highaltitude.log.20090109

[00:01] <edmoore> gordonjcp: had to pick up friend and drive to a specific pub
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[01:20] <Laurenceb> hello
[01:21] <Laurenceb> does anyone know about rocket noise?
[01:22] <Laurenceb> I understand the vibrations have a certain frequency distribution
[01:22] <Laurenceb> but I'm still confused when it comes to MEMS IMU interference
[01:23] <Laurenceb> can anyone explain how to look at this? is there some other property I need to consider? like coherence lenght or something?
[01:27] <SpeedEvil> It shakes the rocket lots.
[01:27] <Laurenceb> lol
[01:27] <Laurenceb> ok... so we have white noise
[01:27] <Laurenceb> thats the sensor
[01:27] <SpeedEvil> So any lack of perfect integration, or cross-coupling of axes gets into your position
[01:27] <Laurenceb> I get that much
[01:28] <SpeedEvil> Or sampling skew, or ...
[01:28] <Laurenceb> yeah, but does the noise itself get in?
[01:28] <SpeedEvil> ?
[01:28] <Laurenceb> I mean its no pure random noise
[01:28] <SpeedEvil> accoustic
[01:28] <Laurenceb> its caused by turbulence
[01:28] <Laurenceb> so its predictable to an extent
[01:28] <SpeedEvil> accoustic vibrations in the structure, accellerations of the whole structure, and buffeting caused by aero forces.
[01:29] <Laurenceb> I'm not sure how much its going to effect the accel drift, or how to model it
[01:29] <SpeedEvil> you need to work out how much noise you'll get.
[01:29] <Laurenceb> the nebula prize guy thinks you can use MEMS to orbit, I'm trying to work out if thats true
[01:29] <SpeedEvil> Which is probably damn hard waithout either a full simulation, or ...
[01:29] <Laurenceb> certainyl with just sensor noise your fine for +-10Km orbit insertion
[01:29] <SpeedEvil> MEMS accelerometers and gyros only?
[01:30] <Laurenceb> yes
[01:30] <Laurenceb> and a "strapdown" approach
[01:30] <SpeedEvil> Hmm.
[01:30] <SpeedEvil> I'd want magnetometers and sun sensors too I think.
[01:30] <Laurenceb> it works for me with the sparkfun 5DOF IMU
[01:31] <Laurenceb> 70m drift after 90 seconds
[01:31] <SpeedEvil> well - yes...
[01:31] <Laurenceb> but hteres no engine attatched to it :P
[01:31] <SpeedEvil> Now, try that but instead of having it static, whirl it round and round.
[01:32] <SpeedEvil> Or attach it to a very large speaker playing Macarena.
[01:32] <Laurenceb> lol
[01:32] <SpeedEvil> Also.
[01:32] <SpeedEvil> 90 seconds is only sensible for a large rocket - if launched from the ground.
[01:32] <Laurenceb> sure
[01:33] <Laurenceb> but it rises with t^2 approx
[01:33] <SpeedEvil> you want to be going for _much_ slower ascent to keep your fuel usage down.
[01:33] <Laurenceb> I dont mind +-10Km
[01:33] <SpeedEvil> ~mach 1 till 5-15Km, depending on size.
[01:33] <SpeedEvil> Otherwise drag goes simply stupid.
[01:35] <Laurenceb> thing is there isnt much you can do about accel noise
[01:35] <SpeedEvil> Of course there is.
[01:35] <SpeedEvil> You integrate it properly.
[01:36] <Laurenceb> as in sample rate >> bandwidth ?
[01:36] <SpeedEvil> yes
[01:36] <SpeedEvil> Or proper filtering that achieves the same effect
[01:36] <Laurenceb> well yeah, I think you need to add some external analogue filtering
[01:37] <SpeedEvil> Also - I'd be worried about spikes.
[01:37] <SpeedEvil> What's your accelerometers going to?
[01:37] <SpeedEvil> - the limits
[01:40] <Laurenceb> not sure ADXL330 is +-6G IIRC
[01:40] <Laurenceb> bbl
[01:40] <SpeedEvil> I'd be worried about spikes outside that
[01:40] <SpeedEvil> too
[01:40] <SpeedEvil> wave
[01:59] <Laurenceb> those shouldnt be real
[02:00] <Laurenceb> but could the low pass filtered version screw things up...
[02:04] <Laurenceb> say theres a smooth acceleration "bump" in one direction, then a spike in the other
[02:05] <Laurenceb> the spike will be filtered out, resulting in a net acceleration
[02:13] <Laurenceb> oh well I'm off, cya
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[10:35] <rjharrison_> testing tracker
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[11:15] <Xenion> Good Morning / Guten Morgen :-)
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[11:28] <rjharrison> .
[11:28] <rjharrison> Cool
[11:28] <rjharrison> back in the office
[11:28] <rjharrison> Just been playing with the tracker
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[11:43] <rjharrison> ?
[11:43] <rjharrison> Weird
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[11:48] <rjharrison> h ed
[11:48] <rjharrison> hu
[11:48] <rjharrison> hi
[11:48] <rjharrison> haha
[11:49] <rjharrison> edmoore any chance of a lunch this w/e
[11:49] <rjharrison> launch
[11:50] <edmoore> don't know yet. emails are still coming in from others with yes/no
[11:50] <edmoore> i would probably er on the side of doubtful
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[11:57] <rjharrison> Ok but there is an outside potential
[11:57] <edmoore> it's been talked about, but given everyone has only just got back, it might be a bit tight
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[12:24] Nick change: edmoore_ -> edmoore
[12:36] <rjharrison> back
[12:36] <rjharrison> Lunch
[12:37] <rjharrison> edmoore I got fldigi working under linux last night
[12:37] <rjharrison> Need to do the same for eee
[12:37] <edmoore> what was the thing about controlling your radio?
[12:37] <rjharrison> I have got cat working with fldigi
[12:38] <rjharrison> It talks direct to the radio via hamlib
[12:38] <edmoore> hamlib...
[12:38] <rjharrison> Can just type in or move the freqency from the rig control screen
[12:39] <rjharrison> hamlib is library for radio coms
[12:39] <rjharrison> goggle
[12:39] <rjharrison> win fldigi come with it all compiled in
[12:39] <rjharrison> it makes vnc and radio tuning very easy
[12:40] <edmoore> just have - awesome
[12:40] <edmoore> is it built into fldigi?
[12:41] <rjharrison> yep
[12:41] <edmoore> ok, awesome
[12:41] <rjharrison> which makes it even nicer
[12:41] <edmoore> may have to add it to fnoble's tracker
[12:42] <rjharrison> With vnc running on my linux box at home I can contol everything and check that the data is being decodeed
[12:42] <edmoore> or see if we can swap fldigi's decoder with the one fnoble's tracker is based upon
[12:42] <rjharrison> Yep it's quite easy in that way when you don't have to do it yourself :)
[12:42] <edmoore> which has nice things like auto peak tracking
[12:42] <edmoore> waterfall would be good tooooo
[12:42] <edmoore> fnoble, ping for later
[12:42] <edmoore> i like xchat
[12:42] <rjharrison> I really like fldigi
[12:43] <edmoore> rjharrison, eee is bloody marvellous
[12:43] <rjharrison> call have you got wireless working>
[12:43] <rjharrison> ?
[12:43] <edmoore> out of the box
[12:43] <rjharrison> BTW how did you go about doing the install?
[12:43] <edmoore> made a usb install stick
[12:43] <rjharrison> There is no bood medium that I can see
[12:44] <rjharrison> boot
[12:44] <rjharrison> ok
[12:44] <rjharrison> and just shove it in
[12:44] <rjharrison> what have you gone for
[12:44] <edmoore> using a windows applet that puts ISOs on sticks
[12:44] <edmoore> tis described in the eeebuntu forum
[12:45] <edmoore> it's described in the eeebuntu forum
[12:45] <edmoore> whoops
[12:45] <edmoore> i went for eeebuntu 2.0 standard
[12:45] <rjharrison> ok
[12:45] <rjharrison> dloading now
[12:45] <rjharrison> that's the hard bit if I remember
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[12:52] <edmoore> after that i found one of those '13 things to do after installing ubuntu 8.10' guides that gives you the command line instructions to add all the appropriate repos and get the basic libraries in
[12:52] <rjharrison_> bloody vista
[12:52] <edmoore> all the 'non free' codecs like wmv, mp3 etc
[12:53] <edmoore> and a better flash engine
[12:54] <rjharrison_> btw edmoore did you go standard or base
[12:55] <edmoore> standard
[12:55] <rjharrison_> Cool
[12:55] <rjharrison_> dloading now
[12:55] <edmoore> thought about base but frankly, have got the room
[12:55] <edmoore> and compiz is kind of nice, in small doses
[12:59] <edmoore> rjharrison, if i hit the 'tune' function on fldigi, i seem to get about a 4hz clicking, on my eee
[13:02] <rjharrison_> humm
[13:02] <rjharrison_> not sure what the tune bit does
[13:02] <rjharrison_> never pressed
[13:02] <rjharrison_> it
[13:02] <rjharrison_> like the description 4hz
[13:03] <rjharrison_> are you getting audo in ok
[13:03] <rjharrison_> audio
[13:04] <fnoble> edmoore: here now
[13:06] <rjharrison_> edmoore's vanished :)
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[13:06] <rjharrison_> weird
[13:06] Nick change: rjharrison_ -> rharrison
[13:07] <edmoore> is back
[13:07] <edmoore> wondering if you saw hamlib
[13:08] <edmoore> simple pre-made library which gives a transparent api to tune, or whatever, most ham radios
[13:09] <fnoble> oh cool
[13:09] <fnoble> got a python lib?
[13:09] <edmoore> will have a look
[13:09] <fnoble> sweet
[13:09] <fnoble> got to love python
[13:09] <edmoore> certainly it had to be compiled when i got fldigi...
[13:09] <fnoble> it has bindings
[13:09] <edmoore> but may be python too
[13:12] <edmoore> looks like they're discussing it for hamlib v2
[13:12] <edmoore> rigserve
[13:13] <edmoore> hamlib pythonised
[13:13] <edmoore> sort of
[13:13] <edmoore> have a look
[13:14] <edmoore> is c++ that scary? can easily make a command line utility from it and plug that into the python program
[13:17] <edmoore> it's in c, even
[13:17] <fnoble> not at all
[13:17] <fnoble> just it is easier if you can use it directly
[13:17] <fnoble> not a show stopper if not
[13:18] <fnoble> im sure it even comes with some kind of basic command line utility anyway
[13:19] <fnoble> ok, need to get some work done
[13:19] <fnoble> bbl
[13:19] <edmoore> snap. packing time
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[14:11] <rharrison> not bat 40 mins to pack
[14:11] <rharrison> bad
[14:14] <edmoore> barely scracthed the surface
[14:14] <edmoore> though I'm trying to take back far less this time round
[14:21] <rharrison> Any one fancy a cross channel launch with a combined booze run?
[14:21] <rharrison> launch uk land france
[14:22] <rharrison> have to get the winds right
[14:34] <gordonjcp> rharrison: heh
[14:34] <gordonjcp> sounds fun!
[14:54] <Tigga_> doing my last pack for uni ever :(
[14:54] <edmoore> awwww
[14:55] <Tigga_> probably a good thing - I hate packing
[14:55] <Tigga_> :D
[14:56] <edmoore> same
[14:56] <edmoore> i think 'wow, manged to pack really light' and then there's a whole load of cusf crap
[14:57] <edmoore> I'm not actually complaining though
[14:57] <edmoore> wouldn't have it any other way
[15:03] <edmoore> rharrison: a french chase would be fun
[15:04] <edmoore> dad gets £1 chunnel crossings
[15:04] <edmoore> so it might be more economical to luanch from folkstone, fill up in france, and chase there
[15:14] <Tigga_> http://www.theregister.co.uk/2009/01/07/scotty_ashes_man_mars_shuttle_plan/
[15:14] <Tigga_> nutter plans to send shuttles to mars...
[15:14] <edmoore> reading the title of the url is probably suffient :)
[15:16] <edmoore> this guy is off his head
[15:16] <edmoore> nothing on the shuttle is designed for that kind of radiation, for one
[15:17] <edmoore> you can't just 'use a bigger parachute' to land on mars, 2
[15:17] <edmoore> infact, not worth it
[15:18] <Tigga_> it just doesn't work :P
[15:19] <edmoore> forwarded it to my old boss for a giggle
[15:20] <edmoore> http://img135.imageshack.us/img135/4861/9062ow3.jpg
[15:20] <Tigga_> fat people are taking over linux?
[15:20] <edmoore> my boss says
[15:20] <edmoore> 'Tosser'
[15:22] <Tigga_> you at work atm then? or a fast replying boss?
[15:22] <edmoore> skype
[15:22] <Tigga_> ah
[15:29] <rharrison> edmoore problem will be getting a launch spot
[15:29] <edmoore> rharrison: agreed
[15:29] <rharrison> 74% eebuntu
[15:29] <edmoore> cool
[15:29] <edmoore> it's good
[15:30] <rharrison> churchill on good winds
[15:30] <rharrison> havy you got fldigi to work yet?
[15:33] <edmoore> yes
[15:33] <edmoore> she works fine
[15:33] <edmoore> sudo apt-get install fldigi
[15:34] <edmoore> but i'd do the '10 things to do as soon as you install ubuntu' things first, just to get all the repos up and running
[15:36] <rharrison> I'v now got 2 eee's as one of the lads here dosn't use his
[15:36] <rharrison> :)
[15:36] <rharrison> 94%
[15:36] <edmoore> ha
[15:36] <edmoore> very nice
[15:36] <rharrison> 900
[15:37] <rharrison> not the 1k
[15:37] <edmoore> i went in between and got the 901
[15:37] <rharrison> did natrium42 finish that dev. last night ?
[15:37] <rharrison> :D
[15:37] <edmoore> dunno- would be impressive if he did!
[15:46] <edmoore> zeusbot would be useful as an interface to a landing predictor
[15:47] <rharrison> humm
[15:47] <rharrison> whats the root password?
[15:47] <rharrison> heh
[15:47] <rharrison> e
[15:54] Nick change: Bluenarf -> EI5GTB
[15:56] <fnoble> edmoore: we can do that
[15:56] <fnoble> what server is it running on?
[15:56] <edmoore> no, i mean our code
[15:57] <fnoble> i know
[15:57] <edmoore> it's not on any server as far as I know
[15:57] <edmoore> you have it on your eee, rob has it on his laptop
[15:57] <fnoble> zeusbot i mean
[15:57] <edmoore> oh right sorry
[15:57] <edmoore> james'
[15:57] <edmoore> hasn't been on my space for a fair while. but I enjoyed having him
[15:57] <fnoble> ok, so we can run our own programs on it
[15:57] <fnoble> cool
[15:58] <edmoore> we should get it on the svn at some point
[15:58] <edmoore> ours or ukhas'
[16:00] <edmoore> also, srcf isn't backed up. this isn't so cool
[16:00] <edmoore> maybe if we put my headless box in the dungeon?
[16:01] <gordonjcp> how much space do you need for backup?
[16:01] <edmoore> it has two identical drives, can rsync one t'other on cron. obviously they're next to each other so floods 'n' that
[16:01] <edmoore> gordonjcp: we can scale it - code = essential, <100MB, pics and vids from flights would be nice - but 10s of GB
[16:02] <gordonjcp> okay
[16:02] <gordonjcp> can't do *tens* of GB but I can give you a shell on my box in finland to pop code across to
[16:03] <edmoore> there should be enough machines floating about in cam - we can probably back up the srcf stuff onto the server in the dungeon
[16:03] <gordonjcp> well the offer's there ;-)
[16:03] <edmoore> thanks :)
[16:03] <edmoore> fnoble: thoughts?
[16:05] <fnoble> sounds good
[16:05] <fnoble> will have to get our end set up first though
[16:06] <edmoore> yep indeed
[16:06] <fnoble> need to educate the luddites of the group in the ways of the svn
[16:06] <edmoore> my only worry (not a big deal though really) is if they say 'you're asking too much' and want us to loose the svn from them aswell
[16:06] <edmoore> but it'd be good to get the website backed up too
[16:06] <edmoore> so i think worth asking them if they wouldn't mind letting is run a cron
[16:06] <fnoble> when i get bored of experimental methods examples i might get the prediction code into the svn
[16:07] <edmoore> that would be very useful
[16:07] <fnoble> edmoore: dont think they would say that
[16:07] <edmoore> it's frustrating having disparate things on different people's laptops
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[16:07] <edmoore> fnoble: thankfully for luddites, tortoise svn makes it super easy
[16:07] <fnoble> edmoore: our svn uses almost no traffic and very little space
[16:07] <gordonjcp> fnoble: it's worth checking *everything* into SVN, no matter how crap
[16:08] <gordonjcp> disk is cheap
[16:08] <fnoble> yeah, but you do need a bit of disipline to update before starting work and commit after finishing EVERY time
[16:08] <edmoore> well, within reason
[16:08] <edmoore> we're not a big group so its easier to amange
[16:08] <fnoble> gordonjcp: trouble is we have a few people writing code who arent up to speed with sing source management
[16:08] <rharrison> is the 10 things in the forum?
[16:09] <edmoore> rharrison: i think mine was a 13 things and on a blog
[16:09] <edmoore> but they usually amount to the same
[16:09] <edmoore> univers repos, codecs, 'non-free' stuff
[16:09] <edmoore> back to svn, we don't want people breaking stuff just cos they're experimenting one afternoon - teaching people about branches might be good
[16:10] <edmoore> basically, it's not disciplined or experienced programmers doing this :)
[16:11] <fnoble> yeah, or just to only commit code once youve got it working
[16:12] <fnoble> and to merge and fix any issues before finally commiting
[16:13] <fnoble> anyway, they are smart people, im sure they will be fine with it after a bit of prodding
[16:37] <edmoore> fnoble: i've read good things about this http://pysvn.tigris.org/
[16:39] <edmoore> but i guess *nix people know what they're doing anyway, and tortoise is the best thing for windows
[16:41] <fnoble> yeah
[16:41] <fnoble> the mac os thingy for svn is good too
[16:44] <edmoore> which thingy is that?
[16:44] <edmoore> i have just been using command line, and also SCPlugin - which just adds an svn menu on contextual clicks
[16:44] <edmoore> + textmate's built in
[16:48] <fnoble> scplugin, thats what i mean
[16:49] <edmoore> yeah, it's a neat little thing
[16:49] <edmoore> happy days
[16:51] <rharrison> can't you just shove the code on source forge or is it kind of secret?
[16:51] <edmoore> fnoble: I reckon we would benefit from another radio at CUSF - one that can be computer controlled and work with the ground station - what do you think? It would, in combination with track-a-tron, be a great asset for us and the distributed listener
[16:51] <rharrison> hehe
[16:51] <rharrison> cool
[16:52] <rharrison> May i suggest the ft817nd
[16:52] <edmoore> rharrison: that's what I had in mind :)
[16:52] <rharrison> Very nice and sensitive too
[16:52] <edmoore> :p
[16:52] <rharrison> And extreemally portable
[16:52] <fnoble> rharrison: the codes not secret, in fact it is publicly accessible at the moment
[16:52] <fnoble> although we dont publish how to get at it
[16:53] <fnoble> rharrison: not going with sf so we can have a bit more control but its basically the same system
[16:53] <edmoore> sf?
[16:53] <rharrison> Just thought that a public system can take care of the backup and stuff
[16:53] <fnoble> sourceforge
[16:54] <fnoble> rharrison: true, but it'll be fine when we get our act together a bit
[16:54] <rharrison> I'm going to shove the code out soon for Icarus
[16:54] <rharrison> + do some circuit digs.
[16:55] <edmoore> could the ukhas SVN run on trac or something?
[16:55] <edmoore> makes it accessible to new people
[16:55] <rharrison> I'm looking forward to the next launch come on CUSF
[16:56] <rharrison> or i'll be back up in the air before you
[16:56] <rharrison> :P
[16:56] <edmoore> there's a lot going on beyond launches atm!
[16:56] <rharrison> You'll all be back at work soon
[16:56] <rharrison> well study
[16:57] <edmoore> 100km is the goal, it takes a lot of ground work
[16:57] <rharrison> hehe
[16:57] <fnoble> rharrison: we are putting a lot of time into the zp welder atm
[16:57] <rharrison> I'm not going there
[16:57] <rharrison> Have you got permission to launch or are you going out of the uk?
[16:57] <fnoble> rharrison: made a balloon on it just before xmas
[16:58] <edmoore> almost certainly won't be able to do it in the UK
[16:58] <edmoore> it's a whole nuther scale of project
[16:58] <fnoble> rharrison: not sure what to do yet, will prolly launch it out over the north sea
[16:58] <rharrison> legal or space
[16:58] <edmoore> well, space is roughy
[16:58] <edmoore> woops
[16:58] <edmoore> legality is partly a function of space
[16:58] <fnoble> rharrison: just the zp i mean, not the biggun with the rocket
[16:59] <edmoore> oh right yes
[16:59] <rharrison> yep
[16:59] <rharrison> I menat the zp
[16:59] <edmoore> oh, uk then
[16:59] <rharrison> zp = north sea
[16:59] <rharrison> or can you launch from uk land ?
[16:59] <fnoble> rharrison: is your next launch going to be your zp?
[17:00] <edmoore> rharrison: i think we were planning on having it come down in the sea
[17:00] <fnoble> rharrison: its a grey area, i think it would be fine on land
[17:00] <rharrison> Humm I think I'll have a problem with legal launch
[17:00] <fnoble> rharrison: its not really illegal
[17:00] <fnoble> rharrison: just if anyting happens you will be in real trouble
[17:00] <rharrison> We'll it's a toy and the sting might snap
[17:01] <fnoble> without insurance to pay off the angry victims
[17:01] <rharrison> But it would probably pop at 3k not 40k if it was full of air rather than a zp with helium in
[17:02] <rharrison> Does anyone insure?
[17:02] <fnoble> rharrison: were working on it but its hard
[17:02] <edmoore> rharrison: now That's a question
[17:02] <fnoble> rharrison: can get something for £700/launch :(
[17:02] <rharrison> Yep there is not enough money for them to be interested
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[17:02] <edmoore> fnoble: not necessarily
[17:02] <fnoble> and thats not even explicitly for the zp
[17:03] <edmoore> that was my guess based on convos with them, on a very optimistic day
[17:03] <edmoore> basically the I question is a work in progress. I certainly wouldn't want to commit us to anything without a lot more work
[17:03] <edmoore> it's too damn expensive
[17:04] <rharrison> Insurance would be cool and I would be happier launching but I think it's going to be the major cost of any launch making it prohibative
[17:04] <fnoble> exactly
[17:04] <fnoble> im inclined to say that if we do everything we can to make it really safe then stuff the insurance
[17:04] <edmoore> For normal hab with sensibly weighed and designed payloads, i wouldn't bother
[17:04] <fnoble> but there are others who disagree
[17:05] <rharrison> The other option is to bugger off somewhere remote and reduce your chances
[17:05] <fnoble> yeah
[17:05] <edmoore> not cheap either
[17:05] <rharrison> But recovery would be a bugger
[17:05] <fnoble> the way i see it, insurance or not if we cause an incident thats the end of CUSF
[17:05] <edmoore> I'm quite happy to ditch into the sea for the time being
[17:05] <rharrison> Need a H'copter
[17:06] <rharrison> probably the end of HAB in the UK
[17:06] <rharrison> I wonder what the met office do
[17:06] <edmoore> oh they'd be absolutely fine
[17:06] <rharrison> They send up squillions of ballons
[17:06] <fnoble> they launch really small balloons
[17:07] <fnoble> dont ever do any harm
[17:07] <rharrison> <500g
[17:07] <rharrison> ?
[17:07] <fnoble> of that order i think
[17:07] <fnoble> certainly lots of the ex-met office stuff ive seen have been 300s and 500s
[17:07] <rharrison> Your payloads are a little bigger than mine ?
[17:07] <rharrison> :)
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[17:08] <edmoore_> whoops, power cut
[17:08] <edmoore_> yeah, the met office would cary on regardless
[17:08] <rharrison> Oh i didn't think they would stop but they must have had a few near misses
[17:08] <edmoore_> it'd only be an issue for amateur HAB for as far as we'd know that insurance was kind of necessary
[17:08] <fnoble> yeah, but my real point is that actually having insurance isnt going to save us if we cock up
[17:09] <rharrison> True
[17:09] <edmoore_> insurance allows you to cock up once - and not be broke
[17:09] <rharrison> You have the other benefit of having no assets
[17:09] <edmoore_> but yeah, it would certainly screw a dev program up
[17:09] <fnoble> edmoore: depends what the cockup is
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[17:09] <fnoble> edmoore: if we dent someones car the insurance will be handy
[17:09] <edmoore_> well, if it's a cock-up not covered by insurance, yeah
[17:10] <fnoble> but if someone gets injured were screwed both ways
[17:10] <edmoore_> but most insurance is good for a life
[17:10] <rharrison> Ie landing on the runway at stanstead
[17:10] <fnoble> rharrison: i dont think even our payloads would do much to an airplane
[17:10] <edmoore_> well we don't launch if there's a risk of that
[17:10] <fnoble> even if it went through the engine
[17:11] <edmoore_> the insurance we were quoted would probably let us injure someone and not go broke
[17:11] <fnoble> ok
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[17:11] <rharrison> I'm not that bothered nut if it hit the wing of a light aircraft or prop on the way down it may be a different story
[17:11] <edmoore_> but yeah, getting it a 2nd time round would be tough
[17:12] <fnoble> anyway, the big risk is the zp canopy coming down and covering something, like a road or a child or something
[17:12] <fnoble> i think tghats the main risk
[17:12] <edmoore_> agreed
[17:12] <edmoore_> i'm almost of the opinion we should leave it
[17:12] <fnoble> leave it?
[17:13] <edmoore_> and let it come down 1000 miles later
[17:13] <edmoore_> yeah
[17:13] <fnoble> as in dont fly it in the uk or dont bother with insurance?
[17:13] <edmoore_> no, cut away from the balloon and leave it
[17:13] <fnoble> edmoore: yeah we could always cut down the payload and let the balloon go into the sea
[17:13] <fnoble> but have the payload land on land
[17:13] <edmoore_> it won't last too long
[17:13] <edmoore_> yeah
[17:13] <edmoore_> like we used to do on early novas
[17:14] <SpeedEvil> There is a guidance about stuff on balloon payloads.
[17:14] <SpeedEvil> sectional density basically.
[17:14] <Tigga_> antartica!
[17:14] <SpeedEvil> as long as you're lighter than a duck, practically everything should more or less shrug it off AIUI.
[17:14] <edmoore_> that's it yeah
[17:15] <edmoore_> we're almost certainly less dense than a duck
[17:15] <rharrison> Well there are some clever ducks
[17:15] <fnoble> edmoore_: how about nitrating the zp canopy?
[17:15] <SpeedEvil> Also.
[17:15] <SpeedEvil> Duct-tape a chicken to the payload.
[17:15] <SpeedEvil> Then it's classed as a birdstrike.
[17:16] <edmoore_> nitrating?
[17:16] <SpeedEvil> flash!
[17:16] <SpeedEvil> ahahahha
[17:16] <fnoble> the thing you do to go from glycerine -> nitroglycerine or cellulose -> nitrocellulose
[17:17] <rharrison> I think payload cutdown is going to be the next project I work on
[17:17] <edmoore_> it may be that zp flights could have a tiny payload at the neck that waits for them to be over sea before trashing them
[17:17] <fnoble> yeah
[17:17] <edmoore_> 200g would be easily achievable, likewise £40
[17:17] <edmoore_> all up
[17:17] <SpeedEvil> O2/H balloons.
[17:18] <edmoore_> that's another solution :p
[17:18] <SpeedEvil> 93%H
[17:18] <SpeedEvil> it'd have nearly the same lift.
[17:18] <rharrison> You'll need boc to fill that baby
[17:18] <SpeedEvil> Plus, you don't need a cutdown.
[17:18] <edmoore_> rharrison: the pen tube method works pretty well, though of course there are thousands of ways to skin this particular cat
[17:18] Action: SpeedEvil likes the hot resistor method.
[17:18] <edmoore_> rharrison: we have a BOC account - easy :)
[17:18] <fnoble> i'd like to see jamie's face when we ask him to deliver us an explosive fill mixture
[17:18] <rharrison> I quite like the hot wire
[17:19] <fnoble> seeing as he is a dept h&s bod as well as the gas man
[17:19] <edmoore_> you need to make sure the piece of nylon you hot wire through it held still
[17:19] <edmoore_> otherwise all the swinging will fatigue the hot wire and break it
[17:19] <edmoore_> it work-hardens and then you have A Problem
[17:19] <rharrison> Yep that thought has occured to me
[17:20] Action: SpeedEvil prefers resistors specced for 350C operating temp.
[17:20] <rharrison> Have cunning plan for that
[17:20] <SpeedEvil> with nylon knotted round them.
[17:20] <edmoore_> rharrison: http://www.kd7lmo.net/hf-aprs_mechanical.html
[17:21] <edmoore_> an obvious and simple solution to that problem
[17:21] <rharrison> Well not very cunning but flexable attachment nylon both sides with a Resistor bridge
[17:22] <fnoble> when you're trying to work out the gain against frequency of an opamp non inverting amplifier with a cap in the feedback loop, do you use the real part or the modulus of the complex gain?
[17:22] <edmoore_> that HF-APRS board does nothing more than badger - in fact a bit less - but 70% of it is the epic amount of radio shizzle
[17:22] <edmoore_> it's almost a blessing we're limited to unlicensed stuff!
[17:22] <edmoore_> modulus
[17:23] <fnoble> edmoore_: thanks
[17:23] edmoore (n=edmoore@88-212-167-121.rdns.as8401.net) left irc: Read error: 110 (Connection timed out)
[17:23] <edmoore_> which reminds me, still got a lab report to do :(
[17:23] Nick change: edmoore_ -> edmoore
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[17:27] <edmoore> fnoble: am being silly. the cron job can run on the dungeon server can't it - and just ssh into the server and copy the cusf folder
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[17:27] <rharrison> opps
[17:27] <rharrison> who is CUSF these days
[17:27] <edmoore> about 10 people
[17:27] <rharrison> is there a list on your site
[17:27] <edmoore> me, fnoble , Tigga_ are on here
[17:28] <edmoore> hallam aswell
[17:28] <edmoore> no
[17:28] <rharrison> Ooh quite big then
[17:28] <edmoore> and then iain, rob, robert, dan, greg
[17:28] <edmoore> sal
[17:28] <rharrison> token female
[17:28] <fnoble> edmoore: that reminds me, we should strip all the specific names from our website
[17:28] <edmoore> really?
[17:29] <fnoble> yeah, its misleading, like everything at the moment goes to rob a
[17:29] <edmoore> oh i seee
[17:29] <edmoore> that kind of thing yeah, i agree
[17:29] <fnoble> it doesnt look proffesional either
[17:29] <edmoore> but not like in the news section :)
[17:29] <fnoble> no no
[17:30] <edmoore> well yeah, i did do that a bit ago on some pages
[17:30] <fnoble> and not like that it was founded by henry carl and rob f
[17:30] <edmoore> after emails to the mailing list were 'dear iain'
[17:30] <fnoble> we should get an agreement with the dept for them to recieve our mail
[17:30] <edmoore> i certainly agree with that
[17:30] <edmoore> a po box
[17:30] <fnoble> i think its easy to do, stores just hold it for you until you pick it up
[17:31] <edmoore> but for mail in general
[17:31] <edmoore> will ask RCF
[17:31] <fnoble> yup
[17:31] <fnoble> edmoore: well now on the contact page it says to contact rob a
[17:32] <edmoore> what with cusf.archive, they may be some merit to using the associated google docs account too
[17:32] <fnoble> edmoore: used to be iain, dont know who changed it to him
[17:32] <edmoore> that is silly - I changed it to nothing
[17:32] <edmoore> i guess people do want phone numbers
[17:33] <edmoore> but really everything should come to the list then one specific person can deal with it if necessary
[17:33] <fnoble> maybe its because the notam is in his name
[17:33] <edmoore> yeah
[17:33] <edmoore> I'm excited about having an expenses paid BOC account in my name :D
[17:34] <edmoore> all the possibilities.....
[17:34] <fnoble> yeah
[17:34] <fnoble> im sure it will be monitored though
[17:34] <edmoore> 'er.... need 15 bottles of hydrogen for elaborate practical joke'
[17:34] <edmoore> ha, yes ofcourse
[17:34] <edmoore> i'm jesting
[17:35] Action: SpeedEvil wants LOX.
[17:35] <edmoore> suitable paperwork/permission to transport the He would be very useful too
[17:35] <rharrison> Ooh are we not supposed to run arround with that stuff
[17:35] <SpeedEvil> it's a hazerdous thingy
[17:35] <edmoore> it's more a departmental thing, I think
[17:35] <rharrison> I had my big cylinder in the back of the car at the w/e
[17:36] <SpeedEvil> you're only supposed to transport it in a placarded vehicle AIUI
[17:36] <edmoore> you're meant to have the appropriate stickers for transport though
[17:36] <rharrison> i think it's 'cos of the lack of air bit
[17:36] <rharrison> Diving cylinders are fine
[17:36] <edmoore> I presume you went through dartford tunnel with your bottle, which is technically not quite kosher
[17:36] <SpeedEvil> With the right permits for transport of hazerdous stuff, special license.
[17:36] <SpeedEvil> IIRC
[17:36] <rharrison> Of couse i did
[17:36] <SpeedEvil> special driving license.
[17:36] <rharrison> I wasn't going to swim
[17:36] <rharrison> :)
[17:36] <rharrison> I did think about it
[17:37] <rharrison> and thought WTF
[17:37] <fnoble> i think its ok in general, its more because the dept is supplying it to us
[17:37] <edmoore> but actually if the account is no in the name of a private individual rather than through the dept, we may be able to jump that fence more easily
[17:37] <fnoble> edmoore: where are we going to move any of it though?
[17:37] <edmoore> rharrison: i'm quite sure it's fine - thousand of people must go through with party helium bottles and stuff all the time, without eclaring and getting the escort
[17:37] <rharrison> EARS
[17:37] <edmoore> fnoble: ears
[17:37] <edmoore> it's a better spot for testing
[17:38] <fnoble> churchill is just as good though
[17:38] <fnoble> maybe
[17:38] <rharrison> thats about it
[17:38] <SpeedEvil> edmoore: there is not enforced, and there is legal.
[17:38] <edmoore> defintely better fnoble
[17:38] <edmoore> for certain things
[17:38] <edmoore> like tethered balloon rocket launch
[17:38] <rharrison> I would like to do a churchill launch this year
[17:38] <SpeedEvil> edmoore: if someone in authority gets pissed off at you, you find out the differetnvce.
[17:39] <edmoore> churchill is fine for normal ballooing though, infact more convenient just because of the facilities
[17:39] <edmoore> but there's def stuff you can't do there that you can do at EARS
[17:40] <rharrison> Thinking about it our bigest exposure is probably a scratched car roof
[17:40] <edmoore> exposure?
[17:41] <SpeedEvil> Think of the children!!!!!!
[17:41] <rharrison> cost
[17:41] <rharrison> They are quite scratch proof
[17:41] <rharrison> i have three I can talk from experiance
[17:42] <rharrison> One biscuit and all fixed, scratched bonnet is more of a problem
[17:42] <edmoore> ears has another advantage in that if it goes in the standard norwhich direction, the first few km before you get out into countryside aren't over suburbia, like they are from churchill
[17:42] <edmoore> it's quite improbably that that would be an issue, though
[17:42] <rharrison> I aggree if you kill the child then you're in doodo
[17:43] <rharrison> Unless you bring down a microlight I agree with you
[17:43] <edmoore> that would be thier fault
[17:43] <edmoore> there's a notam
[17:43] <edmoore> :)
[17:44] <edmoore> hackaday has got really good recently
[17:44] <rharrison> right i'm off home
[17:44] <rharrison> I'm on a promise tonight as the wife wanted oysters.
[17:45] <rharrison> Can't stand them myself.
[17:45] <edmoore> sacrifices
[17:45] <rharrison> But if she can swallow those there's not much she won't swallow
[17:45] <edmoore> get a bottle of fizz - will make up for it
[17:45] <rharrison> So in other words I won't be on later
[17:45] <edmoore> we got the implication...
[17:46] <edmoore> have a good evening!
[17:46] <rharrison> Will do
[17:46] <rharrison> I won't be posting the pictures
[17:46] <rharrison> nights all
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[17:47] <fnoble> lovely man
[18:17] <SpeedEvil> Warm tomorrow.
[18:17] Action: SpeedEvil sighs.
[18:17] <SpeedEvil> means I have to get up on roof and concrete.
[18:20] <edmoore> it feels like -8 in cambridge tomorrow according to GFS
[18:22] <SpeedEvil> http://eddirt.frozenreality.co.uk/index.php?id=534 relevant cartoon is relevant.
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[19:12] <natrium42> hi
[19:14] <akawaka> hello
[19:14] <gordonjcp> SpeedEvil: lol
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[19:51] rjharrison (n=rharriso@80.176.172.227) joined #highaltitude.
[19:51] <rjharrison> injured
[19:51] <rjharrison> opening oysters
[19:51] <rjharrison> screwdriver almst through hand
[19:52] <rjharrison> ouch
[19:55] <fnoble> jesus sounds bad
[19:58] <edmoore> rjharrison: eeek - what's the damage?
[20:06] <rjharrison> can type one hand
[20:06] <rjharrison> puncture wound
[20:06] <edmoore> major eeek
[20:06] <edmoore> i guess that wasn't the dired outcome this evening
[20:06] <rjharrison> btween bones in hand
[20:06] <edmoore> that deep!?
[20:06] <rjharrison> yep
[20:07] <rjharrison> i hate f'ing oysters
[20:07] <edmoore> should have the champagne anyway
[20:07] <edmoore> will help with the pain
[20:11] <natrium42> rjharrison, :/
[20:11] <natrium42> at least you didn't pull a laurence
[20:13] <edmoore> what did laurence do?
[20:14] <natrium42> cut the tip of his finger off or something with a cutter
[20:14] <natrium42> had to be sewn on
[20:14] <edmoore> I don't remember that
[20:14] <edmoore> mind must be going
[20:14] <natrium42> that's what he told me, dunno
[20:14] <natrium42> :D
[20:15] <natrium42> pretty hard core
[20:15] <natrium42> i got superglue into my eye one time
[20:15] <natrium42> had to be scraped off with some tool
[20:16] <natrium42> x_o
[20:16] <natrium42> building is serious business
[20:17] <edmoore> yep!
[20:17] <edmoore> i've come pretty close to damamging myself on a lathe before
[20:18] <edmoore> made that mistake everyone makes only ever once - leaving the chuck key in the chuck and turning it on
[20:18] <edmoore> and this was on a Colchester Master 2500 - a fairly serious workshop lathe
[20:19] <natrium42> ouch
[20:21] <edmoore> thankfully it missed my head
[20:21] <edmoore> but only by a bit
[20:21] <edmoore> and that was about 1kg of steel, flung out by the chuck almost instantly accelerating to 625rpm
[20:21] <Hiena> edmoore, add a spring to the chuck key.
[20:22] <edmoore> Hiena: good idea. I don't work there anymore however
[20:22] <Hiena> It will eject automatically the key, when you left it in the lathe.
[20:23] <edmoore> yeah, i see the logic. sounds very sensible
[20:24] <Hiena> Also, i'm usually works on the far side of the lathe leaving at least half meter betveen me and the part.
[20:25] <edmoore> i should stand away from the radius of the chuck i guess
[20:25] <edmoore> i always instinctively do that with bench grinders
[20:25] <edmoore> When one of those breaks up during operation, it is really quite spectacular
[20:26] <Hiena> It could prevent the "coolant in the eye", "burr in the eye" stories.
[20:27] <Hiena> Oh, exploding grinding stones... These my favourites. I killed at least 20 during the last 25 year.
[20:28] <Hiena> Ususally, i'm works a very small parts and plates, and if these stuck in the bench grinder...
[20:39] <rjharrison> Back
[20:39] <rjharrison> Just had nice warm shower
[20:39] <rjharrison> My typing is crap any how so no difference there
[20:40] <rjharrison> I'm still on a promise
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[20:43] <rjharrison> So will be on and offf
[20:43] <rjharrison> balance between wife anf hab
[20:43] <rjharrison> hab is winning
[20:43] <rjharrison> :)
[20:43] <rjharrison> Where's the dr
[20:44] <edmoore> dr?
[20:44] <rjharrison> coxon
[20:44] <rjharrison> just when you need some medical help
[20:44] <rjharrison> Puncture wound with oyster shite
[20:45] <rjharrison> nice
[20:45] <edmoore> it's fri night
[20:45] <edmoore> prob has better things to be doing!
[20:45] <rjharrison> gf over
[20:45] <rjharrison> are there better things
[20:45] <edmoore> i'm not sure of his marital status
[20:49] <Xenion> Gute Nacht alle miteinander / Good Night sleep well ! :-)
[20:49] <rjharrison> +gf
[20:49] <rjharrison> !xyl
[20:49] <edmoore> that's some ham speak i refuse to pick up
[20:50] <rjharrison> combined actually u shoud u'stan !
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[20:51] <edmoore> ?
[21:02] <edmoore> rjharrison: so asside from coming along like a newbie and smashing the altitude record, without defering to elders and betters like any sensible newbie should, what's next on the agenda?
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[21:14] <natrium42> edmoore, how is the HABble?
[21:15] <edmoore> hobble
[21:15] <natrium42> high oltitude balloon?
[21:15] <edmoore> though maybe habble is better
[21:16] <natrium42> i want to do a ground tracker
[21:16] <natrium42> but not much time for that :S
[21:16] <edmoore> a pointing thing?
[21:17] <natrium42> right
[21:17] <natrium42> optical tracking
[21:17] <edmoore> oh right
[21:17] <edmoore> awesome
[21:17] <edmoore> that's what habble needs too
[21:17] <edmoore> for guide stars
[21:17] <rjharrison> ed just read comments
[21:18] <rjharrison> hehe
[21:19] <rjharrison> I'll try to behave more
[21:19] <rjharrison> It's more fun when you don't follow everything plus we all get a new take on things
[21:19] <rjharrison> I'm going for the budget badger
[21:20] <rjharrison> icaurs should be under 100 quid and servicable
[21:21] <natrium42> i worked some on the tracker, but nothing to show yet :P
[21:21] <rjharrison> natrium42 how is it going
[21:21] <rjharrison> hehe you beat me
[21:21] <natrium42> it's going to be very cool, though ;)
[21:21] <rjharrison> I was just going to ping u
[21:21] <edmoore> mmm, we were talking about cheap badger bits
[21:21] <edmoore> was thinking more like £50
[21:21] <edmoore> parts anyway
[21:21] <rjharrison> ahh
[21:21] <rjharrison> so it's not that expensive then
[21:21] <edmoore> we might need some basically disposable things
[21:22] <edmoore> badger is pretty cheap
[21:22] <rjharrison> or is that v 2
[21:22] <edmoore> currently it's very cheap - just the optional telit module that costs
[21:22] <rjharrison> Some how I thought badger was a bit more expensive
[21:22] <edmoore> more than everything else put together, and then some
[21:22] <rjharrison> yep
[21:22] <rjharrison> I have one but to preciouse to sned
[21:22] <rjharrison> send
[21:23] <rjharrison> Fox ing is cool
[21:23] <edmoore> it's not really an expensive thing - it has a good cpu. but arm's are quite a lot cheaper than avr's for a given mips
[21:23] <rjharrison> I guess i'm f'**ed if power goes
[21:23] <natrium42> bbl
[21:23] <rjharrison> ok
[21:24] <edmoore> infact arms are actually cheaper than avrs full stop, in quite a lot of cases - there are cortex m3 parts coming out now at like £2
[21:24] <edmoore> 70mhz 32bit processors
[21:24] <edmoore> amazing
[21:25] <edmoore> scary that my debit card as 30 times the processing speed and 200 times the memory of the apollo lunar module flight computer
[21:26] <rjharrison> hehe
[21:27] <edmoore> but yeah, hardware cost of badger is roughly the same - it's a lassen iq, sd card, radiometrix, and a few optional sensors. that's the nice thing about hab - the hardware is cheap and easy, it's mainly software
[21:30] Simon-MPFH (n=simon@phantom.mpfh.co.uk) left irc: "Leaving"
[21:39] <edmoore> RocketBoy: thanks for the email
[21:39] <edmoore> good news
[21:39] <edmoore> also thanks for the mic
[22:13] <rjharrison> .
[22:13] <edmoore> qua
[22:13] <rjharrison> back 4 a bit wife putting kids to bed
[22:13] <rjharrison> Finally
[22:13] Laurenceb (n=laurence@host86-133-67-102.range86-133.btcentralplus.com) joined #highaltitude.
[22:13] <rjharrison> Night about to start now
[22:13] <Laurenceb> hello
[22:13] <edmoore> lol
[22:13] <rjharrison> Hi Laurenceb
[22:13] <rjharrison> You wait
[22:14] <Laurenceb> greetings
[22:14] <rjharrison> onday you may have 3 kids
[22:14] <rjharrison> noe
[22:14] <rjharrison> one even
[22:14] Action: Laurenceb has spent all day in the attic
[22:14] <rjharrison> I put that down to injury
[22:14] <Laurenceb> not a nice place to spend your time
[22:14] <rjharrison> nice it's night time now you can come out
[22:14] <Laurenceb> lol
[22:14] <rjharrison> You you hand form the eves
[22:14] <edmoore> Laurenceb: it's your natural habitat]
[22:14] <rjharrison> hand
[22:14] <rjharrison> hang
[22:15] <edmoore> there's better gps signal there
[22:15] <Laurenceb> you have to balance on the rafters
[22:15] <Laurenceb> hehe
[22:15] <rjharrison> higher altitude too
[22:15] <Laurenceb> my plan was to use 4 sheets of fibreglass seperated by mylar
[22:15] <rjharrison> In the attic
[22:15] <Laurenceb> it works... kind of
[22:15] <rjharrison> cool
[22:16] <Laurenceb> the problem came when I decided to put them in cross ply
[22:16] <edmoore> Laurenceb: if
[22:16] <edmoore> whoops
[22:16] <Laurenceb> you can find the rafters to stand on through 30cm of fibreglass
[22:16] <Laurenceb> so... baboo poles
[22:17] <Laurenceb> which wasnt exactly easy
[22:18] <Laurenceb> rjharrison: yeah maybe some sort of climbing apparatus is needed
[22:19] <Laurenceb> oh well its almost finished now
[22:23] <rjharrison> cooking escallops now
[22:24] <rjharrison> i'll stop when it gets too much info
[22:24] <Laurenceb> lol
[22:24] <edmoore> plan
[22:24] <edmoore> after stabbing myself, i'd go for something safer
[22:24] <edmoore> like toast
[22:24] <Laurenceb> edmoore: can you help me understand the effect of rocket engine noise on a mems IMU?
[22:25] <Laurenceb> I'm a bit confused... basically can you say that the "noise" is real
[22:25] <edmoore> it's real
[22:25] <edmoore> it's not gaussian
[22:25] <Laurenceb> but that the measurements dont capture all frequencies ect
[22:25] <Laurenceb> so you get a measurement noise/error
[22:26] <Laurenceb> due to inability to capture the engine noise?
[22:26] <edmoore> you'd have to get a piezo gyro on it and log at several khz during a burn
[22:26] <edmoore> just to characterise it
[22:26] <Laurenceb> yeah...
[22:26] <SpeedEvil> The simplest case is if all your input noise is below nyquist, and does not excurse beyond the linear limits of the sensors.
[22:26] <edmoore> essentially, you'd hope most of it is beyonf cutoff of the sensors
[22:26] <edmoore> but there are gremlins
[22:26] <Laurenceb> from what I can see, for most engines its pink noise? (roughly)
[22:27] <edmoore> the proof masses in the mems themselves have resonant frequencies high beyond the bandwidth of the sensor
[22:27] <Laurenceb> yeah
[22:27] <edmoore> if you catch one of them, you're history
[22:27] <SpeedEvil> Shock mounting the accels may be of use, to low-pass-filter
[22:27] <edmoore> as much mehcanical assistance as possible would help i think, yeah
[22:27] <Laurenceb> with a scale frequency of in the order of 20 to 50 Hz ?
[22:28] <edmoore> scale frequency?
[22:28] <Laurenceb> exponential decay
[22:28] <Laurenceb> in magnitude/power with frequency
[22:29] <edmoore> i'm not sure
[22:29] <Laurenceb> from what I've seen, the noise for most large engines is roughly constant or dropping off with lowering frequency below 10Hz or that order
[22:29] <Laurenceb> then its pink noise anove that
[22:29] <SpeedEvil> well
[22:29] <SpeedEvil> It might start off like that.
[22:30] <edmoore> i wouldn't want to say without measuring
[22:30] <SpeedEvil> What it ends up as once your structure starts ringing...
[22:30] <edmoore> on the hybrid burns i've done, i've certainly heard fundamentals above that
[22:30] <Laurenceb> I did have some files for proton, ariane5 ect
[22:30] <edmoore> just with my ears
[22:30] <SpeedEvil> Laurenceb: you're probably going to be doing smaller though.
[22:31] <Laurenceb> yeah
[22:31] <Laurenceb> but a missing resonance isnt a problem?
[22:31] <Laurenceb> its only actual real engine fluctuations we want to capture accurately ?
[22:31] <edmoore> i'd want to capture anything that fucks with my sensors :p
[22:32] <SpeedEvil> If you excite a 5KHz resonance in the structure, then you have a massive 5KHz signal - compared to the real 5KHz output of the engines
[22:32] <edmoore> you can do a modal analysis of your sytructure easily enough seperately
[22:33] <SpeedEvil> Sure. If you accurately know the behaviour of your motor and fuel system under shocks.
[22:33] Action: SpeedEvil points to the apollo pogo.
[22:33] <edmoore> shuttle and ares pogo too :p
[22:33] <SpeedEvil> and the emissions of your motor.
[22:33] <edmoore> but i don't think that would happen so much at a smaller scale
[22:33] <SpeedEvil> shuttle had a pogo?
[22:33] <edmoore> yep
[22:34] <edmoore> it's messed with all of them
[22:34] <edmoore> they fixed it early on though
[22:34] <SpeedEvil> Laurenceb: what sort - gas, liquid, hybrid, solid, nuclear lightbulb?
[22:34] <Laurenceb> SpeedEvil: I'm just curious if orbit is possible with strapdown MEMS
[22:34] <SpeedEvil> Of course it's possible.
[22:35] <Laurenceb> without engine noise it certainly is
[22:35] <SpeedEvil> How easy and inexpensive is the interesting question
[22:35] <SpeedEvil> and how many flights you want to make.
[22:35] <rjharrison> hehe toast
[22:35] <rjharrison> i'm being carefull
[22:35] <rjharrison> 1/2 ltr gin down
[22:35] <rjharrison> one second btl wine
[22:35] <SpeedEvil> My first cut would be magnetometer + GPS + sun-sensor for attitude.
[22:36] <Laurenceb> if you have GPS your fine
[22:36] <rjharrison> div 2
[22:36] <SpeedEvil> Laurenceb: not
[22:36] <SpeedEvil> Laurenceb: you really want to know your pointing angle
[22:36] <Laurenceb> you just need to build it
[22:36] <Laurenceb> sure
[22:36] <SpeedEvil> getting crosswise at supersonic = bad.
[22:36] <Laurenceb> but thats easy enough with magno + thermopiles/sun sensor
[22:37] <Laurenceb> or even just gyros
[22:37] <Laurenceb> position drift is the killer
[22:37] <SpeedEvil> I'm pretty sure actually you can hit orbit with only a 2 axis magnetometer and a timer.
[22:37] <edmoore> scout rockets reliably hit orbit with ticker-tape control systems
[22:37] <SpeedEvil> at least at our northerly position.
[22:37] <edmoore> an avr has got to be able to do it
[22:38] <SpeedEvil> just follow a magnetic field line up.
[22:38] <Laurenceb> and...down?
[22:38] <SpeedEvil> This howerver is probably oversimplifying.
[22:38] <Laurenceb> I'm joking, you use up the fuel
[22:38] <SpeedEvil> You time the engines to cut out when it's tangent
[22:39] <Laurenceb> yeah
[22:39] <SpeedEvil> A research project to give the lowest mass way to deorbit a 3cm heat-sensitive cube would be neat.
[22:39] <SpeedEvil> For microSD RAID return.
[22:40] <edmoore> yeah - just returning your sd card would be pretty cool :)
[22:40] <edmoore> paper aeroplane can theoretically re-enter
[22:40] <SpeedEvil> 16*32gb microSD is damn small.
[22:41] <edmoore> when not a hypercone with an sd card cat the apex?
[22:41] <SpeedEvil> plausible.
[22:41] Action: SpeedEvil sighs.
[22:41] Action: SpeedEvil wants a way to launch 50g payloads cheaply.
[22:44] <SpeedEvil> And more importantly.
[22:44] <SpeedEvil> They should be testing MOOSE and variants.
[22:44] <SpeedEvil> (devices that are 90% likely to return a live human from orbit)
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[23:49] <rjharrison> banning myself from ha
[23:50] <rjharrison> I could tell you about tonight but you would have to be over 25
[23:50] <rjharrison> and I know its after the watershed but
[23:50] <rjharrison> !!!
[23:50] <rjharrison> night all
[23:50] <rjharrison> it's safer this way
[23:56] <akawaka> http://picasaweb.google.com/martin.donlon/Random#5289432932116012018
[23:56] <akawaka> science in action!
[00:00] --- Sat Jan 10 2009