Valentines Day & Love Numbers
Well if we are talking about $50 then you have my attention.
No I am not afraid to use a soldering iron. Amateur radio is not my main interest here. I have the same compulsion many of you out there seem to have, that if I can get more accuracy I want it. I get that content smile on my face when my counter reads a string of zeroes on a measurement that is supposed to do just that.
I am doing a lot better than 1 ppm right now. I have my counter and signal generator agreeing within about 1 Hz at over 500 GHz. When I get one beat in 10 seconds against 20 MHz WWV I have 5 ppb I think. I am close to that but it gets sticky using 20 MHz to communicate, plus the signal is only available in my location for a few hours on most days.
I am doing similar things with voltage but you can't communicate voltage over the radio so I don't have that kind of agreement, more like 50 ppm.
It's all in fun; I have no legitimate need for this accuracy.
Bob
On Friday, February 21, 2014 10:26 AM, Chris Albertson albertson.chris@gmail.com wrote:
On Fri, Feb 21, 2014 at 9:47 AM, Bob Albert bob91343@yahoo.com wrote:
I looked on line and it seems that these receivers are available for about $150 and up. A little out of my price range right now but I'll keep my eyes open.
Watch the thread on this list about the Arduino based GPSDO. I think
you can get the price down to $50. If all you need is something to
calibrate frequency counter then all you need is 9 to 10 digit
accuracy
I'm going to do this just to prove it can be done for a low two figure
price. But first I have to find a decent crystal oscillator that does
not use up 1/2 of my $40 budget.
If you want ultimate precision that you need a good GPS antenna in a
good location, A high-end timing mode GPS receiver and a high-end
double oven quartz oscillator. The cost adds up. But I think if you
relax the specifications and shoot only for 9 to 10 digits you can
greatly reduce the price.
--
Chris Albertson
Redondo Beach, California
500 GHz ? Really? How? Even counting 100 GHz is pushing it.
You mean MHz, no?
-John
==============
Well if we are talking about $50 then you have my attention.
No I am not afraid to use a soldering iron. Amateur radio is not my main
interest here. I have the same compulsion many of you out there seem to
have, that if I can get more accuracy I want it. I get that content smile
on my face when my counter reads a string of zeroes on a measurement that
is supposed to do just that.
I am doing a lot better than 1 ppm right now. I have my counter and
signal generator agreeing within about 1 Hz at over 500 GHz. When I get
one beat in 10 seconds against 20 MHz WWV I have 5 ppb I think. I am
close to that but it gets sticky using 20 MHz to communicate, plus the
signal is only available in my location for a few hours on most days.
I am doing similar things with voltage but you can't communicate voltage
over the radio so I don't have that kind of agreement, more like 50 ppm.
It's all in fun; I have no legitimate need for this accuracy.
Bob
On Friday, February 21, 2014 10:26 AM, Chris Albertson
albertson.chris@gmail.com wrote:
On Fri, Feb 21, 2014 at 9:47 AM, Bob Albert bob91343@yahoo.com wrote:
I looked on line and it seems that these receivers are available for
about $150 and up. A little out of my price range right now but I'll
keep my eyes open.
Watch the thread on this list about the Arduino based GPSDO. I think
you can get the price down to $50. If all you need is something to
calibrate frequency counter then all you need is 9 to 10 digit
accuracy
I'm going to do this just to prove it can be done for a low two figure
price. But first I have to find a decent crystal oscillator that does
not use up 1/2 of my $40 budget.
If you want ultimate precision that you need a good GPS antenna in a
good location, A high-end timing mode GPS receiver and a high-end
double oven quartz oscillator. The cost adds up. But I think if you
relax the specifications and shoot only for 9 to 10 digits you can
greatly reduce the price.
--
Chris Albertson
Redondo Beach, California
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500GHz? You must mean 50GHz.
Because 1Hz at 500GHz is 2E-12. (You're already there at your goal.) And
what frequency counter are you using at half a THz? :- )
(My highest freq 2-way ham contact has been on 403GHz and that took me years
to make.)
-Brian, WA1ZMS/4
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Bob Albert
Sent: Friday, February 21, 2014 1:41 PM
To: Chris Albertson; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] New WWVB modulation format receivers (NOT)
Well if we are talking about $50 then you have my attention.
No I am not afraid to use a soldering iron. Amateur radio is not my main
interest here. I have the same compulsion many of you out there seem to
have, that if I can get more accuracy I want it. I get that content smile
on my face when my counter reads a string of zeroes on a measurement that is
supposed to do just that.
I am doing a lot better than 1 ppm right now. I have my counter and signal
generator agreeing within about 1 Hz at over 500 GHz. When I get one beat
in 10 seconds against 20 MHz WWV I have 5 ppb I think. I am close to that
but it gets sticky using 20 MHz to communicate, plus the signal is only
available in my location for a few hours on most days.
I am doing similar things with voltage but you can't communicate voltage
over the radio so I don't have that kind of agreement, more like 50 ppm.
It's all in fun; I have no legitimate need for this accuracy.
Bob
Am Thu, 20 Feb 2014 16:02:03 -0500
schrieb Chuck Harris cfharris@erols.com:
At 60KHz, it shouldn't be out of range of most
general purpose CPU's, and even the most pathetic DSP.
Actually, I was referring to the price tag associated with having a
custom chip done... ;-) I fully agree that the computing shouldn't be
an issue for anything nowadays.
Why bother with a hardware solution when software can
do it more easily?
Nuts answer: because we can?
Florian
-Chuck Harris
Florian Teply wrote:
Well, if someone comes up with a circuit, I could check how much
chip area that would consume in a 250nm SiGe BiCMOS... Shouldn't be
out of range for a serious time nut ;-)
Florian
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Oops yes I goofed, it's 500 MHz. 500 GHz is beyond state of the art I would think.
So GPS satellites are NIST in miniature it seems. That's a lot of payload but now I have to see how to gain access to it.
Bob
On Friday, February 21, 2014 11:17 AM, Florian Teply usenet@teply.info wrote:
Am Thu, 20 Feb 2014 16:02:03 -0500
schrieb Chuck Harris cfharris@erols.com:
At 60KHz, it shouldn't be out of range of most
general purpose CPU's, and even the most pathetic DSP.
Actually, I was referring to the price tag associated with having a
custom chip done... ;-) I fully agree that the computing shouldn't be
an issue for anything nowadays.
Why bother with a hardware solution when software can
do it more easily?
Nuts answer: because we can?
Florian
-Chuck Harris
Florian Teply wrote:
Well, if someone comes up with a circuit, I could check how much
chip area that would consume in a 250nm SiGe BiCMOS... Shouldn't be
out of range for a serious time nut ;-)
Florian
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As a starting point: Here's an extension of the SAQrx PC sound card receiver that supports 192 KHz sample-rate sound cards. Enough to get you WWVB.
https://sites.google.com/site/swljo30tb
On Fri, Feb 21, 2014 at 10:37 AM, Paul tic-toc@bodosom.net wrote:
Of course the products I referred to don't actually run ntpd and they're
not disciplining the clock. Much like the titular WWVB "Atomic" clock they
periodically run the equivalent of ntpdate.
The problem is that WiFi uses a lot of power
The OP is not looking for a practical solution. He is going to have
to build it. Maybe even use real seven segment LEDS and a wood
cabinet for a 1970's retro look.
--
Chris Albertson
Redondo Beach, California
Hi Paul:
The problem with GPS is you don't get the DST bits.
For the OP that's OK, but if you want local time it isn't.
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
paul swed wrote:
Boy do I need to agree with Chris's comments above. If this is anything
serious GPS really is the answer in all respects. Yes there is the risk of
something happening. But amazingly a lot of the GPS receivers hold onto
time pretty well even without GPS.
The whole WWVB thing makes sense as a frequency transfer method. But is not
at all close to GPS today. Its far more interesting to watch the VLF
propagation behaviors and as a sort of backup frequency reference. LORAN C
simply kicked butt with what it delivered and was on par with and frankly
better then GPS for frequency. At least for me over 20 years of practice.
But one day soon eLORAN may just come back its looking positive.
Sorry not to change the subject.
Regards
Paul.
On Fri, Feb 21, 2014 at 11:46 AM, Chris Albertson <albertson.chris@gmail.com
wrote:
Bob,
If you are looking for an accurate, easy to use timing signal then GPS
is the one you want. WWV and WWVB are what I call "legacy" signals
and while they might be accurate when broadcast there is propagation
delay and unknown atmospheric and ionospheric conditions.
But the question is "How accurate do you need?" If a few tens of
milliseconds is good enough then running NTP over the internet will
work and if you already have an internet connection it's free. If you
need a few nanoseconds then GPS is what you want.
Using your beat with WWV as a benchmark. You were getting about one
part in a million accuracy. It is VERY easy to do 10,000 times better
than that with GPS.
On Thu, Feb 20, 2014 at 8:19 PM, Bob Albert bob91343@yahoo.com wrote:
I would love to discipline my counter and signal generator time bases to
match NIST. Is this possible, and what would I need to do?
I am sure this subject has been covered but I don't know how to find it.
--
Chris Albertson
Redondo Beach, California
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What about converting an 'atomic clock' for this purpose?
Bob
On Friday, February 21, 2014 4:22 PM, Chris Albertson albertson.chris@gmail.com wrote:
On Fri, Feb 21, 2014 at 10:37 AM, Paul tic-toc@bodosom.net wrote:
Of course the products I referred to don't actually run ntpd and they're
not disciplining the clock. Much like the titular WWVB "Atomic" clock they
periodically run the equivalent of ntpdate.
The problem is that WiFi uses a lot of power
The OP is not looking for a practical solution. He is going to have
to build it. Maybe even use real seven segment LEDS and a wood
cabinet for a 1970's retro look.
--
Chris Albertson
Redondo Beach, California
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Am Fri, 21 Feb 2014 11:42:05 -0800 (PST)
schrieb Bob Albert bob91343@yahoo.com:
Oops yes I goofed, it's 500 MHz. 500 GHz is beyond state of the art
I would think.
Depends on your circuit development skills. Bipolars with gain at
500GHz are in principle possible, both in III/V-semiconductors (InP
comes to mind, but even GaAs might do the trick), and in SiGe this is
currently under research. But you're right, 500GHz at system level is
extremely difficult, I'm not aware of any reasonable demonstration.
5THz (= Far Infrared) is much easier in that regard...
So GPS satellites are NIST in miniature it seems. That's a lot of
payload but now I have to see how to gain access to it.
Well, NIST does more than just time, while GPS essentialy is just that:
a precise clock that is also used to calculate positions.
Florian