On Fri, Jan 13, 2012 at 6:29 AM, Jim Lux wrote:
> I suppose one could use some sort of GPRS cellular service and get time, but
> then you're on the hook for a monthly subscription fee, etc.
They sell such devices. They don't require a subscription because
they are receive-only. You don't need
When you are thinking about replacing GPS receivers, don't forget about
every police car, ambulance, fire truck and most of the tractor trailer's
in the US...The latter don't need timing down to the second, but the first
three use it to well under a minute.
One of the first things you learn when o
Any large IT organization has multiple "stratum 1" GPS based
timing receivers.
The public key for our internal routing updates is the time. No time and
the routing would break. We route ~10+ Tb/hr in the 8am-5pm business
day. That would be noticed by our users...
On one building on our campu
On 6/10/11 7:01 PM, Hal Murray wrote:
li...@rtty.us said:
There's an enormous amount of gear out there that gets timing off of GPS.
That's an interesting claim. Does anybody have any data on the usage of GPS
for timing?
I assume there is one in every cell tower and one in every 911 call cen
In message <4f0fc1aa.5070...@earthlink.net>, Jim Lux writes:
>On 6/9/11 1:30 PM, Javier Herrero wrote:
>> I don't think it is feasible... for a cooling reason :)
Soviet had an entire series of spy-satellits powered by reactors,
one of them is still leaking droplets/pellets of sodium from the
cool
Was this message relayed through a probe out about 3 light-months?
-John
> On 6/9/11 1:06 PM, J. Forster wrote:
>> Ha!
>>
>> Nuclear power in space is poltically utterly impossible in the US. There
>> is huge opposition to RTGs, never mind even the thought of reactors.
>
> Hmm..
On 6/9/11 1:30 PM, Javier Herrero wrote:
I don't think it is feasible... for a cooling reason :)
You've got cold space to radiate to: a few hundred watts/square meter at
300K as I recall. And if you run a reactor which is the heat source for
a steam engine of some sort, and the condenser ca
On 6/9/11 1:06 PM, J. Forster wrote:
Ha!
Nuclear power in space is poltically utterly impossible in the US. There
is huge opposition to RTGs, never mind even the thought of reactors.
Hmm.. when I was working on Prometheus aka Jupiter Icy Moons Orbiter
(JIMO) there was a guy from NASA HQ who g
I remember a professor at the University of Wisconsin Madison
who postulated the advancement of Man could be measured by
man's advancing technology of measuring time. We have come
a long way to get down to nanoseconds, LigutSquared notwithstanding.
I suppose the next advance will be to some soft
t; From: "Jim Lux"
> To: time-nuts@febo.com
> Sent: Saturday, June 11, 2011 10:08:18 AM
> Subject: Re: [time-nuts] GPS interference and history...
> On 6/10/11 7:01 PM, Hal Murray wrote:
> >
> > li...@rtty.us said:
> >> There's an enorm
bob-
you coming to greylock?
-Brian, WA1ZMS
On Jun 11, 2011, at 12:13 AM, bownes wrote:
That small hemispherical antenna could also have been 900mhz. I have
one here @ home that is a combined gps/900mhz antenna from an
ambulance tracking system.
On Jun 10, 2011, at 22:01, Hal Murray
On 6/10/11 7:01 PM, Hal Murray wrote:
li...@rtty.us said:
There's an enormous amount of gear out there that gets timing off of GPS.
That's an interesting claim. Does anybody have any data on the usage of GPS
for timing?
I assume there is one in every cell tower and one in every 911 call cen
4). That gets you to a million pretty quick. Add to that the
non-cell tower telcom stuff and you likely double or triple the number.
Bob
-Original Message-
From: Hal Murray
Sent: Friday, June 10, 2011 10:01 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [t
Hal wrote:
What would it cost to replace all of it? If you wanted to do something like
that, what would "it" cover? How about people like us running old recycled
gear? (Z3801A, ThunderBolt, ...)
Not a chance. Probably not consumer navigation receivers,
either. Maybe public safety users.
e time and frequency measurement"
Sent: Friday, June 10, 2011 9:01 PM
Subject: Re: [time-nuts] GPS interference and history...
li...@rtty.us said:
There's an enormous amount of gear out there that gets timing off of GPS.
That's an interesting claim. Does anybody have any data o
That small hemispherical antenna could also have been 900mhz. I have one here @
home that is a combined gps/900mhz antenna from an ambulance tracking system.
On Jun 10, 2011, at 22:01, Hal Murray wrote:
>
> li...@rtty.us said:
>> There's an enormous amount of gear out there that gets timing
Maybe the site has other sensors, like seizmographs or groundwater level
that are not obvious.
-John
>
> li...@rtty.us said:
>> There's an enormous amount of gear out there that gets timing off of
>> GPS.
>
> That's an interesting claim. Does anybody have any data on the usage of
>
Some other users of gps timing that I have noted thru observation or have
personal knowledge of:
Timing for telecom providers (I have seen loran used in the past, but this
option is more or less gone in North America now.)
Timing for power companies
Timing for industrial process control
Timin
li...@rtty.us said:
> There's an enormous amount of gear out there that gets timing off of GPS.
That's an interesting claim. Does anybody have any data on the usage of GPS
for timing?
I assume there is one in every cell tower and one in every 911 call center.
Are there other large categorie
On 06/10/2011 06:42 PM, Bob Camp wrote:
Hi
The FCC (like most US agencies) has a mission to promote as well as
regulate. The promotion side is what drives them to allocate frequencies in
a way that you can reasonably produce gear. They have always come back years
later and tried to change things
gt; Bob
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of William H. Fite
> Sent: Friday, June 10, 2011 9:47 AM
> To: shali...@gmail.com; Discussion of precise time and frequency
> measurement
> Su
cussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS interference and history...
You folks are all far more knowledgeable than I on these issues so I have a
question:
To what extent, from both an engineering perspective and from the standpoint
of public policy, should
Thanks Jim!
Sorry for posting on time-nuts list with time-offset +1 ;-) corrected.
- Henry
--
ehydra.dyndns.info
Jim Lux schrieb:
On 6/10/11 6:55 AM, ehydra wrote:
Jim Lux schrieb:
The MEO height of GPS was a deliberate choice (again, that GPSWorld
series is a fascinating history of how
> From: Chuck Forsberg WA7KGX N2469R
> Sender: time-nuts-boun...@febo.com
> Date: Thu, 09 Jun 2011 12:16:48
> To: ; Discussion of precise time and frequency
> measurement
> Reply-To: Discussion of precise time and frequency measurement
>
> Subject: Re: [time-n
WA7KGX N2469R
Sender: time-nuts-boun...@febo.com
Date: Thu, 09 Jun 2011 12:16:48
To: ; Discussion of precise time and frequency
measurement
Reply-To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS interference and history...
The image frequency for an FM
On 6/10/11 6:55 AM, ehydra wrote:
Jim Lux schrieb:
The MEO height of GPS was a deliberate choice (again, that GPSWorld
series is a fascinating history of how it came about). Don't forget
that one of the original reasons for GPS was for doing midcourse
correction on ICBMs.
Where is this GPSWorl
Jim Lux schrieb:
The MEO height of GPS was a deliberate choice (again, that GPSWorld
series is a fascinating history of how it came about). Don't forget
that one of the original reasons for GPS was for doing midcourse
correction on ICBMs.
Where is this GPSWorld history located?
regard -
He
On 6/9/11 10:36 PM, Henry Hallam wrote:
On Thu, Jun 9, 2011 at 2:42 PM, Jim Lux wrote:
GPS orbits are tough from a radiation standpoint too.
In particular, the orbits are considerably worse for radiation than
GEO, and photovoltaic panels are quite susceptible to radiation. Of
course you co
On Thu, Jun 9, 2011 at 2:42 PM, Jim Lux wrote:
>
> GPS orbits are tough from a radiation standpoint too.
>
In particular, the orbits are considerably worse for radiation than
GEO, and photovoltaic panels are quite susceptible to radiation. Of
course you could put a GNSS in GSO but I think it's n
Jason wrote:
So back to my original question (I didn't mean to spark such a debate)...
These 40,000 transmitter towers... Are they merely talking about
attaching their antennas on existing cell towers or totally new
deployment?
What difference does it make? They will certainly want to cove
Hi
One of the blurbs on Lightsquared talks about them teaming up with Sprint. The
simple answer is that yes indeed these gizmos will show up on Sprint cell
towers. It's not clear what they will do in areas that Sprint does not have a
footprint. It does cut down their real estate requirements qu
New antenna sites are extremely hard to get in the populated US areas,
so I would have to say that given the power levels, and the quantity they
will be piggybacking off of any structure that can hold them.
-Chuck Harris
Jason Rabel wrote:
So back to my original question (I didn't mean to spark
On 6/9/11 1:30 PM, Javier Herrero wrote:
I don't think it is feasible... for a cooling reason :)
if you can have the sun shining on one side of the panels, the other
side can face cold space (at least part of the time), and to a first
order, you can radiate more power than you collect. Hot
On 6/9/11 1:18 PM, William H. Fite wrote:
I well recall the furor over Cassini-Huygens in 1997 but approval was
ultimately granted and, of course, the launch was without incident. Since
then, New Horizons, Galileo, and Ulysses have been launched with far less
public outcry, despite the fact that
On 6/9/11 1:00 PM, Mark Spencer wrote:
Perhaps in the longer term (ie. next the several decades) moving away from the
current wide band spread spectrum scheme to a higher power narrow band scheme
might make more sense for GPS.A previous poster mentioned the use of nuclear
powered satellites t
The main issue with nuclear power in space is that there is a serious
worldwide shortage of Plutonium 238 used in RTG's. This is a different isotope
than the Pu 239 used in nuclear weapons and breeder reactors. Pu 238 is
produced by bombarding Neptunium 237 with neutrons in a reactor, the Np 237
it
From: Jason Rabel
To: time-nuts@febo.com
Sent: Thu, June 9, 2011 2:18:01 PM
Subject: Re: [time-nuts] GPS interference and history...
So back to my original question (I didn't mean to spark such a debate)...
These 40,000 transmitter towers... Are they merely talking about attaching
So back to my original question (I didn't mean to spark such a debate)...
These 40,000 transmitter towers... Are they merely talking about attaching
their antennas on existing cell towers or totally new
deployment?
FWIW, perhaps there wouldn't be as much of a fiasco if every other navigation
a
:16 PM
Subject: Re: [time-nuts] GPS interference and history...
Yes, for instance the aviation industry, WAAS, which is in the L-Bans mobile
satellite assignment, (INMARSAT etc), that L^2 reuses and thus kills.
Lester B Veenstra MØYCM K1YCM
les...@veenstras.com
m0...@veenstras.com
k1
..@febo.com] On
Behalf Of Lester Veenstra
Sent: Thursday, June 09, 2011 3:32 PM
To: 'Discussion of precise time and frequency measurement'; ehy...@arcor.de
Subject: Re: [time-nuts] GPS interference and history...
Actually Chuck it was intermod in the front end creating 10.7 directly.
On Thu, 2011-06-09 at 22:30 +0200, Javier Herrero wrote:
> I don't think it is feasible... for a cooling reason :)
You would think the cooling would be a critical issue (It usually is in
spacecraft), but the Russians flew a few surveillance birds with
reactors on board (and had at least one more s
m scheme to a higher power narrow band
>>>> scheme
>>>> might make more sense for GPS.A previous poster mentioned the use
>>>> of
>>>> nuclear
>>>> powered satellites to achieve higher transmit powers, given the
>>>> ben
anielson
To: time-nuts@febo.com
Sent: Thu, June 9, 2011 12:03:45 PM
Subject: Re: [time-nuts] GPS interference and history...
On 06/09/2011 07:29 PM, Burt I. Weiner wrote:
For many years the FCC has not allowed FM broadcast stations within
certain distances of each other where a 10.7 MHz f
>
> > - Original Message ----
> > From: Magnus Danielson
> > To: time-nuts@febo.com
> > Sent: Thu, June 9, 2011 12:03:45 PM
> > Subject: Re: [time-nuts] GPS interference and history...
> >
> > On 06/09/2011 07:29 PM, Burt I. Weiner wrote:
> >
gt; nuclear
> powered satellites to achieve higher transmit powers, given the benefits
> of GPS
> that option should not be entirely discoutned in my oppinion.
>
>
> - Original Message
> From: Magnus Danielson
> To: time-nuts@febo.com
> Sent: Thu, June 9,
, given the benefits of GPS
that option should not be entirely discoutned in my oppinion.
- Original Message
From: Magnus Danielson
To: time-nuts@febo.com
Sent: Thu, June 9, 2011 12:03:45 PM
Subject: Re: [time-nuts] GPS interference and history...
On 06/09/2011 07:29 PM, Burt I. Weiner
e-mail or any documents attached hereto is
prohibited.
-Original Message-
From: Lester Veenstra [mailto:les...@veenstras.com]
Sent: Thursday, June 09, 2011 8:55 PM
To: 'Discussion of precise time and frequency measurement'
Subject: RE: [time-nuts] GPS interference and history...
Subject: Re: [time-nuts] GPS interference and history...
I seem to recall that some of the high precision users also need to receive
a
satellite delivered differential GPS signal outside of the GPS band.
- Original Message
From: Jim Lux
To: time-nuts@febo.com
Sent: Thu, June 9, 2011 12:32
I seem to recall that some of the high precision users also need to receive a
satellite delivered differential GPS signal outside of the GPS band.
- Original Message
From: Jim Lux
To: time-nuts@febo.com
Sent: Thu, June 9, 2011 12:32:42 PM
Subject: Re: [time-nuts] GPS interference and
On 6/9/11 12:22 PM, Chuck Forsberg WA7KGX N2469R wrote:
According to the John Deere article, the higher performance GPS
receivers, such as those used
for agricultural application and IFR navigation have wider front ends to
obtain more precise information
from GPS signals. The LightSquared transmi
prohibited.
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chuck Forsberg WA7KGX N2469R
Sent: Thursday, June 09, 2011 8:17 PM
To: ehy...@arcor.de; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS interference and
According to the John Deere article, the higher performance GPS
receivers, such as those used
for agricultural application and IFR navigation have wider front ends to
obtain more precise information
from GPS signals. The LightSquared transmitters wouldn't pose such a
problem if they were in orb
The image frequency for an FM receiver with a 10.7 mHz IF
is 21.4 mHz above or below. Perhaps they were worried about
receivers with IFs in the 5 mHz range?
--
Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
Omen Techno
On 06/09/2011 07:29 PM, Burt I. Weiner wrote:
For many years the FCC has not allowed FM broadcast stations within
certain distances of each other where a 10.7 MHz frequency difference
existed. Not exactly the same thing, but did show an understanding of
what can go wrong as a result of good recei
GPS receivers work with very different IF concepts! There is no common
frequency at all.
- Henry
--
ehydra.dyndns.info
Burt I. Weiner schrieb:
For many years the FCC has not allowed FM broadcast stations within
certain distances of each other where a 10.7 MHz frequency difference
existed.
I think it comes down to politicians that delude themselves into thinking
they can legislate the laws of the natural world, and that laws that are
generally applicable to the rest of the world do not apply to them.
-John
===
[snip]
The FCC
> under the direction of Congress has
For many years the FCC has not allowed FM broadcast stations within
certain distances of each other where a 10.7 MHz frequency difference
existed. Not exactly the same thing, but did show an understanding
of what can go wrong as a result of good receiver front end
selectivity. In AM and FM br
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