highaltitude.log.20100923

[00:30] jasonb (~jasonb@12.201.129.162) joined #highaltitude.
[01:13] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) left irc: Ping timeout: 264 seconds
[01:25] DagoRed (~dago@j15-1.nat.iastate.edu) joined #highaltitude.
[01:46] juxta (juxta@ppp203-122-193-94.static.internode.on.net) joined #highaltitude.
[01:49] <SpeedEvil> http://www.thestar.com/videozone/865103--flapping-into-aviation-history - neat
[01:49] <SpeedEvil> flapping human powered flight
[02:25] TraumaPony (~TraumaPon@203-206-28-19.dyn.iinet.net.au) left irc:
[03:09] SpeedEvil (1000@tor/regular/SpeedEvil) left irc: Ping timeout: 252 seconds
[03:11] SpeedEvil (1000@tor/regular/SpeedEvil) joined #highaltitude.
[03:20] SpeedEvil1 (~user@tor/regular/SpeedEvil) joined #highaltitude.
[03:22] SpeedEvil (1000@tor/regular/SpeedEvil) left irc: Ping timeout: 272 seconds
[03:33] sYx66 (~Miranda@bas1-kitchener06-1096764660.dsl.bell.ca) joined #highaltitude.
[03:38] Jasperw (~jasperw@93.89.81.29) left irc: Quit: Leaving.
[03:40] juxta_ (~blah@ppp203-122-193-94.static.internode.on.net) joined #highaltitude.
[03:40] juxta_ (~blah@ppp203-122-193-94.static.internode.on.net) left irc: Client Quit
[04:07] nv1k (~madEngine@173-26-204-56.client.mchsi.com) joined #highaltitude.
[04:11] nv1k (~madEngine@173-26-204-56.client.mchsi.com) left irc: Ping timeout: 240 seconds
[04:16] juxta (juxta@ppp203-122-193-94.static.internode.on.net) left irc: Ping timeout: 240 seconds
[04:17] juxta (Bogaurd@ppp203-122-193-94.static.internode.on.net) joined #highaltitude.
[04:18] juxta_ (juxta@ppp203-122-193-94.static.internode.on.net) joined #highaltitude.
[04:22] juxta (Bogaurd@ppp203-122-193-94.static.internode.on.net) left irc: Ping timeout: 240 seconds
[04:55] juxta (juxta@ppp203-122-193-94.static.internode.on.net) joined #highaltitude.
[04:56] juxta_ (juxta@ppp203-122-193-94.static.internode.on.net) left irc: Ping timeout: 252 seconds
[05:28] Upu (~Upu@ubn.upuaut.net) joined #highaltitude.
[05:36] earthshine (~earthshin@cpc3-orpi1-0-0-cust867.2-3.cable.virginmedia.com) left irc: Quit: Bye bye !
[05:36] earthshine (~earthshin@cpc3-orpi1-0-0-cust867.2-3.cable.virginmedia.com) joined #highaltitude.
[05:53] juxta (juxta@ppp203-122-193-94.static.internode.on.net) left irc: Read error: Connection reset by peer
[05:54] juxta (Bogaurd@ppp203-122-193-94.static.internode.on.net) joined #highaltitude.
[06:05] <earthshine> morning
[06:12] sYx66 (~Miranda@bas1-kitchener06-1096764660.dsl.bell.ca) left irc: Ping timeout: 245 seconds
[06:36] juxta (Bogaurd@ppp203-122-193-94.static.internode.on.net) left irc: Read error: Connection reset by peer
[06:36] juxta (juxta@ppp203-122-193-94.static.internode.on.net) joined #highaltitude.
[06:47] m1x10 (m1x10@ppp089210139002.dsl.hol.gr) joined #highaltitude.
[06:50] Simon-MPFH (~simon@phantom.mpfh.co.uk) joined #highaltitude.
[07:31] juxta (juxta@ppp203-122-193-94.static.internode.on.net) left irc: Ping timeout: 265 seconds
[07:34] natrium42 (~natrium@CPE000625d867e2-CM0014045885be.cpe.net.cable.rogers.com) left irc: Quit: Leaving
[07:43] DagoRed (~dago@j15-1.nat.iastate.edu) left irc: Quit: Off to bed, wish I could chat longer.
[08:12] Stratisphere (~Stratisph@193.200.145.254) joined #highaltitude.
[08:12] <Stratisphere> hey all
[08:12] <Stratisphere> quick question if thats ok
[08:12] <Stratisphere> i'm just about to order a ntx2
[08:13] <Stratisphere> which freq is best advised given what you fantastic lot listen on?
[08:13] <Stratisphere> At 434.65MHz: NTX2-434.65-10 - Transmitter
[08:13] <Stratisphere> NRX2-434.65-10 - Receiver
[08:13] <Stratisphere>
[08:13] <Stratisphere> At 434.075MHz: NTX2-434.075-10 - Transmitter
[08:13] <Stratisphere> NRX2-434.075-10 - Receiver
[08:29] TraumaPony (~TraumaPon@203-206-28-19.dyn.iinet.net.au) joined #highaltitude.
[08:37] <Upu> hey are you in the UK ?
[08:37] <Upu> Stratisphere
[08:37] <Upu> if so people tend to use 434.075
[08:38] <Upu> recieve you will need something a little more sensitive than the NRX module
[08:38] <Upu> like say Yaesu FT-817 seems to be a popular choice
[08:53] <Stratisphere> hey Upu
[08:53] <Stratisphere> yeh I read it on the alien site so I got that one
[08:53] <Upu> Hi there Stratisphere
[08:53] <Stratisphere> and yeh, i assumed the receiver wouldnt be good enough
[08:54] <Stratisphere> any idea on a semi-decent supplier for the yaesu?:
[08:54] <Upu> I got mine from http://www.radioworld.co.uk/catalog/yaesu-ft817nd-transceiver-p-348.html
[08:54] <Stratisphere> oh wow! £500 lol
[08:55] <Upu> yeah they aren't cheap sadly
[08:55] <Upu> get the NTX module direct from Radiometrix will probably be cheaper
[08:55] <Upu> are you in the UK ?
[08:55] <Stratisphere> yeh chucked them an email a few min ago
[08:55] <Stratisphere> yup, i'm the network manager of a secondary school
[08:55] <Upu> Ah ok where abouts ?
[08:55] <Stratisphere> planning the project as a surprise science project for the kids
[08:55] <Stratisphere> herefordshire
[08:56] <Upu> kk sure there is someone about who will lend a hand with a radio
[08:56] <russss> jcoxon probably has a radio you can borrow
[08:56] <Stratisphere> cool, my granddad has a scanner, pretty certain it goes to 434.075... just need to check it does ssb
[08:57] <Stratisphere> you guys really do live up to your kindness on the web lol
[08:57] <Upu> yeah alot don't they just do FM
[08:58] <Upu> also if you want to just fly a payload you may be able to "hitch" a lift on another balloon that already has tracking on it
[08:59] <Upu> something I might do after I'm happy my launches are sucessful
[08:59] <Stratisphere> yeh could be an idea
[08:59] <Stratisphere> mind you, the cost for the balloon & gas doesnt appear to be that much compared to the one-time cost of the electronics
[09:00] <Stratisphere> and we plan to do this many more times :D
[09:01] <Upu> well might as well launch a few at a time then :)
[09:01] <Upu> I think CUSF launched 4 payloads at once ? I might be wrong
[09:05] rharrison (~rharrison@gateway.hgf.com) joined #highaltitude.
[09:09] <Upu> morning Rob
[09:10] <Stratisphere> ha cool. whats the general idea on max weight? obs it depends on the balloon you use, but whats the max lifted
[09:10] <Stratisphere> ?
[09:10] <Upu> think CUSF lifted 3kgs up on a 1.6kg balloon but you're not going to break alititude records with that weight :)
[09:11] <Upu> I might be totally wrong on this
[09:11] <Upu> I think payloads are normally in the 0.5-1kg region
[09:12] <Stratisphere> 3kg!... Hmm... I think some of our students weigh less than that :P
[09:21] <Upu> lol
[09:24] UpuMobile (~UpuMobile@smtp.nevis.co.uk) joined #highaltitude.
[09:25] UpuMobile (~UpuMobile@smtp.nevis.co.uk) left irc: Client Quit
[09:26] UpuMobile (~UpuMobile@smtp.nevis.co.uk) joined #highaltitude.
[09:30] SpeedEvil1 (~user@tor/regular/SpeedEvil) left irc: Quit: Leaving.
[09:30] SpeedEvil (1000@tor/regular/SpeedEvil) joined #highaltitude.
[09:42] <Laurenceb> hi
[09:52] <Laurenceb> Stratisphere, Upu: its possible to receive 434MHz using a cc1020 from Ti - they have an eval board
[09:54] <Laurenceb> tho i havent done this for actual flights
[09:55] <Stratisphere> is it sensitive enough you think for HAB flights?
[09:56] <Laurenceb> noise figure is about 7dB
[09:56] <Laurenceb> it would benefit from a LNA on the front
[09:57] <Stratisphere> Hmm
[09:57] <Laurenceb> possibly 6 - it depends how the decoding works
[09:57] UpuMobile (~UpuMobile@smtp.nevis.co.uk) left irc: Ping timeout: 240 seconds
[09:57] <Laurenceb> you can get LNAs with 1 or 2 dB - so thats at least 4dB gain
[09:59] <Stratisphere> cool... lol there's alot of learning I need to do!
[09:59] <Laurenceb> http://gb.mouser.com/ProductDetail/Texas-Instruments/CC1020EMK-433/?qs=sGAEpiMZZMuyoPqaVfyaE2PDrM%2fQ%252bmBaP06rCKRTCqk%3d
[09:59] <Laurenceb> 4dB about 60% more range
[09:59] <Laurenceb> *is
[10:00] <Stratisphere> will read now! :)
[10:00] <Laurenceb> but yeah if you are new to radio hacking a cc1020 eval kit is kind of complex
[10:00] <Laurenceb> i havent actually got the full setup working myself so not sure how good it is
[10:00] <Stratisphere> lol
[10:02] UpuMobile (~UpuMobile@smtp.nevis.co.uk) joined #highaltitude.
[10:07] <Upu> test
[10:23] <Laurenceb> hello world
[10:23] <jonsowman> morning
[10:25] <SpeedEvil> possibly.
[10:26] m1x10 (m1x10@ppp089210139002.dsl.hol.gr) left irc: Quit: I eat electrons for breakfast and I vomit thunders
[10:41] UpuMobile (~UpuMobile@smtp.nevis.co.uk) left irc:
[10:44] m1x10 (m1x10@ppp089210139002.dsl.hol.gr) joined #highaltitude.
[11:49] chris_99 (~chris_99@84.93.186.126) joined #highaltitude.
[11:49] chris_99 (~chris_99@84.93.186.126) left irc: Changing host
[11:49] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) joined #highaltitude.
[12:06] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) left irc: Ping timeout: 252 seconds
[12:46] eroomde (~ed@nessie.habhub.org) joined #highaltitude.
[13:02] jcoxon (~jcoxon@cpc1-lanc4-0-0-cust720.3-3.cable.virginmedia.com) joined #highaltitude.
[13:04] <jcoxon> 1/2 day! woohoo
[13:12] <jcoxon> guess i'm the only one :-p
[13:12] <m1x10> hey
[13:12] <m1x10> what do u mean 1/2?
[13:12] <jcoxon> half day
[13:13] <m1x10> yeah for what?
[13:13] <jcoxon> oh from work
[13:13] <m1x10> haha
[13:13] <m1x10> :)
[13:13] <jcoxon> as i work slightly longer days i'm meant to have an afternoon off a week to make sure my hours are legal
[13:13] <jcoxon> however i'm usually too busy
[13:13] <rharrison> jcoxon, it's ok for some
[13:14] <jcoxon> taken me 2 months to get an afternoon off
[13:14] <jcoxon> :-p
[13:14] <jcoxon> just been on an ordering spree
[13:14] <jcoxon> ordered new pcbs, components, radio modules...
[13:15] <SpeedEvil> I nearly did a propane powered launch yesterday.
[13:15] LazyLeopard (~irc-clien@chocky.demon.co.uk) joined #highaltitude.
[13:15] <SpeedEvil> http://www.flickr.com/photos/14560445@N08/5016093779/
[13:16] <SpeedEvil> Starting fire with a blowtorch on low, and walked away for a moment to get other stuff to put on.
[13:16] <SpeedEvil> Got distracted, and noticed that the blowtorch had gotten really, really loud.
[13:16] <SpeedEvil> Fortunately, no explosion.
[13:17] <jcoxon> eek
[13:17] <SpeedEvil> The knob and all the plastic on it melted though
[13:18] <SpeedEvil> While clearing up, I found some more suitable plastic for balloons. :)
[13:48] <jcoxon> ping rj
[13:48] <jcoxon> ping rharrison
[13:48] <rharrison> pong
[13:48] <jcoxon> to the bat cave (#ha2)
[13:59] Simon-MPFH (~simon@phantom.mpfh.co.uk) left irc: Quit: Leaving
[14:00] <Darkside> hmm
[14:00] <Stratisphere> hey jcoxon
[14:00] <Stratisphere> you around?
[14:00] <jcoxon> yup
[14:00] <Darkside> here's a kind of n00b question...
[14:00] <Darkside> avr-gcc, as in, what comes with avr studio
[14:00] <Darkside> is this also a c++ compiler?
[14:00] <Darkside> i.e. could i dump in some c++ stuff into my code, and have it still compile?
[14:01] <Stratisphere> coolo, I'm the network manager for a secondary school in herefordshire. We're planning a HAB launch as a surprise science project for some of our kids, we've got alot of stuff already planned out and parts ordered
[14:01] <Stratisphere> one bit we may be lacking is a decent radio to pickup the telemetry (if my granddads doesnt pickup SSB)
[14:01] <Darkside> not many scanners do SSB at UHF frequencies
[14:02] <Stratisphere> upu suggested you may be able to lend us one
[14:02] <Randomskk> Darkside: yes. but I think maybe use avr-g++
[14:02] <Darkside> hmm ok
[14:02] <jcoxon> indeed i may...
[14:02] <Darkside> Randomskk: is that what arduino uses?
[14:02] <Randomskk> Darkside: maybe. both should be on your system. avr-gcc should work with c++ anyway though, name files cpp or cc
[14:02] <Darkside> ok
[14:03] <Stratisphere> cool, well nothing is written yet so no worry/rush. But if it's a case where we cant get one ourselves I would be very grateful if you could
[14:03] <jcoxon> i've got a spare yaesu ft790r
[14:03] <Stratisphere> thats the one you leant to the alien HAB isnt it?
[14:03] <Stratisphere> (i've been doing alot of reading lol)
[14:03] <jcoxon> yup
[14:03] <Stratisphere> cool
[14:04] <Stratisphere> awesome, well i'm going to be idling here most days now :)
[14:04] <jcoxon> okay cool
[14:09] <Stratisphere> we've just ordered alot of kit from sparkfun including stacks of sensors. I've also just placed an order for the NTX2 :)
[14:09] <Randomskk> sweet
[14:10] <Stratisphere> as soon as i've got a demo kit working and together we'll weigh it up and see what balloon we need then order a few :D:D
[14:10] <jcoxon> Stratisphere, yeah thats the best approach
[14:10] <Darkside> lol everyone loves the NTX2..
[14:11] <Darkside> once i miniaturise my HF board, i'll release all the data for it
[14:11] <Randomskk> Darkside: we can't transmit HF from balloons in the UK, though
[14:11] <Darkside> :/
[14:11] <Randomskk> gotta use license free bands
[14:11] <Darkside> really
[14:12] <Darkside> even with an amateur license?
[14:12] <Randomskk> namely 434mhz, ish. and 10mW transmit power.
[14:12] <eroomde> regretably yes.
[14:12] <Randomskk> UK amateurs are not allowed to operate airborne
[14:12] <Darkside> aww what
[14:12] <Randomskk> hence 10mW at 434MHz
[14:12] <Darkside> juxta managed to run a VHF repeater airborne here :/
[14:12] <Randomskk> the same band car keys use to remote unlock, and the same kind of power >__>
[14:12] <Randomskk> your amateur licenses are like, better
[14:12] <Darkside> haha
[14:12] <Darkside> but they cost money here :P
[14:13] <russss> Randomskk: but their aviation regs are more strict
[14:13] <Randomskk> Darkside: ours cost a little bit
[14:13] <Randomskk> russss: true, we do have a fairly good time with that
[14:13] <Randomskk> also like 10mW is enough for anybody
[14:14] chris_99 (~chris9001@unaffiliated/chris-99/x-3062929) joined #highaltitude.
[14:18] <Darkside> pffff just read a paper by one of my supervisors at uni about measuring the gain patterns of HF antennas
[14:19] <Darkside> tl;dr version - get a helicopter, stick a known antenna underneath it (dipole) and fly it around the unknown antenna
[14:19] <Darkside> i lol'd
[14:19] <Darkside> it works extremely well too, the experimental data is very cool
[14:19] <eroomde> Darkside: that's exactly what they do
[14:19] <Darkside> http://docs.google.com/viewer?a=v&q=cache:dUhhXZCDppcJ:dspace.dsto.defence.gov.au/dspace/bitstream/1947/4315/1/DSTO-TR-0654.pdf+dr+chris+coleman+RF&hl=en&gl=au&pid=bl&srcid=ADGEESgaardYaZjVQRuaai0AJMCSfXCCYLVF0sA_iA3WIS1TWG0FLbrHrfLX--WR11OUcDF3oi_D3FuTuRJi75D82Jd3iqnNBM1Yu24Fldy5MnAjPvSxXy_OHr37nv583-VLgZ7SRQdi&sig=AHIEtbQRRmlrsey4CxQsDftCyyt84MvnIw
[14:20] <Darkside> basically taking the classic method of measuring small antennas to the extreme
[14:20] <Darkside> which is cool
[14:20] <eroomde> i have been talking to someone (Randomskk listen in) who makes super-resolution HF arrays for direction finding
[14:20] <eroomde> and they fly a helicopter about to build a model of the complex manifold
[14:21] <Darkside> hahahaha
[14:21] <Darkside> nice
[14:21] <eroomde> Randomskk: i got cut off as we were talking about direction finding
[14:21] <eroomde> but there's more to say
[14:21] <Darkside> http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=0521834813 <-- thats the textbook my supervisor wrote
[14:21] <Randomskk> I read a paper that went through the basics of beamforming and using it for super resolution DF
[14:21] <eroomde> Darkside: invalid isbn
[14:21] <Darkside> hmm
[14:21] <Randomskk> but it didn't really get into the complexities of implementation
[14:22] <eroomde> Randomskk: mm
[14:22] <Darkside> eroomde: check you're copying it right
[14:22] <Randomskk> just like "yeea change the phase and such"
[14:22] <eroomde> did it cover the MUSIC algorithm?
[14:22] <eroomde> that's basically the key
[14:22] <eroomde> and the secret to how we should make one
[14:22] <eroomde> as then we could have several balloons in the sky at once on 434.650 and decode all of them individual with special filtering
[14:22] <Randomskk> I don't believe it did
[14:23] <eroomde> rather than some kind of frequency or temporal bs, which are either scarce or complicated
[14:23] <Darkside> cdma :D
[14:23] <eroomde> ok, well the music algorithm is basically this (and it's gorgeous in its simplicity)
[14:23] <Randomskk> eroomde: whereby the receiver beamforms to just receive from the desired balloon?
[14:23] <Darkside> just do CDMA :D
[14:23] <Darkside> synch the timing with gps
[14:23] <eroomde> cdma through a 3khz LPF-ed VCO?
[14:24] <Darkside> oh man i need to try this
[14:24] <eroomde> i'd like to see that
[14:24] <Darkside> lol
[14:24] <Darkside> well, a cdma-like thing
[14:24] <eroomde> Randomskk: so have an array of say 8 antennas
[14:24] <eroomde> ignore the geometry for now. say an octagon but in reality not as that's full of nulls and stuff. but whatever, and array of 8 antennas
[14:25] <eroomde> you can describe the covariance between antenna x_n and antenna x_(n+a) with a complex number
[14:25] <eroomde> representing the phase and magnitude relationship between each of them
[14:26] <eroomde> so you can then make a covariance matrix (8x8 in our case) of complex values representing the relationship of the incoming signal between each of the antennas
[14:26] <russss> insert maths, receive signal
[14:26] <eroomde> it'll be diagonally symmetric right (relationship between x_1 and x_2 is the same as between x_2 and x_1)
[14:26] <Randomskk> with you so far
[14:27] <eroomde> so once you have that complex covariance matrix, you can do an eigen decomposition on it
[14:27] <Laurenceb> yeah
[14:27] <Darkside> this would be for a fixed station, right?
[14:27] <Laurenceb> thats how MIMO works
[14:27] <eroomde> and each of the eigen value and vecotr pairs you get is a signal that is comping into the array
[14:27] <eroomde> coming*
[14:27] <Laurenceb> eroomde: need cc1020s with time sync
[14:27] <Laurenceb> for the ants
[14:27] <eroomde> you then have to convolve these eigenpairs with the complex manifold of the array (because it's not going to be a pefect hemisphere). that's basically just a calibration step
[14:28] <eroomde> and you can say 'i have a signal at 21.2 degrees azimeth, 14 degreese elevation, with an SNR of 2db) and you're done
[14:29] <Darkside> very cool
[14:29] <Randomskk> beautiful in its simplicity though I get the feeling finding the complex manifold is nontrivial and constructing antennas with electronics to quickly read a synchronised phase and amplitude is also a bit tricky?
[14:29] <eroomde> so you can coule a az-el plot on your display which would have small gausian clouds of samples you were getting, and write special demodulators - so basically you see a cloud of points and say 'decode that cloud there' and it'll be neva25 or whatever
[14:29] <eroomde> Randomskk: exactly
[14:29] <Laurenceb> id go with cc1020
[14:29] <eroomde> so the trick is to make an array such that the menifold is as regular as possible
[14:29] <eroomde> and then treat it as a hemipshere
[14:29] <Laurenceb> but not sure of the best way to time sync
[14:30] <Darkside> Laurenceb: ooh i've heard of those chips..
[14:30] <Laurenceb> maybe a central board
[14:30] <Randomskk> Laurenceb: does it have a clock in? if you fed them all with the same clock source would that actually work?
[14:30] <Laurenceb> yes
[14:30] <Laurenceb> clk in and out
[14:30] <Laurenceb> problem is boards at each ant or central board and coax?
[14:30] <eroomde> Randomskk: so that conversation I had with this guy (who works at roke manor and makes such a system for the miltary) is on the design of a simulated annealing algorithm to iterate to a good manifold design
[14:30] <Randomskk> eroomde: does that work in reverse to transmit in a given direction? you can find a symmetric matrix from the eigen decomposition, right?
[14:31] <eroomde> also you definitely definitely want unresonant elements in the array
[14:31] <eroomde> otherwise the mutual coupling just wrecks any chance you have of a vaguely even manifold
[14:31] <Randomskk> right
[14:31] <Randomskk> unresonant at incoming signal frequency or..?
[14:31] <Laurenceb> yes
[14:31] <Randomskk> I guess that makes transmitting more of a pain?
[14:31] <eroomde> you may say 'gah! detuned!?!?!' but the improvements you get in SNR from the special filtering stuff more than sort that
[14:31] <Laurenceb> yeah - need larger ants
[14:31] <Randomskk> fair enough
[14:32] <Laurenceb> ive got a cc1020 SDR thing hacked up on breadboard
[14:32] <Randomskk> eroomde: better than the track o tron?
[14:32] <Laurenceb> guess a central board isnt scalable
[14:32] <eroomde> you can actively shpae the electronic array manifold (which is something you design based on starting with a fairly even physical one) to put nulls in the direction of interfering sources, for instance
[14:33] <Randomskk> yea, that's quite neat. isn't that kind of how you do the superresolution DF? point nulls?
[14:33] <eroomde> Randomskk: maybe not better than some really long yagis altimately, but if you have several balloons in the air, way better
[14:33] <Laurenceb> could you use it with yasgis?
[14:33] <eroomde> yuck
[14:33] <Darkside> this sounds like a lot of effort to go to for tracking balloons :P
[14:33] <Laurenceb> yes...
[14:34] <eroomde> i mean sure, of course right. but analysing your manifold would be torturous
[14:34] <Laurenceb> yeah actually thats stupid
[14:34] <Randomskk> the other thing that looked interesting is UWB but that seems like it would not be license free exactly
[14:34] <eroomde> it's probably overkill for balloons but as an open hardware project it f*cking rocks
[14:34] <Laurenceb> just steer the yagis manually
[14:34] <Laurenceb> and add adjustable delay lines in software
[14:34] <eroomde> and you'd get all these super keep DX clubs making them in a heart-beat as you could absolutely *cream* competitions with such a set-up
[14:34] <Laurenceb> MUSIC for that sort of setup itsd the best idea
[14:35] <eroomde> super keen*
[14:35] <Darkside> i'm very surprised at the UKs radio regs..
[14:35] <Stratisphere> lol reading this has been cool
[14:35] <Darkside> there's gotta be something you cna use airborne
[14:35] <eroomde> Darkside: can you give me the title of that book? I'll look it up myself
[14:35] <Darkside> apart from the 433MHz ISM stuff
[14:35] <Randomskk> Darkside: yes. 10mW 434mhz
[14:35] <Stratisphere> i feel like i've been privvy to some military secret document (aka, I dont understand a single bit of it lol)
[14:35] <eroomde> Darkside: there are a couple of others
[14:35] <Randomskk> there's a little 868 I think, and some 2.4ghz though FSPL is horrific
[14:35] <eroomde> 167mhz at 500mW iirc
[14:35] <Darkside> http://www.amazon.com/Introduction-Radio-Frequency-Engineering/dp/0521834813
[14:36] <Darkside> its our uni's 3rd year RF engineering textbook
[14:36] <Darkside> we use a bit of it in 4th year too, mainly s-matrix stuff
[14:37] <eroomde> s-matrix?
[14:37] <eroomde> sounds a bit dark
[14:37] <Darkside> scattering matricies
[14:37] <Darkside> i.e for amplifiers, filters, basically any device
[14:37] <eroomde> I have never done any academic courses on anything radio so quite a lot of it is a bit unknown to me
[14:37] <eroomde> i'm happier once it's a bitstream
[14:37] <Darkside> hahaa
[14:37] <Darkside> yes
[14:38] <Darkside> signal processing ftw
[14:38] <eroomde> Randomskk: but yes a super resolution UHF rig would be amazing
[14:38] <Darkside> still, i'm wondeirng if it would be possible to do something like CDMA on that band
[14:38] <eroomde> and would hopefully fit on a roof rack
[14:38] <eroomde> yes, of course
[14:38] <eroomde> and quite likely no one would ntoice
[14:39] <eroomde> if you did code hopping
[14:39] <Darkside> not quite the same as CDMA, but signals added together, then pulled out at the receiver with dsp
[14:39] <Randomskk> eroomde: an FPGA doing maths, 8 or so antennas with cc1020s and a central clock, an output stream of vectors and signals?
[14:39] <eroomde> easy yes
[14:39] <Randomskk> does the decomposition give you the momentary signal amplitude?
[14:39] <Randomskk> with the direction as the vector? or what
[14:39] <eroomde> correct
[14:39] <Laurenceb> http://focus.ti.com/lit/ds/symlink/cc1020.pdf clk input on the osc pin
[14:39] <eroomde> it's all done in a complex space which gives you phase and mag
[14:39] <eroomde> all that info is preserved
[14:39] <Randomskk> neat.
[14:39] <eroomde> apart from when you decimate to baseband
[14:40] <eroomde> and yep, FPGA to USB or something
[14:40] <eroomde> well hang on
[14:40] <Laurenceb> Randomskk: yeah maybe stick a cc1020 on each ant
[14:40] <Randomskk> I really really want to get to use my fpga for something
[14:40] <eroomde> fpga doing the packing and usb
[14:40] <Darkside> big chunky fpga..
[14:40] <Randomskk> I am kind of tempted to try and implement HDCP in it
[14:40] <eroomde> you would to do the dsp on a cpu i think
[14:40] <eroomde> on a laptop
[14:40] <Randomskk> ah, fair enough
[14:40] <Darkside> Randomskk: what fpga?
[14:40] <Laurenceb> need some sort of digital comms to the ants tho..
[14:40] <Randomskk> Darkside: spartan 3e, though I can get others
[14:40] <Darkside> yeah i have a spartan 3e board
[14:40] <Laurenceb> yeah spartan is nice
[14:41] <Darkside> got a friend working on a virtex 6 at uni
[14:41] <Darkside> veeeeeeeeeeery expensive fpga, the virtex 6
[14:41] <Darkside> and he's got a gameboy emulator running on it :P
[14:41] <Randomskk> yea really. the cost on the big ones goes up dramatically
[14:41] <Darkside> using 6 microblaze cores
[14:41] <Darkside> running at 150MHz..
[14:41] <Laurenceb> wow
[14:41] <eroomde> i think you'd want to use the CPU to do the music stuff. there's plenty of horsepower and it'll make it a million times easier to integrate with special decoders
[14:41] <Darkside> hehe
[14:42] <Randomskk> http://retromaster.wordpress.com/a2601/ did an atari 2600 including cpu, memory and graphics unit on a spartan 3e
[14:42] <Darkside> its more a research project about how to do inter-core communication efficiently than anyting
[14:42] <Laurenceb> how far apart would the ants be?
[14:42] <Laurenceb> ~1m or so?
[14:42] <eroomde> Laurenceb: that's the hardest bit
[14:42] <eroomde> designing the manifold
[14:42] <Randomskk> eroomde: that's true. easier to program too, at the end of the day
[14:42] <Laurenceb> youd really need a seperate spi bus to each ant
[14:42] <eroomde> it think after that you just need coherent receivers and decimation and basically shove it into usb.
[14:42] <Laurenceb> as it has to run at a few mbps
[14:42] <Randomskk> Laurenceb: easily done on an fpga
[14:43] <Laurenceb> yes
[14:43] <eroomde> spi? it's gonna have to be quite high bandwidth i think
[14:43] <Randomskk> as is usb, there are ip cores for that
[14:43] <Laurenceb> ~2 to 4
[14:43] <Laurenceb> mbps
[14:43] <eroomde> you'd probably want to grab like 1mhz bandwidth
[14:43] <Randomskk> spi can do quite high bandwidth
[14:43] <Randomskk> as a bus, anyway
[14:43] <Randomskk> the cc is going to be the limiting factor
[14:43] <SpeedEvil> Or you don't bother.
[14:43] <Darkside> eroomde: cripes
[14:43] <Laurenceb> you can do 2 bit conversdion on the cc
[14:43] <eroomde> with 8 antennas that's 8mhz bandwidth at whatever adc resoiltuion your budget will stretch to
[14:43] <Darkside> eroomde: just make your own down converted and stick a big-ass ADC on there
[14:44] <SpeedEvil> And you have a 4 quadrant mixer at each antenna, that feeds onto an IQ summer
[14:44] <Laurenceb> swhy the bandwidth?
[14:44] <Laurenceb> surely a few tens of Khz would be fine
[14:44] <eroomde> so you can see most of 70cm
[14:44] <SpeedEvil> Do you really care about the steering that much
[14:44] <Laurenceb> just enough to see the signal
[14:44] <eroomde> the point of these systems is to be able to grab all of a a band and monitor it
[14:44] <Laurenceb> fairdoos
[14:44] <Laurenceb> i was thinking just for monitoring
[14:44] <eroomde> and you do really need lots of bits on your ADC - that's very important in this app
[14:44] <Laurenceb> - rx etc
[14:45] <Darkside> eroomde: define 'lots'
[14:45] <Laurenceb> you can go to 3 bit
[14:45] <eroomde> 24 would be nice
[14:45] <Darkside> jeez
[14:45] <eroomde> not kidding
[14:45] <Darkside> $$$$$$$$
[14:45] <eroomde> so think about it
[14:45] <Laurenceb> no way thatd be practical
[14:45] <Darkside> ths USRP2 is only 16 or something, isn't it?
[14:45] <eroomde> with a single antenna, when you have a balloon your are listening to at 10mW 400km away, that's fine
[14:45] <Laurenceb> with multiple ants itd get crazy
[14:46] <eroomde> when someone on their 5W handheld 1km talks on your frequency, you are utterly trashed - nothing you can do
[14:46] <eroomde> so who cares
[14:46] <eroomde> but with special multiplexing, you can still see both the balloon and the handheld
[14:46] <Laurenceb> how so?
[14:46] <eroomde> but ONLY if you have the dynamic range to see both of them despite the huge difference in SNR
[14:46] <Laurenceb> switch to a seperate frequency?
[14:46] <eroomde> no, this is the point of the special stuff
[14:47] <eroomde> you can have lots of things on the same frequency
[14:47] <Randomskk> Darkside: USRP2 is 14 bits receive, 16 transmit
[14:47] <eroomde> but as long as they're in difference places you can split them up
[14:47] <eroomde> it's like FDM or TDM
[14:47] <eroomde> but SDM in this case
[14:47] <Laurenceb> guess so
[14:47] <eroomde> that's the joy of this sytem
[14:47] <Laurenceb> but its never going to be perfect
[14:47] <eroomde> it gives you another dimension
[14:47] <eroomde> i reckon mobile phoens should do this
[14:47] <SpeedEvil> Different places * antenna null depth * signal ratios
[14:47] Action: Laurenceb is not convinced
[14:47] <eroomde> you can massively increase the capaicty of each cell
[14:47] <SpeedEvil> eroomde: they sort of are.
[14:48] <SpeedEvil> eroomde: but only at the tower.
[14:48] <eroomde> Laurenceb: why are you not convinced? this is how this tech works
[14:48] <SpeedEvil> eroomde: They segment the tower into octants or more.
[14:48] <Laurenceb> 24bits is massive overkill imo
[14:48] <Randomskk> yea, they do a bit
[14:48] <Laurenceb> even mil gps is only 8 bits
[14:48] <eroomde> well, do the maths
[14:48] <Laurenceb> i just have
[14:48] <SpeedEvil> Rejecting co-channel interference is hard.
[14:48] <Laurenceb> im not convinced >8 bit is worth it
[14:48] <SpeedEvil> And requires everything to just work.
[14:48] <eroomde> you want to hear something 500km at 10mW at the same time as something on 5W 1km away
[14:49] <eroomde> so you can calc how much dynamic range on the adc that you need
[14:49] <Laurenceb> yes but mismodelling
[14:49] <Laurenceb> and weird second order effects etc
[14:49] <eroomde> 24 is a lot yes, i'm not entirely serious for a first system. but 12-16 definitely. rather than 8
[14:49] <SpeedEvil> you somewhat don't care about mismodeling
[14:49] <Laurenceb> the MUSIC technique will never be that good
[14:49] <SpeedEvil> as you can tweak each antenna virtually
[14:50] <Laurenceb> unless you have an ant forest
[14:50] <eroomde> Laurenceb: i'm afraid you're wrong
[14:50] <eroomde> it is that good
[14:50] <Darkside> get a whole bunch of USRP's
[14:50] <eroomde> i've seen live demonstrations of exactly this kind of product
[14:50] <Randomskk> Darkside: seriously expensive
[14:50] <Darkside> :P
[14:50] <Randomskk> but USRP2s can link together for MIMO
[14:50] <Darkside> ooh
[14:50] <Randomskk> at $70 a link cable and $$$$ a USRP2
[14:50] <Randomskk> plus $$$$ for their RX daughterboards
[14:50] <Darkside> hehe
[14:50] <Darkside> yeah..
[14:51] <SpeedEvil> It isn't that bad to just do a demo.
[14:51] <Darkside> need to yoink one from a lecturer for a while
[14:51] <eroomde> I think this can definitely be done chaps
[14:51] <Darkside> about 5 people at uni have them, and don't use them
[14:51] <SpeedEvil> Large wide DDR ram where you just need to supply a new page address every 4096 samples is common.
[14:51] <SpeedEvil> Large sized cheapish ADCs are available.
[14:51] <eroomde> one would have to develop a simple but good front end with a high res dsp and a coherent clock system to go across them.
[14:52] <SpeedEvil> Doing the data reduction in realtime is uch more fun.
[14:52] <eroomde> then an FPGA to do some decimating and packaging
[14:52] <eroomde> well, probably just packaging
[14:52] <eroomde> and then it's a software problem
[14:52] <Randomskk> I don't know you could stream the raw data from FPGA to computer over USB
[14:52] <SpeedEvil> USB3
[14:52] <SpeedEvil> :)
[14:52] <Randomskk> would be required
[14:52] <Randomskk> controller chips are a pita
[14:53] <Darkside> gbit ethernet?
[14:53] <Randomskk> might need something else. firewire is potentially more likely, but rarer
[14:53] <eroomde> it'd probably be worth designing around the usb constraint
[14:53] <Randomskk> gbit ethernet is how the USRP does it
[14:53] <Randomskk> and that's one 14bit receiver
[14:53] <Randomskk> USRP2*
[14:53] <eroomde> aye that could work nicely too
[14:53] <SpeedEvil> you can sort-of-fudge the USB constraint by using multiple cables
[14:53] <Laurenceb> isnt USRP crap for 434?
[14:53] <Randomskk> yea but like
[14:53] <eroomde> that's probably the way to do it
[14:53] <eroomde> just udp
[14:54] <Randomskk> Logic does 24MHz sample rate max over USB, saturating the bus bandwidth, and that's 8 readings at binary 0 or 1 each
[14:54] <eroomde> and then a decent cpu
[14:54] <Randomskk> eroomde: or serveral, since it's ethernet
[14:54] <SpeedEvil> Are the 'hard' applications really that vital?
[14:54] <eroomde> hard?
[14:54] <SpeedEvil> Compared to for example a FPGA or whatever core that can do MAC for all the antennas for two signal sources with uploaded coefficicents for each antenna.
[14:55] <SpeedEvil> That would considerably ease the datarate of the link
[14:55] <Darkside> this would be a very awesome research project
[14:55] <SpeedEvil> The point-cloud aspect is shiny, yes.
[14:56] <SpeedEvil> But may tend to blow the complexity way up.
[14:56] <SpeedEvil> I do wonder how seperate the antennas can be.
[14:57] <SpeedEvil> As in many kilometers + GPS PPS
[14:57] <SpeedEvil> I suspect that'd not really be useful
[14:57] <SpeedEvil> as you'd want the timebase and atmospheric errors to be well under a tenth of a wavelenght
[14:58] Action: Laurenceb realises hes confusing this with MIMO
[14:58] <eroomde> SpeedEvil: yeah actually i must confess my desire to make this was piqued by the thought of a GPS visualiser
[14:58] <Laurenceb> MIMO is different?
[14:58] <SpeedEvil> GPS visualiser is shiny.
[14:58] <eroomde> see the sats pass over in real time
[14:58] <Laurenceb> erm ucenter?
[14:58] <eroomde> but actually that might be pretty tricky as they're so far beneath the noise floor
[14:58] <Laurenceb> oh go tyou
[14:58] <eroomde> no no, i mean one that sees the actual sats
[14:59] johnnyfive|work (~sharkt@70.89.126.174-BusName-Washington.hfc.comcastbusiness.net) joined #highaltitude.
[14:59] <Laurenceb> interesting
[14:59] <eroomde> not just plots where the decoded thing tells them they are
[14:59] <eroomde> *sees* them
[14:59] <SpeedEvil> eroomde: I came up with a really simple design to directly recieve M-code.
[14:59] Action: Laurenceb isnt really following the conversation
[14:59] <Laurenceb> <working
[14:59] <SpeedEvil> eroomde: It did however involve a 34m dish.
[14:59] <Laurenceb> you can detect M code bit edges
[14:59] meefs (ken@shell.kobnet.net) joined #highaltitude.
[14:59] <SpeedEvil> I mean accurately recieve the bitstream.
[14:59] Action: Stratisphere isnt following the conversation atall
[14:59] <Laurenceb> so?
[15:00] <Laurenceb> you dont know what its going to do next..
[15:00] <Laurenceb> oh
[15:00] <Laurenceb> you stream the data
[15:00] <eroomde> nice
[15:00] <Laurenceb> a la DGPS
[15:00] <SpeedEvil> If you do this, you can then do a similar thing to that sample-matching GPS that works on L1 GPS
[15:00] <Laurenceb> clever
[15:00] <SpeedEvil> To get more SNR by using the other signal too
[15:00] <SpeedEvil> the one that's designed for cameras that samples 1s of GPS and records it for later decode
[15:01] <Laurenceb> you could stream the data from your dish
[15:01] <Laurenceb> and use on a delayed bitstream
[15:01] <Laurenceb> to do a DLL+FLL/PLL for the M code
[15:01] <SpeedEvil> :/ AFK - gotta do tidying up of stuff outside before it rains.
[15:02] Action: Laurenceb thinks web based M code dtreaming system
[15:02] Action: Laurenceb wonders how logn before USAF would stick a missile into your dish
[15:02] <johnnyfive|work> mornin
[15:03] <Laurenceb> anyway - i dont quite follow the MUSIC thingymabob
[15:03] <Laurenceb> how far apart would the ants be, and how does it differ from MIMO?
[15:09] <eroomde> Laurenceb: I honestly don't know - we'd have to sim it
[15:10] <eroomde> i guess for 70cm you'd want to try and keep the array "diameter' less than about 2m
[15:10] <eroomde> but i mean the wouldn't all be ina circle
[15:10] <eroomde> necessarily
[15:10] <eroomde> it's a really tough optimisation problem
[15:11] <eroomde> right am off
[15:11] <eroomde> see you
[15:12] <Stratisphere> im off
[15:12] <Stratisphere> thanks for the headache guys :P
[15:12] <Stratisphere> (and thanks for the awesome advice :P)
[15:13] Stratisphere (~Stratisph@193.200.145.254) left irc:
[15:16] chris_99 (~chris9001@unaffiliated/chris-99/x-3062929) left irc: Quit: Leaving
[15:18] <Laurenceb> cya
[15:21] DagoRed (~dago@j15-1.nat.iastate.edu) joined #highaltitude.
[15:25] <Laurenceb> with something 2m and a handful on ants i doubt you could get more than 10dB or so signal selectivity
[15:25] <Laurenceb> maybe in ideal simulation land
[15:25] <Laurenceb> but when its noisey and strapped to a movign car..
[15:25] <Randomskk> only one way to find out for sure, of course.
[15:26] <Randomskk> it's not actually an unforgiving amount of data
[15:26] <Randomskk> say 1mhz data at 16 bits per antenna and 8 antennas
[15:26] <Randomskk> 16MB/s
[15:26] <Randomskk> too much for 100mbps ethernet, sure
[15:27] <Randomskk> but gigabit'd do it. USB2... I don't think so
[15:27] <Randomskk> well
[15:27] <Randomskk> technically USB2 should support 60MB/s
[15:27] <Laurenceb> thing is with cc you can only get 3 bit for I and Q
[15:27] <Randomskk> but in reality I don't know that you can achieve that in real time
[15:27] <Randomskk> ah
[15:28] <Laurenceb> pinning a downconversion board would be massively more complex
[15:28] <Randomskk> might need to do more radio stuff yourself then
[15:28] <Laurenceb> and expensive
[15:28] <Randomskk> yes
[15:28] <Randomskk> true, just look at USRP
[15:29] <Laurenceb> USRP for 434 is a bit lame
[15:30] <Randomskk> it is
[15:30] <Randomskk> also silly expensive
[15:30] <Laurenceb> there are maxim TV tuner ICs
[15:31] <Laurenceb> but much more complex than a cc
[15:39] SpikeUK_ (~chatzilla@212.183.140.31) joined #highaltitude.
[15:40] Nick change: SpikeUK_ -> SpikeUK
[15:49] SpikeUK (~chatzilla@212.183.140.31) left irc: Ping timeout: 240 seconds
[15:50] Laurenceb (80f3fd6c@gateway/web/freenode/ip.128.243.253.108) left irc: Quit: Page closed
[15:56] <SpeedEvil> Randomskk: I see 32M/s on a USB2 disk
[15:56] <SpeedEvil> which isn't terrible
[15:58] <Randomskk> so, just about doable on usb2 maybe
[15:59] <Randomskk> would saturate most of the bus though if you were doing anything else
[15:59] <SpeedEvil> I'd assume you'd need to dedicate it
[16:00] Action: SpeedEvil has been bending iron bars.
[16:00] <Randomskk> manly stuff
[16:00] <SpeedEvil> (well - technically fencewire)
[16:00] <SpeedEvil> I have huge piles of crap sort-of-sorted.
[16:01] <SpeedEvil> And am trying to get to the stage where I have neat piles of sorted crap and a huge pile for the skip.
[16:01] chris_99 (~chris_99@84.93.186.126) joined #highaltitude.
[16:01] chris_99 (~chris_99@84.93.186.126) left irc: Changing host
[16:01] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) joined #highaltitude.
[16:13] lonek (lonek@host81-137-96-89.in-addr.btopenworld.com) joined #highaltitude.
[16:27] <chris_99> hi guys, does anyone here use any electronic simulation packages per chance
[16:27] <chris_99> just looking for a good one
[16:33] <DagoRed> for circuit design I'm assuming?
[16:33] <chris_99> yeah
[16:40] <DagoRed> orchad
[16:40] <DagoRed> pspice
[16:42] <chris_99> cheers DagoRed, can either of those simulate microcontrollers do you know
[16:43] <Randomskk> simulating micros is usually a more specialist task
[16:43] <Randomskk> typically provided for by your microcontroller manufacturer's tools
[16:43] <Randomskk> also at that point you really might be better just breadboarding
[16:44] <DagoRed> chris_99: you never model a micro in that software.
[16:44] StrayVoltage (Tvilling@unaffiliated/twiner) left irc: Ping timeout: 272 seconds
[16:44] <chris_99> a while ago i thought i remember seeing one that could do it though
[16:45] <chris_99> but yeah you're right Randomskk, bread boarding probably makes more sense
[16:45] <DagoRed> chris_99: Just model the parts you want. For instance, and output can be a step output.
[16:45] <Randomskk> yea.
[16:45] StrayVoltage (~blah@c4383BF51.static.bluecom.no) joined #highaltitude.
[16:45] StrayVoltage (~blah@c4383BF51.static.bluecom.no) left irc: Changing host
[16:45] StrayVoltage (~blah@unaffiliated/twiner) joined #highaltitude.
[16:45] <Randomskk> there are simulators for AVRs
[16:46] <Randomskk> but like, they simulate its internals and IO
[16:46] <Randomskk> they don't usually plug into a normal SPICE simulator
[16:46] <chris_99> aha
[16:48] <chris_99> this looks kind of cool http://www.labcenter.com/products/pic18.cfm
[16:49] rharrison (~rharrison@gateway.hgf.com) left irc: Quit: Leaving
[16:55] <m1x10> Hi
[16:55] <DagoRed> waste of time chris_99
[16:58] <m1x10> I just sew that there are some devices called dc-dc converters
[16:58] <Randomskk> yes
[16:58] <Randomskk> they turn DC into DC
[16:58] <Randomskk> usually at a different voltage
[16:58] <m1x10> you give little voltage and it outputs much more
[16:58] <EI5GTB> evening
[16:58] <Randomskk> m1x10: sometimes, you give a lot of voltage and it outputs much less
[16:58] <m1x10> why not use it in HAB?
[16:58] <chris_99> does that make it similar to an op-amp?
[16:58] <m1x10> one battery less weight less space.....
[16:59] <Randomskk> m1x10: some people do. but we don't really need high voltages
[16:59] <Randomskk> m1x10: well yes, but the total power that battery can deliver is constant
[16:59] <Randomskk> chris_99: no. opamps can only output up to their power supply voltages
[16:59] <Randomskk> so you connect +15V to them, the biggest they will output is 15V
[16:59] <Randomskk> DC-DC converters can input 1.5V and output 5V, say.
[16:59] <m1x10> ok
[16:59] <chris_99> cool :) i'm guessing they use capacitors somehow
[17:00] <chris_99> for that
[17:00] <Randomskk> but obviously it draws more current at 1.5V than it supplies at 5V, and they're not perfectly efficient.
[17:00] <Randomskk> chris_99: sometimes. or inductors.
[17:00] <Randomskk> I mean, everything uses capacitors, and inductor based DC-DC supplies use capacitors to smooth the output
[17:00] <Randomskk> you can do a voltage doubler with just capacitors though
[17:00] <chris_99> that sounds a handy little device
[17:00] <Randomskk> yea.
[17:00] <chris_99> normally i use voltage regs
[17:01] <chris_99> to step down
[17:01] <Randomskk> DC-DCs can be more efficient to step down
[17:04] <m1x10> Randomskk, all converters have constant output power?
[17:04] <m1x10> if my system needs less they keep providing the constant one?
[17:05] <Randomskk> m1x10: no
[17:05] <Randomskk> they have mostly-constant output voltage and power depends on your current draw
[17:05] <m1x10> so, what exactly we need. right?
[17:05] <Randomskk> what?
[17:06] <Randomskk> yes, they would let you run a HAB system off a single AA cell
[17:06] <m1x10> so, thats exactly we need. right?
[17:06] <m1x10> oh
[17:06] <Randomskk> but you'd have in total a third of the power, at the end of the day, minus boost inefficiencies
[17:06] <Randomskk> so your system lifetime would be 1/3
[17:06] <m1x10> why is that?
[17:06] <Randomskk> because you have one battery, not three
[17:06] DagoRed (~dago@j15-1.nat.iastate.edu) left irc: Quit: Leaving
[17:06] jcoxon (~jcoxon@cpc1-lanc4-0-0-cust720.3-3.cable.virginmedia.com) left irc: Quit: Leaving
[17:06] <Randomskk> DC-DC converters do not magically make energy
[17:06] <m1x10> lol
[17:07] <Randomskk> e.g. if your load requires 1A of current
[17:07] <Randomskk> and you're feeding it from three batteries
[17:07] <Randomskk> and say that gives you 6V of power from the three batteries
[17:08] <Randomskk> your total power consumption is P=I*V=6W
[17:08] <m1x10> but me using 6 battery pack for total 9v, the total capacity is not increased. total capacity is equal to one battery.
[17:08] <Randomskk> the power being drawn from each battery is P=I*V=2W (2V per cell, 1A still)
[17:08] <Randomskk> now if you use a DC-DC converter from a single cell
[17:08] <Randomskk> it supplies 1A at 6V
[17:08] <Randomskk> to do that it draws 3A at 2V
[17:08] <Randomskk> power in = power out
[17:08] <Randomskk> 3A * 2V = 1A * 6V
[17:09] <Randomskk> so now the one battery is supplying 3A at 2V
[17:09] <Randomskk> which is three times as much current as it was before
[17:09] <Randomskk> so it will die three times quicker
[17:10] <Randomskk> if you use 6 batteries for a 9V supply, the total capacity is six times bigger than one battery
[17:10] <Randomskk> because you're drawing the same current at six times the voltage
[17:10] <Randomskk> each battery has so much total energy it can deliver
[17:10] <Randomskk> you cannot change that
[17:10] <Randomskk> you can muck about with voltages all you like to get what your system needs
[17:11] <Randomskk> but you can't get more energy out of the cell, so using just one cell means one third the total energy of using three.
[17:11] <m1x10> wait. i know that if i use the 6 batteries in series I just increase the voltage output.
[17:12] <Randomskk> yes. but if you draw 1A at 1.5V, that's 1.5W of power
[17:12] <Randomskk> if you draw 1A at the combined 9V, that's 9W of power.
[17:12] <Randomskk> that's six times more power.
[17:12] <Randomskk> same current, but increased voltage => more power
[17:12] <Randomskk> energy is power over time
[17:12] <m1x10> im confused
[17:13] <Randomskk> I think the simplest thing to think about here is that each cell has a fixed energy, which gets used up as you draw current from the cell.
[17:13] <m1x10> ok
[17:13] <Randomskk> each cell provides a certain voltage, which is mostly constant over its life, but does drop a bit.
[17:13] <m1x10> ok
[17:13] <Randomskk> you can take any input voltage you like, and turn it into any output voltage you like, to power your system
[17:13] <Randomskk> but the total power into this converter will match the total power out of it, where the power is the current times the voltage
[17:14] <Randomskk> so, if your converter increases the voltage, it will be drawing more current from the lower voltage than it delivers to the higher voltage
[17:14] <m1x10> ah
[17:14] <Randomskk> such that the input power is the same as the output power
[17:14] <m1x10> it will empty the bats then
[17:14] <m1x10> more quicly
[17:14] <Randomskk> so what matters most really is energy - each cell has some amount of energy, and you can use that energy at any voltage/current you feel like
[17:15] <Randomskk> three cells give three times as much total energy as one cell
[17:15] <Randomskk> so yes, using a single cell and a voltage increaser will empty that single cell quicker
[17:20] stilldavid (~dave@68-64-214-18.static.forethought.net) left irc: Read error: Operation timed out
[17:21] stilldavid (~dave@68-64-214-18.static.forethought.net) joined #highaltitude.
[17:34] jasonb (~jasonb@12.201.129.162) left irc: Ping timeout: 265 seconds
[17:43] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) left irc: Ping timeout: 265 seconds
[17:43] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) joined #highaltitude.
[17:48] rambo (~dago@m70-m78-m79-1.nat.iastate.edu) joined #highaltitude.
[17:49] rambo (~dago@m70-m78-m79-1.nat.iastate.edu) left irc: Client Quit
[17:50] fsphil (~phil@beastie.sanslogic.co.uk) joined #highaltitude.
[17:50] DagoRed (~dago@m70-m78-m79-1.nat.iastate.edu) joined #highaltitude.
[18:01] LazyLeopard (~irc-clien@chocky.demon.co.uk) left irc: Quit: Bye
[18:07] jasonb (~jasonb@12.201.129.162) joined #highaltitude.
[18:09] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) left irc: Ping timeout: 255 seconds
[18:09] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) joined #highaltitude.
[18:09] Laurenceb (~laurence@host86-160-237-102.range86-160.btcentralplus.com) joined #highaltitude.
[18:09] <Laurenceb> hi
[18:09] Action: Laurenceb got hammered by customs :(
[18:09] <Laurenceb> £25
[18:09] <Upu> yeah me too
[18:09] <Laurenceb> its %28 of the value
[18:09] <Upu> £15 + £10 for the admin
[18:10] <Upu> on a GPS chip that cost £22
[18:10] <Upu> well x 2
[18:10] <chris_99> where did you guys order from?
[18:10] <Upu> I got mine from Inventek in th US
[18:11] <chris_99> aha, when i ordered a logic analyser for £30, it didn't get taxed
[18:11] <chris_99> it was from China, if that makes any difference
[18:11] <Upu> yeah sometimes you get ayway with it
[18:13] <Laurenceb> ooh
[18:13] <Laurenceb> they used trhe wrong taric code
[18:14] <Laurenceb> guess i have to argue with customs - that'll be fun
[18:14] <Laurenceb> but i should be able to reduce it to £14
[18:17] smealum (~smealum@85-171-205-215.rev.numericable.fr) joined #highaltitude.
[18:20] <Laurenceb> but the cost of shiupping is added...
[18:20] <Laurenceb> arg this is retarded
[18:20] <Laurenceb> http://www.ukimports.org/inter_company_terms_conditions_incoterms.html
[18:22] SpeedEvil (1000@tor/regular/SpeedEvil) left irc: Ping timeout: 240 seconds
[18:32] <Laurenceb> wonder if you can claim money back from them
[18:34] jasonb (~jasonb@12.201.129.162) left irc: Ping timeout: 255 seconds
[18:36] SpikeUK (~chatzilla@host109-153-237-174.range109-153.btcentralplus.com) joined #highaltitude.
[18:39] nv1k (81bac07b@gateway/web/freenode/ip.129.186.192.123) joined #highaltitude.
[18:40] SpikeUK_ (~chatzilla@host86-164-154-216.range86-164.btcentralplus.com) joined #highaltitude.
[18:41] SpikeUK (~chatzilla@host109-153-237-174.range109-153.btcentralplus.com) left irc: Ping timeout: 245 seconds
[18:41] Nick change: SpikeUK_ -> SpikeUK
[18:49] jasonb (~jasonb@dsl092-009-225.sfo1.dsl.speakeasy.net) joined #highaltitude.
[18:53] Hiena (~Hiena@81.93.195.181.datatrans.hu) joined #highaltitude.
[18:58] <Hiena> Hiya all!
[19:00] <Hiena> Not a HAB question, but maybe one of you knows the answer: How i could identify which peanut butter brand is salty and wich is sweet? It's a kind of exotic (pricey) food here and what i bouth last time it was way too salty.
[19:00] lonek (lonek@host81-137-96-89.in-addr.btopenworld.com) left #highaltitude.
[19:01] <Hiena> Btw, even that one is burned perfectly when mixed ammonium-nitrate.
[19:12] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) left irc: Ping timeout: 252 seconds
[19:25] sbasuita (~ssb@gateway/shell/anapnea.net/x-drztcfccfjzqcpzp) left irc: Quit: leaving
[19:26] sbasuita (ssb@gateway/shell/anapnea.net/x-pvlqprmkiftslriz) joined #highaltitude.
[19:40] <griffonbot> @nearsys: Got the radios last night. The new flight computer keys the radio and transmits, but my D7 only shows the text, position report. #ARHAB [http://twitter.com/nearsys/status/25335705803]
[19:42] SpeedEvil (1000@tor/regular/SpeedEvil) joined #highaltitude.
[19:44] DagoRed (dago@m70-m78-m79-1.nat.iastate.edu) left #highaltitude ("Leaving").
[19:45] DagoRed (~dago@m70-m78-m79-1.nat.iastate.edu) joined #highaltitude.
[19:45] DagoRed (~dago@m70-m78-m79-1.nat.iastate.edu) left irc: Quit: Leaving
[20:00] SAIDias (~SAID@75-170-232-205.desm.qwest.net) got netsplit.
[20:00] ms7821 (Mark@goatse.co.uk) got netsplit.
[20:00] Randomskk (~adam@paladin.randomskk.net) got netsplit.
[20:00] ms7821 (Mark@goatse.co.uk) returned to #highaltitude.
[20:00] Randomskk (~adam@paladin.randomskk.net) returned to #highaltitude.
[20:04] Jasperw (~jasperw@93.89.81.29) joined #highaltitude.
[20:08] G8DSU (5eaddc1d@gateway/web/freenode/ip.94.173.220.29) joined #highaltitude.
[20:11] SAIDias (~SAID@75-170-232-205.desm.qwest.net) got lost in the net-split.
[20:12] johnnyfive|work (~sharkt@70.89.126.174-BusName-Washington.hfc.comcastbusiness.net) left irc: Read error: Connection reset by peer
[20:12] johnnyfive|work (~sharkt@70.89.126.174-BusName-Washington.hfc.comcastbusiness.net) joined #highaltitude.
[20:17] DagoRed (~dago@j15-1.nat.iastate.edu) joined #highaltitude.
[20:18] JetForMe (~JetForMe@nat/yahoo/x-ekqscpeojxyronuv) joined #highaltitude.
[20:20] SpikeUK (~chatzilla@host86-164-154-216.range86-164.btcentralplus.com) left irc: Quit: ChatZilla 0.9.86 [Firefox 3.6.10/20100914125854]
[20:25] johnnyfive|work (~sharkt@70.89.126.174-BusName-Washington.hfc.comcastbusiness.net) left irc: Read error: Connection reset by peer
[20:25] johnnyfive|work (~sharkt@70.89.126.174-BusName-Washington.hfc.comcastbusiness.net) joined #highaltitude.
[20:33] jasonb (~jasonb@dsl092-009-225.sfo1.dsl.speakeasy.net) left irc: Ping timeout: 252 seconds
[20:42] smealum (~smealum@85-171-205-215.rev.numericable.fr) left irc:
[20:47] jasonb (~jasonb@12.201.129.162) joined #highaltitude.
[20:52] natrium42 (~natrium@CPE000625d867e2-CM0014045885be.cpe.net.cable.rogers.com) joined #highaltitude.
[20:55] Hiena (~Hiena@81.93.195.181.datatrans.hu) left irc: Quit: -=Got bored from the net. Gone blowing up things.=-
[21:17] nv1k (81bac07b@gateway/web/freenode/ip.129.186.192.123) left irc: Quit: Page closed
[21:20] JetForMe (~JetForMe@nat/yahoo/x-ekqscpeojxyronuv) left irc: Remote host closed the connection
[21:22] m1x10 (m1x10@ppp089210139002.dsl.hol.gr) left irc: Remote host closed the connection
[21:27] <Laurenceb> eroomde: your MUSIC idea, i wonder if ANC would be more applicable
[21:28] <Laurenceb> using our existing distributed Rx system
[21:28] <Laurenceb> so listeners would stream audio to habhub where the ANC DSP code would run
[21:29] DagoRed (dago@j15-1.nat.iastate.edu) left #highaltitude ("Leaving").
[21:30] <Randomskk> ANC?
[21:31] <SpeedEvil> I would assume that comment is about HF?
[21:32] <SpeedEvil> As it seems unlikely to be able to beamform at 70cm
[21:36] <Laurenceb> adaptive noise cancelling
[21:40] <SpeedEvil> So you mean just correlation, not beamforming?
[21:40] <SpeedEvil> that's much easier
[21:41] <Randomskk> I guess the ANC concept could work really well, if the noise was different for each receiver but the incoming signal the same
[21:41] <Randomskk> I think the AGC would be the issue though
[21:41] <Randomskk> you don't get very much dynamic range after conversion to audio especially after the AGC
[21:41] <Randomskk> a strong noise signal - which they almost all are when the desired signal is 10mW and hundreds of km out - will totally wipe out the balloon
[21:42] <Laurenceb> true
[21:42] <Laurenceb> but itd help bring it out of the noise florr a huge amount
[21:43] <Laurenceb> ANC is much cleverer than just correlation
[21:44] <Laurenceb> http://www-isl.stanford.edu/~widrow/papers/j1975adaptivenoise.pdf
[21:44] <Laurenceb> good paper on it
[21:44] <Laurenceb> anyway, gtg
[21:44] Laurenceb (~laurence@host86-160-237-102.range86-160.btcentralplus.com) left irc: Remote host closed the connection
[21:46] <SpeedEvil> Oh - right - I was asuming this was using existing SSB recievers
[22:04] SpeedEvil (1000@tor/regular/SpeedEvil) left irc: Read error: Operation timed out
[22:06] Upu (~Upu@ubn.upuaut.net) left irc:
[22:08] LazyLeopard (~irc-clien@chocky.demon.co.uk) joined #highaltitude.
[22:15] stilldavid (~dave@68-64-214-18.static.forethought.net) left irc: Quit: Leaving
[22:18] SpeedEvil (~user@tor/regular/SpeedEvil) joined #highaltitude.
[22:21] fsphil (~phil@beastie.sanslogic.co.uk) left irc: Quit: Oh-No! *pop*
[22:23] natrium42 (~natrium@CPE000625d867e2-CM0014045885be.cpe.net.cable.rogers.com) left irc: Read error: Connection reset by peer
[22:35] SpeedEvil (~user@tor/regular/SpeedEvil) left irc: Ping timeout: 272 seconds
[22:37] SpeedEvil (~user@tor/regular/SpeedEvil) joined #highaltitude.
[22:45] LazyLeopard (~irc-clien@chocky.demon.co.uk) left irc: Quit: Bye
[22:50] LazyLeopard (~irc-clien@chocky.demon.co.uk) joined #highaltitude.
[22:52] chris_99 (~chris_99@unaffiliated/chris-99/x-3062929) joined #highaltitude.
[22:57] johnnyfive|work (~sharkt@70.89.126.174-BusName-Washington.hfc.comcastbusiness.net) left irc: Quit: Leaving
[23:05] LazyLeopard (~irc-clien@chocky.demon.co.uk) left irc: Quit: Bye
[23:13] SpeedEvil (~user@tor/regular/SpeedEvil) left irc: Quit: Leaving.
[23:13] SpeedEvil (1000@tor/regular/SpeedEvil) joined #highaltitude.
[23:58] natrium42 (~natrium@CPE000625d867e2-CM0014045885be.cpe.net.cable.rogers.com) joined #highaltitude.
[23:59] DagoRed (~dago@2610:130:102:1200:21c:b3ff:feb8:da45) joined #highaltitude.
[00:00] --- Fri Sep 24 2010