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Anatomy of a "signal generator":
Generally, "jammers" — which are also commonly called signal blockers, GPS jammers, cell phone jammers, wifi jammers, etc. are radio frequency transmitters that are designed to block, jam, or otherwise interfere with radio communications.
A jammer can block radio communications on devices that operates on a given radio frequencies within its range (i.e., within a certain distance of the jammer) by emitting a noise radio carrier. A GPS jammer generates a 1575.42 Mhz interference to prevent your GPS unit from receiving correct positioning signals. The GPS jammer is typically a small, self-contained, battery powered and transmit signal over a small radius. Though illegal to use, these low-tech devices can be bought on the internet for as little as $25. Since they can block devices that record a vehicle's movements, they're popular with truck drivers who don't want an electronic spy in their cabs. They can also block GPS-based road tolls that are levied via an on-board receiver. GPS jamming technology will also disable autopilot in drones to protect individuals' privacy.
In the US federal law prohibits the sale or use of a transmitter (e.g., a jammer) designed to block, jam, or interfere with wireless communications. For this reason some jammer retailers now label jammers as "signal generator kit" so it will just slip through customs and them is to purchaser sole responsibility for ensuring that the operation complies with the applicable laws. One of these "GPS signal generator kit" is the Dealextreme QH-1 Professional GPS Signal Generator Module (It seems that the QH-1 GPS jammer ran out of stock and will not be manufactured anymore, but you can still find HJ-3A GPS and cell phone jammer.). I've always wondered what's inside these jammers, given their cost, so i purchased one "signal generator module" and put under test with RF laboratory equiment, disassembled and photographed them for all to enjoy.
But is it cheaper than tinfoil?
[Ed note: typos and grammatical errors copied from source document, intact. Also note that it is illegal to operate one of these jammers in the US.]
(Score: 1) by Ethanol-fueled on Sunday December 03 2017, @04:27AM (2 children)
I always like what you have to say, but haphazardly throwing around a bunch of military terminology in this case makes you look like a hammer treating every solution as a nail.
Our situation needs to be a little more intimate to the problem at hand. We're way passed TACAN on the ground, we just don't know it yet. I switched majors because chemistry nomenclature was inconsistent. I was in Chem 101 when I learned that the only way forward was to memorize through brute force the nomenclature of mono and polyatomic ions. -ates and -ites are -2 or -3 depending, as one example.
So I decided that I should go back to my exact science of electronics. But then I barfed, because it has the same problem: microwaves have longer wavelengths than millimeter waves. You would think that microwaves would have shorter wavelengths than millimeter waves, but you would be wrong. Microwaves go up to 30 GHz, even though micro is smaller than milli, but millimeter waves are from 30 GHz up to the hundreds of GHz.
(Score: 2) by Aiwendil on Sunday December 03 2017, @12:23PM
So - you are annoyed at that they used the word "micro" in the sense small (which is what the word actually means) and decided to use "milli-" in the sense "1 to 10mm long"?
I'm curious: when armed with ca 1930s knowledge what name would you have chosed for waves smaller than what is currently in practice to use? [parvwave? paulwave? petitwave?]) (if anything - you should be annoyed that it stops at the mm band and not just keeps going ad infinition (maybe renaming the "microwave" band to the centiwave band))
Personally I'm annoyed at that "small" (micro) is used as a word for something specific to begin with - so in part I share your annoyance - but it could have been worse, they could have called them "dwarf-waves" (nano-)
(Score: 2) by VLM on Monday December 04 2017, @01:03PM
You're lucky you got out before they inflicted the WWII era secret radar band designation on you and today people still talk about S band vs X band which is about 5 ghz higher and the other ten or so WWII radar bands. That designation system is really annoying. Even outside radar / ECM, like people call big dish satellite TV "C band" vs the "K band".
My favorite inconsistent metric problem is I've met normies who kinda understand centimeters from being taught CGS at school and then they take the "its all about the 100x" to everything and its possible to get into interesting arguments with people about ping times where they'll insist a 100 ms ping time is 1 second because 100 centimeters is 1 meter.