highaltitude.log.20080912

[00:00] <phatmonkey> jcoxon: I think that's fair enough
[00:00] <jcoxon> it could be the beginning of ukhas membership
[00:00] <gordonjcp> are you setting up a paypal account or something?
[00:00] <phatmonkey> and it'll be hosting available for anyone, so if anyone wants to host tracker things or whatnot, let me know
[00:02] <phatmonkey> jcoxon: judging by the stats on the wiki page and another site I run, we'd make 42p a month from google ads
[00:02] <phatmonkey> not really worth it I think...!
[00:02] <edmoore> :)
[00:02] <edmoore> that's half a member!
[00:02] <phatmonkey> well I'm not sure, maybe higher traffic sites make less money per click
[00:02] <gordonjcp> that's bloody good actually
[00:02] <gordonjcp> more than I get
[00:02] <phatmonkey> i've never understood the adwords pricing
[00:02] <phatmonkey> *adsense
[00:03] Laurenceb_ (n=Laurence@host86-133-69-235.range86-133.btcentralplus.com) joined #highaltitude.
[00:03] <Laurenceb_> hi everyone
[00:03] <phatmonkey> hey laurence
[00:04] <jcoxon> okay i'll email the list about some form of ukhas subscription
[00:04] <Laurenceb_> hi phatmonkey, whats happening?
[00:04] <jcoxon> voluntary of course
[00:04] <phatmonkey> not much!
[00:04] <phatmonkey> we're just figuring out ukhas hosting at the moment
[00:05] <phatmonkey> does anyone actually have a need for hosting?
[00:05] <phatmonkey> because setting up a virtual server wouldn't be hard at all, and suppose i could hand out user accounts
[00:05] <Laurenceb_> what are you doing next year?
[00:05] <phatmonkey> engineering at warwick in 2 weeks now
[00:06] <Laurenceb_> ah cool
[00:06] <phatmonkey> can't wait!
[00:06] <Laurenceb_> congrats on getting in, that sounds like a good course
[00:06] <phatmonkey> I'm not sure really, I have this itch that's telling me to do computer science or something like that
[00:07] <Laurenceb_> eng opens more doors
[00:07] <edmoore> the engineering is useful....
[00:07] <phatmonkey> yeah I suppose
[00:07] <edmoore> you just get more useful physics
[00:07] <phatmonkey> the warwick course is extremely flexible - I think 25% of my course is whatever the hell i want
[00:07] <Laurenceb_> physics is too astract
[00:07] <phatmonkey> so i can do a quarter computer science
[00:08] <edmoore> and compsci can be learned. engineering doesn't touch set theory, but there are some great online text books that cover that kind of stuff
[00:08] <Laurenceb_> isnt set theory in the further maths a level
[00:08] <edmoore> I never did it...
[00:09] <edmoore> to any useful level, anyway
[00:09] <phatmonkey> nope, neither
[00:09] <Laurenceb_> it was sooo long ago :D
[00:09] <phatmonkey> I've already forgotten most of my maths A level
[00:09] <edmoore> but learning haskell with an e-book opened up that world
[00:09] <gordonjcp> urgh, haskell
[00:09] <Laurenceb_> :P
[00:09] <edmoore> they break you in gently for the first term, normally
[00:09] <gordonjcp> I learnt some haskell when I was helping my gf with her CS degree
[00:09] <edmoore> gordonjcp: I adore it!
[00:10] <gordonjcp> edmoore: I just can't see what it's for
[00:10] <phatmonkey> I keep on telling myself with an engineering degree I could easily go into an engineering or computing career. with computer science, there's no way I could do engineering
[00:10] <edmoore> that's the point!
[00:10] <edmoore> phatmonkey: correct.
[00:10] <gordonjcp> it's like the bastard offspring of a shit version of Pascal and a shit version of Python
[00:11] <edmoore> but it's like learning latin. pointless, but gives you a nice perspective on language.
[00:11] <edmoore> and makes you feel special
[00:11] <edmoore> and is actually quite useful in making you think in different ways
[00:11] <gordonjcp> using it reminded me of how much I despise Pascal and made me rather upset about how much someone could fail to understand Python
[00:11] <gordonjcp> edmoore: I bet Forth is better on both counts
[00:11] <edmoore> oh probably, but never learnt that :)
[00:11] <gordonjcp> and as a bonus, Forth is actually useful on embedded stuff
[00:14] <Laurenceb_> edmoore: will the v2 badger have gyros?
[00:14] <edmoore> yep
[00:14] <Laurenceb_> *gyro(s)
[00:15] <Laurenceb_> know which sort yet?
[00:15] <edmoore> 3 axes of
[00:15] <edmoore> adxr300
[00:15] <Laurenceb_> holy electrons
[00:15] <Laurenceb_> sounds good
[00:15] <Laurenceb_> any other sensors?
[00:16] <Laurenceb_> accel?
[00:16] <edmoore> 3 axes of accel
[00:16] <Laurenceb_> I see
[00:16] <edmoore> and 8 16bit adc channels to add magnetometers or thermopiles or whatever
[00:16] <Laurenceb_> hmm was going to look at using one on a parafoil
[00:16] <edmoore> just don't want to put them on the main board
[00:16] <Laurenceb_> yeah
[00:17] <Laurenceb_> but I'd have to do it justice
[00:17] <Laurenceb_> and not just use one gyro channel
[00:17] <edmoore> aye, you'd need a full blown body state estimator
[00:18] <Laurenceb_> well not really
[00:18] <Laurenceb_> for it to work
[00:18] <edmoore> no, but to do it justice :)
[00:18] <Laurenceb_> exactly :P
[00:19] <Laurenceb_> can you recommend any books on body state estimators?
[00:19] <natrium42> FOR GREAT JUSTICE
[00:19] <natrium42> MOVE ZIG
[00:19] <Laurenceb_> *sigh*
[00:19] <natrium42> :)
[00:20] <edmoore> Laurenceb_: 'Optimal State Estimation' by Dan Simon is on my shelf
[00:20] <edmoore> not specifically about inertial stuff, but treats the subject very well from first principles
[00:20] <Laurenceb_> yeah
[00:20] <Laurenceb_> cool thanks
[00:20] <edmoore> goes through to h-infinity filters (like kalman, but not constrained by gaussian assumptions of noise)
[00:21] <Laurenceb_> the basics of quaternions ect is what confuses me
[00:21] <edmoore> oh, same :)
[00:21] <Laurenceb_> I wont try to get into it too much on IRC, but what do you take as your state vector in a basic system ?
[00:22] <edmoore> the outputs?
[00:22] <edmoore> roll pitch yaw, and rates thereof, earth relative frame
[00:23] <edmoore> so euler
[00:23] <Laurenceb_> interesting
[00:23] <Laurenceb_> so not some condensed form of the quaternion representing the state?
[00:25] <Laurenceb_> so... I gues that makes the measurement model matrix easy to calculate
[00:26] <edmoore> yes, those inputs are easier to pass to the system, but the state estimator would use a quaternion internally
[00:26] <Laurenceb_> I'll have to get the book :P
[00:28] <Laurenceb_> I was looking at condensing the state quaternoin down to three variables (possible as it only ever represents a rotation) but the measurement noise covariance matrix became hard to calculate - it looke like it needed jacobians
[00:30] <edmoore> run away!
[00:31] <Laurenceb_> maths is fun
[00:32] <Laurenceb_> hmm if I typecast a signed char equal to <0 to an unsigned char, then back to a signed char, is it unchanged?
[00:33] <jcoxon> right
[00:33] <jcoxon> superbeacon is complete
[00:34] <natrium42> yay
[00:34] <natrium42> does it work superperfectly?
[00:34] <jcoxon> of course not
[00:34] <jcoxon> time to test it
[00:34] <natrium42> :D
[00:38] <edmoore> mil-std-1553 is... actually quite a simple and good idea. I like.
[00:39] <edmoore> how is it suddently 00:40!??
[00:39] <edmoore> oh my god I thought it was about 10!
[00:39] <edmoore> and i've routed about 5 tracks. OHMYGOD
[00:40] <Laurenceb_> hehe
[00:41] <Laurenceb_> edmoore: veroboard
[00:41] <edmoore> noooooo
[00:41] <Laurenceb_> smd on veroboard - its almost as small
[00:42] <edmoore> i will be using veroboard in a bit
[00:42] <edmoore> though there's a cpld I want to start using
[00:43] Action: Laurenceb_ is jealous
[00:43] <edmoore> they look pretty nifty
[00:43] <Laurenceb_> I've spent all day cutting pieces on stainless steel :(
[00:43] <Laurenceb_> *of
[00:43] <edmoore> well, I've done my time this summer
[00:44] <edmoore> got a few days of pure hobbyism now :)
[00:44] <Laurenceb_> I've concluded that construction work sucks
[00:45] <Laurenceb_> it seems to involve excessing amounts of repetitive arm movements (dont laugh)
[00:45] <Laurenceb_> sanding... sawing... painting... ect ect
[00:45] <SpeedEvil> You just need to learn more.
[00:46] <SpeedEvil> And obtain prehensile feet.
[00:46] <SpeedEvil> what for?
[00:46] <SpeedEvil> (the Ss)
[00:48] <Laurenceb_> some doors from an old pub
[00:48] <jcoxon> night all
[00:48] <Laurenceb_> cya
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[00:48] <SpeedEvil> Oh - balloon pieces. I misread that as cutting bits of SS
[00:49] <Laurenceb_> they were quite soft from being dipped so I've cut some pieces of Ss for kick and push plates
[00:49] <Laurenceb_> its like a western salloon now :D
[00:51] <phatmonkey> night!
[00:53] <Laurenceb_> bye
[00:53] <Laurenceb_> me too, cya all
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[06:09] <ShellEvil> http://en.wikipedia.org/wiki/Aerium
[06:09] <ShellEvil> Slightly related
[06:09] <ShellEvil> The one product that CargoLifter got off the ground (though not really)
[06:10] <ShellEvil> 'The hangar (360 m long, 220 m wide and 106 m high) also was equipped with a 180 m cutting table for the envelope's manufacture.'
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[08:01] Nick change: rharrison_quiet -> rhaRRISON
[08:01] Nick change: rhaRRISON -> rharrison
[08:02] <rharrison> morning all, The w/e is nearly upon us!!!
[08:20] <gordonjcp> it is
[08:20] <gordonjcp> I site my RAE in a little over 12 hoursz
[08:20] <gordonjcp> -z
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[08:25] Action: SpeedEvil wishes for a 180m cutting table.
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[08:41] <jcoxon> morning all
[08:48] <jcoxon> are all you guys signed up to the ukhas google groups?
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[08:57] <gordonjcp> nope...
[08:57] <gordonjcp> link?
[08:57] Action: gordonjcp -> (late) work
[09:01] <jcoxon> http://groups.google.com/group/ukhas
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[11:58] <rharrison> edmoore: Fingers crossed box of toys should be with you tromorrow
[12:01] <edmoore> :D
[12:01] <edmoore> thanks!
[12:02] <edmoore> rharrison: I just bought an avr dragon
[12:02] <edmoore> going to do more avr programming as I miss it.
[12:02] <edmoore> I like being able to print out a table of ram on a sheet of a4 and decide what to do with it with pen and pencil.
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[12:07] <edmoore> morning jcoxon
[12:07] <jcoxon> hey edmoore
[12:07] <edmoore> all well in jcoxon land?
[12:07] <jcoxon> hmmm hackaday seems to have disappeared
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[12:07] <jcoxon> indeed, just popping home to fix my parents internet
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[12:08] <edmoore> sounds familiar
[12:08] <edmoore> henry asked me 2 days ago if hackaday was down for me too
[12:09] <jcoxon> they had the failing whale for a bit but now thats gone
[12:10] <edmoore> anyway, down for me
[12:10] <jcoxon> same
[12:10] <jcoxon> oh well
[12:12] <jcoxon> just had a meeting with one of my supervisors - he wants me to write a 10,000 word easy :-(
[12:12] <jcoxon> essay*
[12:14] <edmoore> eeeeeeeek
[12:14] <edmoore> on what?
[12:14] <jcoxon> photodynamic therapy
[12:14] <jcoxon> quite an elegant idea
[12:15] <jcoxon> you give patients a photosensitiser drug which is taken up by cells
[12:15] <jcoxon> as cancer cells are more active they take a lot more
[12:15] <jcoxon> then you shine a light on it to energise the chemical
[12:15] <jcoxon> and it reacts with oxygen and destroys the cells
[12:15] <gordonjcp> presumably this only works with cells you can get at
[12:15] <jcoxon> yeah
[12:15] <jcoxon> its best with skin cancers
[12:16] <jcoxon> though they are now doing it on organs with laproscopic light sources
[12:16] <jcoxon> and you can use more penetrating wavelengths
[12:16] <gordonjcp> my gf's Mum is the secretary for a skin cancer charity
[12:16] <gordonjcp> yeah I suppose you could use something activated by near IR
[12:17] <edmoore> so I went with mate to the scrappy yesterday for get him some wing mirrors
[12:17] <gordonjcp> hrm, if it works with light could you find a chemical that would be activated by X-rays, for example?
[12:17] <edmoore> and they're just the best playground in the world
[12:18] <edmoore> got a complete spare set of bulbs for my astra, including the inetriors, once of which had already gone. Free fuses for life, and loads of really good relays above the fuses - 12V 40A type things. Aaaaand, a bag of 200 30cm cable ties in the back of one of the cars! score!
[12:19] <gordonjcp> scrap yards are great
[12:19] <edmoore> I am going to an actualy scrap metal yard (rather than just cars) this afternoon. just incase there are some gems.
[12:22] <rharrison> edmoore: The dragon is cool. It should have cult status
[12:22] <gordonjcp> be careful
[12:22] <edmoore> gordonjcp: of what?
[12:22] <gordonjcp> that sort of thing can be dangerous
[12:22] <gordonjcp> it can lead to things like traction engine ownership
[12:22] <edmoore> Oh I hoard anyway
[12:22] <edmoore> :)
[12:22] <edmoore> is there a story to that one?
[12:22] <gordonjcp> not personally, no
[12:22] <edmoore> rharrison: what kinda state is the bibular aquisition?
[12:22] <gordonjcp> I did end up buying four Volvo estates once
[12:23] <edmoore> ha
[12:23] <edmoore> well I got all the relays out of a volve yesterday as it happens
[12:23] <gordonjcp> I only wanted one, but the one I wanted was first on the lorry and the guy wouldn't unload just that one and load the others back on
[12:23] <gordonjcp> "if you take one you take the lot"
[12:23] <gordonjcp> 100 quid later...
[12:23] <edmoore> :)
[12:24] <gordonjcp> the scrapyard on Skye used to just be a big quarry
[12:24] <gordonjcp> the council ran it, but they were content to just tow cars in and leave them
[12:24] <gordonjcp> things I've had from there:
[12:25] <edmoore> jcoxon: !!!!
[12:25] <rharrison> edmoore: done aparrently Just pulling iso back fron linux box
[12:25] <edmoore> you live near heven! http://www.killerhurtz.co.uk/howto/scrapyard.htm
[12:25] <edmoore> rharrison: grand! Super keen to read up on yagis
[12:26] <gordonjcp> 200m of 6mm copper pipe, an Eko Ritmo drum machine, a Yamaha PSS-470 keyboard, some Tektronix graphics workstations, a timebase corrector, a vectorscope, some CCTV monitors and cameras, and some ex-council radio transmitters
[12:26] <gordonjcp> as well as various old car parts and stuff
[12:26] <edmoore> gordonjcp: wow, that's a hell of a haul
[12:26] <gordonjcp> oh, that's over a long period of time
[12:26] <gordonjcp> that's just the cool stuff
[12:26] <rharrison> 700 might be one for the post
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[12:27] <gordonjcp> I got the front axle, engine and gearbox from a Citroen 2CV to make a trike out of
[12:27] <jcoxon_> oops tunnel
[12:27] <edmoore> rharrison: I don't follow
[12:27] <gordonjcp> ended up swapping that and a lump of dope for a Honda CD200 motorbike
[12:27] <edmoore> oh mb
[12:27] <rharrison> edmoore: size
[12:27] <edmoore> eeeek
[12:28] <edmoore> how many pages is it?
[12:29] <jcoxon_> rharrison, built the super beacon
[12:29] <edmoore> rharrison: did you get that cylinder trolley in the end?
[12:29] <edmoore> jcoxon: http://www.killerhurtz.co.uk/howto/scrapyard.htm is near you
[12:29] <rharrison> Yep I'm going to post a pic later of it
[12:29] <edmoore> cool - jcoxon, rharrison got a cyclinder trolley with 4 wheels. Just think of it! getting up and down churchill private road
[12:30] <rharrison> Love it with the wheels on the back. Ballons from rocketboy have just arrived 10mins ago along with gps stuff from trimble
[12:30] <edmoore> christmas
[12:30] <rharrison> Like christmas here.
[12:30] <rharrison> :)
[12:31] <rharrison> jcoxon: Beacon 1/2 made. Soldered components on and making Ground Plane attenna tonight with ony 2 radials instead of
[12:31] <edmoore> trying to got up a gently up-hill not very even road up churchill, trying to keep the 2-wheel trolley jack at balance point so you don't have 150kg of cyliner resting on your shoulder, is one of the less fun bits of launch
[12:31] <rharrison> 4
[12:32] <jcoxon_> superbeacon isn't going to have a grounplane
[12:32] <jcoxon_> just a wire antenna
[12:32] <rharrison> I'm hoping to wheel out of the garage by 5meters and inflate :)
[12:32] <rharrison> Ooh.
[12:32] <jcoxon_> just to give the flexibility of where you place it on a payoad
[12:33] <jcoxon_> as the main telementry will want the a groundplane 1/4 wave antenna
[12:33] <jcoxon_> payload*
[12:33] <rharrison> Ok I thought I could just stack two foam platforms of you wanted
[12:34] <jcoxon_> not sure i follow
[12:39] <rharrison> Just take four bits of string and attach them to the corners of the first payload which is just a bit of polystyrene and attach them to another sheet .5m below the first one
[12:39] <jcoxon_> and have 2 groundplane antenna pointing down?
[12:39] <jcoxon_> one above the other?
[12:40] <edmoore> there *could* be some pitfalls with that, but it will probably work.
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[12:40] <rharrison> Or side by side I guess with just one platform.
[12:40] <rharrison> That might be better?
[12:40] <edmoore> I'll explain why based on my limited understanding - this could be one of those times where SpeedEvil flies in and corrects me :)
[12:40] <jcoxon_> on HAPS-1 for the beacon we had the wire poking out the top
[12:40] <jcoxon_> it was pretty good for the whole flight
[12:41] <edmoore> if you have a tx from top payload above gps ant on bottom payload, it may cause problems for one of 2 reasons
[12:41] <jcoxon_> and also doesn't get squashed on landing
[12:41] <edmoore> 1) you will be in trouble if the gps receive frequency is the same as the tx frequency, or is some harmonic of the tx freqency (harmonic = n x main frequency, where n is an integer)
[12:43] <edmoore> so the tx would interfere with the gps in that way - gps have a very very narrow band filter on the input (a SAW filter) and in this case you should be ok - gps freq lies *between* (rather than under) the 3rd and 4th harmonic of 434
[12:44] <rharrison> If superbeacon is small enought could just tie it into the string separating the parachute from the payload. Say 10 meters above. Or trail it 10 meteres below.
[12:44] <edmoore> 2) however, regardless of frequency, you can saturate the LNA - the low noise amplifier - on the gps input. This happens if the tx is too close/too powerful
[12:44] <edmoore> however, anecdotally it seems to work fine for most ballooners, who often have stracks of payloads on a long train
[12:45] <edmoore> like ukhas 1
[12:45] <jcoxon_> rharrison, yeah its pretty flexible, just as long as the gps points up
[12:45] <edmoore> rharrison: yes indeed - that would work well
[12:45] <jcoxon_> edmoore, well ukhas didn't work :-p
[12:45] <edmoore> but the telem did, din't it?
[12:45] <jcoxon_> no
[12:45] <jcoxon_> we lost contact pretty damn early on
[12:45] <jcoxon_> iirc
[12:45] <edmoore> that was wierd - i think we by fluke made a resonant payload train
[12:45] <edmoore> because it was violently chatoic motion all the way up
[12:46] <edmoore> well, if not ukhas 1, it works for eoss and others
[12:46] <jcoxon_> we only found it as some one called the number
[12:46] <jcoxon_> yeah
[12:46] <jcoxon_> :-D
[12:46] <edmoore> moving swiftly on....
[12:46] <jcoxon_> indeed
[12:46] <jcoxon_> best not dwell :-)
[12:46] <edmoore> rharrison: if you have ever heard advice given on keeping the antennas flexible.
[12:46] <jcoxon_> wire antenna are pretty good for beacons methinks
[12:46] <edmoore> don't ask, just accept, on this one.
[12:47] <jcoxon_> right i'll bbl
[12:47] <jcoxon_> cya
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[12:48] <rharrison> edmoore: I'm using some 1mm copper house wire atm
[12:49] <edmoore> rharrison: this was our idea-ette
[12:49] <edmoore> get some foam - sort of stiff like a sponge
[12:50] <edmoore> cut it into a triangle or trapezium
[12:50] <edmoore> 35cm at the base, 17cm height
[12:50] <edmoore> and place the ground plane wireless along the long bottom edge, and the active element vertically. just embdeed the wires somehow
[12:51] <edmoore> that way you get something that will hold its shape
[12:51] <edmoore> but is also flexible so it can land on a greenhouse
[12:51] <rharrison> I thought the GP need to be at 120 degress to the active
[12:51] <rharrison> not at 90
[12:51] <edmoore> aaaah - that antenna was for active pointing up
[12:51] <edmoore> to talk to other hams at similar altitudes
[12:52] <edmoore> this design is more tweaked to make the radiation pattern down - as the listening (us) will always be below the balloon
[12:52] <edmoore> it has a soft of cone shaped downwards radiation pattern
[12:53] <rharrison> Ok so make the GP at 90 degrees to the active
[12:53] <edmoore> minimises the 'waste' of sending transmissions above the horizon
[12:53] <edmoore> yeah
[12:53] <rharrison> the GPs are still active + 5%
[12:53] <rharrison> lenght
[12:53] <edmoore> don't know. sounds fair.
[12:54] <rharrison> active (70/4*.95)
[12:54] <edmoore> there may actually be some mileage to having them angle back slightly, thinking about it.
[12:54] <edmoore> hmmm
[12:55] <rharrison> Reading that stuff I sent you yesterday. There seems to be some loss directly underneath but I think it's still conical
[12:55] <edmoore> yeah, it's just the angle of the 3db cone
[12:56] <edmoore> depends - on a still day you want a tigher down cone
[12:56] <edmoore> on a windy day it's basically just above the horizon
[12:56] <rharrison> yep as it will wobble I guess
[12:56] <edmoore> i would think you'd get away with either
[12:57] <edmoore> yeah nova 8 was going in and out audible ever 3 seconds on descent
[12:57] <edmoore> because of the coning motion on the parachute
[12:57] <rharrison> Longer separtion cord?
[12:57] <rharrison> Should reduce wobble?
[12:58] <edmoore> better designed chute!
[12:58] <rharrison> :) Not this time round
[12:58] <edmoore> because your chutes are built hemisphericlly, they should be more stable
[12:58] <rharrison> I'm going to do a few dummy drops with a 1.5 kg load and see what happens
[12:58] <edmoore> i would suggest cutting some holes in them, but you're already on the wire in terms of drag :)
[12:59] <rharrison> The platform will have a readonable Surface Area
[13:00] <edmoore> yeah - that will help - but make sure it's a decent distance beneath the chute. as you intuited (is that a word?), it will increase the instability from coning, but also make sure the chute is clear of the wake of the payload.
[13:00] <edmoore> if it gets caught up in payload wake then that'll give it some pretty significant stability problems too
[13:01] <edmoore> sorry, *descrese* the instability from coning
[13:03] <edmoore> the reason no chutes can be deployed stabley above mach 2.3~ is because the forebody shock does not dissipate at all, in any reasonable length, which completely interferes with the bow shock created by the parachute, and makes the whole thing flap about like an epileptic jellyfish
[13:04] <rharrison> That must have been intersting to explain to the first astronaughts
[13:04] <edmoore> that's why they didn't deploy till slower!
[13:05] <rharrison> Yep when the air density increased. Can't remember if they used a slowing shute or not
[13:05] <rharrison> Breaking shute even
[13:06] <edmoore> they did - really nasty dynamic pressures
[13:06] <edmoore> you normally deploy at mach2
[13:07] <edmoore> because also the standard 'entry body' design, stable hypersonically, starts becoming unstable at mach1.8
[13:07] <edmoore> then you wait until a speed where you can safely deploy a parachute that will give you the landing speed you want
[13:12] <edmoore> the fun we're having is trying to get our boosted dart to land safely for the space rocket
[13:13] <edmoore> we've got it doing mach 4 when it hits the spike of dynamic pressure on the way down
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[14:25] <edmoore> goodness. http://www.astroflight.com/index.php?main_page=product_info&cPath=9&products_id=123
[14:25] <edmoore> you pay for it, but man, that's a powerful motor
[14:26] <edmoore> the standard robot wars ones were 750W for that weight
[14:28] <rharrison> Did you do that robot wars stuff?
[14:31] <edmoore> yeah
[14:31] <edmoore> from age 13 to about 17
[14:31] <edmoore> got me into engineering. along with mars pathfinder.
[14:36] <rharrison> Nice one, I always fancied a go at it. Did you get very far against the competition?
[14:40] <edmoore> Yeah, not too bad. Helped with some heavies then mainly did featherweights
[14:40] <edmoore> and helped out with a few events
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[16:19] <edmoore> passing storm seems to be causing a flakey connection
[16:22] <rharrison> I may do the becon test launch from cambridge! Is there anyone down there who would be up for a chase in a couple of weeks?
[16:22] <rharrison> At a more reasonable time of day?
[16:25] <gordonjcp> I'll try to receive it from up here, if I can get my ten-element yagi built
[16:30] <edmoore> rharrison: poss in a couple of weeks
[16:30] <edmoore> fergus is on holiday atm
[16:30] <edmoore> I'm on holiday next week
[16:30] <edmoore> but i think we're both around in the last week of sept
[16:58] <rharrison> Let do it in the last week then depending on weather. I'll try to get the beacon finished this weekend
[16:58] <rharrison> gordonjcp: Get that antenna built :)
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[18:30] <ShellEvil> http://www.youtube.com/watch?v=Q-VDdSnCu4s
[18:30] <ShellEvil> ...
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[19:02] <edmoore> novel!
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[20:01] <robert1971> on a prommise tonight so you may not see me till much later or tomorrow am
[20:01] <robert1971> :)
[20:02] <edmoore> ha, sounds like words have been had
[20:03] <edmoore> I think I'm going to pub it.
[20:03] <robert1971> Nice one, is Friday... Mind U it's friday every day for you at the moment
[20:04] <robert1971> keep fingers x'ed for box 2 morrow
[20:04] <edmoore> Well until 2 hours ago
[20:04] <natrium> british post works on saturday?
[20:05] <edmoore> natrium: yep
[20:05] <natrium> that's cool
[20:11] <robert1971> Royal Mail... Well it is for now
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[20:33] <fuzzylugnuts> Hey folks
[20:36] <natrium> hi
[20:37] <fuzzylugnuts> I made up a worksheet for predicting the balloon size needed for reaching neutral buoyancy at a given altitude, would you guys please validate it against the stuff you use?
[20:41] <natrium> sure, just post it somewhere
[20:42] <fuzzylugnuts> I'm moving it to my server now
[20:42] <fuzzylugnuts> http://68.34.212.42/neutralb.xls
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[20:51] <fuzzylugnuts> that sheet isn't good for stuff above 100,000 ft.
[21:00] <fuzzylugnuts> I'm going to make a little model balloon this weekend and see if the gore calculation is right.
[21:04] <edmoore> it seems that if night/day makes such huge differences to balloons, and our spreadhseets don't take account of that, we're doing something wrong.
[21:06] <fuzzylugnuts> I don't see how we can, except for overestimating the balloon volume
[21:08] <edmoore> it's possible. I am dire at thermodynamics, but i'm sure we could get close with some fairly basic heat transfer sums
[21:09] <fuzzylugnuts> well if you figure it out let me know : )
[21:09] <edmoore> ha. will get out my notes.
[21:09] <fuzzylugnuts> ok : )
[21:09] <fuzzylugnuts> my specialty is nuclear instrumentation, not thermodynamics
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[21:13] <jcoxon> evening all
[21:14] <edmoore> ello
[21:15] <fuzzylugnuts> jcoxon: http://68.34.212.42/neutralb.xls
[21:16] <fuzzylugnuts> if you do NB calculations, could you please check the sheet against what you came up with?
[21:16] <fuzzylugnuts> edmoore: I'd be more inclined to have a little ballast drop every 24 hours than mess with thermo
[21:18] <edmoore> indeed, but to get an idea of how much ballast you need to drop....
[21:19] <edmoore> I appreciate that several payloads will be lost in just getting an idea of what happens, but that doesn't preclude doing some sums to try and get a ballpark idea of what you're dealing with.
[21:19] <fuzzylugnuts> I'd love to know the temperature of the gas in daytime/nightime
[21:20] <edmoore> that's hopefully what i'll figure out.
[21:20] <fuzzylugnuts> A, good
[21:20] <fuzzylugnuts> I won't be launching until next year anyways, so hopefully by then the predictions will be mature
[21:22] <edmoore> it'll be a useful plugin for some grand sim of everything
[21:22] <fuzzylugnuts> Yeah
[21:23] <fuzzylugnuts> Luckily the NOAA ATDD group is 1 department away from me. I hope I can get some info from them
[21:23] <fuzzylugnuts> http://www.atdd.noaa.gov/Oak_Ridge_Climate_Additions/oakridgemetcurrent.htm
[21:24] <edmoore> cool. we just grab the GFS grib files.
[21:24] <fuzzylugnuts> ?
[21:25] <edmoore> oh, just the forecasts we use for simming
[21:25] <fuzzylugnuts> ah, ok
[21:25] <edmoore> wind vectors and temp at lots of altitudes
[21:25] <fuzzylugnuts> oh that'd be lovely
[21:26] <edmoore> well, grib files are what you want to look for
[21:26] <fuzzylugnuts> I'll see if they'd like to help.
[21:26] <edmoore> they come in 0.5 x 0.5 degree boxes
[21:26] <edmoore> right, new pub with a micro-brewery. See you all later!
[21:26] <fuzzylugnuts> Laters!
[21:26] <jcoxon> hehe
[21:27] Nick change: edmoore -> edmoore|away
[21:27] <fuzzylugnuts> I had enough gin and some sort of chilled clear stuff this past business trip to hold me over for a while : P
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[22:24] <fuzzylugnuts> I think the gore calculation is right, but this model balloon is sucking to make : P
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[22:38] <fuzzylugnuts> Hey
[22:41] <smealum> hey
[22:42] <natrium> smealum, what are you doing here?!
[22:42] <smealum> not much atm
[22:42] <smealum> what are you doing here ?
[22:42] <smealum> oh
[22:42] <smealum> oops
[22:42] <smealum> wrong channel
[22:42] <smealum> lol
[22:42] <natrium> ...
[22:42] <smealum> sorry, i didn't actually mean to come here
[22:43] <natrium> maybe it's fate
[22:43] <smealum> old autojoin from when i was working on a stratospheric balloon last year
[22:43] <natrium> so you are going to start a high altitude mission?
[22:43] <smealum> nope, already done with it ^^
[22:43] <smealum> it was a school project last year
[22:43] <smealum> more or less failed though
[22:43] <smealum> lol
[22:44] <natrium> ah, sorry to hear that
[22:44] <natrium> so you didn't get it back?
[22:44] <smealum> actually, we did
[22:44] <smealum> but we were two classes working on it
[22:44] <smealum> and the second class was in charge of the system to activate the camera and take pictures
[22:44] <smealum> it didn't work.
[22:44] <smealum> so no pictures
[22:45] <natrium> couldn't you do it again?
[22:45] <smealum> really a shame, the pictures on your website were awesome ^^
[22:45] <natrium> thx
[22:45] <smealum> nah, it was last year's project, done now :/
[22:48] <natrium> you missed very cool flights by some people in this channel
[22:48] <natrium> http://www.nivnac.co.uk/blog1.php
[22:48] <natrium> pics are incredible
[22:49] <smealum> wow
[22:49] <smealum> this is amazing
[22:51] Nick change: edmoore|away -> edmoore
[22:51] <edmoore> on cue :p
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[23:02] <Laurenceb_> ello
[23:02] <fuzzylugnuts> jesus. as crappy as this balloon was made, I could'nt squish it to pop it.
[23:03] <Laurenceb_> they are tough
[23:03] <fuzzylugnuts> yeah, I think this mylar+kapton tape on the seams is going to be great
[23:03] <edmoore> works for us!
[23:03] <Laurenceb_> you've made an envelope?
[23:04] <fuzzylugnuts> just a tiny one
[23:04] <fuzzylugnuts> edmoore: you use it too?
[23:04] <Laurenceb_> what materials are you using?
[23:04] <fuzzylugnuts> ...mylar and kapton tape?
[23:04] <edmoore> kapton tape, anyway
[23:04] <edmoore> its useful
[23:04] <fuzzylugnuts> ah, yeah
[23:04] <edmoore> it's low tempt gaffa
[23:05] <edmoore> temp*
[23:05] <fuzzylugnuts> there is a nearly infinite supply of it on ebay
[23:08] <fuzzylugnuts> it might be because this is so small and it was only a 20cm diameter 6 gore balloon, but it was nearly impossible to line the edges up parallel for taping. I'd have to have them on a 20cm diameter form
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[23:09] <edmoore> doesn't suprise me
[23:09] <edmoore> we found problems with a 5m dia balloon!
[23:09] <fuzzylugnuts> Yea, thats what worries me
[23:10] <fuzzylugnuts> I need to make like, a section of plastic that has the same curvature of the balloon I'm trying to make, in both directions
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[23:12] <fuzzylugnuts> I can see why tube balloons are so attractive
[23:12] <edmoore> :)
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[23:16] <fuzzylugnuts> ah, balls to it. As fun as it would be, I have enough work to do.
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[23:27] <Laurenceb_> does a c for loop always execute once?
[23:27] <Laurenceb_> ie is it like a do ... while loop?
[23:28] <edmoore> doesn't have to execute once
[23:28] <edmoore> for(i=1;i<0;i++){}
[23:28] <edmoore> a compiler might catch that - I've never tried
[23:29] <edmoore> infact that probably would execute some number of times
[23:29] <edmoore> till whatever 'i' is overflows
[23:30] <edmoore> no, gibberish. of course it wouldn't execute
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[23:32] <Laurenceb_> :P
[23:32] <Laurenceb_> ok
[23:33] <Laurenceb_> right... parafoil code is getting close to being finished, tronics is as well
[23:33] <fuzzylugnuts> my balloon failure: http://3.bp.blogspot.com/_juQlvTFvz7s/RwJKKmeMuPI/AAAAAAAAAOk/iYyxK-jeTPQ/s1600/meteoriteperucrater324qghkj.jpg
[23:34] <fuzzylugnuts> ; P
[23:34] <Laurenceb_> lol
[23:34] <Laurenceb_> hopefully I'll have everything ready by november
[23:36] <fuzzylugnuts> good luck
[23:39] <natrium> Laurenceb_, the condition is always checked before the body is executed
[23:44] <Laurenceb_> k
[23:45] <Laurenceb_> yeah the cutdown works :D
[23:45] Action: Laurenceb_ inhales some white smoke
[23:46] <fuzzylugnuts> don't bogart that cutdown, my friend.... pass it over to me : )
[23:47] <Laurenceb_> I've stuck the code up on the wiki
[23:47] Action: fuzzylugnuts smokes the code
[23:47] <Laurenceb_> I've tried to make it reset resistant, so if you aren't pressing the "dead man" switch as it boots, it can get back to where it left off
[23:49] <Laurenceb_> the on/off switch, dead man switch and rs232 jack are on a seperate bit of board that's going to be embedded in the top of the enclosure
[23:50] <Laurenceb_> once the lipos are installed all being well the side panel can be epoxied in place, as you can control everything and upload new code over the rs232
[00:00] --- Sat Sep 13 2008