Self tuning??? That must translate to broadband, unfiltered, and capable of jamming anything they didn't anticipate being in use back then...Okay, so this design is 16 years out of date, but Limor posted all design details for this phone jammer. Don't think it will affect 4G, since it wasn't implemented yet at the time.
http://ladyada.net/portfolio/2006/index.html To date, this is the only set if build-it-yourself plans I have seen for such a device. 73
Hahah. Wow.. We have derailed the hell out of this thread, haven't we? I was just kidding on the drone jammer gun. I was being rediculous, in response to the comments about crashing RC planes with radios..Self tuning??? That must translate to broadband, unfiltered, and capable of jamming anything they didn't anticipate being in use back then...
Keep in mind that jammers, being illegal, have no quality control, and if it interferes with medical equipment or businesses big enough to lobby congressmen, a murder charge or a six figure fine could be in your future.
That said, this is what you do.... find a noise source for that band (commonly available for testing applications) and a suitable amplifier. Everything needed to build a jammer is available as modules that can be easily bought and connected via SMA adapters.
One time (long ago in the 802.11g days) I made a square wave oscillator using a schmidt trigger (at around 40MHz i think) and I had placed a little DC motor with an aluminum fan blade on it next to the circuit so the parasitics caused by the fan blade moving by the circuit modulated the oscillator. Although my intent was to just watch it on the scope hoping to see a sweeping frequency, it killed my wifi instantly. I can't remember what schmidt trigger I used, but it was either fast enough to have GHz harmonic content or something on the board was acting as a resonant circuit, not sure. It was sure interesting at the time though!
But charging over $3k for a "jammer gun", now that's just laughable. Not a chance in hell... Especially when it has a ridiculous Bushnell scope on it as if the multi-band (probably log periodic) beam antenna inside the gun actually had less than a 30° beam angle... Nope, not buying it, even if I had a legit need and the money to waste lol. Not to mention that 80w from a handheld device like that will kill even the best drone-style HVLi battery in a few minutes...
Well, sorry I blew up then. You wouldn't want your mint cobra 2000 falling out of the sky. When you take this hobby beyond a microphone, comments like that are received differently.Hahah. Wow.. We have derailed the hell out of this thread, haven't we? I was just kidding on the drone jammer gun. I was being rediculous, in response to the comments about crashing RC planes with radios..
Couldn't you just parallel two of them?Back on the "super-clarifier-diode" topic:
I did receive my "SLIDER DIODES - Pkg of 5 For CB/10 Meter Radios QRP PLL Tuning VARACAP Clarifier" from Six-Star electronics on Ebay. Shipping took less than 2 days from click-to-mailbox.. Impressive..
However, I was disapointed with the range/performance of these varactors. In a typical 0v-8v or 0v-9v tuning circuit, they have about half the capacitance range of a Motorola MV1404 and about 2/3 the range of an NTE611.. They do have about twice the range of a typical varactor used in a CB clarifier circuit from the factory, but they are a FAR CRY from the "super-clarifier-diodes" of yesteryear.
That said, I'm sure I'll use them for something and for the price & convenience of availability, hey.. I'm not complaining. Be sure and check out the seller's (6-star) "other items" as well. They sell some really neat stuff for radio tinkering & upgrades..
You could do a lot of things but remember: To increase the tuning range, we want to increase the difference in capacitance across the range of voltage adjustment (~8V at one end, to negligible voltage at the other). When you place the two varactors in parallel, you are doubling the capacitance across the entire range. This would be fine if the varactors would go all the way to 0 capacitance. They don't. They have a lower range value. So by doubling, in effect, you are pushing the entire range of adjustment lower. This may be fine, as long as you don't mind "tuning down" from channels to get to desired frequencies. But, it's possible to move the whole range so far "south" that you can't even get to the base channel frequency. Increasing the supply voltage to the potentiometer end of the circuit does push things back "north" but not nearly enough and you can't go too high on the voltage without causing other problems within the circuit.Couldn't you just parallel two of them?
Awesome post, Andy.. Well, that's bordering on the limits of my analog circuit theory to try to fully understand everything that's going on there.. It's intriguing nonetheless.. I wonder if it would be possible to produce that circuit on a tiny pcb using all smt components for the purpose of a "drop-in" solution for clarifier mods.Interesting how this gets mentioned.
Galaxy, at least in their EARLY years, did use 2 diodes along with and RF Switch (D33) to offset the downward forcing...
View attachment 60272
When you went to Channels below - Like BAND A and BAND B - C92 was used to pull down the tuning range D30 (additional) and D94 (Series-Lo-pass ripple filter SEE:AN612) - when the system needed to push up the tuning range - Bands C, D, and E - it was grounded out enabling it to work in PARALLEL with the Varactors output to help with linearity of the tuning range in the band to help out the PLL's incessant desire to "twang" - in specific instances of weak regulation and drift - when the PLL and the VCO loop on occasion would struggle to match and lock in -this helps offset the needed (or not needed) capacitance to "swing" the channels in the selected Band.