NMEA stream for its display will be a few hundred
milliseconds slow, dependent on the chosen data products and serial baud
rate, as NMEA gives the time of the previous second mark.
David N1HAC
On 12/27/20 9:54 AM, Andy Talbot wrote:
I've just had a look around the house,
I am not sure why they would be discouraged. We have known of the
gravitational red-shift for a while and it is of course part of GPS
calculations. The Mossbauer effect, which involves a very narrow
nuclear resonance, was used to demonstrate it in 1959 over a height of
22.5 meters (the
Note that WWVB is 60kHz, not 65kHz.
David N1HAC
On 10/18/20 10:35 AM, paul swed wrote:
Andre you can add layers of litz wire. You actually have litz wire? Thats
hard to find these days. But it most likely will need to be more than a few
layers. I would slip to small pieces of cardboard on both
I had to change from my "Marine Standard" 3 ft whip and preamp to a
small loop antenna and high-gain preamp, but am getting the signal in a
lot of noise and spherics in NH such that an Austron 2100F is locking.
There is a big difference between 1MW from Nantucket and 75kW from New
Jersey!
Hi Paul,
Is Wildwood transmitting now or will they be? I am not seeing anything
in NH.
Thanks,
David N1HAC
On 8/5/20 10:00 AM, paul swed wrote:
Hello to fellow time nuts.
Warm up those old Austrons. eLORAN out of New Jersey has been on the air
intermittently prior to a test run next week.
Would someone be able to send me a PDF of the Austron 2100F manual? I
have an F, but would also be interested in looking at the T manual, as
well. Thanks.
73,
David N1HAC
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The generic WWVB receivers in radio-controlled clocks are essentially
TRF receivers using a 60kHz crystal as the tuned element.
David N1HAC
On 7/22/20 2:26 PM, Hal Murray wrote:
tsho...@gmail.com said:
I myself did some experimenting with a tuned loop antenna through a 60 kHz
crystal
I have an 8640B in the lab. Bizarre instrument.
David
On 7/13/20 2:57 PM, Richard (Rick) Karlquist wrote:
On 7/13/2020 11:34 AM, jimlux wrote:
There are also "frequency locked" devices that are not "phase locked"
- they essentially discipline an internal oscillator by adjusting its
You can watch the PBS American Experience program on him, "The Secret of
Tuxedo Park" here:
http://www.pbs.org/wgbh/americanexperience/films/secret-tuxedo-park/#part01
David N1HAC
On 5/12/20 7:56 PM, Tom Van Baak wrote:
Yes, the book about Loomis by Jennet Conant is highly recommended. The
I use splitters made for satellite TV with good results, I think. They
have response 5 MHz to >2 GHz and pass DC from any of the outputs to the
input, so any or all GPS receivers can feed the antenna. Some cabling
can be done with F connectors, or I add adapters as necessary (F to BNC
The service manual says it is a manufacturer's part number T06/46 which
is a Saft number and a Google search shows a number of equivalents,
including the Tadiran.
David N1HAC
On 3/29/20 5:35 PM, Charles Steinmetz wrote:
Matthew wrote:
It looks like I need to replace the battery in my
I think it would be a dead-band.
David N1HAC
On 3/10/20 2:41 PM, djl wrote:
Is this effectively dither on the control voltage?
On 2020-03-10 10:30, Skip Withrow wrote:
Hello Time-Nuts,
A couple of weeks ago I posted regarding some weird behavior of the
Trueposition GPSDO that I was seeing.
I still maintain that if people want another hour in the evening, they
can get up an hour earlier. Why do they think they need to change the
clocks? Some people just can't deal with reality and need someone else
to make their decisions for them. OK, I will step off my soapbox now. :-)
Re: China, I heard a piece on NPR that gave the opinion that the virus
would only survive a few hours on a surface. Anything coming from China
should be fine. We are probably more likely to die from panic. ;-)
David N1HAC
On 2/4/20 4:54 AM, Clint Jay wrote:
Actinic short wavelength UV
There are simple circuits that can do a 50% duty cycle /3, then double
to 10 MHz and filter. You can search for Divide by 1.5.
David N1HAC
On 9/18/19 8:54 AM, Bruce Griffiths wrote:
> Dual JK flipflop configured as divide by 3 producing a 33% duty cycle 5MHz
> output which is filtered to
The BG7TBL design (that happens to be the designer's ham call sign) is
also available on eBay in various versions. I do have one. Seems to
work. The problem I have with it is that it only outputs NMEA from the
GPS receiver. There is no lock info from the serial port.
David N1HAC
On 9/10/19
Also, as I have found, some plastics don't just delay but actually
absorb the signal.
David N1HAC
On 9/6/19 2:28 PM, Bob kb8tq wrote:
> Hi
>
> The gotcha with putting anything on top of a GPS antenna is that it impacts
> the phase
> shift from the sat’s. How important that is gets quickly into
Leo -
I do believe you mean non-monotonic, rather than non-monotonous. Not
being monotonous is a good thing. :-)
David N1HAC
On 7/9/19 1:20 PM, Leo Bodnar wrote:
> It's not very good, it is highly non-linear and even worse - nonmonotonous.
> It sometimes produces runt pulse glitches when you
I have a number of Garmin GPS-35s and GPS-18s. In checking before the
rollover, some had their RTC still running and one had lost the battery
backup. The ones with the correct date were OK as-is and the other just
needed the Nonvolatile Memory updated with the correct date to come back
into
In digital filtering, decimation is a reduction of sample rate,
truncation is a reduction of precision. Interpolation can refer to
either of the opposite processes. The terms downsampling and upsampling
can be used to avoid confusion with regards to sample rate. I am trying
to come up with
Just inside a window can work for a GPSDO. One of our labs at Dartmouth
has metallic-tinted windows, so for that we hang a little puck antenna
just outside. Not ideal, but it gets signal.
David
On 1/1/19 11:53 PM, Hal Murray wrote:
>> I do realise that the long term stability of the GPSDO
It appears Canada tries to match the US to save confusion. The US
changed the dates starting in 2007 (making clocks in earlier systems
like VCRs obsolete) and Canada followed suit. Who knows what Congress
will do in the future (abolish DST? I hope!), so programming a system
to be good to
Maybe the link came through the list OK?
On 12/4/18 11:16 PM, David G. McGaw wrote:
> Sorry about that garbled link. Blame Dartmouth's over-zealous IT. Just
> look for "rtl-sdr direct sampling mode" at rtl-sdr dot com.
>
>
> On 12/4/18 11:09 PM, David G. McGaw wrote:
&g
Sorry about that garbled link. Blame Dartmouth's over-zealous IT. Just
look for "rtl-sdr direct sampling mode" at rtl-sdr dot com.
On 12/4/18 11:09 PM, David G. McGaw wrote:
> Actually, an RTL-SDR can because there is direct access to the ADC
> available by soldering to intern
Any of the RSPs from SDRPlay will cover it and they are great units,
starting at $109 US. I am literally using an RSP1A right now.
David N1AHC
On 12/4/18 9:08 PM, W7SLS wrote:
> Hello,
>
> Great discussion on this and other topics here.
>
> Just looked up the specs for the SDRPlay RSP2:
>
Actually, an RTL-SDR can because there is direct access to the ADC
available by soldering to internal pads:
www.rtl-sdr.com/rtl-sdr-direct-sampling-mode/ That will give you 8-bit,
14.4Msps.
But as has also been said, a good sound card sampling 24 bits at 192kHz
can be used.
David N1HAC
On
That is the specified jitter. They have also said in communications that it
has about 50mS resolution. That is as close as they are willing to say a
system can be synchronized with it. Perhaps someone will discover a clever way
to enhance that.
BTW, I have been told it has also been
As was said, IRQ delay is +/-100 mS from the second edge, hardly what a
Time-Nut is looking for.
David
On 12/4/18 1:07 PM, Hal Murray wrote:
>> The one thing I wish is that there were access to the synchronized analog
>> signal and/or a 1PPS. Even a top of the minute would be useful. It
It does a very good job of pulling the signal out of the noise. It
works in NH, traditionally a fringe region, in all but the most shielded
of rooms. I also had occasion to test it for Everset in Kangerlussuaq,
Greenland. I found it had no trouble acquiring at any time of the day.
If the
Correct.
David N1HAC
On 9/27/18 12:55 PM, Dave B via time-nuts wrote:
> ... Because I'm sure I should be able to figure this out for myself!
>
> I have (as many of you do also) one of the venerable Trimble Thunderbolt
> devices. No problem with that. All works fine, and is run 24/7, UPS
>
I consider saving WWV/WWVH/WWVB to be ON topic. They may not be as
precise as some on this list like to achieve, but they are publicly
available methods of time dissemination. I am very concerned that
factions of NIST consider that this should no longer be part of their
mission.
David
Unfortunately, this one is inaccurate. It talks of impact to radio
controlled "Atomic Clocks", but does not mention WWVB, only WWV and WWVH.
David N1HAC
On 8/24/18 3:51 PM, Adrian Godwin wrote:
There seem to be 2 :
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