That Custom-Tailored Obama Scandal You Ordered Is Finally Here
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71 thoughts on “Solyndra: John Daily.”
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That Custom-Tailored Obama Scandal You Ordered Is Finally Here
| The Daily Show With Jon Stewart | Mon – Thurs 11p / 10c | |||
| That Custom-Tailored Obama Scandal You Ordered Is Finally Here | ||||
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Comments are closed.
The scandals are all over the place. It’s just that the lame stream media have refused to mention them or identify them as scandals. When the comedians start on something, though, it may have hit critical mass.
LightSquared is worse.
“The four-star Air Force general who oversees Air Force Space Command walked into a highly secured room on Capitol Hill a week ago to give a classified briefing to lawmakers and staff, and dropped a surprise. Pressed by members, Gen. William Shelton said the White House tried to pressure him to change his testimony to make it more favorable to a company tied to a large Democratic donor.”
http://www.thedailybeast.com/articles/2011/09/15/lightsquared-did-white-house-pressure-general-shelton-to-help-donor.html
“LightSquared’s bold $14 billion plan, its detractors said, could cripple Global Positioning Satellite (GPS) systems and threaten aviation safety, disrupt military and rescue operations, and interfere with high-tech farming equipment and the everyday navigation devices used by millions.”
“Several major Democratic campaign contributors and longtime Obama supporters have held investments in the company and its affiliates during its tangled decade of existence. They include Obama’s good friend and political donor Donald Gips, his former White House personnel chief, who now serves as U.S. ambassador to South Africa. Records show that Gips maintained an interest, worth as much as $500,000, as the FCC was weighing LightSquared’s request.
Obama himself was an early investor and came to the presidency a firm believer in expanding broadband. He remains close to other early investors, like Gips and investment manager George W. Haywood, inviting some to luxe social events at the White House and more intimate gatherings like a night of poker and beer.
Obama installed one of his biggest fundraisers, Julius Genachowski, a campaign “bundler†and broadband cheerleader, as chairman of the FCC, whose staff granted LightSquared a special waiver to operate.
LightSquared’s current majority owner, hedge fund manager Philip Falcone, made large donations to the Democratic Party while his broadband request was pending before the FCC. He and LightSquared executives met with White House officials. Neither Falcone nor the White House would comment on what was discussed.
LightSquared employs lobbying firms that wield formidable Democratic firepower: Ed Rendell, former governor of Pennsylvania and onetime chair of the Democratic National Committee, as well as the firm of former House Majority Leader Richard Gephardt.
Jeffrey J. Carlisle, the company’s vice president for regulatory affairs, served with Genachowski and Gips on Obama’s transition team.”
http://www.thecuttingedgenews.com/index.php?article=52446
Any real evidence that there is interference with properly engineered GPS, Bruce? This sounds like prime farm-grade BS.
Color me more than a bit querulous here, but isn’t it a bit whack to suggest that future broad band expansion be held hostage by incompetent engineering of the GPS systems?
(The problems with cronyism are real, and a separate issue. But welcome to Washington on that one, it isn’t limited to the BHO administration.)
Re: Carrick (Sep 16 15:49),
You mean like with a high gain tuned antenna with a high-Q tuner? Try putting that in a cell phone. Satellite signals are weak. A higher power signal anywhere close in frequency could easily overwhelm the satellite signal. I’m sure you could build a GPS receiver that wouldn’t have that problem but how much would it cost? Probably too much to be able to put it in a cell phone or a car window mounted navigation device that sells for less than $100. GPS is old technology (1973), relatively speaking, and you can’t modify it now. Cellular telephony is about the same vintage. The 802.11 Wi-Fi spec wasn’t issued until 1985. It’s a little hard to engineer a system to be able to resist interference from a technology that hasn’t been invented yet.
And so should government be able to decide the future of technology? Or interfere in market forces at all?
Government, where it is involved, should be in education not regulation!
Hmm…..
Roy Weiler
Carrick:
“One of the bands allocated to LightSquared, called the “upper band,” sits right next to spectrum set aside exclusively for GPS (Global Positioning System). Its “lower” band is farther from the GPS frequencies but has been used by satellite services that make GPS more accurate.”
“The first step in that process was a series of tests focused on the upper band, which LightSquared had planned to use for its initial rollout. Those tests found massive disruption to GPS, so the carrier proposed starting out in the lower band and using the higher frequencies only after the problems there had been worked out. Interference in the lower band is not likely to affect as many GPS devices, though critics say the impact might still be significant for many devices.”
http://www.pcworld.com/businesscenter/article/236501/lightsquared_vs_gps_raises_big_spectrum_issues.html
A series of tests in April had serious effects on several types of GPS systems, according to the National Positioning Navigation and Timing (PNT) Systems Engineering Forum. The Forum conducts assessments for the Space-Based PNT Executive Committee, a government agency set up to coordinate efforts around GPS and similar systems.
Tests in an anechoic chamber at White Sands Missile Range in New Mexico showed a simulated LightSquared network knocked out GPS receivers used for aviation, surveying, agriculture, the U.S. Coast Guard and Garmin personal navigation devices. All the aviation units lost their GPS connections, as did all the tested high-precision receivers for scientific use by NASA.
The PNT agency also reported the results of “live sky” tests conducted using a production transmitter set up and operated by LightSquared at Holloman Air Force Base in New Mexico. Among other things, those tests showed that police cars lost their GPS reception within about 600 feet from the tower and ambulances and fire trucks lost service about 1,000 feet away. General Motors’ OnStar vehicle navigation systems also were significantly degraded, the agency said.
http://www.computerworld.com/s/article/9217632/LightSquared_report_due_amid_criticism_over_GPS_interference_issue_
“The RTCA, a nonprofit corporation that advises the Federal Aviation Administration, said its tests showed that LightSquared’s operations in one part of its spectrum band would make GPS unavailable to aircraft over a large region of the Northeastern U.S. RTCA recommended LightSquared not be able to use that band, and called for further study.”
Is that enough for you Carrick?
Still the question is Bruce… if you have crappy designed GPS receivers, should we as data consumers be held hostage to their incompetency?
That’s the take home message, nothing you’ve said changes that question or its implications.
(BTW, nobody including me is calling for an immediate end of “further study”. Further study is still ongoing.)
Carrick,
I don’t think anyone suggests that it would be inappropriate to weigh relative costs and benefits; at some point, a change in standards for GPS receivers may very well make economic sense. The issue here seems to be that there is a huge installed based of equipment which could be put out of service, or be diminished considerably, if this company is allowed to go forward with it’s plans. If there is in fact real potential for disruption of existing services (and that sure seems to be the case), then it seems to me wise to make sure that a) “properly designed” GPS equipment can in fact be made at reasonable cost for the current (widespread) GPS applications, and b) the economic cost to force the replacement of equipment made unusable by this technology be carefully weighed….. before ever allowing the company to go forward.
The application of political pressure to a military officer raises my BS antenna pretty quickly. If this is such a swell idea, then the company should be making it’s case purely on the merits; it ought not need any political influence. My guess is the Obama administration will quickly recognize that making many millions of people’s personal GPS units non-functional has the potential to lose a lot of votes. I expect something along the line of recent decisions on EPA regulations of CO2 emission from power plants.
SteveF as I understand the issue, it isn’t a change in the GPS standards, it’s more along the lines that many GPS receivers don’t meet existing standards. As you will notice in Bruce’s comments, the proposed new broadband channel does not overlap with the GPS channel. The defect is in the GPS receiver not having a narrow enough filter to eliminate cross talk from adjacent channels.
So I guess we’re supposed to sit our arse and accept slow downloads so cheap foreign GPS chips can continue to operate at a literally substandard level. IMO, if you sell a GPS that is defective, and IMO any GPS receiver that is interfered with by previously specified out-of-band signals, the onus is on the manufacturer to fix the defect.
Remember too, there is a cost to suck-a$$ data transfer rates. Probably this adds up much more quickly than a one-up repair of defective GPS receivers.
As to this being political, since when is anything FCC related not political?
Carrick, I knew you were full of it from past discussions, but you top yourself this time.
Re: Carrick (Sep 16 19:28),
Yes, that’s precisely what we’re required to do. And you are only asserting that the chips and receivers are substandard. More likely they are manufactured to the GPS specifications as originally issued.
Ask the opposite question: should every GPS receiver (and probably satellites as well) in the world be replaced so a few people in the US can get faster downloads? Verizon 4G is quite fast, averaging 6.44Mbps in a recent test, and doesn’t interfere with GPS as far as I know.
Right Bruce, you parrot politically motivated BS, then can’t comment on technical issues, and I’m full of it. When’s the last time you installed an OEM GPS module on a printed circuit board? (I have, yesterday was the most recent.) All you know is the political tripe you parrot, nothing else.
DeWitt, the proposal was to use a frequency band that is outside of the band used by the GPS receivers. If they are being interfered by signals that meet proper power specifications than are outside of their band, then it is a defect in the GPS receiver not in the new technology.
That doesn’t mean we turn on the new signals until the old problem is fixed, but the proper response is to force GPS manufactures who sell substandard devices to bring their devices up to standard, not hamstring everybody else.
Regarding 6 Mbps, you think that’s a fast download rate? Also, upload speeds, which is what most of us outside of the consumer market are interested in, is still only a paltry 1 Mbps. We need something closer to 802.11/g, e.g., 54 Mbps.
Re: Carrick (Sep 17 08:58),
Need 54Mbps? How many high-def movies do you want to stream at once? Current FIOS speeds aren’t that fast, although the capability for 150 Mbps is anticipated. And power is likely the problem. More likely Lightspeed is the one using substandard technology so too much power bleeds over into lower (or higher) frequencies. No matter how well designed the receiver, it can still be jammed with enough power.
BTW to be clear:
“Manufactured to GPS specifications” mean they can e.g. lock on L1 from the satellites and compute a position. When you are dealing with RF frequency equipment, resilience of the equipment to out-of-band interference is a separate issue from meeting those specifications.
In a very technical sense, if you are given the frequency band reserved for GPS (e.g., the reserved component in the L1 band), hypothetical maximum signal out of band signal strength, it is an engineering requirement that your system still operate properly when an out-of-band signal that meets the standard is present.
If it doesn’t, that is by definition sub-standard performance. If you look at the frequency bands for GPS and LightSquared, there is a 23-Mhz spacing between them and that used by GPS.
LightSquared uses 1526-1536MHz, GPS uses 1575.5 mHz. If there were significant overlap outside of the band used by LightSquared by signals generated by LightSquared, then under FCC regulations, LightSquared would be in violation of the standard, and should be prevented from broadcasting until this problem is fixed.
The problem is that some (about 0.5%) of the GPS receivers have poor frequency response and are interfered with by signals that meet FCC regulations in the 1526-1536MHz band. It is a problem with the filtering in the GPS receivers, not in the transmitted signal. And it is a fixable problem.
If you sell somebody a $10,000 precision GPS system, and it quits working because it fails due to a signal that meets existing FCC regulations, sorry that I’m not crying tears for you if you have to take it back and install few dollars worth of electronic components to repair the problem you created with your bone-headed engineering to start with.
(Most GPS receivers, including the one in your phone, likely won’t get affected, but this is something that I’d like to see the test results on.)
Speaking of politicized, what do you think Bruce is doing, if not trying to turn what is a technical issue into an argument about the Obama administration policies? What a complete friggin’ joke.
DeWitt, I think you are thinking of the primary user of the extra bandwidth as being consumer related (I thought I made that clear I wasn’t discussing consumer applications). It’s not. There are many civilian and military related applications besides streaming movies that need a higher bandwidth than is currently available with broadband wireless.
This is speculation, and what you suggest is false. The problem is in some (0.5%) of the GPS receivers being sensitive to out of band signal rather than LightSquared generating a signal with a substantial overlap with the band used by GPS receivers.
Carrick (Comment #81624)
September 16th, 2011 at 7:28 pm | Reply w/ Link
SteveF as I understand the issue, it isn’t a change in the GPS standards, it’s more along the lines that many GPS receivers don’t meet existing standards.
Your understanding is incorrect. GPS transmitters and receivers were designed to operate in a “quiet” band. That was the FCC designation. The underlying reason was the difficulty in placing high powered transmitters into orbit.
The receivers have no problem when competing signals are the same strength as the satellite signals. The problem comes when you have a signal a billion times stronger on an adjacent channel.
Imagine you are sitting in a quiet park listening to the birds. Now imagine you are in the same park and someone is running a lawnmower nest to you. The birds and the lawnmower are on different frequencies
Now try and design and build a filter that blocks the sound of the lawnmower and allows you to hear the birds while completely blocking out the sound of the lawnmower.
Carrick, just because some people bribed some people to give them spectrum that will destroy GPS so they can make billions while helping people download porn faster, doesn’t make your stupid blustering right.
“This is speculation, and what you suggest is false. The problem is in some (0.5%) of the GPS receivers”
The testing suggests otherwise. “All the aviation units lost their GPS connections”
All of them. Every one. Not .5%. Every one.
ferd, I think I am correct. The width of the GPS signal is only 1 MHz, the upper corner of LightSquared is 35 MHz below it. The idea that this is a hypothetical “quiet” band is just silly. You want to know why?
Because if it were, the band reserved for GPS would have been widened.
Secondly, a billion times stronger signal? That would put it at around 4 billion watts, a bit of exaggeration here perhaps?
LOL.
Bruce:
You believe everything you read? Bruce accepts hyperbole and exaggeration, when it aligns with his political beliefs of course. And anybody who points out when he’s spouting nonsense is just “stupid”. Heh.
If you’re right about bribery of course I’m quite in favor of an investigation and jailing of those responsible. But of course this is hyperbole on your part and I know better than to take anything you say seriously.
Here’s more detail:
And again for Bruce, this debate isn’t about porn downloads…
The lack of a higher speed bandwidth has immediate commercial, civil defense and military implications. You guys are like people arguing against an interstate system because some people will be forced to move.
This is clearly a disruptive technology, not arguing that. The question is whether being disruptive is a sufficient criterion to prevent its adoption.
Carrick (Comment #81665)
September 17th, 2011 at 10:30 am | Reply w/ Link
ferd, I think I am correct
Power is proportional to the square of the distance. The GPS transmitters are in orbit, 20000km. The earth is 6000km radius. The competing stations are going to be located something like an average of 0.4km in urban areas.
So, even if the transmitters were the same power, the effective power at the receivers would be minimum ((20000-6000)/.4)^2 = 1.2 billion times stronger (satellite directly overhead).
However since GPS uses an array of satellites, which are farther away when not directly overhead, the G4 system would on average be more than 1.2 billion times stronger, even if it was restricted to the same power levels as the satellites.
What matters is the power of the signal at the receiver, not at the transmitter, unless you are claiming now that the satellite used by LightSquared is somehow interfering with the GPS satellites.
And the power of the LightSquared signal at the receiver is not one billion times stronger than GPS L1 signal. That is patently false. (Otherwise, we’d all get cooked by the LightSquared signal.)
Seriously there is a lot of knee jerk reaction going on here, in some cases, from people who are usually much more deliberative. This isn’t a new story, it’s quite an old one, and if you haven’t been following it, my suggestion is do some reading then post (beyond the pseudoscience crap that Bruce posts).
Carrick (Comment #81667)
September 17th, 2011 at 10:41 am | Reply w/ Link
Here’s more detail:
FCC Chairman Julius Genachowski
Julius Genachowski was nominated by President Obama, who had been a friend since their days at Harvard Law School. He was a prolific fund-raiser.
So, the FCC chairman’s qualifications:
1. Friend of Obama
2. Lawyer
3. Fundraiser
Now read what the FCC chairman said:
“And they never did what they were supposed to do, which was manufacture receivers then that would not interfere with the next band over.†”
Notice how misleading he is. He is talking about interference CAUSED by receivers. This issue has nothing to do with GPS receiver caused interference. It has to do with interference caused by G4 transmitters, which cannot be effectively filtered for the same technical reasons that you cannot filter out a lawnmower so you can hear the birds in the park.
What you have is a lawyer using weasel words to try and mislead the gullible to help promote a company that is heavily invested in by Obama supporters and fund raisers. It stinks of corruption and cronyism. The reason why the US is in such trouble, the corruption in Washington being used to the advantage of a few at the expense of the many.
Carrick (Comment #81669)
September 17th, 2011 at 11:02 am | Reply w/ Link
What matters is the power of the signal at the receiver, not at the transmitter
—–
Agreed, that is what I calculated, the effective power at the receiver. At the receiver, the G4 transmitters have 1.2 billion times the effective power of the GPS satellites, for the same transmitter power. Sounds like you are as confused as the FCC chairman, or are you trying to mislead people on purpose?
Carrick, “The lack of a higher speed bandwidth has immediate commercial, civil defense and military implications. ”
Not as immediate as the destruction of the GPS system.
But go ahead Carrick, keep beclowning yourself.
fergle:
You really don’t know what you’re taking about do you?
They are different frequency bands, and it is routine to filter out adjacent bands.
If it were 1,000,000,000 stronger at the surface that would put its power around 30 dBW (compared to around -160 dBW for GPS signals on the ground). You really think that’s true?
If there is “confusion” here, it’s over transmission loss versus received power.
Carrick, “The lack of a higher speed bandwidth has immediate commercial, civil defense and military implications. â€
Why not simply pick a band with a significantly higher frequency than GPS? The higher the frequency of the band you are transmitting in, the higher the effective bandwidth of the signal you can transmit and still stay within band.
This, if LightSquared was to operate on frequencies double what they are proposing to use, then there would be no interference with GPS, and they could increase the bandwidth of their signal. It would be a win-win all around.
fergle the problem is we are running out of non-military bandwidth to use.
The better solution would be to repurpose some of the claimed but unused military bandwidth, but that isn’t in the cards either.
I think there is a discussion in moving the LightSquared upper band farther away from the GPS band.
Carrick (Comment #81673)
September 17th, 2011 at 11:28 am | Reply w/ Link
You really don’t know what you’re taking about do you?
They are different frequency bands, and it is routine to filter out adjacent bands.
Actually I do know what I’m talking about. I hold a US advanced amateur radio license, granted me by the FCC, which is the highest classification of ham license you can hold in the US. This is an difficult license to obtain and the exam requires considerable understanding of radio theory including interference and filters. I also hold a restricted radio operators license, which allows me to operate outside the amateur bands.
Carrick (Comment #81675)
September 17th, 2011 at 11:37 am | Reply w/ Link
fergle the problem is we are running out of non-military bandwidth to use.
———–
GPS operates < 1.6GHz. There are tons of allocations above that, specifically for mobile operations such as proposed by LightSquared, extending up to 300GHz. Have a look.
http://upload.wikimedia.org/wikipedia/commons/4/45/United_States_Frequency_Allocations_Chart_2003_-_The_Radio_Spectrum.jpg
Carrick,
With regard to the issue of relative received power, the typical GPS received signal is ~1.8 X10^-13 watt. The proposed ground based LightSquared stations are hundreds to thousands of watts. How much of those 100’s to 1000’s of watts reach a GPS receiver will (of course) depend on the distance from the transmitter, but with such huge power differentials, it is fair to say that at a minimum the potential for interference is real.
The potential for interference is confirmed in the following letter to the FCC, written by an Obama appointee: http://en.wikipedia.org/wiki/LightSquared#cite_note-23
.
According to Wikipedia:
“On April 5, 2011, with respect to concerns raised by the U.S. GPS Industry Council and NTIA about LightSquared’s MSS/ATC operations, the FCC states that LightSquared cannot commence offering a commercial terrestrial service until the FCC concludes that the harmful interference concerns have been resolved. They also emphasize that responsibility for protecting services rests not only on new entrants but also on incumbent users themselves, who must use receivers that reasonably discriminate against reception of signals outside their allocated spectrum.”
.
Apparently responding to the concerns raised by NTIA (once again from Wikipedia):
“In June 2011, LightSquared unveiled a new plan for deploying its network which would use the lower frequency band of 1526-1536MHz (23MHz away from GPS) for the initial deployment and delay use of the upper band closer to GPS until a later date. They also proposed a 3dB reduction in the base station radiated power.” (for those not familiar: -3 dB is a 50% reduction)
.
So it sounds to me like there are in fact serious concerns about interference with GPS reception. Wikipedia goes on to say that GPS receivers have very sensitive front ends and little filtration so as to not attenuate the already very weak (fractional femtowatt) satellite signals. I have not been able to find good technical descriptions of what is/is not possible in the way of improved selectivity for compact GPS systems. The additional cost/size/power consumption for more selective GPS receivers is probably a critical piece of information in weighing costs and benefits. I do know that disabling a lot of people’s car navigation systems (regardless of the benefits in availability of G4 reception) is not a politically wise choice. Interfering with my boat’s navigation system would really tick me off (especially if it made nighttime navigation dangerous or impossible), but Mr. Obama is not likely going to get my vote anyway. 🙂
.
I still think politicians pressuring military officers to change congressional testimony is always a bad thing. It is also incredibly stupid politics.
Here is a high performance gps filter. Looking at the performance graph, 23mhz off center frequency, the filter is about 3db down, so it basically does nothing to filter out Lightsquared.
http://www.idt.com/products/getDoc.cfm?docID=18640067
Re: Carrick (Sep 17 11:28),
A 10E9 stronger signal than -160dbW would be -70dbW not 30dbW.
ferd b,
Yikes!
Looks like the filter would have to be twice as narrow as that one to provide meaningful protection from signals 23 MHz away from the center of the GPS band. The higher frequency LightSquared band would appear to require a MUCH more narrow pass band. Do you know if anyone makes such filters?
DeWitt, you’re right… 1e9 in power is only 90 dB. I was thinking amplitude.
SteveF and Fergle, according to what I’ve read, the “non-cheap” GPS receivers already have narrow enough filters to handle the interference. The “SAW” filters (surface acoustic wavefilters) such as linked by fergle are of the “cheap” variety, the ones that the FCC “mandated be replaced in 2004 (and which LightSquared claims many companies choose to ignore) use “BAW” (bulk acoustic wave) filters or thin film bulk acoustic resonator (FBAR) filters (see this data sheet for an example).
fergie, once you go above 2 GHz, issues with transmission losses due to attenuation and propagation effects are huge, so this wouldn’t work for broadband wireless digital communication, unless you put up an awful lot of towers.
We don’t use 2 Ghz or higher for our own telemetry work because of the problems with its transmission. Usually we employ the 900 MHz band, like this FreeWave radio.
By the way, we do employ precision GPS systems that we custom build for our instrumentation, so I’m not a complete noob on the issues on this either, and would have problems if there were interference that wasn’t economically solvable.
I appreciate you have experience with ham radio systems, but does that qualify you to categorically state whether engineering solutions do or don’t exist, and how economically practicable they would be?
Some of the back story is the land-based internet people are going to be put out of business when true high-speed broadband wireless appears, and they are behind part of the protesting (blocking a disruptive technology that puts them out of business.) The companies who would rather complain than fix their products are the other.
I’m not belittling the issues, as a GPS user, they could potentially affect me too. As I said, I’m glad this is getting further study before the switch is flipped on.
SteveF, also part of the proposed short-term mitigation of interference involves restricting LightSquared to the lower half of their licensed band.
I think this is probably a fair compromise, if it can be show to minimize interference, as long as there is a “drop dead date” for GPS manufacturers to address the issues with receivers that aren’t in compliance
Carrick (Comment #81685),
Looking at the data sheet you linked to, it does appear that there is about a 25 dB attenuation 23 MHz below the center of the GPS band, which may be enough to solve most interference problems, although I suspect that for a receiver close to a ground tower there could still be issues (I assume these kinds of issues will in fact be studied in detail). BTW, my boat’s GPS navigation system was made before the 2004 date of the FCC mandate you reference. A new one costs several thousand dollars… so I hope I can get an updated receiver portion, and not have to buy a whole new system.
Carrick,
One more thought. The center of the GPS band is in fact only 15 MHz above the upper end of the LightSquared band. Even the filter you linked to does not appear to provide very much protection 15 MHz away… new hardware may need to be developed.
SteveF, I suspect you won’t have a problem on your boat, unless you were to go directly by a tower siting by a river bank, or navigate on a river through a city (e.g., Chicago River comes to mind).
I also suspect for my applications, no changes would be needed, because we are usually deploying our systems in remote locations, where large cell phone tower signal strength is rarely the main problem.
Short term, I think the FCC are going to only allow the low-half of the band to be used, and I think even for existing GPS systems that are known to have issues, that should lead to minimal interference problems.
Like Bruce (he and I agree on this), nothing should be allowed to be turned on, until everything is fully vetted and the economic consequences of the decision are fully understood.
However, I don’t think the people attacking LightSquared are being totally fair on this, because the GPS companies own most of the culpibility for the currently situation.
One should realize that LightSquared has spent money putting a satellite in orbit, and people had seven years to plan, and FBAR systems with an 8-MHz bandwidth have been on the lab-bench at least that long, but sometimes industry doesn’t respond until the last possible moment. This is one of those “sometimes” IMO.
Re: Carrick (Sep 17 13:55),
Even the BAW filter is only about 30db down, compared to the 12.8db gain at the center of the channel, at 1.552 GHz. And it’s not much better on the high frequency side than the SAW filter at 1.598GHz. If the SAW filter is adequate for rejection of cell phone frequencies, than even the BAW filter might be marginal on the low frequency side.
The next question is, how does Lightsquared’s proposed transmission power compare to cell phone base station power of less than 100W?
That 0.5% interference figure is from Lightsquared so it’s not exactly unbiased either. Dish Network also has a proposal for an open access 4G nationwide system that won’t interfere with GPS but has fewer towers planned.
Here’s the actual report submitted to the FCC. It would seem that high precision GPS devices require broadband reception.
The 6.4Mbps speed was actual user experience in the field. Try hooking 20 or 200 computers to your 802.11g or n system and see what sort of average speed you get.
Carrick reading the above it seems you have made a right royal ass of yourself.
@ Carrick “a billion times stronger signal? That would put it at around 4 billion watts, a bit of exaggeration here perhaps? LOL.”
If the power received by a GPS signal is around 1.8 X10^-13 watt, then Carrick a billion times stronger would make it around 1.8 X10^-4 watts, making you in error by over 2,000,000,000,000,000%. Thats over two Quadrillion percent.
If I were you Carrick at this stage, after claiming to be a technical whiz, I would quietly slink off and either stop posting or change my handle.
Somehow I find American humour somewhat strange. 1100 employees lose their jobs and this is supposed to be funny?
As for the scandal Solyandra said “The leadership and actions of President Barack Obama, Energy Secretary Steven Chu and the U.S. Congress were instrumental in concluding this offer for a loan guarantee,†said Solyndra CEO and founder, Dr. Chris Gronet. “The DOE Loan Guarantee Program funding will enable Solyndra to achieve the economies of scale needed to deliver solar electricity at prices that are competitive with utility rates. This expansion is really about creating new jobs while meaningfully impacting global warming.â€
AND Goldman, Sachs & Co. acted as exclusive financial advisor to Solyndra in connection with this loan guarantee application.
But who needs scandals – get rid of that #$%* as soon as possible!
DeWitt:
I couldn’t find anything that stated there was an overlap in the frequency band used by the high precision GPS devices & LightSquared. Perhaps you could point out where it states thats?
Secondly, here’s the latest DOD specs.
This specification seems to require that the GPS operate in a 24 MHz band, and filter out signals that are outside of this band.
Thirdly, industry has known about the FCC decision since 2004.
Forthly, laboratory filters have existed since 2004 that can go as narrow as 8MHz, so “violates laws of physics” isn’t a viable answer.
What other explanations are there than insular corporate mentality?
IMO, companies should answer for the failure to meet their corporate obligations, which includes adhering to FCC & DOD regulations, standards and specifications, and not the parties affected by their failure to comply. But that’s just me.
This isn’t a very good argument. This no different a problem than sharing a land-line with 200 computers.
RIchard, you’re correct… I did make a mistake there and already admitted to it. When firgle was discussing 1e9 more power, I managed to confused power with amplitude in my computation… DeWitt beat you to this, but congratulations for second place. You’ll find the trophy for that in the women’s restroom.
Re: Carrick (Sep 17 20:15),
From page 9:
If you get 20Mbps download speed from your ISP, I can guarantee you that the channel you share with 100-200 other customers has way more than an order of magnitude higher bandwidth.
That’s a pretty non-technical paragraph DeWitt, and more to the point, I don’t see anything there that states that there is an overlap in the bands. I think they need to spell this out in a bit more detail so we know what “filtering” they are talking about.
As would the broadband wireless provider of course. When I mentioned numbers like 54 MBps, I was referring to the individual user, not the total bandwidth available.
Re: Carrick (Sep 17 20:49),
Well, according to the cover letter, it’s been redacted from the classified version and apparently written for policy makers, not scientists.
Here’s another tidbit that you probably already know. The channel spacing for the 802.11g standard is 5 MHz. The problem is that the actual bandwidth of the signal is closer to 30 MHz even though the standard calls for 22 MHz. What that means is that only three non-interfering channels are actually available for a single site, 1,6 and 11.
According to information theory, the same bit-rate requires the same frequency bandwidth regardless of the center frequency. The frequency bandwidth for DVB satellite TV is nominally 30 MHz for a bit-rate of 90 Mbps. And that’s the FWHM or 3db bandwidth. That makes a spacing of only 20MHz between a high bandwidth data system and the satellite GPS band look a little questionable all by itself.
DeWitt:
Unfortunately, from my experience, making something classified is another way to bury details you don’t want people to argue with you about. I’m pretty skeptical there’s much classified about precision GPS systems that rely only on the civilian L1 band.
The explanation for the higher band width is (eventually) they will use other bands in addition to this little band parked close to the GPS frequency. Eventually there will be another band made available for precision GPS too. That’s been in the works for a while.
DeWitt, actually it occurs to me that the information may not be classified but it very well could be export restricted. Not going to look at the US Commerce Department list, or the DOD one, but I suspect we’d find precision GPS systems listed on one of them.
Carrick:
Will your GPs project be resistant to this “interference?” You say you are soldering it – is it the SMT chip or a module? Can you share which one, either way? I ask because I just got through building a tilt-compensated compass for the boat and was thinking of moving on to a gps project – in addition to the other two gps’s already on board.
BTW, I have an amateur radio “Extra” license which i had thought was the most exalted currently granted and I can assure you all that means i know only a little more than nothing, which of course doesn’t mean I can’t know a lot. But in my case think “nothing.”
On the $2,000 marine gps nav system, I thought it better to run on pc. This way, I can change hardware, software, charts, and the gps (and the nmea and seatalk stuff) piece by piece as the technology advances rather than having a big chunk made obsolete by the passing of one small system component.
back to the original topic here:
There is a great phrase about change in political regimes; “Swept into office.”
i suspect that whenever we have a party change in administration, the first term team is populated by children, mostly because they are available – not built into the woodwork in their occupations as yet. They are swept in because they were not nailed down.
So you get the kind of actions which someone with more experience in making mistakes would know better than to do. One might think that the weak links in this cadre would be discovered and cleaned out during a second term, but likely not, it takes longer which is why a long run like the Reagan – Bush one starts to look competent eventually – they also staffed with older people, although i can’t prove it.
i know a lot of you guys watch the incumbents like a hawk. The effect or impact of their various mistakes varies – anbd the visibility, too I thought the most colossally stupid thing they’ve done recently was to schedule O’s talk the same night as one of the Repub debates. It insulted the Repubs needlessly, and if it had happened would have reduced viewership of O’s talk as well as the debates. If you thought the debaters would make fools of themselves, then fewer people would see it happen. it was stupid in every possible way.
And if it was an accident, then the ignorance was astounding. A lot of the mess these folks make isn’t visible, but this one sure was.
J ferguson, we base our GPS system off of this OEM chip:
Navsync Wi125.
This particular chip is designed for stationary or slow-moving vessels. However, it is engineered to provide a PPS-aligned “f0” clock frequency (e.g., 10 Mhz) in addition to a PPS that is accurate to 40 ns.
Based on the current proposal to only use the lower frequency band and to drop the power, I suspect there won’t be any issues with a system like mine. If you get close enough to the tower, I suspect it would be an issue, but right at the tower, multi-pathing screws up your GPS in any case…
I suspect this isn’t ideal for your application, since it is very high end (generating “f0” for example). Garmin sells some pretty nice OEM packages . I’d recommend the GPS 18xPC, since this has a serial output and is easy to read on almost any computer. On a LINUX system, the PPS can be used as hardware flow control, so line your GPS updates to the second at microsecond accuracies… nice but not essential for most navigational applications. (Other companies sells a similar products, but I’ve had really good luck with this particular “hockey puck” GPS.)
We use very-low-power LINUX based computers, LINUX because the extensibility of the software, very low power because they need to operate for long periods of time unattended. We use this GUMSTIX Overo, which would be ideal for your applications if you use LINUX. For example if you want it to have wireless, get the Overo Air. You’d need one of their expansion boards with it. That would give you WIFI, BLUETOOTH, 2 USB ports, an ethernet port, 2 serial ports and an HDMI monitor port.
Not including the monitor (which you only need to turn on for debugging it of course, unless you want to use it to display your current position via e.g. google map) these types of systems (GPS + LINUX) run on DC and draw around 5W of power, so depending on application and the size of your boat, you could get away with running it off a small solar panel + battery. Expect to pay about $70 for the solar panel (up to about 40 W), and then you’ll need a “decent” solar controller, e.g. something like this Morningstar SS6L-12 Sunsaver 6 Solar Controller. Those go for about $40 bucks.
Hope that is of some help!
Carrick,
I looked a little into 4G specs. Initially the bandwidth will be in the range of 5-20 MHz. But you aren’t going to get 20 Mbps for the individual user with bandwidth that low. 1Gbps is going to require a bandwidth greater than 50 MHz, or pretty much the entire spectrum band allocated to Lightsquared. There’s no way that’s not going to interfere with the L1 GPS band.
Of course you could always buy a dual frequency GPS receiver like the Leica SR 520 that receives on L2 as well as L1. It’s on sale for $7,900.
Your BAW filter doesn’t meet the DoD 2008 specs sharp cutoff ideal filter at ±12Mhz either. It’s more like -20 to +25 MHz at best. So much for a 4 MHz guard band. 80db down at 1536 MHz may not cut it when Lightsquared’s signal is more than 90db greater than the satellite signal. Do we know if Lightsquared’s signal is going to have a sharp cutoff at 1536 MHz or is that the -3db point?
It did not take this thread long to get off the rails and in fact it appears to be a record low for direct comments on the subject at hand – that Lucia presented by way of the Jon Stewart video.
The band width interference issue in the side tracked discussion would appear to a libertarian to be one of property rights, albeit those granted in a somewhat indirect fashion by the government. I have not thought it through so I do not know where I would come down on this particular issue.
Meanwhile, I was hoping to comment on what Jon Stewart said. Jon is rather transparent and his little comic shtick in the video was obviously his attempt at damage control. No discussion of the bigger issues of government involvement in such endeavors, but rather taking that involvement for granted and then doing a bit of comedy on this outlier exception to the rule of government promoting green energy.
Jon claims he exist purely for entertainment and that he does not have a serious political message. Unfortunately polls indicate that a large share of his followers think otherwise. I recall him lecturing Jim Kramer on people following his lead when the market crashed and in effect blaming Kramer for misleading the public on investments. So ironic that Kramer and Stewart with their physicakl humor being very much the same and both have followings that probaly take what either says way too seriously and Jon gets it for Kramer but not for himself.
I suppose it might be my age, but I have never been impressed with Jon’s (Kramer’s) humor and satire and primarily for all grimacing and animation that it involves. Would not a more cerebral comedian assume that his audience gets it when a point is being made without a grimace or funny face clue? What’s that all about?
DeWitt:
As you may be aware the formal limit on data transfer rate depends on both the bandwidth and the signal-to-noise. (See this formula). You can’t just look at the band-width to determine the channel capacity.
My suspicion is LightSquare’s interest in this channel is the lack of any other high amplitude interfering signals, and hence larger S/N. But who knows?
I’ve been following my own advise and done more reading…
L2 depends on receiving L1, so interference on the L1 channel can prevent reception of the L2 channel as well.
carrick,
thanks much. I can very much use your suggestions. best regards, john
Carrick (81726),
So if you have very good S/N (say 2^12), you could get up to 13 bits per Hz of bandwidth. A 30 MHz band might yield 390 megabit total available. Still, that would seem to be a rather severe limit unless towers were closely spaced so that there are never too many users on one tower. Upload seems another issue.
SteveF, at the GPS band, 16-bits of S/N is very common at the GPS band, but your point is correct—one needs more bandwidth than LightSquared currently owns to get to the break-even point where wireless finally delivers the coup de grace to hardwired ethernet.
If you read LightSquared literature their business plan is to eventually get to 100 MBps per customer. I believe this is achieved by combining satellite with land-based broadcasting.
Uploading at 100 MBps is still an other issue, there is a demand for it, so it will be interesting to see how that plays out.
j ferguson, you’re welcome. Let me know if you have any further questions on this.
Kenneth Fritsch (Comment #81724),
Jon Stewart takes potshots at all politicians when they do stupid things. Of course, as you note, his shots at Mr. Obama seem focused on “stupidly implemented” rather than “stupid idea in the first place”. He doesn’t seem to give that deference to people he disagrees with politically. I don’t watch him more than a few times each year, since I find his act tedious and his phony even-handedness distasteful.
This provided an interesting contrast: http://www.greentechmedia.com/content/images/articles/Solyndra-versus-Military.jpeg
But yes, the whole Solyndra affair represented some particularly stupid decisions coupled with an unfortunate tendency to view anything green job-related with rose-colored blinders.
“…unfortunate tendency to view anything green job-related with rose-colored blinders.”
which would make it look black, rather the red which was likely to ensue.
Zeke, the difference here is future military systems are always a very high risk proposition, and failure always results in a large loss of money (and sometimes lives)
You’d like to think that people building photovoltaic cells follow a somewhat more risk adverse strategy than that allowed when one is making “one of a kind” systems, like the military does.
So really… it’s not a very good analogy.
The real scandal was when BO got his defense briefing and was told two Brazillion soldiers died in Iraq yesterday. The President put his head in his hands and asked , “Oh my God, How many is a brazillion?” …
Thin film is the future of solar panels, and the company that makes a breakthrough in that technology will make a fortune, as it will be much cheaper than the current technologies, which while proven, are still expensive. I say keep going with thin film research, and keep government funding for it.
Carrick,
My projects are PIC based. Get them running with an Arduino, then move to something with less overhead. Like a lot of DIY projects then tend toward exceedingly complex solutions to what at first seem simple problems. Avoid expense at all costs.
thanks for offer to advise.
john
More evidence of corruption in the Lightsquared debacle.
“On Monday, a second witness, Anthony Russo, director of the National Coordination Office for Space-Based Positioning, Navigation, and Timing, told The Daily Beast that he too was asked by the OMB to insert the 90-day timeframe into his testimony before the House Science Committee, but he refused. The hearing originally was scheduled for Aug. 3, then rescheduled for Sept. 8.
Russo says he assumed that the White House approached all of the other witnesses and asked them to insert the paragraph into their prepared testimony. Russo scoffed at the notion that the testing could be complete in 90 days, and ended up editing out that claim. While Shelton told Congress that the White House exerted pressure on him to insert that claim, Russo told Eli that he considered it more “guidance†than pressure.
Still, how many witnesses told Congress that testing could be done in 90 days based on this “guidance†from administration officials? One former FCC commissioner tells Eli that putting a 90-day window on testing would be unprecedented. For one thing, tests like this take some time to execute, but testing often produces unpredicted outcomes.
In fact, that’s the whole point of conducting the tests. When those arise, then more testing will be required to resolve the issues discovered, and on a matter as complex as dealing with interference to global navigational systems, 90 days sounds like a ridiculously short period of time.”
http://hotair.com/archives/2011/09/20/white-house-offered-guidance-to-second-witness-in-lightsquared-inquiry/
bugs:
Problem is that the $500 mill was not for research but for production and distribution of a costly, flawed, largely unmarketable product. The money was to prop up a failed venture which had political connections and green cachet. The money was not to improve the technology or advance green science.
The is not the first instance in US history of top level federal officials improperly favoring a dud private company. However, the overt, brazen, amateurish handling of the matter by this current in-group is atypical.
Zeke.
If the 500M that went into Solyndra had come with the kind of government direction and oversight the F35 had you would see a much higher cost, and if it had lasted as long as the F35 program ( christ.. I worked on a early concept development in late 1980s) then you might have a good comparison..
http://www.jsf.mil/history/his_prejast.htm
As carrick notes defense projects are very high risk affairs. To mitigate that risk the government spends Billions. When they fail, the amount of wasted money is enormous.
The stupidity of the F35, as you can see from the history, lay in the notion that we could build something that would satisfy all the services and the various missions of the services…. and land the stupid thing on a carrier.
http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDest&plckBlogPage=BlogViewPost&plckPostId=Blog%3A27ec4a53-dcc8-42
Re: Steven Mosher (Sep 20 12:08),
Even in the highly unlikely event that you could, it’s highly unlikely that it would actually cost less per plane than designing and building different planes for the different services and missions. Only a bean counter with no idea of the complexity of the problem would recommend doing it with a single basic design.