Someone at my radio club uses some mode of operation where accurate
time is required. He said the standard Windoze clock does not keep
sufficiently accurate, so he has software which updates from an NTP
server every 4 seconds or so. It's not exactly a denial of service
(DOS) attack, but seems almo
Elio
Just downloaded the information. The schematic really is shaping up very
nicely.
On the dumps any suggestion for looking at them?
Thanks for your hard work.
Regards
Paul
WB8TSL
On Wed, Nov 7, 2012 at 7:24 PM, Elio C wrote:
> I'm sorry for the long delay (due to personal reasons) but at last
There are 2 different things here.
"Setting" the time based on a single query.
"Disciplining" the local clock
Many of the built in NTP clients just "Set" the time every X
Setting one of these to "SET" the local clock every X seconds is a less
than good thing.
If you timing needs are loose,
On 11/7/12 5:42 PM, shali...@gmail.com wrote:
That sounds odd, as most radios take tens of millisecond, if not hundreds to
switch from transmit to receive and back in any mode other than break-in CW.
Further JT65 is used with propagation modes that typically do not have a stable
or predictable
The symbol time for JT65 is 2.69 baud or 0.372 seconds so one symbol
is about 70,000 miles of propagation. The information I found online
says synchronization needs to be within 1 or 2 seconds for decoding
and closer is better.
http://www.qsl.net/zs2pe/VHF/Downloads/JT65%20Technical%20Specs.txt
That sounds odd, as most radios take tens of millisecond, if not hundreds to
switch from transmit to receive and back in any mode other than break-in CW.
Further JT65 is used with propagation modes that typically do not have a stable
or predictable propagation time like moonbounce or meteor scat
Hi
JT65 needs at most +/- 0.5 seconds. Just about any proper NTP running
continuously on a Windows machine will do far better than that. There's no need
for massive update rates to make it all happen.
Bob
On Nov 7, 2012, at 8:00 PM, Jeff Stevens wrote:
> David,
>
> What mode is your fri
OK thanks for the pointer to joe taylor will look him up.
This would be familiar to the very weak signal work I was doing years ago
about 15 and I used discreet ICs to process very weak signals that were
slow. But we would use a common view reference such as wwvb or a am radio
station. These days y
David,
What mode is your friend using that he finds the need to do an ntp
update every 4 seconds? I'm familiar with JT65 , but that does fine
with a +/- 1 second error.
-Jeff
W7WWA
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Hi
I think you would do a lot better with a cheap GPS rather than fiddling with
NTP for this level of timing. No real need for a GPSDO, just the raw pps and
time of day straight out of the GPS. Probably no need for a timing grade GPS,
just one with a PPS.
Bob
On Nov 7, 2012, at 6:47 PM, David
Based on a sample of one (my NTP), I can hold the clock frequency to 0.1PPM.
Seems to me you could compute the adjustment requirements from such a number.
-Original Message-
From: Chris Albertson
Sender: time-nuts-boun...@febo.com
Date: Wed, 7 Nov 2012 15:02:41
To: Discussion of preci
I'm sorry for the long delay (due to personal reasons) but at last I was
able to dump the contents of the PSD chips which contains the firmware of
the FEI FE-5680A rubidium frequency standard!
I have also updated the schematics with some more details/information.
You will find the new schematics at
Hi Paul think synchronous data transmission where you cant detect enough
signal to synchronise reliably via the bit edges received. Initially
developed for LF (136kHz) where the ERP of amateur antennas is very low.
Google Joe Taylor but not for his Nobel prize, who's original interest was
Moonb
On 7 November 2012 23:28, wrote:
> We had a presentation at our radio club several months ago on digital HF
> modes, and part of the presentation was on JT65 and apparently it needs
> a precise synchronized time fix on both ends for an exchange to occur.
> I do not recollect all of the details th
Hi
They did indeed exist. I haven't seen one for 10 years or so.
Bob
On Nov 7, 2012, at 7:30 AM, Bob Camp wrote:
> Hi
>
> There were a *lot* of firmware updates to the Oncores. I don't know if the
> re-flash images are still out there or not. If they are, it wouldn't hurt to
> upgrade the c
We had a presentation at our radio club several months ago on digital HF
modes, and part of the presentation was on JT65 and apparently it needs
a precise synchronized time fix on both ends for an exchange to occur.
I do not recollect all of the details that were presented, but they did
say that th
Sure enough every 4 seconds would work, as would every 2 seconds. But I
bet every 1000 seconds would work as well.
We need some more details but it seem he has something badly misconfigured
if 4 seconds updates are required.
On Wed, Nov 7, 2012 at 1:41 PM, David Kirkby wrote:
> Someone at my ra
Some finicky software becomes upset if time is stepped backwards too
far.
I have seen PC hardware clocks that drifted 30 seconds a day but that
only matters during a restart. The more common problem involves OS
time drift, often amounting to seconds per minute, caused by bad
System Management Mod
Interesting I am unaware of any amateur service requiring that tight of
a timing relationship.
At least modern PC clocks do not drift that badly in a few minutes. So it
is pretty odd.
Without further detail I am at a loss for why you need to do that.
Maybe he is tinkering with spreadspectrum?
Regar
Some Windows NTP clients like Tardis can calculate and implement a
clock frequency adjustment instead of stepping the clock if the time
adjustment is below a specified limit. If he was using an application
that was upset by the time being stepped, then that might allow less
frequent updates.
If h
Someone at my radio club uses some mode of operation where accurate
time is required. He said the standard Windoze clock does not keep
sufficiently accurate, so he has software which updates from an NTP
server every 4 seconds or so. It's not exactly a denial of service
(DOS) attack, but seems almos
Back in the early 2000's Randy Warner was working at Synergy and posting
here. He provided a lot of good and accurate details about the Oncores
to the list. You might want to search the archive for his name and scan
through the posts. He was a fabulous, accurate source while he was
posting here
Never found an Oncore firmware file... can you point me to anyone of them?
I'm curious to see one.
On Wed, Nov 7, 2012 at 1:30 PM, Bob Camp wrote:
> Hi
>
> There were a *lot* of firmware updates to the Oncores. I don't know if the
> re-flash images are still out there or not. If they are, it wou
Hi
There were a *lot* of firmware updates to the Oncores. I don't know if the
re-flash images are still out there or not. If they are, it wouldn't hurt to
upgrade the card. I don't think it will fix your problem, but it won't hurt
either.
Bob
On Nov 7, 2012, at 1:06 AM, Ed Palmer wrote:
> H
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