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Jonny 290 posted:i'm just a few miles from DIA so I expect really good results playing with ADS-B this time I live under an ORD flight path and am part of a hackerspace near MDW and there's still too much loving intermod in chicago to do ads-b on a rtlsdr or hackrf without a more selective antenna and/or filtering so good luck, basically post your success and motivate me to build a 1090 specific antenna
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Feb 5, 2015 23:16
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| # ? May 27, 2024 14:25 |
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PuTTY riot posted:u gonna put it on that tram you've got up in the air? i keyed up a 'peater ~30 miles away on my drive home last night and now I want to put one up on my roof. I can't even hit the 440 repeater from my driveway cause I'm kind of on the side of a hill for general listening imma hang it off of my backup backup dual-band antenna, a Comet 2x4SR. It's UHF mount so if I want to play around with a 1090 MHz antenna all I need is a piece of wire and a PL-259. Storysmith posted:I live under an ORD flight path and am part of a hackerspace near MDW and there's still too much loving intermod in chicago to do ads-b on a rtlsdr or hackrf without a more selective antenna and/or filtering Going to be playing with those IF filter functions that somebody unlocked - and maybe build an attenuator too
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Feb 5, 2015 23:29
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r820t2 seems solid so far i have found os x software lacking and will be booting win7 or lumix in a VM shortly. also jesus christ look at this dude's SDR setup. http://www.nitehawk.com/w3sz/osxhpsdrserver.htm
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Feb 6, 2015 05:46
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oh and here's a really good hour talk on sdrs and specifically setting up a distributed network to snag signals, aggregate them and let you capture all kinds of poo poo. https://www.youtube.com/watch?v=r5BTUVPeoVY
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Feb 6, 2015 07:11
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if you like looking at pretty waterfalls there's a new sdr# rtlsdr driver for you! http://www.rtl-sdr.com/new-sdr-rtl-sdr-driver-lnamixervga-gain-settings-decimation 
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Feb 6, 2015 18:42
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jesus christ is there a psk test going on there or smth or do you just have a good antenna =/
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Feb 6, 2015 19:00
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Jonny 290 posted:r820t2 seems solid so far does it have to look so awful
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Feb 6, 2015 19:09
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Bloody posted:does it have to look so awful GREYBEARDS WITH AILMENTS RUNNING WINDOWS 95 Yes.
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Feb 6, 2015 19:11
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Jonny 290 posted:jesus christ is there a psk test going on there or smth my "rig" is an extreme hackjob rtlsdr+ham it up in a shielded .1in thick aluminum box with a long wire on a 9:1 balun in my attic. this is connected to the closet radio pc (lol) via a 16ft usb cable that only carries the data +/- with power being supplied in the attic by a radio shack linear 12v supply and some lm317s
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Feb 6, 2015 19:14
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niiiiice. do you think the ham it up is worth it? i need sdr hf coverage but dont want to risk one of the cheap-cheap chinakits
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Feb 6, 2015 19:15
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Jonny 290 posted:niiiiice. do you think the ham it up is worth it? i need sdr hf coverage but dont want to risk one of the cheap-cheap chinakits there's some drivers ( http://www.rtl-sdr.com/new-experimental-r820t-rtl-sdr-driver-tunes-13-mhz-lower ) that let you try out direct sampling without any soldering or modification to the hardware. personally direct sampling never worked for me, I tried the hardware mod on an old stick and the drivers on the one I use now, but because of my close proximity to some shortwave broadcasters (praise jesus) things the intermodulation distortion made tuning a pain in the rear end because you have to slide the center frequency around to have them not sit on the actual signal you want to receive. I mention this b/c like half of the chinakit rtl based "full band" radios are just direct sampling mods, although there are more expensive upconverter based ones now apparently. I bought the ham it up because it was on amazon and looked more professionally designed than the chinakit radios so while imo it was worth it, you may find similar performance from direct sampling if there is no nearby qrm or even a chinakit radio if its good edit: I'm not sure if what I'm describing is intermodulation so i will describe it with my idiot words: powerful signals will sweep forwards and backwards across your receive spectrum at what seem like harmonics of the frequency, even if those harmonics are really far away, for example, with direct sampling I was able to listen to narrow FM noaa weather radio (normally like 160 ish MHz) with the center frequency set in the low tens of MHz. It's like similar to intermodulation or something, I'm pretty sure its an artifact of the ADC architecture of the rtlsdr and some physical limitations of signal/sampling theory. If someone smarter than me can tell me what was really going on it would own Dairy Days fucked around with this message at 19:31 on Feb 6, 2015 |
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Feb 6, 2015 19:24
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Palace of Hate posted:there's some drivers ( http://www.rtl-sdr.com/new-experimental-r820t-rtl-sdr-driver-tunes-13-mhz-lower ) that let you try out direct sampling without any soldering or modification to the hardware. personally direct sampling never worked for me, I tried the hardware mod on an old stick and the drivers on the one I use now, but because of my close proximity to some shortwave broadcasters (praise jesus) things the intermodulation distortion made tuning a pain in the rear end because you have to slide the center frequency around to have them not sit on the actual signal you want to receive. I mention this b/c like half of the chinakit rtl based "full band" radios are just direct sampling mods, although there are more expensive upconverter based ones now apparently. I bought the ham it up because it was on amazon and looked more professionally designed than the chinakit radios so while imo it was worth it, you may find similar performance from direct sampling if there is no nearby qrm or even a chinakit radio if its good gonna try out dem drivers tonight
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Feb 6, 2015 22:33
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did yall see theres a new chip r820t2 or smth? looks like u can get them on the cheap too http://www.hamradioscience.com/rtl2832u-r820t-vs-rtl2832u-r820t2/ http://www.ebay.com/itm/221666812856
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Feb 6, 2015 23:54
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yeah thats the one i just got in. haven't really prodded all its orifices fully, but it at least isn't any worse i should take a spin down the FM dial on gqrx for ya tonight. the number of HD FM signals is insaaaaaane. sucks that its encrypted and if the stations dont pay their $1300 licensing fee every month, all of a sudden no HD FM receivers will be able to listen
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Feb 6, 2015 23:56
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corporations loving ruin the airwaves every time we let them touch them
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Feb 6, 2015 23:57
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Jonny 290 posted:yeah thats the one i just got in. haven't really prodded all its orifices fully, but it at least isn't any worse omg we have a classical station
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Feb 7, 2015 00:40
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why the gently caress is broadcast radio encrypted. how did we get to a point where the FCC is that hosed up
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Feb 7, 2015 00:41
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DAB+ may be old and not very good but at least it's not encrypted lol curious to see what they do with the old FM band, assuming they ever manage to convince enough people to buy new radios
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Feb 7, 2015 09:48
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theres still broadcast tv stations around here that are on analog for some reason. i imagine it'll be the same way for radio. i dont know much about SDR still and im way too used to utwente at this point. being able to look at a huge chunk of spectrum in waterfall owns, but i need more spectrum to listen to.
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Feb 8, 2015 02:11
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Korean Boomhauer posted:theres still broadcast tv stations around here that are on analog for some reason. i imagine it'll be the same way for radio. Also utwente (i.e. University of Twente) is located in the east of the Netherlands so you won't get certain transmissions due to location and conditions that you may get at your location and vice versa. To me it's interesting to compare stations between local and remote receivers
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Feb 8, 2015 02:19
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direct sampling didn't work for me either :/
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Feb 9, 2015 22:30
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Feb 12, 2015 08:59
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random surprise! mrs was going thru a box of sweaters she threw under the bed before we left, and somehow my Icom PCR100 made it in there very very cool little radio. i wish i had the PCR1000 for SSB, but this one's still nifty. http://www.notpurfect.com/main/pcr100.html
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Feb 13, 2015 06:48
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 adjusted some wiring this morning. I should probably get a little pigtail or something that's more flexible than the coax. only thing I want to do now is get an extension cable for the speaker mic and mount it over on the other side of the center console. it works surprisingly well with my nmo mount antenna
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Feb 13, 2015 21:16
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hell yeah nice!  i am going to mount my PCR100 this weekend and then take freshpics of the radio toys. also was considering raising the apex of my 40 meter dipole up a few feet so it's actually usable - it resonates on point right now, but it's too low to the RV and the impedance is too low
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Feb 13, 2015 21:19
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that analog onstar thing has got to go. there's a cubby you can get for ppl w/o onstar but im not gonna pay $30 for one on a parts website. patiently waiting for one to pop up on ebay. e: just took a 5 min "smoke break" and hid that white wire coming out of the tape deck behind the trim so its not interfering w/ that flip up door. ftw. PuTTY riot fucked around with this message at 22:48 on Feb 13, 2015 |
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Feb 13, 2015 21:22
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my wife's friend's husband works on cop radios and cop radio towers. would it be worth seeing what kinda out of service gear he has? is it hard to reconfigure public service band stuff? I don't mind the limited displays and programming difficulty (speaking of-- how hard is tracking down the programming software?) he's 5 hours away down on the coast tho
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Feb 14, 2015 18:09
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heh oops despite the 'motorola' in the title i've never posted http://batlabs.com/ which is the big 'gently caress you motorola, here's how to program these things' site. moto is incredibly protective of their programming software and still actively hunts it down. it is still findable. midland and other companies dont give nearly as much of a gently caress
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Feb 14, 2015 18:22
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ty. seems like a good choice for local 'peater use since they have a good amount of power and seem like they'd be reliable cause cops. now I just need to find a dual band version.. I have more trouble reaching that one from my driveway
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Feb 14, 2015 18:46
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you wont find dual band commercial rigs except in super weird situations. usually public service radios are single band with relatively tightly tuned front ends to stop all that intermod. this is why you can't like take one of the VHF rigs that cover 160-174 or whatever and retune them down, theyre literally built too well. now you know why cops have six radios in they car this is why we use them, though. if you can get a moto tuned up on 70cm or 2 meters, you have a bulletproof radio that doesn't care about 11.5 volts or 107 degrees F in the trunk and has great sensitivity and wont get overloaded and will put out 50 or 70 or 110 solid watts key-down 24/7 the channelization thing kind of sucks but there's nothing saying you can't program in all the local repeaters and then just every simplex channel in your band plan. boom you effectively have a ham rig with a vfo
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Feb 14, 2015 19:29
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so I could get a 2m rig and a 70cm rig and have 2 antennas. gonna read that site u linked now that I'm not on my phone
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Feb 14, 2015 20:20
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or even one antenna, if you want to get a diplexer http://www.mfjenterprises.com/Product.php?productid=MFJ-916B
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Feb 14, 2015 20:56
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achievement unlocked: lost blood while building an antenna
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Feb 14, 2015 20:56
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a poem by e e "Mac" cummings, titled: Bob made a winnerquote:i have owned many receivers over the years
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Feb 15, 2015 06:52
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i disassembled my spare spectrum analyzer module to get some parts today, most of the switch contacts on the front panel were broken and those are a massive pain to replace so i'd mostly kept it for spares anyway there's some pretty nice modular hardware in the 8558B analyzer: first mixer is a completely passive balanced mixer, YIG oscillator in the background  LO in is 2050-3550 MHz, IF out is 2050 MHz, the ports can be reversed since it's passive 10 dB step attenuator is completely passive and a module with SMA ports  the YIG oscillator inside covers 2050-3550 MHz, i haven't powered it up outside the unit yet since the driver board needs +15, -12.6 and +19.5V and several control signals i might build a synth with that as the VCO there's a 2050 MHz cavity filter and mixer to convert to ~300 MHz, not sure if that's usable for anything interesting only other significant takeaway is some SMB cabling and a inline RF limiter with 10W CW in/0dBm out my plan for the mixer is to use it with the LO output from my other analyzer to make a tracking generator, i've got it hooked up with the bladeRF as a 2050 MHz signal generator since the YIG is fairly complicated to use hookup is uncomplicated, the RF in port is now the output, here's the filter response for a NMT 450 duplexer, RX side  over all there's a lot of ripple in the amplitude over large frequencies but it's more or less completely flat for small spans, i suspect it's the LO out that's varying in amplitude just need to build a stable 2050 MHz source and a levelling amplifier to eliminate the ripple and i've got a tracking generator!
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Feb 15, 2015 19:55
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oh man i forgot how much I like the icom PCRs. switched input filters, low control overhead requirements... now i want to go ahead and do what ive wanted to for like 20 years and pick up a PCR1000. i'd look at a -1500 (which would match my IC-208 perfectly omg) or a -2500 (which is just dope) but they are so loving expensive
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Feb 16, 2015 02:39
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 pretend this is my house. Can I put a lightning arrester on that and then go straight down and maybe 6 ft over to my utility ground with whatever gauge copper wire and be protected? Seems like a waste of coax to go down just to go back up again. I want to make sure I do it right though.
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Feb 16, 2015 20:39
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PuTTY riot posted:
yeah go buy some AWG 6 ground wire, you will be fine. keep your bend radius large, lightning jumps off corners and sharp points no problemo.
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Feb 16, 2015 20:40
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sweet, gracias. i figured it was that simple but lightning is scary and we actually get a lot of it here
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Feb 16, 2015 20:46
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better to have that fat rear end #6 conducting it down the side of the house than your coax braid, yep yep. C RADIO S: because there is literally 0 competent os x software for running Icom PCR radios, i am writing a curses application obv UI is ugly and i'm just throwing stuff up to learn curses but it is an interactive console program with 30 mS mainloop running fine right now 
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Feb 16, 2015 20:54
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