highaltitude.log.20080818

[00:12] <SpeedEvil> move it too fast?
[00:12] <SpeedEvil> rotational limit on the guyro?
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[08:51] <jcoxon> morning all
[08:52] <gordonjcp> jcoxon: morning
[08:52] <jcoxon> hey gordonjcp
[08:52] <jcoxon> good weekend?
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[09:08] <jcoxon> morning edmoore
[09:08] <jcoxon> stripped the canon down to 110g :-)
[09:08] <jcoxon> from 275g
[09:09] <jcoxon> they're really modular so you can remove sections such as the flash or the lcd screen by just undoing a few screws
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[09:40] <jcoxon> whooo got remote capture working
[09:47] <gordonjcp> http://oddstrument.com/2008/08/06/call-this-number/
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[16:55] <edmoore> hi jcoxon
[16:55] <edmoore> and fergusnoble
[16:55] <edmoore> and everyone
[16:55] <jcoxon> hey edmoore
[16:56] <edmoore> good news on the camera
[16:56] <edmoore> sorry for not replying earlier, have had a pretty hectic day
[16:56] <jcoxon> its not working now :-(
[16:56] <jcoxon> hehe, no worries
[16:56] <edmoore> oh?
[16:56] <jcoxon> might have taken it a little too far
[16:57] <edmoore> you need an svn
[16:57] <jcoxon> i'm thinking one of the flex connectors has come lose
[16:57] <edmoore> you could just back up to the previous revision
[16:57] <edmoore> a hardware svn
[16:57] <jcoxon> the time machine isn't working yet sadly
[16:57] <edmoore> think how much sculptors would like that
[17:00] <jcoxon> there hasn't been any magic smoke released
[17:00] <jcoxon> so i'm thinking its fixable
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[17:32] <jcoxon> damn it
[17:34] <jcoxon> i think this camera is bust
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[18:59] <jcoxon> hey edmoore
[19:04] <edmoore> i seem to have the world's slowest net connection, apologies in advance
[19:04] <jcoxon> hehe
[19:05] <edmoore> pinging google through laptop takes 104ms
[19:05] <Shanuson> you mean you are using trums?
[19:05] <edmoore> 30ms on server connected to same router
[19:05] <edmoore> server faster, but still ludicrously slow
[19:05] <edmoore> trums?
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[19:28] <fergusnoble> edmoore: hello
[19:28] <edmoore> hi
[19:29] <fergusnoble> how are things?
[19:29] <fergusnoble> discovered some cool stuff lying around in the lab today
[19:29] <edmoore> not bad, thought setting up wireless sharing is non trivial
[19:29] <edmoore> oh?
[19:29] <fergusnoble> like some solar sail material
[19:30] <fergusnoble> aluminised mylar 900A thick
[19:30] <fergusnoble> and a whole bunch of various thicknesses of kapton
[19:30] <SpeedEvil> Fun.
[19:31] <edmoore> that's always useful - stealable?
[19:31] <fergusnoble> prolly
[19:31] Action: SpeedEvil has used GPRS - 1000ms pings common.
[19:31] <fergusnoble> i dont think there is anyone working there anymore
[19:31] <edmoore> in the clave room?
[19:32] <fergusnoble> edmoore: certainly can steal enough to try the cool chute construction idea
[19:32] <fergusnoble> yeah
[19:32] <SpeedEvil> under 1um seems impractical to fab with.
[19:32] <fergusnoble> SpeedEvil: was maning the kapton
[19:32] <SpeedEvil> ah.
[19:32] <fergusnoble> *meaning
[19:33] <fergusnoble> the solar sail stuff is really flimsy
[19:33] <fergusnoble> its like its not there
[19:33] <fergusnoble> i actually thought it was an empty box lol
[19:33] Action: SpeedEvil ponders gold leaf balloon.
[19:34] <edmoore> yeah, will be good to experiment with that
[19:34] <fergusnoble> http://www.youtube.com/watch?v=HZSkM-QEeUg
[19:34] <fergusnoble> started making the balloon making rig today
[19:35] <SpeedEvil> What do you do?
[19:35] <fergusnoble> as a job?
[19:35] <SpeedEvil> End up with a zig-zagged balloon rolled onto teh roller?
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[19:35] <fergusnoble> oh right - yup
[19:35] <SpeedEvil> Like an accordian?
[19:35] <edmoore> I think on a balloon we could be looking at about 1.8kN opening force for the ringslot with a mach 0.4 deployment
[19:35] <fergusnoble> its built up in layers yes
[19:36] <edmoore> 1.65m effective diameter
[19:36] <edmoore> as a comparison, I did some brief analysis on an equivalent cruciform parachute, whose openeing forces were about twice as high
[19:36] <fergusnoble> awesome, nice work
[19:38] <fergusnoble> brb
[19:38] <SpeedEvil> fergusnoble: so you roll it multiple times, adding one width of a feeder roll each time?
[19:38] <fergusnoble> yeah
[19:39] <edmoore> balloon = rocket
[19:39] <fergusnoble> the new layer goes on top, so you take the top ply of the old stuff, and weld to the bottom ply of the new sheet
[19:40] <SpeedEvil> fergusnoble: then just weld the 'other' edges, to get a complete tube?
[19:40] <fergusnoble> (each sheet is folded in half on the roll, so its like a v section)
[19:40] <fergusnoble> SpeedEvil: only have to weld on one side as the plastic comes on the roll folded in half
[19:40] <SpeedEvil> fergusnoble: Oh - I was assuming you were welding lots of rolls together.
[19:40] <SpeedEvil> fergusnoble: not just two
[19:40] <fergusnoble> we are
[19:41] <SpeedEvil> fergusnoble: I mean - once you have the zigzag stack, you need a final pass to join the top and the bottom
[19:41] <fergusnoble> 1 sec, ill show you
[19:41] <fergusnoble> oh right, yeah we do
[19:42] <SpeedEvil> Are you doing the top/base 'properly' - or just tying a knot in it?
[19:42] <edmoore> so what sort of state is the rig in?
[19:42] <fergusnoble> properly
[19:42] <fergusnoble> edmoore: just a frame so far
[19:42] <SpeedEvil> :)
[19:43] <fergusnoble> SpeedEvil: when i say properly, we have come up with a shortcut method that gives good results but still only needs streight welds
[19:43] <fergusnoble> so we dont cut it into curves or anything
[19:43] <SpeedEvil> Cone?
[19:43] <fergusnoble> no, its hard to explain
[19:43] <SpeedEvil> Or decagon or something?
[19:44] <fergusnoble> you make a starfruit
[19:44] <SpeedEvil> nvm. there are any number of ways to do it - it's what you can figure out how to make easily that's the hard part :)
[19:44] <fergusnoble> and then pinch it in at a certain place and it makes the top curve
[19:44] <fergusnoble> yeah, we can try some different things
[19:45] <SpeedEvil> http://en.wikipedia.org/wiki/Carambola ?
[19:45] <fergusnoble> yeah
[19:45] <fergusnoble> kinda like that
[19:46] <SpeedEvil> Hmm.
[19:46] <fergusnoble> the folds in the plastic are the concaves and the welds are the points of the sart
[19:46] <fergusnoble> *star
[19:46] <SpeedEvil> What if you simply chop the ends of the zigzag stack at a diagonal, and then join successive layers?
[19:46] Action: SpeedEvil tries to visualise 3D geometry.
[19:47] <fergusnoble> SpeedEvil: its basically that, plus another step which makes it curve better
[19:47] <fergusnoble> it cant really be explained in words very well
[19:47] <SpeedEvil> Why do you need a 'good' shape?
[19:47] <fergusnoble> we dont really
[19:47] <SpeedEvil> Does it really matter in other words.
[19:47] <SpeedEvil> As long as it doesn't leak :)
[19:48] <fergusnoble> mainly for use we want to increase the radio of surface area to volume
[19:48] <fergusnoble> that makes a better performance balloon
[19:48] <fergusnoble> obv a sphere is the best
[19:48] <SpeedEvil> First assume a spherical horse.
[19:49] <fergusnoble> if you have heavy payloads you need to take into account the distn of load through the film and then you end up with the 'natural' (hot air balloon) shape
[19:49] <SpeedEvil> Stress concentrations are bad.
[19:49] <fergusnoble> but our payload is light compared to the tensile strength of the film
[19:49] <SpeedEvil> and I suppose a perfect shape avoids that as much as possible.
[19:49] <SpeedEvil> Yeah.
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[19:50] <SpeedEvil> it'd be a problem if you filled it on the ground and were trying to fly a lawn-chair.
[19:50] <fergusnoble> ill get iain to upload a photo we took of all our test shapes i nthe same room together
[19:50] <SpeedEvil> :)
[19:50] <fergusnoble> it looks cool
[19:51] <edmoore> gah, i hate bloody wireless on linux
[19:51] <SpeedEvil> Worked out the film you're going to use?
[19:51] <edmoore> right, going out to play some sport. this arsing thing can wait
[19:52] Action: SpeedEvil passes edmoore a wire.
[19:52] <fergusnoble> yeah, were going to buy some of the stuff andy elson had left over from the qinetiq balloon
[19:52] <fergusnoble> was specially made for zp duty
[19:53] <fergusnoble> tbh, its not that critical
[19:53] Action: SpeedEvil ponders where the ozone layer is.
[19:53] <fergusnoble> any PE sheeting will do
[19:53] <fergusnoble> somewhere between 10-30u
[19:53] <edmoore> fergusnoble: cool. We could have an unofficial wiki-ish site on this server
[19:53] <edmoore> cusf come badgerworks
[19:53] <edmoore> or infact just on srcf
[19:54] <fergusnoble> ok
[19:54] <SpeedEvil> Ah. 10-50Km. So balloons are not totally through it.
[19:54] <fergusnoble> iain is going to email the photo in a couple of hours, he is eating now
[19:54] <fergusnoble> SpeedEvil: worried about UV effects?
[19:55] <SpeedEvil> fergusnoble: wondering about it
[19:55] <SpeedEvil> fergusnoble: even at 30Km, it's attenuating very short UV by 10^6
[19:55] <SpeedEvil> http://upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Ozone_solar_UV_absorb_DNA_action.jpg/300px-Ozone_solar_UV_absorb_DNA_action.jpg
[19:56] <fergusnoble> its not up there for that long either
[19:56] <SpeedEvil> Nope.
[19:56] <SpeedEvil> What are you hoping for - a week?
[19:56] <fergusnoble> a few hours?
[19:57] <SpeedEvil> Ah.
[19:57] <fergusnoble> something like that
[19:57] <edmoore> fergusnoble: this'll be a cool mission http://www.pegasushabproject.org.uk/wiki/doku.php/missions:haps:haps-1
[19:57] <fergusnoble> i think the film andy has was made up without any uv stabilisers added as it helps the weld consistency
[19:57] <fergusnoble> edmoore: yeah im excited
[19:58] <SpeedEvil> fergusnoble: I have a hard time imagining it degrading much before a week anyway.
[19:58] <fergusnoble> yeah
[19:58] <edmoore> you'd have though helium diffusion out of it would become a pita more quickly than UV degradation
[19:59] <fergusnoble> edmoore: yup
[19:59] <fergusnoble> you'd need lots of ballast for a week
[19:59] <SpeedEvil> I wonder if hydrogen diffuses slower.
[19:59] <SpeedEvil> Or faster.
[19:59] <fergusnoble> i think SNOX is almost entirely ballast
[19:59] <edmoore> though on the couple of occassions that I have used latex balloons that have been on the ground for several hours (or more) on very bright summers days, they have either burst lower than expected or spontaneously
[19:59] <fergusnoble> SpeedEvil: would be a bit quicker
[20:00] <edmoore> we left one overnight once after a day of tests that died about 8km prematurely
[20:00] <edmoore> SpeedEvil: you'd anticipate faster as it's smaller
[20:00] <fergusnoble> SpeedEvil: but the molecule is a similar size i think
[20:00] <edmoore> but thyere could be some other factors which I've not considered
[20:00] <SpeedEvil> edmoore: H2
[20:01] <fergusnoble> if you were using hydrogen you could fly a chemical hydrogen generator
[20:01] <fergusnoble> to top it up
[20:01] <SpeedEvil> fergusnoble: I was thinking of that.
[20:01] <SpeedEvil> fergusnoble: most ones that I've thought of they have problems freezing.
[20:01] <fergusnoble> SpeedEvil: very true
[20:01] <SpeedEvil> fergusnoble: for example, lye+Al, the lye freezes.
[20:01] <fergusnoble> yeah, most things need water
[20:02] <edmoore> oh good point
[20:02] <edmoore> that would be the factor which I haven't considered
[20:02] Action: SpeedEvil ponders Na+Ka eutectic dropped onto ice.
[20:02] <SpeedEvil> K
[20:03] <fergusnoble> ok, i really must go skype the welding machine supplier
[20:03] <fergusnoble> brb
[20:03] <SpeedEvil> Wave.
[20:06] <edmoore> fergusnoble: data point 4 u: >80g peak deceleration on chute deployment
[20:06] <edmoore> so greater forces than boost
[20:07] <fergusnoble> ooh, thats a big yank
[20:07] <edmoore> yup
[20:07] <edmoore> with a very low opening foces design
[20:07] <fergusnoble> for subsonic deployment?
[20:08] <fergusnoble> how did you decide the q at opening?
[20:09] <edmoore> 0.4M
[20:09] <edmoore> i.e mach 0.4
[20:09] <edmoore> reefing is an option, but adds complexity
[20:09] <edmoore> anyhoo, am off. bbl
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[20:25] <fergusnoble> bastards, slackers!
[20:25] <fergusnoble> its too late to do anything about my query apparently
[20:26] <fergusnoble> its only 3pm there
[20:26] <fergusnoble> :)
[20:26] <fergusnoble> http://vimeo.com/1549681
[20:27] <fergusnoble> ^^^ just got this video through today
[20:30] <akawaka> holy shit thats awesome
[20:31] <fergusnoble> http://vimeo.com/1549703 - the directors cut :)
[20:35] <akawaka> the finish is awesome, thats with no polishing?
[20:35] <fergusnoble> thats how it came off the machine
[20:35] <fergusnoble> it looks better in the video
[20:36] <fergusnoble> than in real life, but yeah they did a good job
[20:38] <Hiena> fergusnoble, good choose of the music. ;)
[20:39] <fergusnoble> i didnt make it, it was the guys at the machine shop
[20:39] <fergusnoble> but yeah
[20:57] <Shanuson> whats the name of the band of that song?
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[22:09] <G8KHW> FYI - Rapid Electronocs has a sale on from mid day tomorrow to mid day Thursday - where end column pricing applies (i.e. 10+ 100+ or 1000+ pricing)
[22:20] <fergusnoble> if only they did mechanical components :(
[22:20] <fergusnoble> anyone know a place to get timing belts and pulleys etc?
[22:21] <fergusnoble> RS want a ridiculous amount
[22:24] <G8KHW> rarnell are normally a bit cheaper
[22:24] <G8KHW> farnell
[22:44] <jcoxon> evening all
[22:50] <jcoxon> fergusnoble, G8KHW, you guys around this weekend?
[22:50] <fergusnoble> yup
[22:51] <jcoxon> coolio
[22:51] Action: jcoxon checks the weather
[22:52] <jcoxon> looks okay
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[22:54] <fergusnoble> jcoxon: yeah sunday looks the best
[22:54] Action: Laurenceb collapses into his chair
[22:54] <Laurenceb> hi folks
[22:54] <gordonjcp> what time are you planning on launching?
[22:55] <Laurenceb> launching on sunday? cool
[22:55] <jcoxon> ummm it'll depend a bit on the weather
[22:55] <gordonjcp> ok
[22:55] <jcoxon> but 10am
[22:55] <Laurenceb> good luck
[22:55] <jcoxon> give as much time to search as poss
[22:55] <jcoxon> thanks
[22:55] <Laurenceb> :P
[22:55] <gordonjcp> I've got about half an hour's drive to the spot I want to try and RX from
[22:55] <jcoxon> oh cool
[22:55] <jcoxon> just building the backup beacon now
[22:55] <gordonjcp> that reminds me, I'd better fix the car
[22:55] <Laurenceb> gordonjcp: where are you?
[22:56] <gordonjcp> Laurenceb: Glasgow
[22:56] <fergusnoble> jcoxon: what happened to the photos on natrium's tracker?
[22:56] <Laurenceb> well if you get it from there that would be amazing
[22:56] <gordonjcp> I figured that if jcoxon can hear it from London with just a handie with a rubber duck, I can have a crack with a decent-ish yagi
[22:56] <gordonjcp> Laurenceb: I don't know if I'll hear it, but it's got to be worth a shot
[22:57] <Laurenceb> tuning could be tricky
[22:57] <gordonjcp> why's that, how stable is the TX?
[22:57] <Laurenceb> but if you have experience, guess its a lot easier
[22:57] <jcoxon> fergusnoble, ummm, they've been deleted :-)
[22:57] <Laurenceb> it can vary by a few hundered hz
[22:57] <Laurenceb> but slowly
[22:57] <gordonjcp> Laurenceb: pff
[22:57] <Laurenceb> :D
[22:57] <gordonjcp> Laurenceb: that's what AFC is for
[22:57] <Laurenceb> yeah
[22:58] <fergusnoble> gordonjcp: we have had some drift a lot, some not so much, depends on how well insulated they are
[22:58] <Laurenceb> yeah - in my experience a few hundered
[22:58] <Laurenceb> KHz max
[22:58] <jcoxon> out of everything the beacon will be the easiest to pick up
[22:58] <jcoxon> then probably sstv
[22:58] <Laurenceb> but I was keeping them warm
[22:58] <gordonjcp> few hundred *kHz*?
[22:58] <Laurenceb> no hertz
[22:58] <gordonjcp> well, I can tune in 5kHz steps
[22:59] <Laurenceb> yeah - you sometimes have to retune as it drifts outside the range of the soundcard
[22:59] <Laurenceb> ie ~ 1 to 5 Khz depending on the software modem/protocol
[23:00] <gordonjcp> thought it was AFSK?
[23:00] <Laurenceb> well time to get my ram use down
[23:00] <Laurenceb> yes
[23:00] <Laurenceb> but you transmit fm
[23:00] <Laurenceb> and recieve using ssb
[23:01] <Laurenceb> which downconverts your fm down to audio frequency
[23:01] <gordonjcp> hm, I don't have ssb
[23:01] <gordonjcp> hang on, that makes no sense
[23:01] <Laurenceb> jcoxons sstv might be different
[23:01] <gordonjcp> if you're using AFSK then you transmit audio frequencies over FM
[23:01] <jcoxon> Laurenceb, actually i'm doing fm
[23:01] <jcoxon> no ssb
[23:01] <gordonjcp> and what you receive, you receive with an FM receiver as audio tones
[23:01] <Laurenceb> ah
[23:02] <gordonjcp> you'd only use SSB if you were doing FSK, where you shift the carrier
[23:02] <Laurenceb> well with our 300 baud technique we just use afsk software on the ground
[23:02] <Laurenceb> the transmission is fm
[23:02] <Laurenceb> but thats not what jcoxon is using
[23:03] <G8KHW> We have been using FSK for most flights - AFSK on Nova 1
[23:05] <gordonjcp> ok, so fsk not afsk, for which I'd need an ssb receiver?
[23:05] <G8KHW> - but not for this flight (as I understand it)
[23:05] <jcoxon> yeah not this flight
[23:05] <G8KHW> AFSK + SSTV?
[23:05] <gordonjcp> ok
[23:06] <jcoxon> i've been testing it using FM on my reciever
[23:06] <gordonjcp> hm, I'll need some sstv software
[23:06] <gordonjcp> I may just record what I grab to minidisc and decode later ;-)
[23:06] <G8KHW> AFSK packet
[23:07] <G8KHW> and presumably Audio SSTV
[23:07] <G8KHW> ?
[23:07] <G8KHW> whatever thats called
[23:08] <jcoxon> gordonjcp, i recommend truetty for the packet
[23:08] <jcoxon> it seems to work well
[23:09] <G8KHW> jcoxon - for the SSTV are you receiving it with FM or SSB?
[23:09] <jcoxon> FM
[23:09] <gordonjcp> jcoxon: think that's Windows though
[23:09] <jcoxon> oh you on linux
[23:09] <jcoxon> it runs in wine
[23:09] <gordonjcp> oh ok
[23:10] <gordonjcp> I might port multimon to jack ;-)
[23:10] <gordonjcp> well, either jack or pulseaudio
[23:10] <jcoxon> :-)
[23:11] <gordonjcp> let it share the audio in with other apps
[23:11] <jcoxon> oh also i could then run it on mac os x
[23:11] <gordonjcp> that way I can just dump a raw audio capture, and run various decoders
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[23:12] <fergusnoble> edmoore: http://vimeo.com/1549703
[23:14] <edmoore> wicked
[23:15] <edmoore> vimeo account details in the text file?
[23:15] <edmoore> </admin nazi>
[23:16] <fergusnoble> edmoore: they are in there
[23:16] <fergusnoble> also: http://www.srcf.ucam.org/~cuspaceflight/images/PICT0018.JPG
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[23:17] <fergusnoble> SpeedEvil: this is the photo of the balloons
[23:18] <edmoore> number 3 looks good to me
[23:18] <edmoore> well, and the beautiful squid :)
[23:18] <fergusnoble> yeah, iain and i think no.3
[23:18] <jcoxon> they look really good
[23:19] <fergusnoble> although the huge pillow on the right is very comical
[23:20] <fergusnoble> edmoore: they only too iain a day each on his own
[23:20] <fergusnoble> doing it all manually
[23:20] <edmoore> yeah, fairly conclusive
[23:20] <edmoore> 3 looks the most promising to me
[23:20] <fergusnoble> yeah
[23:20] <edmoore> oh right, you said that
[23:20] <edmoore> sorry was on phone
[23:21] <edmoore> well yeah, I guess volume/surface area ratio + stress concentrations are the two criteria, and 3 clearly wins
[23:21] <fergusnoble> although there are things to be said for the pillow
[23:21] <G8KHW> jcoxon: I should be OK for the weekend - I'll book the site later in the week
[23:22] <fergusnoble> jcoxon, G8KHW: we have a new full bottle of He at Churchill iuw
[23:22] <fergusnoble> too big to transport, but yo could launch there instead
[23:22] <edmoore> jcoxon: are you looking to launch?
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[23:23] <jcoxon> edmoore, yeah
[23:23] <jcoxon> hmmmmho, the age old question
[23:23] <edmoore> what's that?
[23:23] <jcoxon> EARS vs Churchill
[23:24] <G8KHW> jcoxon: have you got the code for the JPG to SSTV converter?
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[23:24] <jcoxon> G8KHW, yup
[23:24] <jcoxon> http://fkurz.net/ham/sstvtx.c
[23:24] <G8KHW> at ta
[23:24] <jcoxon> if it could be made to go a bit quicker...
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[23:25] <edmoore> churchill has helium. ears has ears
[23:25] <edmoore> fergusnoble: some of the best money I ever spent was on a kurt machining vice
[23:26] <jcoxon> is it a hassle to get permission for churchill?
[23:26] <fergusnoble> no, we have a notam
[23:26] <jcoxon> oh i know that, i meant the college itself
[23:26] <fergusnoble> all we have to do is notify the grounds manager
[23:28] <fergusnoble> what size balloon are yo going for btw?
[23:28] <edmoore> it's easy
[23:28] <jcoxon> 1.2
[23:28] <edmoore> that's not a consideratiuon, we just send an email
[23:28] <G8KHW> jcoxon: thats an amazingly simple prog
[23:29] <edmoore> and assuming they don't have a wedding on or something, it's all gravy
[23:29] <edmoore> or a sheduled heli landing
[23:29] <jcoxon> it did take him an hour of so to right
[23:29] <edmoore> right, back in about half an hour
[23:29] <jcoxon> write*
[23:29] <edmoore> fergusnoble: very cool vids
[23:29] <edmoore> am getting proper excited
[23:33] <G8KHW> jcoxon - do you know what takes all the time (WAV production i suspect)
[23:34] <G8KHW> I gess it should be pretty pplatform independent if its file in file out
[23:35] <jcoxon> G8KHW, i'm not sure what takes the time
[23:35] <jcoxon> could floating point be an issue?
[23:37] <fergusnoble> G8KHW: tried running it through gprof?
[23:38] <G8KHW> yeah - i was going to suggest a profiler
[23:38] <G8KHW> so it only accepts 320x256 JPGs?
[23:39] <jcoxon> yeah
[23:39] <jcoxon> well i said that i could do the resizing myself
[23:40] <jcoxon> and 320x256 is the sstv standard
[23:40] <G8KHW> thats OK - just trying to work out where the CPU is likly to be goinging
[23:41] <G8KHW> since its not converting the JPG much - thwn I stick with my 1st guess
[23:41] <jcoxon> i've spoken to teh QSSTV guy about a command line version (as i reckon his code would be more optimised)
[23:43] <G8KHW> Its in 2 distinct phases 1) read in JPEG into memory array 320x256 x RGB
[23:43] <G8KHW> convert memory array to wav file (add sync pulses etc)
[23:44] <G8KHW> should be easy to profile
[23:45] <fergusnoble> G8KHW: the loop with comment "find back to old phase" could be made a lot quicker i think
[23:45] <G8KHW> even some printfs with time would show you the elapsed time e.g. printf("%ld",time(0l));
[23:46] <fergusnoble> should be able to do it in one
[23:46] <fergusnoble> rather than several steps
[23:48] <fergusnoble> i = ceil(sstv->phase * sstv->samplerate / (2.0*M_PI))
[23:48] <fergusnoble> calculate phase as before
[23:49] <fergusnoble> might shave a bit off as its done every pixel
[23:51] <G8KHW> just trying to work out what its doing - suspect its changing the frequency for a new pixel - but aliging the phase
[23:52] <fergusnoble> i dont know what it does :) but i think doing that is equivalent
[23:53] <G8KHW> ah - I was trying to work out what it does - so I can write it my way - which will be better ;-)
[23:53] <jcoxon> haha
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[23:53] <jcoxon> well the guy who wrote it is on #hamradio
[23:54] <jcoxon> dj1yfk is his nick
[23:54] <G8KHW> ah well cu guys - night
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[23:55] <natrium42> hi
[23:55] <jcoxon> hey natrium42
[23:58] <fergusnoble> jcoxon: can you see if that change helps the speed? i cant compile it on os x
[23:59] <fergusnoble> see if it doesnt break it
[23:59] <fergusnoble> :)
[23:59] <natrium42> what's new?
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[23:59] <jcoxon> fergusnoble, will try it in a couple of minutes
[23:59] <jcoxon> just finishing this beacon
[23:59] <fergusnoble> ok, cool beans
[23:59] <natrium42> jcoxon, what's the weather forecast?
[00:00] --- Tue Aug 19 2008