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atomicthumbs posted:hmm multipsk can decode a whole bunch of digital modes, AND directly control an RTLSDR dongle. guess I'll give it a tr ham_software_interface_design.png
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Mar 27, 2014 10:54
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atomicthumbs posted:hmm multipsk can decode a whole bunch of digital modes, AND directly control an RTLSDR dongle. guess I'll give it a tr lol dumb lil baofeng overload story from dis morning: had baofeng on, monitoring uni pd and the hospital, nothing going on. hear DMR bleeding thru hospital freq @ traffic light, turn left and go over a bridge and blammo cop w/ lights on and dude pulled over. i guess i have a quasi radar-detector in the city
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Mar 27, 2014 15:39
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my baofeng still hasn't arrived after 1 month. 
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Mar 27, 2014 15:41
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i got mine overnighted from amazon cause i wanted it so bad
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Mar 27, 2014 15:42
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yeah spend the extra $5 and get em from a US prime distributor. otherwise you may never get it. shipping logistics on the chinese radios is flaaaaaaaaaky, it's worth the bucks to ensure you're buying one that is already in the states
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Mar 27, 2014 15:57
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Jonny 290 posted:yeah spend the extra $5 and get em from a US prime distributor. otherwise you may never get it. shipping logistics on the chinese radios is flaaaaaaaaaky, it's worth the bucks to ensure you're buying one that is already in the states Nah I'm not in the states anyway so it's a wash.
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Mar 27, 2014 16:20
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just got the arrl handbook 2014 edition and their RFI guide at work, just leafing through the handbook and it seems like pretty much everything you'd want to know is in there, preliminarily highly recommended
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Mar 27, 2014 17:45
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yeah i was digging through the 2013 handbook and it is really good. i kind of want a dead tree version when i was a kid i won a contest for a copy of the ARRL antenna book, this was probably the single most influential text i've read in the context of my career and life
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Mar 27, 2014 17:48
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I wonder if there's a connection between having Tech Tomes as a child and posting in YOSPOS. my grandparents knew I liked computers so they bought me the 11th edition of Upgrading and Repairing PCs for christmas in 1999, when I was 7 I read the whole thing, and here I am
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Mar 27, 2014 18:18
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My library had a couple of old as poo poo books about ham radio from the 50s and 60s. so I read those when I was a kid. there was no internet then  when I finally figured out there was a local club and met a ham I was asking him questions about how conditional licensing worked and he laughed and asked me what I was reading and I showed him the old as poo poo books from the library. so he gave me a couple of newer books, code tapes and some CQ and 73 magazines.
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Mar 27, 2014 18:26
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 I borrowed this book from our sleepy north carolina town's library so much that the librarian pulled me aside one day and gave it to me. "nobody else has checked it out in twenty years. you seem to enjoy it a lot." a good librarian
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Mar 27, 2014 18:45
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block level schematic of the 23cm txcvr is pretty much done now, i decided to build each block with a solder-pad for semi-rigid coax so i can test each individual filter, mixer, amp etc. without too much trouble ended up using a PSA4-5403 for the first filter, then a 0-30 dB digitally stepped attenuator for a basic AGC (for FM it's only needed to prevent blocking and intermod), a avago/HP INA01286 MMIC amp, then a coarse band pass to get harmonics from the LNA, the mixer, a coarse BPF then out through the coax and to the (to be designed) discriminator board which will have a SAW filter, decided to change the discriminator to a MC3362 double conversion IC since it gives me a bit more latitude with the final filter BW (could put in a 3-4 kHz wide filter for DV reception for example, or even build it with a filter-selector, shifting the second LO could let me do auto FM centering and narrower steps) some calculations indicated it'll have a noise floor of about 1 dB, and be able to discriminate signals all the way down to the theoretical limits of FM for transmit there's just a coax input to the mixer and PA, still going to do direct FM on the first LO (86.85 MHz) at the remote board, some band-pass filtering to get mixer harmonics and a 2W PA made from a MGA-83563 preamp and a SPB-2026Z PA chip, then into the T/R IC switch a helical band-pass filter will provide harmonic and image rejection, and the antenna-unit will be powered and controlled via a single cat5 cable, and two cheap coaxes for IF in/out
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Mar 27, 2014 19:03
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a quick word of warning regarding static buildup on antennas antennas that don't have a DC short and that are placed in dry windy air can build up a hell of a static charge, normally this isn't a problem because your radio has some kind of DC bleeder resistor or short internally, but if you use an antenna switch they usually leave the unconnected inputs open, the capacitance of a coax can have a hell of a lot of energy and voltage in it. my old ham group had several PA stages blow in a kenwood because of a dipole antenna with no balun. they solved this by installing a large value bleeder resistor across each pole, preventing buildup in the first place another solution would be to modify the switch by adding some resistors for the active preamp I will take a two-pronged approach to this, by using a special ultra-low capacitance ESD protection diode from TI and by using the same type of inductor i used for the bias-tee build to provide a DC short to prevent slow buildup ESD events from touching the antenna (which can happen in my case) typically have frequency components in the hundreds of MHz (we tested it by rubbing against some chairs at work and picking it up on the scope) so a diode is needed to protect against them using only the ESD diode would allow a voltage to build up to about 7V before clamping occurred, which could cause interference on windy days, because of this i feel that the DC-short + separate protection diode is the way to go only downside is the diode is like 1x1mm, how the hell are you supposed to mount them...
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Mar 27, 2014 20:06
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Things i learned from ham radio web forums -it's safe to keep running windows XP connected to the internet indefinitely as long as you have a virus scanner -windows 8 has left behind linux/android in the mobile space because it has a common interface for desktop and mobile (nm that windows only has like a 2% mobile market share) -linux sucks because you sometimes have to install drivers and you never have to with windows also, I wonder how many old farts complaining about linux because it's "hard to setup" will in the next breath try to castigate "appliance operators" and "no-coders" for being lazy/stupid
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Mar 27, 2014 21:26
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longview posted:only downside is the diode is like 1x1mm, how the hell are you supposed to mount them... what's the package type?
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Mar 28, 2014 12:22
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http://www.ti.com/product/tpd1e05u06 2X2SON, apparently
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Mar 28, 2014 15:47
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i was going to offer suggestions but the ti website has this neat feature where it crashes chrome for me so lol
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Mar 28, 2014 15:54
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gently caress i have to pay tax on my baofeng and the administrative costs are like 3x the actual tax gently caress the dutch poastal system
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Mar 28, 2014 15:56
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Oh, no sweat. Just SMT place it. You might have to use a bit of solder paste on the pads then use a hot air reflow gun to heat the component pads and melt the solder. Failing that, you might be able to dead bug the part and just jumper it to some through holes. Should be fine for just dissipating static charges unless you expect some huge current to hit it.
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Mar 28, 2014 16:09
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update: their site also crashes ie.
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Mar 28, 2014 16:19
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another update for u: firefox managed to get the pdf of the layout. easy solution is gonna be to deadbug it. gently caress doing no-lead parts by hand.
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Mar 28, 2014 16:23
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Bloody posted:i was going to offer suggestions but the ti website has this neat feature where it crashes chrome for me so lol worksforme
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Mar 28, 2014 16:25
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i do use scriptsafe so ymmv
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Mar 28, 2014 16:25
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spankmeister posted:worksforme same
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Mar 28, 2014 16:26
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I should take pictures of the process our test repair operators use to replace ceramic filters. Those things are a nightmare.
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Mar 28, 2014 17:19
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little bit of 17 and 12 meters today, just using a tuner on the Windom got W1AW out of Vermont, woop
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Mar 30, 2014 00:25
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i've fallen into it and am now researching what the best way is to send data over gigabit ethernet from a pair of RTLSDRs if I go through with this I will build a Box with a single-board computer, USB/PoE/battery powered power supply, dual LNAs, dual RTLSDR dongles, and a pair of jacks on the top for whip antennas (or one jack and LNA and a splitter)
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Mar 30, 2014 04:54
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Gnuradio (lol) will Fart data over tcp or udp out of the box
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Mar 30, 2014 04:59
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the raspberry pi only has 100baseT tho
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Mar 30, 2014 05:28
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more like raspberry poo
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Mar 30, 2014 05:54
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atomicthumbs posted:i've fallen into it and am now researching what the best way is to send data over gigabit ethernet from a pair of RTLSDRs use rtl_tcp
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Mar 30, 2014 09:06
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atomicthumbs posted:i've fallen into it and am now researching what the best way is to send data over gigabit ethernet from a pair of RTLSDRs integrated I/Q demodulator chip (linear), ADC (linear), FPGA, unless you want to to be easy
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Mar 30, 2014 09:41
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in other news i finally got my baofeng.  looking forward to mess with local mall cops
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Mar 30, 2014 09:42
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got my MMICs so gonna try to build a first prototype of the active preamp next week, still waiting on the chassis and the final connectors but should be able to test the circuit and the ESD protection
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Mar 30, 2014 09:47
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spankmeister posted:in other news i finally got my baofeng. congrats, was it the UV82 you bought? not sure if it's been brought up but CHIRP is the way to go for programming pretty much all ham radios, the UI is very open source but after a month or two it almost starts to make sense  i like to pre-program all the repeater channels with appropriate subtones (most repeaters here are still 1750 based), a few typical talk-channels like 145.550, and a typical scan rotation with maritime channels and other frequencies of interest
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Mar 30, 2014 09:58
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longview posted:congrats, was it the UV82 you bought? UV-5RE+ i ordered a programming cable from china but it hasn't arrived yet luckily i have years of experience with bad ui design so programming it from the radio itself is a hassle but doable
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Mar 30, 2014 10:15
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spankmeister posted:use rtl_tcp my intent is that it still be portable. i guess I might as well use a USB hub or pair of cables instead of dealing with ethernets longview posted:integrated I/Q demodulator chip (linear), ADC (linear), FPGA, unless you want to to be easy easy is good
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Mar 30, 2014 10:17
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atomicthumbs posted:my intent is that it still be portable. i guess I might as well use a USB hub or pair of cables instead of dealing with ethernets idgi becuase you say atomicthumbs posted:i've fallen into it and am now researching what the best way is to send data over gigabit ethernet from a pair of RTLSDRs and then you say you don't want to use ethernet?
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Mar 30, 2014 10:29
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By the way here's some audio clips of ham guys talking to austronauts aboard mir space station back in 95 or so: http://www.gadgeteer.us/CLIPS.HTM trigger warning: realaudio
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Mar 30, 2014 10:31
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atomicthumbs posted:hmm multipsk can decode a whole bunch of digital modes, AND directly control an RTLSDR dongle. guess I'll give it a tr the latest TempleOS beta.
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Mar 30, 2014 14:03
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