10 Oct
2017
10 Oct
'17
5:39 a.m.
In the US, the surplus equipment market occasionally
had GPS-trained
oscillators that could provide 10Mhz and 1pps clocking as well as NMEA
output. They were parts of CDMA cellphone base stations, each of which
had at least two. The one I have was made by HP. I also have one that
is a Motorola device that was used to synchronize simulcast transmitters
in repeaters.
That is the kind of box (from other manufacturers) that we use as well, attached
to a PC with 1PPS and NMEA and to the repeater with 10 MHz.
Chrony on the PC keeps the Linux clock within 10us (usually within 1-2us) which
we require for the simulcast, and 10 MHz provides the exact transmit frequency
reference.
Power... well, maybe it has an oven stabilized crystal oscillator. Or very
old digital logic that is a bit too power-hungry. Of course a lowcost uBlox/
SiRF module is easy to get going and provide 1PPS for ntpd.
The LeoNTP box is a plugin-and-forget network clock, of course not the cheapest
solution. A Raspberry Pi can be used, I have one in the IPv6 NTP pool at
2a00:f10:103:201:ba27:ebff:fefd:984
Rob
10 Oct
10 Oct
5:59 a.m.
New subject: new ntp server for amprnet
They do indeed. There is an "oven ready" light on the HP's front panel
and a large fibreglas-wrapped object taking up much of the space inside
the box.
The Motorola device has no NMEA output, but can produce 2.5, 5, 10,
12.5, or 25MHz reference frequencies depending on jumper settings inside
the box.
I wish I had a use for them. Right now they're just another piece of
the junk piled up in my garage. I use the NTP-syncronized clocks in
my computers as my primary time reference because they're on all the
time anyway.
- Brian
On Tue, Oct 10, 2017 at 11:39:13AM +0200, Rob Janssen wrote:
Power... well, maybe it has an oven stabilized
crystal oscillator.
10:54 a.m.
New subject: new ntp server for amprnet
All,
I've added the NTP servers in this email thread to the Services Wiki (I
didn't include Bigben since that's not on AMPRNet, let me know if you
think I should add it, Brian).
Also, my NTP server is a Stratum 2 that pulls from various military,
industrial, government and educational Stratum 1 servers in North
America (including AMPRGW).
John, be sure to let us know when you've assigned a 44 IP to your server.
For reference, my NTP Server address is: kb3vwg-001.ampr.org (44.60.44.1)
73,
- Lynwood
KB3VWG
11:07 a.m.
New subject: new ntp server for amprnet
I think UCSD would appreciate it if not a lot of external people use
Bigben as it's already pretty busy serving thousands of hosts on campus.
- Brian
On Tue, Oct 10, 2017 at 10:54:51AM -0400, lleachii--- via 44Net wrote:
I've added the NTP servers in this email thread to
the Services Wiki (I
didn't include Bigben since that's not on AMPRNet, let me know if you think
I should add it, Brian).
11:56 a.m.
New subject: new ntp server for amprnet
On Tuesday, October 10, 2017 2:39:13 AM PDT Rob Janssen wrote:
I had one of the surplus CDMA units for my test gear but after many years of
service it finally died so I replaced it with one of the Leo Bodnar GPS
references. It's nice for test gear and as a reference for my SDR but doesn't
have the 1PPS for NTP use.
Recently I picked up one of these:
http://www.ebay.com/itm/GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock…
There are lots of similar units available on ebay and with 10Mhz and 1PPS
outputs they can be used for both purposes. Mine will be feeding one of my
Raspberry Pi systems.
--
Ken - N7IPB
Email: n7ipb(a)wetnet.net
JID: n7ipb(a)jabber.wetnet.net
PGP Sig: F42B EF90 3CD3 31C7 3056 122E 993A 7B2E 5138 C42A
Life isn't like a bowl of cherries.....
It's more like a jar of jalapenos.
What you do today is likely to come back and burn you in the butt tomorrow.
In the US, the
surplus equipment market occasionally had GPS-trained
oscillators that could provide 10Mhz and 1pps clocking as well as NMEA
output. They were parts of CDMA cellphone base stations, each of which
had at least two. The one I have was made by HP. I also have one that
is a Motorola device that was used to synchronize simulcast transmitters
in repeaters.
That is the kind of box (from other manufacturers) that we use as well,
attached to a PC with 1PPS and NMEA and to the repeater with 10 MHz.
Chrony on the PC keeps the Linux clock within 10us (usually within 1-2us)
which we require for the simulcast, and 10 MHz provides the exact transmit
frequency reference.
Power... well, maybe it has an oven stabilized crystal oscillator. Or very
old digital logic that is a bit too power-hungry. Of course a lowcost
uBlox/ SiRF module is easy to get going and provide 1PPS for ntpd.
The LeoNTP box is a plugin-and-forget network clock, of course not the
cheapest solution. A Raspberry Pi can be used, I have one in the IPv6 NTP
pool at 2a00:f10:103:201:ba27:ebff:fefd:984
2599
days inactive
2599
days old
4 comments
4 participants
participants (4)
-
Brian Kantor -
Ken Koster -
lleachii＠aol.com -
Rob Janssen