What are you designing that requires robustness against GPS jammers?
If it's a consumer-oriented project the result of a well-designed GPS jammer being used near your design is that it will be jammed there's not much you can do to prevent it at a reasonable cost. And GPS jammers don't emulate any naturally-occurring interference conditions that I know of so what's the point.
If it's a military design then you're likely asking in the wrong place.
In any case if you're doing your own GPS/RF designs and thinking about also doing the design work required to harden them against a well-designed GPS jammer then you surely know how to make a well-designed GPS jammer already.
but obviously no kits are available and nobody will help with construction (well, I definitely wouldn't.)
Simply building it from the plans given would require a significantly-above-amatuer level of electronics skill and significant investment in test equipment.
If you are in the United States, it is illegal to intentionally jam any rad io service, including GPS. (...and weirdly, it is also quasi-illegal to ja m radio devices that are illegally operating without a license or even on t he wrong spectrum, but that's an entirely different story!)
And even if you are not in the US, I just don't feel like helping you. I paid good money for my GPS units and frankly, wouldn't appreciate them be ing jammed, by you or anyone else.
In my day job, I turn people like you (at least those in the US) into the F CC's Enforcement Bureau all the time. I have no tolerance for it at all.
Your existing and proposed GPS jammer is illegal in the USA: Federal law prohibits the operation, marketing, or sale of any type of jamming equipment, including devices that interfere with cellular and Personal Communication Services (PCS), police radar, Global Positioning Systems (GPS), and wireless networking services (Wi-Fi).
Enforcement advisory:
Old FCC Enforcement Bureau blog on the topic of jamming:
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Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
"Every Class B device states that: 'The devices must accept any interference received, including interference that may cause undesired operation.'
So technically, if I import a jammer from another country, I am legally allowed to use it because it emits a small enough broadcasting radius that I don't require a license, and other devices must accept the interference."
The type of person who must think it's always legal to shoot whomever you like so long as the gun was legally acquired and conforms to all relevant e.g. magazine capacity restrictions
Totally irrelevant. FCC Part-15 Rules for Class-B devices establish the la wful requirements for unlicensed, low-power devices AUTHORIZED pursuant to the Communications Act.
But the Act itself explicitly prohibits jammers regardless of their output power. By the way, the Act also prohibits the manufacture, sale, marketing , or commercial transportation of jammers. (302a(b)).
Here is the full text of Title-47, US Code, Chapter-5, Sub-Chapter-III, Par t-1, Section(333):
333. Willful or malicious interference: No person shall willfully or maliciously interfere with or cause interferen ce to any radio communications of any station licensed or authorized by or under this chapter or operated by the United States Government.
In short, this topic has been beat to death. There is no legal way to operate a jammer unless you are the US Government.
Note however, that "possession" of a jammer is not explicitly prohibited, a lthough I think you would be hard-pressed to explain its existence if you n either admitted to manufacturing it yourself, or somehow transported it int o your possession (whether purchased, bartered, traded, gifted, etc...)
In the dozen or so jammer cases I've been involved with over the years, the FCC agents will require the surrender of the jammer (in-rem arrest) or, in one case, verified destruction of the device. I've not personally had any connection with jammer cases that went any further than this. Most people are reasonable enough to take the opportunity to wiggle-out of what would otherwise be an enormous financial penalty, even for a first offense. I th ink it's something like $100,000+ today, even for a first offense.
Do you have an FCC license to transmit on the frequencies used by GPS receivers? Probably not. Therefore, it's not legal for you to intentionally transmit on GPS frequencies. GPS is not included in the frequencies allowed for Part 15 intentional radiators. The power levels required for a workable GPS jammer will be well in excess for what is allowed in Part 15 unintentional radiators. So, unless you can find a clause anywhere in the FCC rules and regs that specifically allows unlicensed operation on GPS frequencies, it's a fair assumption that such transmissions are not allowed. Got it?
Accepting interference refers only to unlicensed operation, such as wi-fi and Part 15 devices. In general, licensed services have priority over unlicensed services. Most everything with a commercial license requires the approval of an FCC recognized frequency coordinator before the FCC will issue a license to operate. This is to prevent mutual co-channel interference.
The general assumption is that if the FCC rules and regs fail to allow some manner of operation, it is by default not allowed. Such rules were made for the convenience of those who lack any common sense in how to act, such as not jamming other services.
Don't you have something better to do than to push your interpretation of the FCC rules and regs?
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Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
In the interest of accuracy, that was a reader comment to the first FCC blog entry by "KiRaShi.ca":
"Jammin' - A Hit for Bob Marley, a Miss for Communications" February 9th, 2011 by Michele Ellison - Chief of Enforcement Bureau
Does posting to the FCC Blog page somehow convey instant credibility to a random reader who couldn't be bothered to include the chapter and verse in the rules and regs and how he came to his brilliant conclusion? Methinks not. Please find a better quote or cite with which to start an argument errr... discussion. One might suspect that you actually agree with the readers comment, which is why I tried to explain how "accepting interference" works.
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Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
If you are developing a commercial GPS product, you should hire some time from an EMC lab. These labs are Faraday cages with absorbing pyramids inside the cage. The lab is sometimes situated deep underground in some old mine.
As a bonus you get various high power noise generators as well as calibrated antennas to subject a calibrated EMC field on your device.
If this is not what you need, I can't help you :-)
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