highaltitude.log.20080614

[00:04] Action: Laurenceb is getting angry with matlab
[00:04] <Laurenceb> its sooooo slooowww
[00:05] phatmonkey (n=ben@scooby.firshman.co.uk) left irc:
[00:06] <natrium42> slow matlab or slow computer?
[00:06] <Laurenceb> probably a bit of both
[00:06] <Laurenceb> I'm out of ram
[00:22] edmoore_ (n=edmoore@pomegranate.chu.cam.ac.uk) left irc:
[00:58] flowolf (n=flowolf@unaffiliated/flowolf) joined #highaltitude.
[02:13] Laurenceb (i=Laurence@dhcp38-010.sthughs.ox.ac.uk) left #highaltitude.
[02:29] flowolf (n=flowolf@unaffiliated/flowolf) left irc: "Leaving"
[05:49] akawaka (n=akawaka@external.treyarch.com) left irc: Read error: 110 (Connection timed out)
[06:20] defy (n=defy@ip-118-90-72-36.xdsl.xnet.co.nz) joined #highaltitude.
[06:30] rcaron__ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[06:36] rcaron_ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[07:17] defy (n=defy@ip-118-90-72-36.xdsl.xnet.co.nz) left irc:
[07:18] Laurenceb (i=Laurence@dhcp38-010.sthughs.ox.ac.uk) joined #highaltitude.
[07:33] edmoore (n=edmoore@pomegranate.chu.cam.ac.uk) joined #highaltitude.
[07:50] <Laurenceb> hi edmoore
[07:53] <edmoore> yo
[07:54] <edmoore> beautiful day
[07:54] <Laurenceb> :P
[07:54] <Laurenceb> I've got my SiGe sampler talking to matlab
[07:55] <edmoore> awesome
[07:55] <Laurenceb> can pick out some noise when the ant is plugged in
[07:55] <Laurenceb> but there is a lot of stuff seemingly coming from the unit itself
[07:56] <Laurenceb> annoyingly to actually pick up a satellite is quite a lot of work
[07:56] <Laurenceb> you have to code a early prompt late loop
[07:57] <Laurenceb> at the moment its giving me I Q values at 8MHz
[08:00] <Laurenceb> it should be possible to connect the ASIC directly to an ARM7 or something similar, I you only really need all the correlation hardware to get a lock, and it might be possible with just a fairly powerful uC
[08:02] <Laurenceb> of course these things work much more nicely with an FPGA
[08:05] <edmoore> yeah
[08:06] <edmoore> well every cots gps we deal with seems to just be an arm7
[08:07] <Laurenceb> if your doing correlations on a processor its very wasteful
[08:07] <edmoore> i guess
[08:07] <Laurenceb> you could use DMA to get the data into RAM
[08:08] <Laurenceb> now I need some GPS sat chip codes :P
[08:13] Simon-MPFH (n=simon@phantom.mpfh.co.uk) joined #highaltitude.
[08:15] <Laurenceb> edmoore: I've been playing around with 4nec2
[08:16] <Laurenceb> but for carbon fibre I guess youd need a complex refractive index...
[08:17] <Laurenceb> I'm not sure how flexible it is for moddelling things like that, havent had chance to play with it much
[08:17] <edmoore> yes, I did some basic white board bashing with my limited first principles knowledge
[08:17] <edmoore> I think I got somewhere, but it was certainly complex
[08:18] <Laurenceb> isnt there published data?
[08:18] <edmoore> not that I have found yet - the idea was only conceived in a pub yesterday evening
[08:18] <Laurenceb> how about plastic nose code with patch ant inside?
[08:18] <Laurenceb> *cone
[08:19] <edmoore> the old plastic nosecones which are both lightweight and can take 850 degrees celcius?
[08:19] <edmoore> :p
[08:19] <Laurenceb> 850.....
[08:19] <Laurenceb> wow
[08:19] <edmoore> yeah it re-enters at mach4
[08:19] <Laurenceb> thats some KE
[08:19] <edmoore> It is a bit of a head-scratcher in many ways
[08:20] <edmoore> keep coming across new problems]
[08:20] <Laurenceb> the old cork ablative?
[08:22] <Laurenceb> this is maybe a stupid question, but how come rockets dont normally get that hot?
[08:23] Action: Laurenceb revises some thermodynamics
[08:25] <edmoore> Laurenceb: they do
[08:25] <edmoore> on the way back in
[08:26] <edmoore> i mean the stagnation temp is 850 degrees
[08:26] <edmoore> I'm not actually expecting much bulk of the rocket nose to get there
[08:26] <Laurenceb> well actually, the heating at Mach4 is going to also come from the high velocity of the air molecules?
[08:26] <edmoore> no because you have to factor the stock wave sitting just infront of it
[08:26] <Laurenceb> ah
[08:27] <Laurenceb> whats the scaling relationship with velocity then?
[08:29] <edmoore> the v terms are all v^2
[08:29] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) joined #highaltitude.
[08:29] <Laurenceb> ah
[08:29] <Laurenceb> hi jcoxon
[08:29] <edmoore> but there's other stuff, but it's not really my competance!
[08:30] Action: Laurenceb contemplates dimensional analysis
[08:30] <Laurenceb> or I could wikipedia it
[08:30] <jcoxon> good morning
[08:32] <jcoxon> hows everyone?
[08:32] <Laurenceb> finished yesterday
[08:32] <jcoxon> Laurenceb, congrats
[08:32] <Laurenceb> thanx
[08:33] <edmoore> great, I am
[08:34] <Laurenceb> edmoore: the nosecone seems the obvious choice... just need something RF transparent and heat resistant
[08:34] <jcoxon> edmoore, that was slightly star warsy
[08:34] <Laurenceb> hehe
[08:35] <edmoore> Laurenceb: agreed
[08:35] <edmoore> I want to do something there
[08:35] <edmoore> gold leaf under some kind of ceramic paint
[08:35] <edmoore> or something
[08:35] <Laurenceb> what about the heat decomposing the resin in the RF ?
[08:35] <edmoore> need another receiver for the way down though
[08:36] <Laurenceb> s/RF/CF
[08:36] <edmoore> i don't follow
[08:36] <Laurenceb> hmm good point, maybe have no GPS during the ascent?
[08:37] <edmoore> definately not an option
[08:37] <edmoore> we need it
[08:37] <Laurenceb> ok, so nose is at 850C, but the heat will be conducted into the CF tube
[08:37] <Laurenceb> but the gps will cut out anyway after a second or less
[08:37] <Laurenceb> ok maybe a couple of seconds
[08:38] <edmoore> well it should only be a skin temperature of 850 for a tiny length of time
[08:38] <edmoore> there's a shload of drag
[08:38] <Laurenceb> ah, that makes more sense
[08:38] <Laurenceb> PTFE ?
[08:38] <edmoore> possibly, will keep investigating
[08:39] <Laurenceb> IIRC its ok up to as much as 300C
[08:39] <edmoore> wa thinking maybe aerogel or something crazy
[08:39] <edmoore> i want to use aerogel somewhere
[08:39] <Laurenceb> and the good thing is above that temperature it thermally decomposes, so presumably the reactions will be endothermic
[08:41] <Laurenceb> my point with the GPS is: there surely isnt much point in gps between the ignition point and reentry, so why bother with an upwards facing ant?
[08:41] <edmoore> oh there def is
[08:42] <Laurenceb> as the limits will mean it cuts out
[08:42] <Laurenceb> hmm, how high do your datapoints go?
[08:42] <edmoore> but do the suvat equations - there's a fair amount of time between 515m/s up and 515m/s down
[08:42] <Laurenceb> sure
[08:43] <Laurenceb> got you, I'm stupid
[08:43] <edmoore> so we may, hopefully, get a lock
[08:43] <Laurenceb> and at apogee :P
[08:43] <edmoore> we're not relying on it, but it'd be great if we got some alt datapoints off the gps
[08:43] <edmoore> including, yes, the magic apogee
[08:43] <Laurenceb> have you managed this with your test flight(s) ?
[08:43] <edmoore> which is the whole point of this affair :)
[08:43] <edmoore> we've not been above 515 yet
[08:44] <edmoore> just ordered the carbon fibre thought
[08:44] <edmoore> for the beast rocket
[08:44] <Laurenceb> what gps did you have onboard?
[08:44] <jcoxon> has everything swung in to action?
[08:44] <edmoore> mach2 from sea level is no walk in the park
[08:44] <edmoore> lassen
[08:44] <Laurenceb> ah, so you can set it to dynamic
[08:44] <edmoore> bingo
[08:44] <edmoore> may try something else later
[08:45] <Laurenceb> just 1 Hz ?
[08:46] <edmoore> well the ublox's look nice
[08:46] <edmoore> not cheap
[08:46] <edmoore> but might give the 5s a whirl
[08:46] <Laurenceb> I had one
[08:46] <Laurenceb> but gave it to Rocketboy
[08:46] <edmoore> did you have a chance to play with it?
[08:47] <Laurenceb> yes, was a bit dissapointed
[08:47] <Laurenceb> by the noise
[08:47] <Laurenceb> but I guess thats good, it was just less heavily filtered
[08:47] <Laurenceb> and its the price you pay for the extra update rate
[08:47] <edmoore> if only they gave us the sourcecode
[08:48] <edmoore> hey, in 3 years you'll be able to design your own one
[08:48] <Laurenceb> :P
[08:48] <edmoore> we'll be coming to you insisting you build is orbital ones
[08:48] <Laurenceb> hehe
[08:49] <Laurenceb> I tried to update mine with new firmware, and suspect I broke it
[08:49] <jcoxon> firmware is always tricky
[08:50] <Laurenceb> it was a prototype, not one of the production modules... god knows how it got up on ebay
[08:50] <edmoore> haha
[08:51] <Laurenceb> http://en.wikipedia.org/wiki/Polytetrafluoroethylene
[08:51] <Laurenceb> looks like what you want
[08:53] <Laurenceb> "While PTFE itself is chemically inert and non-toxic, it begins to deteriorate after the temperature of cookware reaches about 500 °F (260 °C), and decompose above 660 °F (350 °C).[12] These degradation products can be lethal to birds, and can cause flu-like symptoms in humans"
[08:53] <Laurenceb> so dont tell the RSPB
[08:54] <jcoxon> ooo did you guys see the bbc new article about balloons and birds
[08:54] <Laurenceb> no
[08:54] <jcoxon> http://news.bbc.co.uk/1/hi/uk/7447381.stm
[08:55] <jcoxon> but its more for mass balloon launches
[08:55] <jcoxon> one launch a month isn't going to do any harm
[08:56] <edmoore> they shouldn't fly into the bloody things
[08:57] <jcoxon> its more they eat them
[08:58] <edmoore> fair enough
[08:58] <jcoxon> http://www.flickr.com/photos/jcoxon77/2577493146/
[08:58] <edmoore> pretty!
[08:59] <edmoore> can you tell me every single thing written on the gsm modem?
[08:59] <Laurenceb> http://books.google.co.uk/books?id=eu3tB1Jpm-sC&pg=PA119&lpg=PA119&dq=ptfe+endothermic+decomposition&source=web&ots=3eQjbazTg7&sig=ovwlt6mam2Uz38suvaXvrn75ACU&hl=en&sa=X&oi=book_result&resnum=8&ct=result#PPA129,M1
[08:59] <Laurenceb> sorry huge url
[09:00] <Laurenceb> jcoxon: nice
[09:00] <jcoxon> edmoore, what do you mean?
[09:00] <edmoore> don't worry
[09:00] <edmoore> zoomed in
[09:01] <jcoxon> siemens mc75
[09:03] <jcoxon> they are lighter then the telits
[09:03] <jcoxon> http://uk.farnell.com/1305957/mechanical-office-workplace/product.us0?sku=siemens-mc75-module&_requestid=186330
[09:05] <Laurenceb> edmoore: pages 128/9
[09:05] <edmoore> ty laurenceb
[09:06] <Laurenceb> lovely materials science
[09:09] <edmoore> yeah am temped by the seimens things
[09:10] <edmoore> might try soeone less expensive than farnell, though
[09:10] <jcoxon> :-)
[09:10] <edmoore> the money and space saved on a telit could mean we could change to a ublox and still be quids in
[09:11] <jcoxon> they way teh connector is on the goliath the mc75 sits a bit higher which means there is more space on the board
[09:13] <edmoore> it has mounting holes too, which is nice
[09:13] <edmoore> ok cool, something to talk to fungus about for v2
[09:14] <jcoxon> one annoying thing with the goliath is that they haven't brought out many of the extra functions such as the serial ports
[09:15] <edmoore> such is life
[09:15] <edmoore> right, Ima gonna getta dresseda
[09:15] <edmoore> and have some breakfast
[09:15] <edmoore> catch you later
[09:16] <Laurenceb> bye
[09:16] <edmoore> thanks for the link alurencebe
[09:16] <edmoore> Laurenceb: , even
[09:16] edmoore (n=edmoore@pomegranate.chu.cam.ac.uk) left irc:
[09:23] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) left irc: "Leaving"
[09:53] MetaMorfoziS (n=avr@3e44b94c.adsl.enternet.hu) joined #highaltitude.
[10:23] Hiena (n=Hiena@81.93.195.181.datatrans.hu) joined #highaltitude.
[10:23] <Hiena> ' morning!
[10:35] borism (n=boris@195-50-211-47-dsl.krw.estpak.ee) left irc: Read error: 145 (Connection timed out)
[10:51] flowolf (n=flowolf@unaffiliated/flowolf) joined #highaltitude.
[11:20] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) joined #highaltitude.
[11:41] rcaron (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[11:43] Hiena (n=Hiena@81.93.195.181.datatrans.hu) left irc: "-=Halt!=-"
[11:55] rcaron__ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[12:06] rcaron_ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[12:14] rcaron__ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[12:19] rcaron (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[12:27] rcaron_ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[12:35] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) left irc: "Leaving"
[12:54] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) joined #highaltitude.
[13:12] <Laurenceb> wow
[13:14] <Laurenceb> about 30 eurofighters just flew over
[13:15] <Laurenceb> this is insane
[13:15] <Laurenceb> over 30 eurofighters, 4 awaks planes, 2 hercules transport, several sinister looking white jets and other stuff flying over
[13:16] <Laurenceb> wtf is going on WW3 ?
[13:19] <Laurenceb> jcoxon: spotted many planes around today?
[13:24] <Laurenceb> aha http://news.bbc.co.uk/1/hi/scotland/7453788.stm must have been part of that :P
[13:32] edmoore (n=edmoore@pomegranate.chu.cam.ac.uk) joined #highaltitude.
[13:34] Laurenceb (i=Laurence@dhcp38-010.sthughs.ox.ac.uk) left irc: Read error: 104 (Connection reset by peer)
[13:35] edmoore (n=edmoore@pomegranate.chu.cam.ac.uk) left irc: Client Quit
[13:41] flowolf (n=flowolf@unaffiliated/flowolf) left irc: "Leaving"
[13:43] rcaron (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[13:46] flowolf (n=flowolf@unaffiliated/flowolf) joined #highaltitude.
[13:53] rcaron__ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[13:56] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) left irc: "Leaving"
[14:06] Laurenceb (n=laurence@dhcp37-186.sthughs.ox.ac.uk) joined #highaltitude.
[15:09] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) joined #highaltitude.
[15:25] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) left irc: "Leaving"
[15:31] MetaMorfoziS (n=avr@3e44b94c.adsl.enternet.hu) left irc: Remote closed the connection
[15:38] Hiena (n=Hiena@81.93.195.181.datatrans.hu) joined #highaltitude.
[16:20] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) joined #highaltitude.
[16:55] MetaMorfoziS (n=avr@dsl51B69A70.pool.t-online.hu) joined #highaltitude.
[17:12] akawaka (n=akawaka@cpe-76-173-152-142.socal.res.rr.com) joined #highaltitude.
[17:21] rcaron_ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[17:32] rcaron (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[17:44] rcaron (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[17:56] rcaron_ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[17:57] Nick change: Hiena -> H_pancake
[18:03] rcaron_ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[18:10] Simon-MPFH (n=simon@phantom.mpfh.co.uk) left irc: Read error: 101 (Network is unreachable)
[18:10] Simon-MPFH (n=simon@phantom.mpfh.co.uk) joined #highaltitude.
[18:14] rcaron__ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[18:16] rcaron (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[18:25] rcaron_ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[18:47] akawaka (n=akawaka@cpe-76-173-152-142.socal.res.rr.com) left irc: Read error: 110 (Connection timed out)
[19:02] rcaron (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) joined #highaltitude.
[19:04] akawaka (n=akawaka@cpe-76-173-152-142.socal.res.rr.com) joined #highaltitude.
[19:05] wickerwaka (n=akawaka@cpe-76-173-152-142.socal.res.rr.com) joined #highaltitude.
[19:11] Nick change: H_pancake -> Hiena
[19:13] rcaron__ (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: Read error: 110 (Connection timed out)
[19:24] akawaka (n=akawaka@cpe-76-173-152-142.socal.res.rr.com) left irc: Read error: 110 (Connection timed out)
[19:45] rcaron (n=rcaron@c-75-68-113-23.hsd1.nh.comcast.net) left irc: "leaving"
[19:46] jcoxon (n=jcoxon@host86-144-103-14.range86-144.btcentralplus.com) left irc: "Leaving"
[20:02] flowolf (n=flowolf@unaffiliated/flowolf) left irc: "Leaving"
[20:15] borism (n=boris@195-50-211-47-dsl.krw.estpak.ee) joined #highaltitude.
[20:16] <Hiena> http://www.vimeo.com/1161514 <=Good movie...
[20:19] <wickerwaka> http://www.vimeo.com/1109226?pg=embed&sec=1109226
[21:30] Simon-MPFH (n=simon@phantom.mpfh.co.uk) left irc: "Leaving"
[21:33] edmoore (n=edmoore@pomegranate.chu.cam.ac.uk) joined #highaltitude.
[22:20] mc- (n=mfcastle@cpc4-glfd1-0-0-cust538.glfd.cable.ntl.com) joined #highaltitude.
[22:27] <mc-> hi edmoore, was reading the logs
[22:27] <mc-> with such a light rocket, are you sure it would get to 850C?
[22:28] <edmoore> that's the stagnation temperature of the flow
[22:28] <edmoore> which is not quite the same thing as the rocket itself heating up to 850, as I said
[22:28] <mc-> isn't the stagnation temp a little distance away from the CF?
[22:28] <edmoore> not right at the tip
[22:29] <mc-> how about a spike at the tip, to move the stagnation point away from the structure?
[22:30] <edmoore> I'm not worried about the tip heating up, we can deal with that - it's getting an antenna up there
[22:30] <edmoore> or not, if it does not need to be up there
[22:31] <mc-> It going to heat up for <1min isn't it? So a GPS ant wouldn't get very hot.
[22:31] <edmoore> well it's the pointy bit that worries me
[22:32] <edmoore> basically we need to keep a supersonic nosecone, and get antenna reciving in there
[22:32] <edmoore> so there are a few variables to jiggle about
[22:32] <mc-> ogive or Von Karman nosecone shape?
[22:34] <mc-> I've put 2 patch antennas back to back to make an omnidirectional, it worked
[22:34] <mc-> And I have some helical omnis here as well
[22:35] <edmoore> I don't know what shape yet - iain is still simming
[22:35] <edmoore> I'm looking at trying something different for the antenna
[22:35] <edmoore> don't know if it'll work - will test it on a balloon a few times
[22:35] <edmoore> would solve some problems anyway
[22:36] <edmoore> right, it's time for me to head out into the night
[22:36] <edmoore> bbl
[22:36] edmoore (n=edmoore@pomegranate.chu.cam.ac.uk) left irc:
[22:41] mc- (n=mfcastle@cpc4-glfd1-0-0-cust538.glfd.cable.ntl.com) left irc:
[23:11] Hiena (n=Hiena@81.93.195.181.datatrans.hu) left irc: "-=Halt!=-"
[23:31] <Laurenceb> hi folks
[23:33] Action: Laurenceb listens to his hdd swapping like mad :-(
[23:33] <Laurenceb> anyone here installed eclipse on ubuntu ?
[23:34] flowolf (n=flowolf@unaffiliated/flowolf) joined #highaltitude.
[00:00] --- Sun Jun 15 2008