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[00:01] <SpeedEvil> http://www.berr.gov.uk/consultations/page52505.html
[00:01] <SpeedEvil> The civil space program in britain
[00:01] <SpeedEvil> and how it should be funded - consultation
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[00:30] <russss> err, spend more money with them? Deregulate? Get rid of that silly space act?
[00:30] <SpeedEvil> I'm currently attempting to download the PDF on the consultation.
[00:31] <SpeedEvil> And being annoyed by my 'broadband'
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[07:57] <edmoore> morning all
[07:57] <edmoore> Sparky68: a delayed congrats on the 790
[07:57] <edmoore> lovely rig :)
[07:57] <Sparky68> :D
[07:57] <Sparky68> I'm looking forward to being able to monitor other peoples launches
[07:58] <Sparky68> PLus my own of course (once I get the project launched)
[07:58] <edmoore> where are you, geographically?
[07:58] <Sparky68> Orpington, Kent
[07:58] <edmoore> building your own yagi would be a good project - amazing what you can do with £15 and a trip to homebase
[07:59] <edmoore> great location - you can track all of our stuff :)
[07:59] <Sparky68> yeah I plan on doing that as Yagi's seem to start at around £50 upwards
[07:59] <Sparky68> :)
[07:59] <edmoore> you'll learn a lot more doing it DIY too, and the results are just as good
[07:59] <Sparky68> any plans online for DIY Yagi's?
[07:59] <edmoore> there are some really good calculators
[08:00] <edmoore> let me show you the one I've used (just need to boot up my windows vm)
[08:01] <Sparky68> thanks
[08:01] <edmoore> yagi calculator for vhf/uhf by dl6wu
[08:03] <Sparky68> found it
[08:03] <Sparky68> thanks
[08:03] <edmoore> just eneter the numbers and you're good to go
[08:04] <edmoore> the yagi we use is 9 elements, and it's pretty loud
[08:04] <Sparky68> great
[08:04] <Sparky68> i'll try it out on my windows machine later
[08:04] <edmoore> may be worth trying something slightly short - fits in the car more easily
[08:04] <edmoore> ah, another non-windows user
[08:04] <Sparky68> OSX
[08:04] <edmoore> you'll be at home here :)
[08:05] <edmoore> CUSF runs off Macs, jcoxon is a mac user too
[08:05] <Sparky68> :)
[08:08] <edmoore> so you have plans for an eventual payload too:)
[08:08] <Sparky68> sort of - Canon Ixus 400 controlled by Atmega328 on a Servo tilt mount doing both video and stills
[08:09] <Sparky68> Also temp and pressure sensors
[08:09] <Sparky68> and GMS module
[08:09] <edmoore> radio downloink or hitching a lift?
[08:09] <Sparky68> yeah 433MHz downlink
[08:10] <Sparky68> thinking about putting an accelerometer in there too
[08:11] <Sparky68> data will be logged onto an SD card as well as down the RF link
[08:11] <edmoore> nice good datasets from well instrumented balloon flights are a great resource
[08:11] <Sparky68> never done this before so this is all new to me
[08:13] <edmoore> makes it more worth doing
[08:14] <Sparky68> yeah i'm looking forward to it
[08:15] <edmoore> right, time to be off. talk to you later
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[08:15] <Sparky68> cya
[08:57] <Sparky68> Question about RF links if anyone is here?
[09:06] <gordonjcp> sure
[09:07] <gordonjcp> don't ask to ask
[09:07] <Sparky68> Just wondering how you guys test your RF links? The 433MHz modules will only work long distance if they are up high and have no obstructions
[09:07] <Sparky68> so the only real test as far as I can see is when they are up in a balloon and many miles away
[09:14] <gordonjcp> pretty much
[09:14] <gordonjcp> you can estimate the performance of a link though
[09:15] <gordonjcp> and if you stick one end on a high building and stand a long way away that can give a good approximation
[09:23] <Sparky68> i see
[09:23] <Sparky68> thanks
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[10:36] <gordonjcp> how heavy a package is it practical to fly?
[10:36] <gordonjcp> could you do about a kilo?
[10:36] <Sparky68> i think some payloads have been up to 2KG
[10:37] <Sparky68> but that is just from reading stuff - not done it myself
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[13:32] <Sparky68> You guys should have a GALLERY page on the website showing all of the great HAB pictures
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[14:14] <juxta> does anybody know of any balloon stockists in Australia?
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[15:18] <Laurenceb> hi
[15:19] <SpeedEvil> ih
[15:41] <Laurenceb> I was thinking about MRI
[15:41] <Laurenceb> I think you can make earth field practical if you can extract an entire slice per free induction decay
[15:42] <Laurenceb> your limited by the line width to the amount of information you can get out at 2KHz
[15:42] <Laurenceb> but I think you can get 1M voxel in 5minutes
[15:43] <Laurenceb> e.g. 1Litre scan volume, 1mm cubes as voxels
[15:44] <Laurenceb> if you have slices along z, then each slice is retreived using a gradient along x
[15:44] <Laurenceb> then you have a prn code applied at different angles and phases in the x/y plane
[15:45] <Laurenceb> you can use a process similar to the doppler/delay space inversion in gps to retrieve slices
[15:49] <Laurenceb> actually you have to follow that inversion with a matrix technique to reproduce viewable images
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[15:58] <Laurenceb> SpeedEvil: I think you could so it with a sound card
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[16:05] <SpeedEvil> Hmm.
[16:06] <SpeedEvil> I'm unsure there is a great point in sticking to earths field.
[16:06] <SpeedEvil> vs - say - a maxwell coil maybe 1000* earths field and using the middle quarter
[16:08] <Laurenceb> yeah
[16:08] <Laurenceb> higher field gives you more information per decay
[16:09] <Laurenceb> I'm not sure how operational machines manage to get out useful data as fast as they do
[16:09] <Laurenceb> maybe they dont wait for an entire decay
[16:09] <SpeedEvil> They don't
[16:10] <Laurenceb> but I'm not sure how you get the spins back into a well defined state from that point
[16:10] <SpeedEvil> The above book went into that somewhat
[16:10] <Laurenceb> ok that explains how you do it fast enough
[16:10] <Laurenceb> I need to read it properly
[16:11] <Laurenceb> but anyway, if you do wait for en entire decay you can use PRN to extract an entire slice at a time
[16:11] <SpeedEvil> Also there is the obvious fact that when you put a gradient field, and apply a 900MHz - or whatever - pulse, you can just as easily (from a magnetics point of view) apply a 890,880,870, ... pulse at the same time
[16:11] <SpeedEvil> And do multiple parallel slices
[16:12] <SpeedEvil> Just makes the transmitter harder to build and hte reciever
[16:12] <Laurenceb> ah yes
[16:12] <Laurenceb> provided they are seperated by some distance
[16:12] <SpeedEvil> Hmm
[16:12] <Laurenceb> so that how you get FMRI to work
[16:12] <Laurenceb> so the x and y gradients dont make them overlap
[16:13] <SpeedEvil> I wonder if you excite the whole damn volume with a PRN, if you can extract the data that way
[16:13] <Laurenceb> heh theres probably a way
[16:13] <SpeedEvil> yeah
[16:14] <SpeedEvil> I think a lot of the current approaches are to make the maths tractable.
[16:14] <Laurenceb> yes thats what it looks like to me
[16:14] <Laurenceb> its very easy to grab from the sound card and muck about as much as you like in octave
[16:14] <SpeedEvil> And maybe to some extent - a lot of lock-in to 1990s ways of doing stuff
[16:16] <SpeedEvil> I'm currently wondering if I can build a nice cheap 16 bit DAQ
[16:16] <SpeedEvil> ~5MHz
[16:17] <Laurenceb> http://pastebin.com/m5a8c49fb
[16:17] <SpeedEvil> You'd need what as a minimum.
[16:17] <SpeedEvil> A couple of gradient coils, a couple of sampling coils, and an excitation coil?
[16:18] <Laurenceb> http://pastebin.com/m5f7256d2
[16:18] <SpeedEvil> and you may be able to misuse the gradient coil to do excitation
[16:18] <Laurenceb> yeah
[16:18] <SpeedEvil> At least at this frequency.
[16:18] <SpeedEvil> At 900MHz it'd be harder.
[16:19] <Laurenceb> actually one sampling coil, two gradient coils, excitation coil and a main field/z gradient coil
[16:19] <SpeedEvil> don't you need quadrature to pull out the phase properly?
[16:19] <Laurenceb> those bits of code I pastebinned, if you compile the c code and run the script
[16:19] <Laurenceb> depends if you want to extract phase or not
[16:19] <SpeedEvil> hmm
[16:20] <Laurenceb> its just a quick spectrum demo
[16:20] <Laurenceb> if you talk into the mic its nice
[16:20] Action: SpeedEvil looks at the degaussing coild he's been saving from old TVs.
[16:21] <Laurenceb> you need to install octave
[16:22] <SpeedEvil> I need to reinstall my memories from when I'd just done the last course of maths.
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[16:27] <Laurenceb> that sound card code reminds me - I need to write a RTTY decoder in c
[16:33] <Laurenceb> unfortunately my mic doesnt work properly - you have to litterally hit it to get anything out
[16:33] <Laurenceb> maybe a preamp not turned on? - it works ok under windows
[16:40] <juxta> is powering a digital camera designed to run from 2xAA's (3v) from a 3.3v regulator likely to cause dramas?
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[16:41] <Laurenceb> nope
[16:41] <SpeedEvil> probably not
[16:41] <Jon_Apex> unlikely
[16:41] <Laurenceb> new AA cells are more than 1.5v
[16:41] <SpeedEvil> 3.2V is a common voltage for 2 new AA cells
[16:41] <juxta> ah excellent
[16:41] <Laurenceb> 3.4V or more is likely with some
[16:41] <SpeedEvil> yueah
[16:42] <Jon_Apex> whack a diode in there if you really want
[16:43] <juxta> I thought about that, but a diode would usually have a voltage drop of a bit more than .3v, wouldnt it?
[16:43] <Jon_Apex> depends on the diode, but yes, probably
[16:43] <Jon_Apex> i'd be very surprised if the camera complained at 3V3 though
[16:44] <juxta> :)
[16:44] <juxta> thanks guys
[16:44] <Laurenceb> also the camera probably has a switched mode supply
[16:44] <Laurenceb> so avoiding a diode will improve the efficiency
[16:44] <Laurenceb> what brand camera?
[16:45] <juxta> unsure at this stage
[16:45] <juxta> whatever ebay coughs up for cheap
[16:45] <juxta> :)
[16:45] <juxta> most likely a canon or a kodak by the looks of things
[16:45] <Jon_Apex> argos do a cheap Canon one (can run CHDK) for about £35 IIRC
[16:45] <Laurenceb> nice
[16:45] <juxta> argos?
[16:45] <Laurenceb> I've used premier ones before, but canon is way better
[16:46] <Laurenceb> oh your austrailian?
[16:46] <Jon_Apex> its a 2x1.5V AA jopb as well
[16:46] <juxta> indeed I am :)
[16:46] <Jon_Apex> ah right, Argos isn't going to be much use then
[16:46] <juxta> hehe
[16:47] <Jon_Apex> we got a Canon A610 (or similar) from ebay for about £30 for Apex I
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[16:47] <Jon_Apex> was quite heavy though, and needed 6V
[16:47] <juxta> 6v isnt a prob, there's 6v on my payload
[16:47] <Jon_Apex> :)
[16:47] <juxta> but weight.. yeah, hehe
[16:48] <juxta> I haven't found anywhere to buy balloons in aus
[16:48] <Jon_Apex> the lens array was quite heavy on that one
[16:48] <juxta> but by the looks of things, big ones are quite pricey
[16:48] <Laurenceb> is there an APEX page?
[16:48] <Jon_Apex> http://wiki.ukhas.org.uk/projects:apex-i
[16:48] <Jon_Apex> and details on Apex II (still in progress) here:
[16:48] <Jon_Apex> http://ukhas.org.uk/projects:apex-ii
[16:49] <Laurenceb> you're at cambridge?
[16:49] <Jon_Apex> I am now :)
[16:49] <Laurenceb> ah cool
[16:49] <Laurenceb> congratulations
[16:50] <Jon_Apex> thanks :)
[16:50] <juxta> I'm interested in getting sponsorship for my project, I should look into it
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[16:50] <Laurenceb> hmm I guess this is becoming a theme
[16:50] <Jon_Apex> looking forward to getting involved with CUSF
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[16:50] <Jon_Apex> haha
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[16:50] <jcoxon> evening all
[16:50] <Jon_Apex> hi
[16:50] <juxta> hi jcoxon
[16:52] <jcoxon> hey
[16:53] <Jon_Apex> I'm off, see you all later
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[16:55] <Laurenceb> http://wiki.answers.com/Q/What_do_rocks_eat
[16:57] <juxta> jcoxon - I noticed you gave the guys from the ALIEN project a bit of a hand with their comms, was wondering if I oculd bug you with a few questions :)
[16:57] <jcoxon> haha
[16:57] <jcoxon> juxta: of course
[16:58] <juxta> I'm building something similar to their atmega board, except I'm using an arduino
[16:58] <jcoxon> okay
[16:58] <juxta> so not much difference on that side of things, but I need some advice from anybody who can offer some on recievers
[16:58] <jcoxon> right
[16:58] <jcoxon> where are you based?
[16:58] <juxta> Australia
[16:59] <juxta> seems it's hard to find much here
[16:59] <jcoxon> and you want advice on radio comms
[16:59] <jcoxon> the first step is to find out about what the laws are like
[17:00] <juxta> yeah - I'm looking at using the NTX2, I've found them at a reasonable price, and checked out the licensing
[17:00] <jcoxon> here in the UK the rules are very restrictive
[17:00] <jcoxon> hence why we use the ntx2 as its licence exempt
[17:00] <SpeedEvil> In the US - with a ham license, you can do _lots_
[17:00] <Laurenceb> arrrrrrduino
[17:00] <juxta> 433mhz is license exempt here, no restictions on air/ground based etc
[17:00] <jcoxon> up to what power?
[17:00] <juxta> i think 20mw
[17:00] <juxta> or maybe 25
[17:01] <jcoxon> oh right, its 10mW here
[17:01] <Laurenceb> you can get plenty of range with that
[17:01] <jcoxon> the ntx2 module is a great module, easy to work with
[17:01] <jcoxon> if you can find a module that does 25 then even better
[17:01] <juxta> yeah, it seems fairly straight forward
[17:01] <juxta> hmm. I'll email the supplier and see if they suggest anything, let me just double check the licensing
[17:01] <jcoxon> the key with the ntx2 is that it varies freq according to voltage
[17:02] <jcoxon> most other modules are more on or off
[17:03] <jcoxon> sorry - you really asked about receivers, ham receivers are the best option really
[17:03] <jcoxon> the receiver pairs that you get with the transmitters are usually terrible
[17:03] <jcoxon> and scanners are good but not great
[17:04] <juxta> jcoxon: just checked the legislation, it's 25mW on 433.05-434.79 :)
[17:04] <juxta> yeah - I figured with the temperatures there would be freq. drift and a small non-tunable receiver would be useless
[17:05] <juxta> I saw the Yaesu transiever which seems to be pretty popular
[17:05] <SpeedEvil> Also the reciever pairs are unfortunately very bad sensitivity
[17:05] <SpeedEvil> generally
[17:05] <juxta> ah, that makes sense
[17:06] <juxta> so in terms of receivers - I can't seem to find much short of about $400-500AUD :(
[17:07] <jcoxon> juxta: yeah they aren't cheap
[17:07] <jcoxon> i have 2 radios
[17:07] <Laurenceb> I've been experimenting with chipcon transceivers
[17:07] <jcoxon> a yaesu ft790r
[17:07] <jcoxon> and a ft817
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[17:07] <Laurenceb> look at the UM12 module on sparkfun.com
[17:07] <jcoxon> both are great for ballooning
[17:07] <Laurenceb> that based on the chipcon IC from Ti, but I havent flown one yet
[17:07] <jcoxon> ft790r is old and cheaper but only does 430-440
[17:08] <jcoxon> while ft817 does HF, VHF and UHF
[17:08] <jcoxon> so is good for ham stuff
[17:08] <Laurenceb> CUSF have flown a few, but using them like a NTX2
[17:09] <juxta> I don't presently hold a ham license, so 430-440 would be ideal for me - I looked for the ft790r, can't find it here on ebay
[17:09] <jcoxon> they are relatively rare considering their age
[17:09] <juxta> Laurenceb: i'll have a look
[17:09] <jcoxon> appear about once a month
[17:09] <juxta> the FT-7800R is not too badly priced I guess
[17:10] <juxta> but i'm not sure if it's really suitable
[17:10] <jcoxon> the key is doing SSB (USB and LSB)
[17:10] <jcoxon> rather then FM
[17:10] <juxta> I'm sorry - can you fill me in on the acronyms? :)
[17:11] <jcoxon> np
[17:11] <jcoxon> so FM is frequency modulated - like normal commercial radio
[17:11] <juxta> yep, i know that one ;p
[17:11] <jcoxon> SSB is a mode that takes half of FM
[17:12] <jcoxon> it allows for increased efficiency
[17:12] <juxta> I see
[17:12] <juxta> as in, greater sensitivity?
[17:12] <jcoxon> basic radios often just do FM, more advanced do SSB and to get the nice distances
[17:13] <jcoxon> SpeedEvil and I have a nice wiki page, one sec
[17:13] <juxta> cheers
[17:14] <jcoxon> http://ukhas.org.uk/guides:tracking_guide
[17:16] <jcoxon> see the background section
[17:16] <juxta> so something like the Yaesu FT-1807M wouldnt be capable of SSB? (It's cheap, hence my asking)
[17:16] <juxta> thanks, reading into ssb now
[17:17] <jcoxon> Yaesu FT-1807M won't do ssb unfortunately
[17:17] <juxta> there's an FT-4700RH on ebay here, but it's in 'unknown' condition
[17:18] <jcoxon> link
[17:18] <juxta> http://cgi.ebay.com.au/Yaesu-FT-4700RH-dual-band-VHF-UHF-transceiver_W0QQitemZ250508467683QQcmdZViewItemQQptZAU_Electronics_Radio_Equipment?hash=item3a5377dde3&_trksid=p3286.c0.m14
[17:18] <jcoxon> again FM only
[17:19] <jcoxon> for lots of hams they only really need FM
[17:19] <juxta> fair enough
[17:21] <jcoxon> and i suspect that ham radio isn't a massive hobby in australia
[17:21] <juxta> so if I'm following correctly, with SSB, the radio listens at 434.07X mhz, the transmitter transmits at 434.07X + 1000hz for a space, +1200hz for a mark?
[17:22] <Laurenceb> http://en.wikipedia.org/wiki/Fan_death <- wow
[17:22] <juxta> Laurenceb: is that the soouth koren thing?
[17:22] <jcoxon> because your radio receives a band of the radio spectrum you then hear 2 tones
[17:22] <Laurenceb> yes
[17:22] <juxta> haha
[17:22] <juxta> yep, following now :)
[17:23] <juxta> so I've got to find a reasonable priced receiver that's capable of SSB on ~433 mhz
[17:23] <jcoxon> yeah
[17:23] <jcoxon> you could look at scanners as well
[17:23] <juxta> a scanner being just a receiver?
[17:23] <jcoxon> they often are a little less sensitive but might be more accessible/cheaper
[17:23] <jcoxon> yesr
[17:25] <juxta> hrm
[17:25] <juxta> only 10 of those on ebay here currently
[17:27] <jcoxon> if you live near a ham club they might have one to borrow or ones for sale
[17:28] <juxta> yeah - I have a mate who holds a ham license, I think he's involved in a club or two, will have to see if he know anybody willing to loan/sell one
[17:28] <jcoxon> thats a good place to get 2nd hand radios
[17:29] <juxta> so without fm alone, the receiver won't be of much use?
[17:30] <jcoxon> for ballooning using the low power method that we use you really need SSB
[17:30] <juxta> fair enough
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[17:31] <juxta> there seem to be some ICOM transcievers with SSB around the $800 mark, but they're only HF :(
[17:31] <jcoxon> if you can use licenced radio power then FM might suffice
[17:31] <jcoxon> how about from Hong Kong
[17:32] <juxta> most of the radios on the Aus ebay are from HK, hehe
[17:34] <juxta> http://cgi.ebay.com/YAESU-FT-790R-MKII-UHF-TRANSCEIVER-TECH-SPECIAL-LOOK_W0QQitemZ270467602558QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3ef920187e
[17:34] <jcoxon> that would work
[17:35] <jcoxon> i think its a newer model then my 790
[17:35] <jcoxon> looks slightly different
[17:35] <juxta> wonder if it actually works though
[17:35] <jcoxon> or maybe an older model
[17:39] <juxta> jcoxon: how about this?
[17:39] <juxta> http://cgi.ebay.com/Icom-IC-741-IC-471A-E-UHF-all-mode-tranceivr-IC471-SSB_W0QQitemZ160368752074QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2556b8f5ca
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[17:41] <jcoxon> juxta: tis good but no oversea us buyer
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[17:41] <juxta> jcoxon: that's okay, there are some people who run handy services for that here :)
[17:42] <jcoxon> i think it looks good
[17:42] <jcoxon> RocketBoy: evening
[17:42] <jcoxon> RocketBoy: http://cgi.ebay.com/Icom-IC-741-IC-471A-E-UHF-all-mode-tranceivr-IC471-SSB_W0QQitemZ160368752074QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item25
[17:42] <jcoxon> 56b8f5ca
[17:42] <RocketBoy> yo yo
[17:42] <jcoxon> oops that went over 2 lines i think
[17:43] <jcoxon> looking at receivers for juxta (is based in australia)
[17:43] <juxta> thanks for this by the way guys :)
[17:44] <juxta> there's a handheld one in the UK too
[17:44] <juxta> http://cgi.ebay.co.uk/Kenwood-TH-F7E-2-70cm-Handheld-With-SSB-0-1300mhz_W0QQitemZ230386851176QQcmdZViewItemQQptZUK_ConsumerElectronics_SpecialistRadioEquipment_SM?hash=item35a4205d68&_trksid=p3286.c0.m14
[17:45] <RocketBoy> the 1st one is in the US - and he says no overseas buyers :-(
[17:46] <juxta> RocketBoy: that's okay, we can get around that
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[17:50] <juxta> I'll keep an eye on that icom one
[17:50] <juxta> though I should get to bed now.. damn timezone differences
[17:50] <juxta> it's 3:20am here :(
[17:50] <jcoxon> hehe yeah
[17:51] <jcoxon> night juxta
[17:51] <juxta> thanks for all your help everybody :)
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[17:51] <RocketBoy> The TH-F7E seems sensitive enough - but I cant tell what (if any) filter they have for SSB
[17:52] <juxta> RocketBoy: the ICOM is probably easier for me to get hold of in any case
[17:53] <jcoxon> right i better go
[17:53] <jcoxon> cya
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[17:53] <Laurenceb> I've used a ICOM
[17:53] <juxta> would you reccomend it Laurenceb?
[17:53] <Laurenceb> I've used a scanner
[17:53] <Laurenceb> the problem is power
[17:54] <juxta> as in powering it?
[17:54] <RocketBoy> the IC-471 has a SSB filter (see http://www.radioamateur.eu/schemi/IC471_user.pdf) but isn't that sensitive at 0.3uV
[17:56] <juxta> RocketBoy: I don't know much (anything) about ham transcievers - is that likely to be an issue?
[17:57] <gordonjcp> just saying 0.3uV isn't terribly helpful
[17:57] <gordonjcp> that's -118dBm for 12dB SINAD, which is not to be sniffed at
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[18:00] <gordonjcp> furthermore with a properly calibrated test set you can probably get that up a bit, at the expense of some bandwidth
[18:01] <gordonjcp> my TK-705 is currently giving about -117dBm sensitivity but I can get -120dBm if I only want 500kHz worth of channels
[18:02] <gordonjcp> spreading it out for the whole 2MHz of the 2m band makes it a bit less sensitive
[18:02] <gordonjcp> it's still only 3dB gain, you could get a better aerial and better coax
[18:03] <juxta> I think I might place a bid on the ICOM IC-741 in that case :)
[18:03] <juxta> ...in the morning ;p
[18:03] <RocketBoy> (I have said this before and I'll say it again) it all comes down to how sentitive you want it to be - The IC-7000 is speced at 0.11uV the FT817 at 0.125uV the FT870 at 0.18uV ... (for similar S/N)
[18:04] <gordonjcp> yeah
[18:04] <Laurenceb> wonderfull
[18:04] <Laurenceb> someone has left a dewar of LN2 next to me with the bung replaced by tissue
[18:04] <Laurenceb> its now half full of LOX
[18:04] <gordonjcp> and the FT817 gets 0.125uV for 12dB SINAD *if* you happen to have Mr Yaesu's own personal 817 which is supercooled with liquid helium
[18:05] <Laurenceb> good job to tissue didnt fall in :-/
[18:05] <gordonjcp> Laurenceb: :-O
[18:05] <Laurenceb> boom
[18:05] <gordonjcp> practically, the 817 gets about 0.2-0.3uV for 12dB SINAD
[18:05] <RocketBoy> gordonjcp - so your saying that thats not the same for the others - its all relative
[18:06] <gordonjcp> RocketBoy: well there is a certain amount of variation between different sets
[18:06] <gordonjcp> manufacturing tolerances and so on
[18:06] <juxta> hmm - actually, before I go, can someone give me a rough idea what the transceiver like the ICOM would wiegh?
[18:06] <RocketBoy> accepted but if you go by the specs there is almost 9dB difference for the same S/N between 0.11uV and 0.3uV
[18:07] <gordonjcp> RocketBoy: *if* you're getting that performance
[18:07] <RocketBoy> 9dB is the difference between say 100Km range and 300Km range
[18:08] <gordonjcp> well, it's not as simple as that
[18:08] <RocketBoy> what I'm really talking about is the realtive performnce
[18:08] <gordonjcp> you might get 300km range with the less sensitive receiver and 100km with the more sensitive one
[18:08] <RocketBoy> not if they are performing to the spec
[18:09] <juxta> whoops, manual has the weight. shipping is going to cost me $100USD if I buy it, ouch
[18:09] <gordonjcp> RocketBoy: nope
[18:09] <gordonjcp> even if they are entirely to spec
[18:09] <RocketBoy> explain
[18:09] <gordonjcp> the more sensitive one is potentially more prone to intermod problems
[18:09] <gordonjcp> furthermore
[18:09] <RocketBoy> oh sure
[18:09] <gordonjcp> a rig like the 817 has a frontend as broad as a barn door
[18:10] <RocketBoy> sure sure - but just on sensitivity alone
[18:10] <gordonjcp> so your theoretical 0.11uV sensitivity is somewhat hampered by the TETRA transmitter a few miles away
[18:10] <juxta> night all
[18:10] <RocketBoy> I have never encountered interference problems when tracking balloons
[18:11] <gordonjcp> whereas the 471 with its big clunky old helical filters is going to be a little bit less sensitive on 70cm and *absolutely stone deaf* outside the passband
[18:12] <gordonjcp> RocketBoy: you may not be hearing interference but it will still be desensing the receiver
[18:12] <gordonjcp> often by quite a bit
[18:13] <RocketBoy> so based on the practical experiance we have in tracking balloons I would say thet the main issues are sensitivity and filter bandwidth
[18:13] <gordonjcp> yup
[18:14] <gordonjcp> tbh if you picked up an old duplexer and tuned it for 70cm and then followed it up with a good >10dB preamp then you'd probably get more out of that
[18:14] <RocketBoy> may be in central london - not in the wilds of east anglia
[18:15] <gordonjcp> you'd be surprised
[18:15] <gordonjcp> got a spectrum analyser?
[18:15] <RocketBoy> not on me
[18:16] <gordonjcp> stick a reasonably wideband antenna - 3-ele yagi with a folded dipole, say - onto yer handy little Anritsu and wander out to a "quiet spot"
[18:16] <gordonjcp> set it to scan from about 420 to about 460
[18:16] <gordonjcp> watch in amazement as it goes apeshit at both ends
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[18:21] Action: RocketBoy slings IC-R7000 on the bench and fires it up on 420MHz with a 1/4 wave
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[18:41] <RocketBoy> 420MHz to 460Mhz - pleanty of faint stuff - but nothing that even lifts the S meter
[18:41] <RocketBoy> so no apshit here
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[19:01] <Laurenceb> does anyone have some RTTY mp3 files?
[19:01] <Laurenceb> or equivalent
[19:02] <SpeedEvil> There is on eon the wiki
[19:02] <SpeedEvil> I think
[19:02] <Laurenceb> http://www.srcf.ucam.org/~cuspaceflight/wiki/doku.php?id=badger1 <- nice
[19:04] <Laurenceb> aha http://ukhas.org.uk/_media/projects:badgerrtty.ogg.zip?id=projects%3Abadger&cache=cache
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[19:20] <Laurenceb> http://www.armadilloaerospace.com/n.x/Armadillo/Home/News?news_id=368
[19:20] <SpeedEvil> nea
[19:21] <SpeedEvil> ^t
[19:22] <natrium42> haha, cooking hot dogs with rocket exhaust
[19:22] <natrium42> better not be hydrazine
[19:23] <SpeedEvil> You can do better than that.
[19:24] <SpeedEvil> http://metalab.at/wiki/Salami_Rocket
[19:25] <natrium42> wtf
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[20:31] <jcoxon> hey all
[20:31] <Jon_Apex> evening
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[20:49] <jcoxon> ping rjharrison
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[20:59] <jcoxon> hey guys, what happened to nova 14?
[20:59] <jcoxon> was it recovered?
[20:59] <jcoxon> (the one with the uplink)
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[21:05] <SpeedEvil> I think not
[21:05] <SpeedEvil> It just splashed
[21:05] <SpeedEvil> Or at least, I don't recall any mention of a recovery
[21:06] <jcoxon> found it in the logs
[21:07] <jcoxon> the other question is - the last rjharrison launch
[21:07] <jcoxon> when, and what happened
[21:08] <jcoxon> (no one has updated the launch list)
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[21:28] <jcoxon> hey russss would it be possible for me to go to the hackspace on sat afternoon?
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[22:05] <russss> jcoxon: yeah sure
[22:05] <russss> it's open till 5:30
[22:05] <russss> on saturdays
[22:06] <jcoxon> okay cool
[22:06] <jcoxon> what equipment is there? and are people there often?
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[22:07] <russss> jcoxon: best to ask in the channel whether anyone is there
[22:08] <jcoxon> fair enough
[22:08] <russss> hardware-wise we don't have a huge amount of useful stuff yet. We just bought a bench power supply
[22:10] Action: natrium42 doesn't have a bench power supply :(
[22:11] Action: jcoxon doesn't have one either
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[22:12] <russss> we have a guy who is going to bring a logic analyzer and 100MHz digital scope
[22:12] <russss> because he has them spare (!)
[22:12] <jcoxon> oh yeah was he at the last meeting
[22:12] <russss> he's pretty cool
[22:12] <jcoxon> i'm interested in checking out what sort of antenna i can put up :-p
[22:12] <russss> ah. Not really sure, roof access is pretty limited
[22:13] <russss> I just got my USRP
[22:13] <jcoxon> oooo cool
[22:14] <russss> if you buy it with the enclosure they send it as a kit of parts, heh
[22:15] <jcoxon> lots of soldering then
[22:16] <russss> nah I mean the board is assembled
[22:16] <russss> but the enclosure comes in lots of bits :P
[22:16] <jcoxon> oh right, smaller packaging
[22:16] <jcoxon> i've ordered a new radio module for my payload
[22:16] <jcoxon> so that 'll be complete soon
[22:19] <russss> cool
[22:20] <jcoxon> am now working on the daughter board to control ballast :-)
[22:28] <jcoxon> bbl
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[23:03] <SpeedEvil> random - has anyone purchased glass recently - and knows what size of sheets it's delivered to the glaziers in?
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[00:00] --- Wed Oct 14 2009