date:20110202

On Wed, Feb 2, 2011 at 9:29 AM, Don Latham d...@montana.com wrote:
 so, once the safety of life equipment is in place, with controlled
 purchase of receivers no doubt, the consumer signals can be shut off at
 will. And we're SOL. Neat.

That is why the Russians and EU are each spending billions to build
their own systems.  They are smart not to trust the US to manage GPS.
Soon there will be three systems up there and most receivers will be
able to make use of all three.

-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

2011-02-02 Thread Eric Garner

Since this issue is a concern, write the FCC oversight committees:


House of Representatives:

http://democrats.energycommerce.house.gov/index.php?q=subcommittee/subcommittee-on-oversight-and-investigations-0

(note: the democrats part of the URL is because the house.gov site
is broken into majority and minority sites and the current house
majority has apparently not gotten their ducks in a row yet)

Senate:
http://commerce.senate.gov/public/index.cfm?p=CommunicationsTechnologyandtheInternet




On Wed, Feb 2, 2011 at 9:29 AM, Don Latham d...@montana.com wrote:
 so, once the safety of life equipment is in place, with controlled
 purchase of receivers no doubt, the consumer signals can be shut off at
 will. And we're SOL. Neat.
 cynical Don

 Mark Spencer
 That's quite possible, another option is that aviation receivers may err
 on the
 side of caution and not use GPS signals that are considered to be degraded
 beyond a certain level.   This is just speculation on my part.

 As other posters have pointed it seems a bit ironic that shortly after
 shutting
 down Loran in the US this issue emerges, although I seem to recall there
 is a
 move towards a new GPS frequency band for safety of life applications (the
 L5
 Signal IIRC ?)

 Your comment about the improvements in signal processing is a good one and
 pondering this issue a bit more I wonder how much advancement has occurred
 in
 timing receivers over the years versus consumer devices which likely have
 a
 shorter product cycle.   This may lead to more issues in timing
 applications.



 - Original Message 
 From: jimlux jim...@earthlink.net
 To: time-nuts@febo.com
 Sent: Wed, February 2, 2011 6:45:29 AM
 Subject: Re: [time-nuts] From GPS World - Lightsquared has been given the
 goahead


 what was interesting is that the jamming/fail to get fix was at a closer
 distance for the consumer receiver than for the FAA approved receiver
 for aircraft.  Maybe it's better signal processing in the (presumably
 newer) consumer receiver.

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 To unsubscribe, go to
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 --
 Neither the voice of authority nor the weight of reason and argument are
 as significant as experiment, for thence comes quiet to the mind.
 R. Bacon
 If you don't know what it is, don't poke it.
 Ghost in the Shell


 Dr. Don Latham AJ7LL
 Six Mile Systems LLP
 17850 Six Mile Road
 POB 134
 Huson, MT, 59846
 VOX 406-626-4304
 www.lightningforensics.com
 www.sixmilesystems.com


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-- 
--Eric
_
Eric Garner

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[time-nuts] Lightsquared and a little math

Hi

Let's see, a 13 mile circle is pi r squared = ~ 530 square miles. 
40,000 times 530 is ~ 21 million square miles. 
Wikipedia tells me that the area of the US is 3.79 million square miles.

On that basis, there's not going to be anywhere in the US that you *can* get
GPS to fly a plane. Jamming detected = could be a problem = you can't trust
it.

I suspect that there indeed will be remote parts of Alaska or the like that
you will indeed still have un-jammed coverage in a plane. 

Now for the best case:

5.6 miles loss of fix = just under 100 square miles. That's 3.94 million
square miles of jamming. That's still greater than the area of the US. I'm
sure we'll have some left over to jam Canada and Mexico as well. Again,
there will be patches where you can get a fix, but they will be the
exception rather than the rule. 

File an IFR flight plan based on any of this - no way. Insure an airline
that does that - no way. Run an airline based on VFR only not going to
happen. Is everything GPS based - no, but there's a lot of the country where
it is.

Not at all clear how you will keep aviation going under those conditions
unless Lightsquared replaces all their gear with *type accepted*
replacements. Where do I sign up for my free gps? 

Let's suppose they have big pockets and do all that.

At the consumer level, you have 128 thousand square miles with urban canyon
issues. Good bet that's every place with an urban canyon in the country.
Essentially cross off GPS in every large city.

Out here in the sticks, things are a little better. Only a bit over 17
thousand square miles lost. Except ... do you have any hills or mountains
near you? Back to the paragraph above if you live anywhere other than
western Kansas.  

Why are they setting this up - to get internet to people. Where are the
transmitters going - where people live. The consumer numbers may not sound
as bad, but there's a lot of country that is pretty empty. Look at any cell
coverage map to get a good idea how much. You still nuke a lot of voters
with only 17 thousand square miles. Not to mention fire, police, EMS, and
the DHL guy. 

Then you have the federal law about 911 tracking on cell phones. How does
that work - GPS. Under what conditions - worse than an urban canyon (no sky
at all). You *at least* have the urban canyon area to deal with and likely
worse. Any bet your cell phone GPS is as RF rugged as the one in your car?
I'm not taking that bet. Bop up the coverage area a bit more.

So average urban canyon with airborne and what do you get - just a bit over
a half million square miles. My guess is that's the whole area of the
country that has a population dimensioned in multiple people per square
mile. 

So we have:

1) Multiple Airplanes running into mountains
2) Many houses burning to the ground
3) Lots of 911 calls getting miss directed and people dying as a result
4) Joe six pack getting lost on the way to the beer store

All could be what nukes this. I'm betting on number 4 ...

Bob



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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

2011-02-02 Thread paul swed

True enough there will be three systems heck many channels also.
But that reality actually means my magical HP 3801 may not work or could
become unreliable at best.
So how do we hack those new receivers for time-nuts purposes for $29?
Regards
Paul

On Wed, Feb 2, 2011 at 12:50 PM, Eric Garner garn...@gmail.com wrote:

Since this issue is a concern, write the FCC oversight committees:

House of Representatives:

http://democrats.energycommerce.house.gov/index.php?q=subcommittee/subcommittee-on-oversight-and-investigations-0

(note: the democrats part of the URL is because the house.gov site
is broken into majority and minority sites and the current house
majority has apparently not gotten their ducks in a row yet)

Senate:

http://commerce.senate.gov/public/index.cfm?p=CommunicationsTechnologyandtheInternet

On Wed, Feb 2, 2011 at 9:29 AM, Don Latham d...@montana.com wrote:
so, once the safety of life equipment is in place, with controlled
purchase of receivers no doubt, the consumer signals can be shut off at
will. And we're SOL. Neat.
cynical Don

Mark Spencer
That's quite possible, another option is that aviation receivers may err
on the
side of caution and not use GPS signals that are considered to be
degraded
beyond a certain level. This is just speculation on my part.

As other posters have pointed it seems a bit ironic that shortly after
shutting
down Loran in the US this issue emerges, although I seem to recall there
is a
move towards a new GPS frequency band for safety of life applications
(the
L5
Signal IIRC ?)

Your comment about the improvements in signal processing is a good one
and
pondering this issue a bit more I wonder how much advancement has
occurred
in
timing receivers over the years versus consumer devices which likely
have
a
shorter product cycle. This may lead to more issues in timing
applications.

- Original Message
From: jimlux jim...@earthlink.net
To: time-nuts@febo.com
Sent: Wed, February 2, 2011 6:45:29 AM
Subject: Re: [time-nuts] From GPS World - Lightsquared has been given
the
goahead

what was interesting is that the jamming/fail to get fix was at a closer
distance for the consumer receiver than for the FAA approved receiver
for aircraft. Maybe it's better signal processing in the (presumably
newer) consumer receiver.

___
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and follow the instructions there.

--
Neither the voice of authority nor the weight of reason and argument are
as significant as experiment, for thence comes quiet to the mind.
R. Bacon
If you don't know what it is, don't poke it.
Ghost in the Shell

Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com

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--
--Eric
_
Eric Garner

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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

  I wonder how much advancement has occurred in
 timing receivers over the years versus consumer devices which likely have
 a shorter product cycle.   This may lead to more issues in timing
 applications.


Many timing receivers already have decent anti-jam features.  They
were designed for use on cell towers around RF transmitters so their
protection from overload is at least listed in the specs.   I doubt
this was even a design requirement for automotive GPS
-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Frequency multiplication

Hi

The noise depends a *lot* on exactly which part you are talking about. It
also depends on weather you are using the (noisy) internal PLL's or just
talking about the (not quite so noisy) gates. A good guess for most FPGA
PLL's is around -110 to -130 dbc at a few hundred KHz offset. 

On top of the basic noise floor, some chips have charge pumps in them that
create very real spurs. Others have internal oscillators related to setup
and operation. In some cases these can be turned off, in others not so much.

Bottom line - there's a lot to look into, and they are unlikely to help you
out. 

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Geraldo Lino de Campos
Sent: Wednesday, February 02, 2011 12:23 PM
To: time-nuts@febo.com
Subject: [time-nuts] Frequency multiplication

Following the thread on frequency multiplication, does someone know about
the phase noise of the FPGAs PLLs? I couldn't find information on this.
If phase noise is acceptable, it can be a flexible and economical solution.

-- 

Geraldo
gera...@decampos.net
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Re: [time-nuts] Lightsquared and a little math

 Let's see, a 13 mile circle is pi r squared = ~ 530 square miles.
 40,000 times 530 is ~ 21 million square miles.
 Wikipedia tells me that the area of the US is 3.79 million square miles.

By the same logic, all of the office space in New York could not fit
in New York.  But it does because they stack it 20 or 100 floors one
on top of the other.

I suspect the areas will overlap with very dense coverage in urban
areas.  Perhaps in some places there is 50 or 100 channels of coverage
and in others one or even zero.

-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] From GPS World - Lightsquared has been given thegoahead

Hi

Three systems all sharing a common frequency band. Since this is straight
front end overload type jamming - I'd bet it'll take out all three systems.
The Lightsquared stuff might even be closer to one of the other systems than
it is to GPS. If it is, add another layer to the conspiracy theory.

More or less what this would mean is that the rest of the world gets fine
GPS coverage and it stops working inside the US. 

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chris Albertson
Sent: Wednesday, February 02, 2011 12:44 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] From GPS World - Lightsquared has been given
thegoahead

On Wed, Feb 2, 2011 at 9:29 AM, Don Latham d...@montana.com wrote:
 so, once the safety of life equipment is in place, with controlled
 purchase of receivers no doubt, the consumer signals can be shut off at
 will. And we're SOL. Neat.

That is why the Russians and EU are each spending billions to build
their own systems.  They are smart not to trust the US to manage GPS.
Soon there will be three systems up there and most receivers will be
able to make use of all three.

-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Lightsquared and a little math

Hi

I'm sure their deployment is indeed population driven. You will still likely
be fine over parts of Alaska and Montana. Over the high density traffic
areas on the coasts - unlikely.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chris Albertson
Sent: Wednesday, February 02, 2011 1:09 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lightsquared and a little math

 Let's see, a 13 mile circle is pi r squared = ~ 530 square miles.
 40,000 times 530 is ~ 21 million square miles.
 Wikipedia tells me that the area of the US is 3.79 million square miles.

By the same logic, all of the office space in New York could not fit
in New York.  But it does because they stack it 20 or 100 floors one
on top of the other.

I suspect the areas will overlap with very dense coverage in urban
areas.  Perhaps in some places there is 50 or 100 channels of coverage
and in others one or even zero.

-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Lightsquared and a little math

2011-02-02 Thread Pete Lancashire

Go back to my orig post the FCC has given the go ahead .. to late ?

On Wed, Feb 2, 2011 at 9:57 AM, Bob Camp li...@rtty.us wrote:
 Hi

 Let's see, a 13 mile circle is pi r squared = ~ 530 square miles.
 40,000 times 530 is ~ 21 million square miles.
 Wikipedia tells me that the area of the US is 3.79 million square miles.

 On that basis, there's not going to be anywhere in the US that you *can* get
 GPS to fly a plane. Jamming detected = could be a problem = you can't trust
 it.

 I suspect that there indeed will be remote parts of Alaska or the like that
 you will indeed still have un-jammed coverage in a plane.

 Now for the best case:

 5.6 miles loss of fix = just under 100 square miles. That's 3.94 million
 square miles of jamming. That's still greater than the area of the US. I'm
 sure we'll have some left over to jam Canada and Mexico as well. Again,
 there will be patches where you can get a fix, but they will be the
 exception rather than the rule.

 File an IFR flight plan based on any of this - no way. Insure an airline
 that does that - no way. Run an airline based on VFR only not going to
 happen. Is everything GPS based - no, but there's a lot of the country where
 it is.

 Not at all clear how you will keep aviation going under those conditions
 unless Lightsquared replaces all their gear with *type accepted*
 replacements. Where do I sign up for my free gps?

 Let's suppose they have big pockets and do all that.

 At the consumer level, you have 128 thousand square miles with urban canyon
 issues. Good bet that's every place with an urban canyon in the country.
 Essentially cross off GPS in every large city.

 Out here in the sticks, things are a little better. Only a bit over 17
 thousand square miles lost. Except ... do you have any hills or mountains
 near you? Back to the paragraph above if you live anywhere other than
 western Kansas.

 Why are they setting this up - to get internet to people. Where are the
 transmitters going - where people live. The consumer numbers may not sound
 as bad, but there's a lot of country that is pretty empty. Look at any cell
 coverage map to get a good idea how much. You still nuke a lot of voters
 with only 17 thousand square miles. Not to mention fire, police, EMS, and
 the DHL guy.

 Then you have the federal law about 911 tracking on cell phones. How does
 that work - GPS. Under what conditions - worse than an urban canyon (no sky
 at all). You *at least* have the urban canyon area to deal with and likely
 worse. Any bet your cell phone GPS is as RF rugged as the one in your car?
 I'm not taking that bet. Bop up the coverage area a bit more.

 So average urban canyon with airborne and what do you get - just a bit over
 a half million square miles. My guess is that's the whole area of the
 country that has a population dimensioned in multiple people per square
 mile.

 So we have:

 1) Multiple Airplanes running into mountains
 2) Many houses burning to the ground
 3) Lots of 911 calls getting miss directed and people dying as a result
 4) Joe six pack getting lost on the way to the beer store

 All could be what nukes this. I'm betting on number 4 ...

 Bob



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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

On Wed, Feb 2, 2011 at 10:02 AM, paul swed paulsw...@gmail.com wrote:
 True enough there will be three systems heck many channels also.
 But that reality actually means my magical HP 3801 may not work or could
 become unreliable at best.
 So how do we hack those new receivers for time-nuts purposes for $29?

For $29?  Maybe a home brew antenna with better patterns and maybe
even nulls aimed at nearby transmitters.  It is surprisingly easy to
build a helix antenna.

A notch filter can also be constructed to notch out the jammer if it
is out of band.  A twin T design might be  effective and low cost

Microwave is line of site so maybe just a meter plate that blocks view
of the transmitter.

The solution for a fixed timing receiver will be much easier than for
a mobile GPS receiver.
-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Lightsquared and a little math

Hi

There's no decision that they take that they can't reverse. That goes double
for something like this that was done pretty quickly. 

My guess is that they have a limited rather than a full approval at this
point. From the article proceed with ancillary terrestrial component
operations does not sound like a full license.

If you do a little Google work on the topic, there are a lot of different
services and outfits impacted by this (not just GPS). None of them are happy
and all of them are likely on the phone to their favorite legislator and /
or lawyers. 

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Pete Lancashire
Sent: Wednesday, February 02, 2011 1:13 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lightsquared and a little math

Go back to my orig post the FCC has given the go ahead .. to late ?

On Wed, Feb 2, 2011 at 9:57 AM, Bob Camp li...@rtty.us wrote:
 Hi

 Let's see, a 13 mile circle is pi r squared = ~ 530 square miles.
 40,000 times 530 is ~ 21 million square miles.
 Wikipedia tells me that the area of the US is 3.79 million square miles.

 On that basis, there's not going to be anywhere in the US that you *can*
get
 GPS to fly a plane. Jamming detected = could be a problem = you can't
trust
 it.

 I suspect that there indeed will be remote parts of Alaska or the like
that
 you will indeed still have un-jammed coverage in a plane.

 Now for the best case:

 5.6 miles loss of fix = just under 100 square miles. That's 3.94 million
 square miles of jamming. That's still greater than the area of the US. I'm
 sure we'll have some left over to jam Canada and Mexico as well. Again,
 there will be patches where you can get a fix, but they will be the
 exception rather than the rule.

 File an IFR flight plan based on any of this - no way. Insure an airline
 that does that - no way. Run an airline based on VFR only not going to
 happen. Is everything GPS based - no, but there's a lot of the country
where
 it is.

 Not at all clear how you will keep aviation going under those conditions
 unless Lightsquared replaces all their gear with *type accepted*
 replacements. Where do I sign up for my free gps?

 Let's suppose they have big pockets and do all that.

 At the consumer level, you have 128 thousand square miles with urban
canyon
 issues. Good bet that's every place with an urban canyon in the country.
 Essentially cross off GPS in every large city.

 Out here in the sticks, things are a little better. Only a bit over 17
 thousand square miles lost. Except ... do you have any hills or mountains
 near you? Back to the paragraph above if you live anywhere other than
 western Kansas.

 Why are they setting this up - to get internet to people. Where are the
 transmitters going - where people live. The consumer numbers may not sound
 as bad, but there's a lot of country that is pretty empty. Look at any
cell
 coverage map to get a good idea how much. You still nuke a lot of voters
 with only 17 thousand square miles. Not to mention fire, police, EMS,
and
 the DHL guy.

 Then you have the federal law about 911 tracking on cell phones. How does
 that work - GPS. Under what conditions - worse than an urban canyon (no
sky
 at all). You *at least* have the urban canyon area to deal with and likely
 worse. Any bet your cell phone GPS is as RF rugged as the one in your car?
 I'm not taking that bet. Bop up the coverage area a bit more.

 So average urban canyon with airborne and what do you get - just a bit
over
 a half million square miles. My guess is that's the whole area of the
 country that has a population dimensioned in multiple people per square
 mile.

 So we have:

 1) Multiple Airplanes running into mountains
 2) Many houses burning to the ground
 3) Lots of 911 calls getting miss directed and people dying as a result
 4) Joe six pack getting lost on the way to the beer store

 All could be what nukes this. I'm betting on number 4 ...

 Bob



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Re: [time-nuts] GPS receiver jamming

2011-02-02 Thread John Green

The timing grade receiver I have, a Z3801 absolutely lays down at the
least possible amount of on frequency signal. My automotive grade
Garmin is immune to even high levels. It may be that the slightest
degradation is unacceptable to the Z3801. More testing is needed. If
these anticipated transmitters are merely close in frequency with no
actual energy at GPS frequencies, this looks like an excellent
business opportunity for someone to make and sell GPS antennas with
aggressive filtering. If they actually emit energy at GPS frequencies,
we are pretty much done for. I have seen the Youtube video of a
military GPS resisting jamming but I seriously doubt they would become
common place.

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Re: [time-nuts] Lightsquared and a little math

2011-02-02 Thread Stanley Reynolds

Wonder if the clients of this network reduce power as cell phones do to 
increase 
battery life and reduce interference or they will use a dish on the fixed 
clients, not that would help with interference from the sat. The web site reads 
like the sat will distribute the internet signal direct to the clients:  
http://www.lightsquared.com/what-we-do/technology/ 


Stanley



- Original Message 
From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Wed, February 2, 2011 12:09:07 PM
Subject: Re: [time-nuts] Lightsquared and a little math

 Let's see, a 13 mile circle is pi r squared = ~ 530 square miles.
 40,000 times 530 is ~ 21 million square miles.
 Wikipedia tells me that the area of the US is 3.79 million square miles.

By the same logic, all of the office space in New York could not fit
in New York.  But it does because they stack it 20 or 100 floors one
on top of the other.

I suspect the areas will overlap with very dense coverage in urban
areas.  Perhaps in some places there is 50 or 100 channels of coverage
and in others one or even zero.

-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Lightsquared and a little math

On Wed, Feb 2, 2011 at 10:36 AM, Stanley Reynolds
stanley_reyno...@yahoo.com wrote:
 The web site reads
 like the sat will distribute the internet signal direct to the clients:

People will hate this service.  Going up to geo-sync adds a noticeable
and annoying lag do unavoidable speed of light round trip time of
flight.  This is one reason the phone companies have been investing in
fiber for long haul.
-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Lightsquared and the FCC

2011-02-02 Thread Pete Lancashire

by then those in the FCC who ok'ed this will be working as a lobbyist

-pete

On Wed, Feb 2, 2011 at 7:32 AM, John Green wpxs...@gmail.com wrote:
 If the FCC weren't a government entity they would be called whores.
 This reminds me of the time several years ago when it was taking a
 year or more to get a grant for a 800 MHz license. The FCC granted
 thousands, yes thousands of requests from the company that would
 become Nextel all in one day. Quite often granting them a license for
 a frequency that was already licensed at the same location by someone
 else. All who objected were told to shut up and go away. Some years
 later when interference to public safety systems by Nextel got bad
 enough, the FCC made Nextel relocate those systems to different
 frequencies less prone to interference. But, they granted them access
 to the adjacent 900 MHz spectrum without having to file paperwork.
 When the first plane crashes because of Lightsquared interference, I
 hope the political s**t storm drowns those clowns.

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Re: [time-nuts] Frequency multiplication

2011-02-02 Thread David Armstrong

FPGA's do not have good jitter performance.  Both Altera and Xilinx have
app notes and specs on what to expect for jitter performance.  


Particularly when using high speed DACs (like the ADI AD9739) the
technique used is to drive the DAC with a good quality clock, then the
DAC drives the FPGA.   With high speed dac's like this there is often a
DLL used to optimize the data edges with respect to the clock.

Similar techniques are used in the other direction ADC ._ FPGA.  The
good clock is given to the DAC which presents the clock to the FPGA.

The clock out of an FPGA may be good enough depending on what you are
using it for but check carefully!





On Wed, 2011-02-02 at 10:47 -0800, Hal Murray wrote:
  Bottom line - there's a lot to look into, and they are unlikely to help you
  out.  
 
 There are a lot of FPGAs used in DSP applications where the clock to the 
 front end ADC is critical.  So I'd expect there would be some in-house 
 knowledge about this area.  It may be that all the help you will get is 
 Don't do that.
 
 
 
 I think Altera uses PLLs.
 
 Xilinx uses DLLs, D for delay, a long chain of gates with an adjustable tap.  
 So the output signal will jump in time when the tap switches.
 
 FPGAs are designed for digital logic rather than clock hacking.  I remember 
 some story from years ago about clocking troubles being traced back to input 
 threshold changes due to nearby outputs switching.  I forget the details.  I 
 think that particular problem was solved by moving all the output pins away 
 from the clock input pin.
 
 The smaller FPGAs are not expensive.  It might make sense to dedicate a whole 
 chip to something like a clock mux.
 
 You could always use an external PLL and put the digital dividers in a FPGA.
 
 



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Re: [time-nuts] Lucent RFTG-M-XO

On Wed, Feb 2, 2011 at 5:42 AM, Ruslan Nabioullin rnabioul...@gmail.com wrote:
 Has anyone been successful in using a Lucent RFTG-M-XO with NTP? ...it seems 
 as though the module does not output a
 timecode but only a PPS signal

If the only output is a PPS than the interface to NTP is simple.  Run
the rs-232 level converted PPS into pin-1 on a serial DB9 connector,
well OK ground for PPS signal return. ( I forgot the pin number for
the ground.)  Remember that in rs232 logic 1 is a negative voltage,
logic 0 is positive.

You will need a second reference clock to number the seconds but a
pool server is good enough for that


-- 
=
Chris Albertson
Redondo Beach, California

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[time-nuts] Fwd: 10MHz to 80MHz frequency multiplier suggestions

2011-02-02 Thread SAIDJACK

 
Hello Raj,
 
our ULN-1100 and ULN-2550 GPSDO's use a 100MHz VCXO locked to the 10MHz  
OCXO via an ADF4002 PLL with less than 40Hz bandwidth. After careful  
optimization of the layout and the loop filter, the phase noise results are  
quite 
excellent at 100MHz, see the attached plot. The plot shows two versions of  
the PLL loop filter from the design phase of the products, one has been more  
optimized. You can see that the noise floor is almost -170dBc/Hz at  100MHz.
 
You get the best of two worlds: the absolute frequency accuracy of the  
GPSDO, and the very low phase noise of the VCXO above the PLL bandwidth. It is  
clearly visible that the VCXO phase noise inside the loop bandwidth is 
actually  also reduced by locking it to the 10MHz OCXO (the PN curve below the 
loop  bandwidth frequency of ~30Hz would just continue going up without the  
PLL)
 
Low Noise 100MHz VCXO's are readily available at mouser  and digikey (so 
are 80MHz units), and programming the ADF4002 is  straight forward with the 
help from the AD online tools. It can be bit-banged  with any microcontroller.
 
bye,
Said




From: Raj _vu2zap@gmail.com_ (mailto:vu2...@gmail.com) 
Date:  January 31, 2011 21:11:46 HST
To: Discussion of precise time and  frequency measurement 
_time-nuts@febo.com_ (mailto:time-nuts@febo.com) 
Subject:  Re: [time-nuts] 10MHz to 80MHz frequency multiplier  suggestions
Reply-To: Discussion of precise time and frequency  measurement 
_time-nuts@febo.com_ (mailto:time-nuts@febo.com) 





I was contemplating the same thing. I fed the output to a bifilar  
transformer and 
diode doubler and got good results. I have  to add an amp and double it 
again twice
more. It is still on  breadboard. The object was to multiply the error 8x 
and  compare.

Probably a PLL locking to 80 Mhz  will retain the long term accuracy of the 
TBolt  reference.

Raj,  vu2zap

At 31-01-2011, you wrote:

I'd like to convert the 10MHz output of a  Thunderbolt to 80MHz: it should 
be


used as a 3.3V clock for an A/D  converter.


Even if I have already taken a look to  documentation from KO4BB and Wenzel


regarding frequency  multiplier,


I'm asking if you have some more references  or even better, some schematics


of a working 8x  multiplier.





. thanks in  advance


_  Elio  Corbolante.



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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead


Chris wrote:


A notch filter can also be constructed to notch out the jammer if it
is out of band.  A twin T design might be  effective and low cost


Unfortunately, unless the interfering carrier is much too far away to 
be a problem in the first place, the phase shift of the notch filter 
(and particularly its changes with temperature) will appear 
essentially as a variable-length coax on your antenna -- not what you 
want for precision timing applications.


Best regards,

Charles





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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

On Wed, Feb 2, 2011 at 1:01 PM, Charles P. Steinmetz
charles_steinm...@lavabit.com wrote:
 Chris wrote:

 A notch filter can also be constructed to notch out the jammer if it
 is out of band.  A twin T design might be  effective and low cost

 Unfortunately, unless the interfering carrier is much too far away to be a
 problem in the first place, the phase shift of the notch filter (and
 particularly its changes with temperature) will appear essentially as a
 variable-length coax on your antenna -- not what you want for precision
 timing applications.

What would be the range of variability?Are we talking about 10% of
the period of the 1.5GHz signal?  I could live with that or is the
effect much greater?  My simple understanding of the twin-t comes from
my use of it at audio frequencies.  Maybe there are better filter
designs.


-- 
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

2011-02-02 Thread J. Forster

Most GPS users care about position, not time.

-John

===


 Chris wrote:

A notch filter can also be constructed to notch out the jammer if it
is out of band.  A twin T design might be  effective and low cost

 Unfortunately, unless the interfering carrier is much too far away to
 be a problem in the first place, the phase shift of the notch filter
 (and particularly its changes with temperature) will appear
 essentially as a variable-length coax on your antenna -- not what you
 want for precision timing applications.

 Best regards,

 Charles





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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

2011-02-02 Thread bownes


Of the 2 lc orgs I administer or am a member of, and the roughly 8 other lc 
orgs I  interact with on a regular basis, only one uses lc certified gps equip. 
The others are all consumer grade or don't use gps. 

However, a slew of filings and letters from the lc community might not be a bad 
idea, if only to lay the groundwork for the inevitable lawsuits. 


On Feb 2, 2011, at 3:06 PM, Rex r...@sonic.net wrote:

 On 2/2/2011 7:25 AM, jimlux wrote:
 
 
 I got the impression that it wasn't modeled, but was an actual field test of 
 some sort.  I'll have to go back and reread.
 
 But, it's possible that the consumer receiver has better multipath and 
 interference rejection, if only because it's newer. Aviation stuff takes 
 longer to go through the approval cycle, so it tends to lag consumer 
 electronics in terms of technology adoption.
 
 
 
 From the paper submitted by the GPS manufactureres to the FCC
 http://www.gpsworld.com/gnss-system/signal-processing/lightsquared-jamming-report-11030
 
 it seems they simulated the Lightsquared signal with test equipment and made 
 measurements in an anechoic chamber of effects on GPS signal reception to a 
 couple of popular GPS receivers. Using this data they extrapolated real-world 
 effects with path loss calculations. Ironically, it probably wouldn't be 
 legal or safe to make the jamming measurements in a real, open space, 
 environment.
 
 The paper says the Lightspeed transmitters can be up to around 15 kW EIRP in 
 a band right adjacent to GPS. I would think filtering out that signal to 
 avoid overload would be a daunting task.
 
 
 
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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

2011-02-02 Thread Rex


On 2/2/2011 2:29 PM, bownes wrote:

Of the 2 lc orgs I administer or am a member of, and the roughly 8 other lc 
orgs I  interact with on a regular basis, only one uses lc certified gps equip. 
The others are all consumer grade or don't use gps.

However, a slew of filings and letters from the lc community might not be a bad 
idea, if only to lay the groundwork for the inevitable lawsuits.




Pardon my ignorance, but I can't immediately work out what you mean by 'lc'.



On Feb 2, 2011, at 3:06 PM, Rexr...@sonic.net  wrote:


On 2/2/2011 7:25 AM, jimlux wrote:


I got the impression that it wasn't modeled, but was an actual field test of 
some sort.  I'll have to go back and reread.

But, it's possible that the consumer receiver has better multipath and 
interference rejection, if only because it's newer. Aviation stuff takes longer 
to go through the approval cycle, so it tends to lag consumer electronics in 
terms of technology adoption.



 From the paper submitted by the GPS manufactureres to the FCC
http://www.gpsworld.com/gnss-system/signal-processing/lightsquared-jamming-report-11030

it seems they simulated the Lightsquared signal with test equipment and made 
measurements in an anechoic chamber of effects on GPS signal reception to a 
couple of popular GPS receivers. Using this data they extrapolated real-world 
effects with path loss calculations. Ironically, it probably wouldn't be legal 
or safe to make the jamming measurements in a real, open space, environment.

The paper says the Lightspeed transmitters can be up to around 15 kW EIRP in a 
band right adjacent to GPS. I would think filtering out that signal to avoid 
overload would be a daunting task.







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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

2011-02-02 Thread bownes

Sorry. Life critical. Fire, ems, law enforcement, aviation, etc. 



On Feb 2, 2011, at 3:37 PM, Rex r...@sonic.net wrote:

 On 2/2/2011 2:29 PM, bownes wrote:
 Of the 2 lc orgs I administer or am a member of, and the roughly 8 other lc 
 orgs I  interact with on a regular basis, only one uses lc certified gps 
 equip. The others are all consumer grade or don't use gps.
 
 However, a slew of filings and letters from the lc community might not be a 
 bad idea, if only to lay the groundwork for the inevitable lawsuits.
 
 
 
 Pardon my ignorance, but I can't immediately work out what you mean by 'lc'.
 
 
 On Feb 2, 2011, at 3:06 PM, Rexr...@sonic.net  wrote:
 
 On 2/2/2011 7:25 AM, jimlux wrote:
 
 I got the impression that it wasn't modeled, but was an actual field test 
 of some sort.  I'll have to go back and reread.
 
 But, it's possible that the consumer receiver has better multipath and 
 interference rejection, if only because it's newer. Aviation stuff takes 
 longer to go through the approval cycle, so it tends to lag consumer 
 electronics in terms of technology adoption.
 
 
 From the paper submitted by the GPS manufactureres to the FCC
 http://www.gpsworld.com/gnss-system/signal-processing/lightsquared-jamming-report-11030
 
 it seems they simulated the Lightsquared signal with test equipment and 
 made measurements in an anechoic chamber of effects on GPS signal reception 
 to a couple of popular GPS receivers. Using this data they extrapolated 
 real-world effects with path loss calculations. Ironically, it probably 
 wouldn't be legal or safe to make the jamming measurements in a real, open 
 space, environment.
 
 The paper says the Lightspeed transmitters can be up to around 15 kW EIRP 
 in a band right adjacent to GPS. I would think filtering out that signal to 
 avoid overload would be a daunting task.
 
 
 
 
 
 
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Re: [time-nuts] Possibly OT: Frequency Divider boards for sale

2011-02-02 Thread David C. Partridge

 And again - capacitors are not C0G, I was getting my wires crossed with 
another project.


Regards,
David Partridge


-Original Message-
From: David C. Partridge [mailto:david.partri...@perdrix.co.uk] 
Sent: 02 February 2011 17:16
To: 'teksco...@yahoogroups.com'; 'tekscop...@yahoogroups.com'; 
'hp_agilent_equipm...@yahoogroups.com'; 'testequiptra...@yahoogroups.com'; 
'Discussion of precise time and frequency measurement'
Subject: RE: Possibly OT: Frequency Divider boards for sale

The documentation in 

http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202.1.pdf 

has just been updated.

Regards,
David Partridge


-Original Message-
From: David C. Partridge [mailto:david.partri...@perdrix.co.uk]
Sent: 02 February 2011 14:08
To: 'teksco...@yahoogroups.com'; 'tekscop...@yahoogroups.com'; 
'hp_agilent_equipm...@yahoogroups.com'; 'testequiptra...@yahoogroups.com'; 
'Discussion of precise time and frequency measurement'
Subject: Possibly OT: Frequency Divider boards for sale

I have just shipped out a large batch of the updated version of my frequency 
divider boards.

I have about 20 complete boards (with all components fitted except RF 
connectors) available for sale.

The cost for these is GBP70 each including Signed For delivery to anywhere on 
the planet (GBP65 for UK customers).

I also have a similar number of bare 4-layer printed circuit boards available.

The cost for these is GBP20 each including postage (Signed For is GBP5 extra).

Details here:

http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202.1.pdf and

http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202%20Schematic.pdf

PS I really will get round to doing something with the website ...

Regards,
David Partridge



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Re: [time-nuts] Lightsquared and a little math


Hi

It certainly will not be fast by any standard.

Bob

-Original Message- 
From: Chris Albertson

Sent: Wednesday, February 02, 2011 1:45 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lightsquared and a little math

On Wed, Feb 2, 2011 at 10:36 AM, Stanley Reynolds
stanley_reyno...@yahoo.com wrote:

The web site reads
like the sat will distribute the internet signal direct to the clients:


People will hate this service.  Going up to geo-sync adds a noticeable
and annoying lag do unavoidable speed of light round trip time of
flight.  This is one reason the phone companies have been investing in
fiber for long haul.
--
=
Chris Albertson
Redondo Beach, California

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Re: [time-nuts] [time nuts] Frequency Multiplication

2011-02-02 Thread Sean M. Bietz

Here's a paper on phase noise in Actel's devices. As a note Actel's antifuse 
technology is a bit different than than other companies in the CPLD/ FPGA 
market.  They're OTP, rad hard, and very secure.  I've seen them used as a 
system security measure between an external modem and an internal CPLD/ FPGA.  
I did some design work a few years ago rolling PLLs into CPLDs for Stratum 3 
applications and the results were very interesting.  I was using the brand X 
devices tested in the paper below and confirmed some of the results. 

http://www.actel.com/documents/JitterWP.pdf

Sean

On Feb 2, 2011, at 2:17 PM, time-nuts-requ...@febo.com wrote:

 Send time-nuts mailing list submissions to
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 When replying, please edit your Subject line so it is more specific
 than Re: Contents of time-nuts digest...
 
 
 Today's Topics:
 
   1. Re: From GPS World - Lightsquared has been given thegoahead
  (Chris Albertson)
   2. Re: Lightsquared and a little math (Bob Camp)
   3. Re: GPS receiver jamming (John Green)
   4. Re: Lightsquared and a little math (Stanley Reynolds)
   5. Re: Lightsquared and a little math (Chris Albertson)
   6. Re: Frequency multiplication (Hal Murray)
   7. Re: Lightsquared and the FCC (Pete Lancashire)
   8. Re: Frequency multiplication (David Armstrong)
 
 
 --
 
 Message: 1
 Date: Wed, 2 Feb 2011 10:20:21 -0800
 From: Chris Albertson albertson.ch...@gmail.com
 Subject: Re: [time-nuts] From GPS World - Lightsquared has been given
thegoahead
 To: Discussion of precise time and frequency measurement
time-nuts@febo.com
 Message-ID:
AANLkTimK_bzjZS03n7v2PJPPNmD_yfaGRRd_y=2gm...@mail.gmail.com
 Content-Type: text/plain; charset=ISO-8859-1
 
 On Wed, Feb 2, 2011 at 10:02 AM, paul swed paulsw...@gmail.com wrote:
 True enough there will be three systems heck many channels also.
 But that reality actually means my magical HP 3801 may not work or could
 become unreliable at best.
 So how do we hack those new receivers for time-nuts purposes for $29?
 
 For $29?  Maybe a home brew antenna with better patterns and maybe
 even nulls aimed at nearby transmitters.  It is surprisingly easy to
 build a helix antenna.
 
 A notch filter can also be constructed to notch out the jammer if it
 is out of band.  A twin T design might be  effective and low cost
 
 Microwave is line of site so maybe just a meter plate that blocks view
 of the transmitter.
 
 The solution for a fixed timing receiver will be much easier than for
 a mobile GPS receiver.
 -- 
 =
 Chris Albertson
 Redondo Beach, California
 
 
 
 --
 
 Message: 2
 Date: Wed, 2 Feb 2011 13:23:55 -0500
 From: Bob Camp li...@rtty.us
 Subject: Re: [time-nuts] Lightsquared and a little math
 To: 'Discussion of precise time and frequency measurement'
time-nuts@febo.com
 Message-ID: 60b8a8a8e6584d2cb3affad4f5bf9...@vectron.com
 Content-Type: text/plain;charset=us-ascii
 
 Hi
 
 There's no decision that they take that they can't reverse. That goes double
 for something like this that was done pretty quickly. 
 
 My guess is that they have a limited rather than a full approval at this
 point. From the article proceed with ancillary terrestrial component
 operations does not sound like a full license.
 
 If you do a little Google work on the topic, there are a lot of different
 services and outfits impacted by this (not just GPS). None of them are happy
 and all of them are likely on the phone to their favorite legislator and /
 or lawyers. 
 
 Bob
 
 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Pete Lancashire
 Sent: Wednesday, February 02, 2011 1:13 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Lightsquared and a little math
 
 Go back to my orig post the FCC has given the go ahead .. to late ?
 
 On Wed, Feb 2, 2011 at 9:57 AM, Bob Camp li...@rtty.us wrote:
 Hi
 
 Let's see, a 13 mile circle is pi r squared = ~ 530 square miles.
 40,000 times 530 is ~ 21 million square miles.
 Wikipedia tells me that the area of the US is 3.79 million square miles.
 
 On that basis, there's not going to be anywhere in the US that you *can*
 get
 GPS to fly a plane. Jamming detected = could be a problem = you can't
 trust
 it.
 
 I suspect that there indeed will be remote parts of Alaska or the like
 that
 you will indeed still have un-jammed coverage in a plane.
 
 Now for the best case:
 
 5.6 miles loss of fix = just under 100 square miles. That's 3.94 million
 square miles of jamming. That's still greater than the area of the US. I'm

Re: [time-nuts] Lightsquared and a little math


Stanley wrote:

Wonder if the clients of this network reduce power as cell phones do 
to increase battery life and reduce interference or they will use a 
dish on the fixed clients, not that would help with interference 
from the sat. The web site reads like the sat will distribute the 
internet signal direct to the clients


The issue is not signals from satellites, which are very 
weak.  Satellite operators serving mobile and portable devices (which 
generally cannot employ high-gain, narrow-beamwidth antennas like the 
dish antennas used for stationary (fixed, in FCC parlance) 
satellite services such as direct-to-home television reception) have 
found that there are significant coverage holes and have asked the 
FCC to allow them to use an ancillary terrestrial component (ATC) 
-- i.e., base transcievers on towers, like cellular base stations -- 
to cover the holes.  The ATC rules, as they are currently written, 
require the ATC component to be ancillary to and integrated with a 
robust satellite system that is available to all system users (the 
integrated service rule).


Even with ATC, the Mobile Satellite Service (MSS) has never really 
caught on, so it represents a fair chunk of spectrum getting very 
little use.  Some MSS providers seek to create primarily-terrestrial 
systems with an essentially vestigial satellite component.  The FCC 
(in its National Broadband Plan -- see 
http://www.broadband.gov/plan/) has started to move toward allowing 
terrestrial-only services to operate on a co-primary basis with the 
MSS on MSS spectrum, which has emboldened MSS 
licensees.  Lightsquared, which is an MSS licensee, petitioned for a 
conditional waiver of the integrated service rule, which the FCC granted:


http://fjallfoss.fcc.gov/edocs_public/attachmatch/DA-11-133A1.pdf

One of the conditions imposed by the FCC was the creation of a 
process to address interference concerns regarding GPS and, further, 
that this process must be completed to the Commission's satisfaction 
before LightSquared commences offering commercial service, pursuant 
to the approval of its request, on its L-Band MSS frequencies.  This 
process is expected to be completed within 90 days.  See paragraphs 
39-43 of the FCC order linked above.


So:  The FCC seems determined to allow the expanded use of L-band MSS 
frequencies for terrestrial use to deliver mobile broadband services, 
and Lightsquared is just one company looking to benefit.  The primary 
threat to GPS (GPS L1 is 1575.42 GHz) is from terrestrial base 
stations serving mobile devices and operating up to 1.559 GHz, 
although millions of mobile handsets operating between 1.6265 and 
1.6605 GHz may also be a worry.


The FCC has made way more than its share of boneheaded technical 
decisions over the decades (to name just the most visible tip of the 
iceberg: NTSC, multiplexed FM stereo, NRSC preemphasis of AM signals, 
AM stereo, forcing the switch to digital television, choice of 
ATSC/8VSB as the digital television standard, choice of IBOC as the 
AM/FM digital radio standard, etc., etc. -- and that's just in the 
broadcast area).  This time, it's a mad, desperate dash to find 500 
MHz of spectrum usable for mobile broadband in the next 5 years.


In my view, this technical tone-deafness at the FCC persists because 
there has been no engineering expertise or background at the 
Commission(er) level since ... well, I'm not sure there ever was, but 
perhaps in the 1930s-'40s.  The FCC staff is supposed to provide 
engineering support, but Commissioners often do not listen to the 
staff as carefully as they should and sometimes the staff gets it 
wrong.  IMO, the 5-person Commission should always include at least 
one engineer and one economist so that at least in theory it has 
enough expertise to do a reality check on proposals at the Commission level.


Thus, the truth (at least as I see it) is much more complicated than 
a simplistic conspiracy theory -- but then, it always is.


Best regards,

Charles






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Re: [time-nuts] Lightsquared and a little math


Sorry, GPS L1 is, of course, 1575.42 MHz (or 1.57542 GHz).

Charles



Stanley wrote:

Wonder if the clients of this network reduce power as cell phones 
do to increase battery life and reduce interference or they will 
use a dish on the fixed clients, not that would help with 
interference from the sat. The web site reads like the sat will 
distribute the internet signal direct to the clients


The issue is not signals from satellites, which are very 
weak.  Satellite operators serving mobile and portable devices 
(which generally cannot employ high-gain, narrow-beamwidth antennas 
like the dish antennas used for stationary (fixed, in FCC 
parlance) satellite services such as direct-to-home television 
reception) have found that there are significant coverage holes 
and have asked the FCC to allow them to use an ancillary 
terrestrial component (ATC) -- i.e., base transcievers on towers, 
like cellular base stations -- to cover the holes.  The ATC rules, 
as they are currently written, require the ATC component to be 
ancillary to and integrated with a robust satellite system that is 
available to all system users (the integrated service rule).


Even with ATC, the Mobile Satellite Service (MSS) has never really 
caught on, so it represents a fair chunk of spectrum getting very 
little use.  Some MSS providers seek to create primarily-terrestrial 
systems with an essentially vestigial satellite component.  The FCC 
(in its National Broadband Plan -- see 
http://www.broadband.gov/plan/) has started to move toward allowing 
terrestrial-only services to operate on a co-primary basis with the 
MSS on MSS spectrum, which has emboldened MSS 
licensees.  Lightsquared, which is an MSS licensee, petitioned for a 
conditional waiver of the integrated service rule, which the FCC granted:


http://fjallfoss.fcc.gov/edocs_public/attachmatch/DA-11-133A1.pdf

One of the conditions imposed by the FCC was the creation of a 
process to address interference concerns regarding GPS and, further, 
that this process must be completed to the Commission's satisfaction 
before LightSquared commences offering commercial service, pursuant 
to the approval of its request, on its L-Band MSS 
frequencies.  This process is expected to be completed within 90 
days.  See paragraphs 39-43 of the FCC order linked above.


So:  The FCC seems determined to allow the expanded use of L-band 
MSS frequencies for terrestrial use to deliver mobile broadband 
services, and Lightsquared is just one company looking to 
benefit.  The primary threat to GPS (GPS L1 is 1575.42 GHz) is from 
terrestrial base stations serving mobile devices and operating up to 
1.559 GHz, although millions of mobile handsets operating between 
1.6265 and 1.6605 GHz may also be a worry.


The FCC has made way more than its share of boneheaded technical 
decisions over the decades (to name just the most visible tip of the 
iceberg: NTSC, multiplexed FM stereo, NRSC preemphasis of AM 
signals, AM stereo, forcing the switch to digital television, choice 
of ATSC/8VSB as the digital television standard, choice of IBOC as 
the AM/FM digital radio standard, etc., etc. -- and that's just in 
the broadcast area).  This time, it's a mad, desperate dash to find 
500 MHz of spectrum usable for mobile broadband in the next 5 years.


In my view, this technical tone-deafness at the FCC persists because 
there has been no engineering expertise or background at the 
Commission(er) level since ... well, I'm not sure there ever was, 
but perhaps in the 1930s-'40s.  The FCC staff is supposed to provide 
engineering support, but Commissioners often do not listen to the 
staff as carefully as they should and sometimes the staff gets it 
wrong.  IMO, the 5-person Commission should always include at least 
one engineer and one economist so that at least in theory it has 
enough expertise to do a reality check on proposals at the Commission level.


Thus, the truth (at least as I see it) is much more complicated than 
a simplistic conspiracy theory -- but then, it always is.


Best regards,

Charles






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Re: [time-nuts] Lightsquared and a little math

2011-02-02 Thread Bob Bownes

 In my view, this technical tone-deafness at the FCC persists because there
 has been no engineering expertise or background at the Commission(er) level
 since ... well, I'm not sure there ever was, but perhaps in the 1930s-'40s.
  The FCC staff is supposed to provide engineering support, but Commissioners
 often do not listen to the staff as carefully as they should and sometimes
 the staff gets it wrong.  IMO, the 5-person Commission should always include
 at least one engineer and one economist so that at least in theory it has
 enough expertise to do a reality check on proposals at the Commission level.


The NTIA and technical folks I've worked with @ the FCC over the years
have been fantastic. It's the translation of their recommendations to
the Commissioner level where it gets tricky. Politics enters the
equation and makes things icky to us engineering types. The fact that
the commissioners have 5 year terms (unless, of course, they quit) and
often have odd overlap with any political entities in charge of the
white house or congress make it even ickier. Add in the position of
chairman of the commission and the effect of that over the other
Commissioners _and_ their fundamentally independent nature from each
other, and the ickiness factor starts to go non linear.

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[time-nuts] more on the lightsquared

2011-02-02 Thread Pete Lancashire

he FCC turned up its nose at assertions by some that the entire
process was conducted in near-stealth mode as well as on an admitted
fast-track, filed during a period coinciding with Thanksgiving and
winter holidays so that it would pass with little notice. “We conclude
that the pleading cycle for LightSquared’s request — in which the
Comment Public Notice was issued on November 19, 2010, with comments
due on December 2, 2010, and reply comments due on December 9, 2010 —
is sufficient for the decisions we make herein.”


http://www.gpsworld.com/gnss-system/news/fcc-grants-go-ahead-potential-interferer-with-gps-signal-10989?utm_source=GPSutm_medium=emailutm_campaign=Survey-Scene_01_28_2011utm_content=fcc-grants-go-ahead-potential-interferer-with-gps-signal-10989

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Re: [time-nuts] Lightsquared and a little math

2011-02-02 Thread Mike S


At 01:45 PM 2/2/2011, Chris Albertson wrote...

On Wed, Feb 2, 2011 at 10:36 AM, Stanley Reynolds
stanley_reyno...@yahoo.com wrote:
 The web site reads like the sat will distribute the internet signal 
direct to the clients:


People will hate this service.  Going up to geo-sync adds a noticeable
and annoying lag do unavoidable speed of light round trip time of
flight.


Latency will only be an issue where service would otherwise be 
unavailable. Satellite latency is better than no connection at all. The 
bulk of their coverage is with terrestrial stations, but they also have 
a satellite to fill the gaps:


The nationwide LightSquared network, consisting of approximately 
40,000 cellular base stations, will cover 92 percent of the U.S. 
population by 2015...LightSquared is using terrestrial and satellite 
technology to ensure constant connectivity, regardless of location. The 
LightSquared satellite, built by Boeing, was launched into 
geostationary orbit over North America in November 2010.


Does anyone know the timing synchronization requirements for LTE? This 
network may offer a supplement to current GPS/CDMA based time 
solutions. (says I, trying to get this thread back to time-nuts) 



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Re: [time-nuts] more on the lightsquared

2011-02-02 Thread lists

Lot of good public comment did me on IBOC, BPL, and the XM-sirius merger. :-(  

I wrote an email to both my senators, provide the original link and a tinyurl 
equivalent. I hope the readers on this list have spread the gospel. Diane 
Feinstein has a pull down for FCC issues on her email template. 


-Original Message-
From: Pete Lancashire p...@petelancashire.com
Sender: time-nuts-boun...@febo.com
Date: Wed, 2 Feb 2011 16:34:59 
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: [time-nuts] more on the lightsquared

he FCC turned up its nose at assertions by some that the entire
process was conducted in near-stealth mode as well as on an admitted
fast-track, filed during a period coinciding with Thanksgiving and
winter holidays so that it would pass with little notice. “We conclude
that the pleading cycle for LightSquared’s request — in which the
Comment Public Notice was issued on November 19, 2010, with comments
due on December 2, 2010, and reply comments due on December 9, 2010 —
is sufficient for the decisions we make herein.”


http://www.gpsworld.com/gnss-system/news/fcc-grants-go-ahead-potential-interferer-with-gps-signal-10989?utm_source=GPSutm_medium=emailutm_campaign=Survey-Scene_01_28_2011utm_content=fcc-grants-go-ahead-potential-interferer-with-gps-signal-10989

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Re: [time-nuts] Lightsquared and a little math