I was able to save it to iBooks on my phone and can print from that.
Chris
KD4PBJ
> On Sep 3, 2018, at 9:52 AM, jimlux wrote:
>
> On 9/3/18 5:52 AM, Richard (Rick) Karlquist wrote:
>>> Also worth checking out "Dean's book":
>>>
>>> http://www.ti.com/tool/PLL_BOOK
>>>
>>> This makes a great
Charles,
Attached is another way to do it. A higher charging voltage
increases capacitor voltage linearity over the range of the ADC
making curve compensation easier.
The bus switch has a very low on resistance to pretty much discharge
the cap. The design is pretty old - I'm sure there are
Use the phase detector output to drive the tristate control input of a fast
CMOS tristate state buffer (eg 74HC126 or faster) which in turn drives the RC
network eliminating the diode.
Then correct for the exponential charging characteristics using the micro.
For best results increase ADC
Charles wrote,
>
> According to my tests, the B-C junction of a high-quality 2N3904 has
> about 50pA of leakage at 20vDC reverse voltage.
That's good to know, but the problem I had with this circuit was with the
forward current at a low forward voltage. With this phase detector, the
HC4046 makes
We sound like we could be cousins, Scott. When we bought our current house,
I discovered that the previous owner had built a Faraday cage in a small
room off the basement. I put all my stuff in there. I also have a generator
with magneto ignition so I should be good to go when the end-of-the-world
Actually
I do have much of my equipment inside a shield room, not for tinfoil hat
reasons but to keep experimental systems from causing interference and to
eliminate existing RF sources in the 800 Mhz to 8 Ghz range as error sources in
measurements.
If one is concerned there are lots of old
Gentlemen, I've found this discussion interesting and informative. This
household works on quantum information theory rather than engineering so
there is much for us to learn.
I must observe that if an event takes out the entire GPS system (which a
Carrington event would not do) we will have
Hello to the group I won't quote figures here but did indeed help UrsaNav
do testing. Hey 90 days with a HP 5071 that was a sweet deal at the cost of
some power.
They do send corrective data in the signal from reference sites and that
helps propagation corrections in the receive software.
It was
On Fri, Sep 7, 2018 at 8:32 PM Bob kb8tq wrote:
> This is Time Nuts, not end of the world nuts …..
> ...
> I think we’ve all heard plenty of “the world is ending” stuff.
>
But the availability of a T service under adverse conditions and the
ability of a system which consumes a T reference to
Hi
Yup, and over something the size of a harbor, that works ok. It was done with
the “old”
Loran in a similar fashion and a couple of other ways as well. Expanding any
of it to
cover a country is a very different thing …..
I spent a lot of years trying to sell the designers of these
Hi Jim,
On 09/08/2018 10:02 PM, Jim Harman wrote:
> Magnus said,
>
> It would be interesting to test the linearity of the TIC separately for
>
> instance.
>
> I have done some testing of the TIC. It works quite well for the Arduino
> Uno with its 1 V full scale ADC setting, but the exponential
Hi
The differential approach to eLoran involves running two local receivers. You
look at the time of arrival on one
and use it to “calibrate" the time of arrival on the other. Put another way -
you look at the difference between the
two arrival times. They can both “wander” over a 250 ns
Magnus said,
It would be interesting to test the linearity of the TIC separately for
instance.
I have done some testing of the TIC. It works quite well for the Arduino
Uno with its 1 V full scale ADC setting, but the exponential shape of the
RC charging from the 5 V is quite evident if you use
Bob,
I believe that information is transmitted with the eloran signal.
Way back when, I remember there was an added pulse called the LDC
pulse. I had to modify that pulse with each transmission based on
an input to the transmit timing unit from the computer.
I found the following on it:
Hi
The gotcha is the differential corrections. That’s not the way these systems
are set up to work. They
function with no external input other than the timing signal its self.
Providing bandwidth to do correction
signaling just isn’t part of the overall system design. If you wanted to use
Hi
> On Sep 8, 2018, at 1:53 PM, Scott McGrath wrote:
>
> This is precisely the scenario even a short GPS blackout of 1-2 weeks would
> cause. Its not that GPS is not the finest time transfer system ever
> devised. Its that with the loss of legacy systems we’ve lost the ability to
>
This is precisely the scenario even a short GPS blackout of 1-2 weeks would
cause. Its not that GPS is not the finest time transfer system ever devised.
Its that with the loss of legacy systems we’ve lost the ability to degrade
gracefully.
With a eLORAN system cell networks during a
On Tue, Sep 4, 2018 at 3:23 PM Graham / KE9H wrote:
>
> The following are active GPS NOTAMs.
Didn't know NOTAMs went out for GPS interruptions but of course they
do. Surprised, actually, that there are so many. And yet, life goes
on. Must be all those WWV backups.
On Fri, Sep 7, 2018 at 4:50 PM paul swed wrote:
> Mobile phone time is good enough.
And is often pretty darn good.
Should WWVB go off the air (and it's far from certain that it will),
there might be a market for a USB dongle that plugs into a PC that
outputs the correct code on 60 kHz. I'm
Lady Heather now has some partial support for the Lars GPSDO. It does not
directly send any commands to the device (I don't have one yet to implement
that), but you can use the !u or !t keyboard commands to do that,
Heather treats the Lars GPSDO as a time interval counter. You need to start
When I posted this “bargain” at time-nuts on Wednesday, Sept. 5
the seller had sold ~170. Today (Saturday), I see that sales are just short of
300.
—
So, time-nuts has market reach, and true bargain buyers :-)
BTW, let us know ... if you received a lemon.
greg, w9gb
==
> FTDI UT232R-200 cable,
Hi
I believe the 50 ns is the “as transmitted” signal from the tower. The “as
received” signal after going
through all the various gyrations is not that good on a ~1 second basis.
One of the gotchas here is that we lump “systems” into one giant bag. That’s
not a good way
to analyze
On 9/7/18 10:05 PM, John Reid wrote:
Hi all,
discussion of how to keep accurate time without access to GPS seems very
on topic to me.
These people involved in major catastrophe ('end of the world' as you
put it) scenarios have a wealth of experience in other ways of keeping
accurate time.
kb...@n1k.org said:
> You are not trying to run a cell system when checking your local oscillator
> against LORAN.
The eLoran committee said 50 ns. Is that good enough for cell towers?
Too bad it isn't up so we could collect some data.
--
These are my opinions. I hate spam.
Here is an interesting and fairly recent link regarding eloran and
telecom.
https://rntfnd.org/2017/09/17/telecom-organization-recommends-eloran-system/
The report is here:
https://access.atis.org/apps/group_public/download.php/36304/ATIS-095.pdf
Page 11 has an nice table called "Time and
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