Hi,
My university would like to have a 1ms precise source of time to do
some networking experiments (measure one way propagation delays
etc...). So I wandered on the internet to find the best choice with a
budget of ~1000€ (~1100 American dollars).
I've been overwhelmed by the number of
jim...@earthlink.net said:
So really, it's a matter of finding a place to put your Garmin receiver and
string a cable that's not too long to your *nix box running ntp.
The place to put your Garmin receiver may not be as simple as it sounds.
It needs a good view of the sky. Roof is best, but
Thanks all
I decided to replace the batteries, expecting delivery any minute now.
Surprisingly expensive to replace those NiCd's.. Anyway, after looking at
the schematics a bit, I was able to stop the relay chatter by setting the
unit to charge, and holding down the reset switch for a couple of
On Thu, 19 Feb 2015 18:11:08 +0100
Matt matta...@gmail.com wrote:
My university would like to have a 1ms precise source of time to do
some networking experiments (measure one way propagation delays
etc...). So I wandered on the internet to find the best choice with a
budget of ~1000€ (~1100
I think the easiest cable to make really long, if one must be long is the
antenna cable. Use 100 meters of the kind of cable they use for cable
TV. It comes double shield and has those compression type F connectors.
The cable can cary both the GPS signal and power for the amplifier that is
- Original Message -
From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com
Sent: Friday, February 20, 2015 10:25 AM
Subject: Re: [time-nuts] Looking for advice to get a submillisecond setup
On 2/20/15 6:30 AM, Chris Albertson wrote:
I think the easiest cable to make really
Chuck
Thanks and indeed I do need filters that I have not experimented with and
in that respect this would be more like some of the circuits discussed here
on time-nuts.
I am using nice controlled delay lines and at $66 each thats pretty
un-attractive.
But hey when you get them for 50 cents at a
Chuck wrote:
To make decent use of this technique, I believe that you would have
to install 20 to 30dB of 5MHz rejection, and a 10MHz low pass filter
in the output circuitry * * *
The 5MHz rejection filter is necessary to prevent phase anomalies
from appearing due to the beating of
On 2/20/15 6:30 AM, Chris Albertson wrote:
I think the easiest cable to make really long, if one must be long is the
antenna cable. Use 100 meters of the kind of cable they use for cable
TV. It comes double shield and has those compression type F connectors.
The cable can cary both the GPS
Experimenting with a 74ls86 XOR doubler for 5 to 10 Mhz. Typically this
would use a 90 degree phase shift to the other gate. The gate acting as a
mixer to produce 10 Mhz.
The reason to experiment is that I have noticed most of the doubler
discussions take a 5 Mhz square wave filter it to a sine
I think you're getting into receivers that are well into the hundreds of
dollars range, if bought new.
For an inexpensive NTP for few hundred dollars to get better than a
millisecond end of things, I think the integrated GPS antenna/receiver
with a suitable computer right next to it is the
Not sure how small your University is, Matt. But most telco/networking
departments will have an NTP infrastructure already, that may include local
GPS clocks. If you look around at the ntp servers on the university LAN and
find one or more stratum-1's with millisecond or less delay, you probably
Hi Paul,
It isn't that it is bad, it is just that 5 and 15MHz products at
8 to 10dB down isn't very encouraging.
To make decent use of this technique, I believe that you would have
to install 20 to 30dB of 5MHz rejection, and a 10MHz low pass filter
in the output circuitry
And, that is in
TSD11 or TSD12? I have a couple of the latter and they seem to be the same at a
PRS10 that I have. I have done some measurements on frequency and stability and
they are in spec or there about. Hooked up to RS232, they look and drive like a
PRS10. I use the RbMon tool. The ID string is in fact
Hello
My 1250A has drifted outside the range of the front panel control, so the
coarse adjust needs some fiddling. The manual makes mention of a special
tool to be used for this. I don't have the tool, the closest I can get is a
10 bamboo stick that I cunningly liberated from my wifes sushimaking
I am unsure which country you are in but the UK supplier
http://www.galleon.eu.com/computer-time-clock.html has a range of
reasonably priced units that may fit your requirements.
Regards
Peter Torry
On 20/02/2015 16:40, Chris Albertson wrote:
I think you're getting into receivers that
On Fri, Feb 20, 2015 at 1:10 PM, Tom Miller tmiller11...@verizon.net
wrote:
- Original Message - From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com
Sent: Friday, February 20, 2015 10:25 AM
Subject: Re: [time-nuts] Looking for advice to get a submillisecond setup
On 2/20/15
Standalone receivers don't have to be expensive. Take a look at the GPS
receiver modules at sparkfun.com. They are under $100 (some way under),
and some either require or can take an external antenna, and they
provide 1 PPS output. Garmin themselves sells receiver boards without
integrated
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