highaltitude.log.20090411

[00:03] <Laurenceb> I seem to remember something about 5khz on NOVA11
[00:03] <Laurenceb> if the IF bandpass is 6KHz ie +-3KHz I'm not sure how well it'll work
[00:04] <Laurenceb> the radiometrix TX is ~+-2.5KHz so you may get a bit throught
[00:05] <Laurenceb> gtg
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[00:13] <rjharrison> nights
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[05:08] <natrium42> .
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[07:17] <rjharrison> moring all
[07:17] <rjharrison> Today is pre launch day
[07:17] <rjharrison> Only T -25 hours to go
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[07:21] <rjharrison> Good moring jcoxon
[07:21] <jcoxon> morning
[07:21] <rjharrison> Just checking the js
[07:21] <natrium42> rjharrison, enough time?
[07:21] <jcoxon> my internet is very patchy
[07:21] <jcoxon> so i might disappear
[07:21] <rjharrison> np
[07:22] <rjharrison> natrium42 yep that's fine for me I think steve is busy building the yagi
[07:22] <jcoxon> rjharrison, still on for tomorrow?
[07:22] <rjharrison> Yep
[07:22] <rjharrison> It's going to be a fast launch
[07:23] <jcoxon> run me through the plan
[07:23] <rjharrison> weather is a bit dicy for any record attempts
[07:23] <rjharrison> Drive to ears for ~8 am
[07:23] <rjharrison> Test Uplink coms working
[07:23] <rjharrison> Clear ldistener data
[07:24] <rjharrison> We could do with as many people as possible using the latest code
[07:24] <rjharrison> Which I think I have here
[07:24] <jcoxon> yup
[07:24] <rjharrison> Will post in a sec
[07:24] <rjharrison> Steve will be cordinating ATC coms
[07:24] #highaltitude: mode change '+o jcoxon' by ChanServ!ChanServ@services.
[07:25] <rjharrison> Cameras is going up set at 2minvideo every 4 mins and 8 pics
[07:25] <jcoxon> Welcome to #highaltitude - discuss anything to do with high altitude projects (balloons, gliders, etc) www.ukhas.org.uk, wiki.ukhas.org.uk . Icarus 3 Flight Sunday 12/04/09 07:00GMT, Track: http://www.robertharrison.org/tracker/ More info: http://wiki.ukhas.org.uk/current_launch_details
[07:25] <rjharrison> Assent rate will be fast
[07:26] <jcoxon> sensible
[07:26] <rjharrison> Judged by my fair hand
[07:26] <jcoxon> i would even consider records as you are doing other things such as uplink
[07:26] <rjharrison> wouldn't
[07:26] <rjharrison> ?
[07:26] <jcoxon> yeah
[07:26] <jcoxon> sorry
[07:27] <natrium42> jcoxon, that's not how you change topic :P
[07:27] <rjharrison> Yep there will be no alt record atempt tomorrow
[07:27] <rjharrison> BTW technically Icarus !! Launch 2
[07:27] <rjharrison> opps II
[07:27] <jcoxon> natrium42, its how i've always done it ;p
[07:27] <natrium42> rofl
[07:28] <rjharrison> I'm going to set up VNC access here
[07:28] <jcoxon> oops
[07:29] <jcoxon> hehe natrium42 i thought i had /topic'd
[07:29] <rjharrison> Looking for a volunteer to control fldigi here
[07:29] <jcoxon> and so was very confused...
[07:29] Topic changed on #highaltitude by jcoxon!n=jcoxon@212.183.134.64: Welcome to #highaltitude - discuss anything to do with high altitude projects (balloons, gliders, etc) www.ukhas.org.uk, wiki.ukhas.org.uk . Icarus II Flight Sunday 12/04/09 07:00GMT, Track: http://www.robertharrison.org/tracker/ More info: http://wiki.ukhas.org.uk/current_launch_details
[07:29] <jcoxon> thats better
[07:30] <rjharrison> Yep
[07:31] <natrium42> :)
[07:33] <jcoxon> hmmm nothing back from olimex - guess they have good friday
[07:42] <rjharrison> natrium42 would you mind if I post the track to space near us tomorrow
[07:43] <natrium42> not at all, feel free to delete the previous one
[07:43] <rjharrison> I'll move the logs to the next free mission ID
[07:44] <natrium42> i deleted it, don't really need the track
[07:44] <rjharrison> ok np
[07:44] <rjharrison> I will do some testing today to make sure all is fine
[07:45] <natrium42> k, cool
[07:51] <rjharrison> i assume i should be using tracker and not track
[07:52] <natrium42> yeah, track is the old version
[07:52] <natrium42> but they use the same DB
[07:53] <jcoxon> track is good for low bandwidth
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[08:37] <rjharrison> natrium42 working
[08:37] <natrium42> excellent
[08:39] <jcoxon> :-)
[08:49] <rjharrison> hum how do you past code into the wiki?
[08:52] <rjharrison> dome it
[08:52] <rjharrison> http://www.spacenear.us/wiki/doku.php?id=dlistening:client:radioclient5
[08:55] <jcoxon> cool got it
[09:03] <rjharrison> Ok it looks like it is going to be a bit cludy tomorrow but I'm not proposing that changes anything
[09:03] <jcoxon> why cludgey?
[09:03] <rjharrison> cloudy :)
[09:04] <jcoxon> oh right
[09:04] <jcoxon> clouds are pretty
[09:04] <rjharrison> Ok whiteout
[09:04] <rjharrison> with the chance of rain
[09:04] <rjharrison> Yeaterday's forcast was for sun
[09:04] <jcoxon> it might change...
[09:04] <rjharrison> but it is bankholiday
[09:05] <natrium42> g'nite all
[09:05] <jcoxon> night natrium42
[09:05] <jcoxon> rjharrison, do you have google earth installed?
[09:06] <jcoxon> could you pop on it and find out the long and lat for Aldeburgh, Suffolk
[09:07] <icez> lon: 52.148343 lat: 1.599798
[09:11] <jcoxon> thanks icez
[09:12] <jcoxon> other way round though :-p
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[09:15] <icez> woops
[09:16] <Hiena> That word sounds bad in the explosives factory.
[09:27] <jcoxon> bbl
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[10:01] <shellevil> jco: google maps - find @56n,3e works
[10:10] <rjharrison> Tidying up the desk
[10:14] Action: shellevil should prolly do more garden tidying.
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[11:27] <sbasuita> Laurenceb, hey, you said that the ericssons use 9600 baud, right? Do you happen to know if they use parity or how many stop bits?
[11:28] <Laurenceb> I've forgotten
[11:28] <Laurenceb> 8N1 maybe
[11:28] <Laurenceb> rig it up to hyperterminal and type "AT"
[11:29] <sbasuita> Ooh!
[11:29] <Laurenceb> it should reply with "OK"
[11:29] <sbasuita> I'm getting responses at 9600 8n1
[11:29] <sbasuita> yes
[11:29] <sbasuita> : )
[11:29] <Laurenceb> try AT+CMGS
[11:29] <sbasuita> =/
[11:29] <sbasuita> ERROR
[11:29] Action: Laurenceb looks it up
[11:30] <Laurenceb> http://www.experts-exchange.com/Programming/Wireless_Programming/GSM/Q_21740368.html
[11:30] <sbasuita> networkmanager on ubuntu is going mental
[11:30] Action: sbasuita has the ericsson at command reference
[11:30] <Laurenceb> cool
[11:30] <Laurenceb> you may have to use PDU mode
[11:31] <Laurenceb> instead of text mode - theres some code on the wiki
[11:32] <Laurenceb> http://pastebin.com/dff53a68
[11:34] <sbasuita> Laurenceb, what is PDU?
[11:34] <Laurenceb> its a compressed HEX mode
[11:35] <Laurenceb> I'm not sure if it actually runs across the network
[11:35] <shellevil> it's not hex
[11:35] <shellevil> it's the native format I think
[11:36] <shellevil> SMSs are not native ascii, but some 7 bit packed format
[11:36] <Laurenceb> sure, it goes in as hex
[11:36] <Laurenceb> yeah
[11:36] <Laurenceb> thats what I meant
[11:39] <Laurenceb> hmm I remember what going on with that code
[11:40] <Laurenceb> I discovered that I didnt need the smscen in the PDU string with my phone
[11:41] <Laurenceb> but theres a function there to obtain the sms center
[11:41] <Laurenceb> you probably need to play about a bit - in my experience the different ericsson phones do it in slightly different non standard ways
[11:42] <Laurenceb> its kind of annoying
[11:43] <Laurenceb> omg.. http://dl0tud.tu-dresden.de/~dj1yfk/zm/09-04-03/F-OB804020neu-rr.JPG
[11:43] <Laurenceb> no wonder the HF transmitter got picked up
[11:52] <Laurenceb> uck? you have to swap the leading 0 for 44
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[12:10] <rjharrison> Boo
[12:13] <sbasuita> : O
[12:32] <edmoore> yakasha
[12:32] <edmoore> about to go though
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[12:47] <jcoxon> rjharrison, i got the message forwarded to the balloon_sked list
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[15:51] <edmoore> afternoon all
[15:51] <edmoore> morning stilldavid and natrium42
[16:04] <shellevil> afternoon
[16:04] Action: shellevil has been hedgetrimming and shredding today.
[16:04] <shellevil> And slashing his face with razor blades.
[16:05] <shellevil> (well - is 4mm a slash?)
[16:05] <shellevil> A) appointment with doctor, refer to hospital to drain cyst. B) razor blade.
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[16:28] <edmoore> hi g8khw
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[16:57] <jcoxon> afternoon all
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[17:00] <jcoxon> hey G8KHW
[17:02] <G8KHW> hey jcoxon
[17:03] <jcoxon> all set for tomorrow?
[17:04] <G8KHW> yep - everything ready - yagi finished
[17:04] <G8KHW> nice job - even if i do say it myself
[17:05] <jcoxon> excellent
[17:05] <jcoxon> i'm in Aldeburgh so will track from there
[17:10] <G8KHW> ah OK - excellent - sounds like it will be an early launch
[17:10] <jcoxon> yeah
[17:12] <G8KHW> http://imagebin.org/45147
[17:12] <G8KHW> http://imagebin.org/45149
[17:13] <G8KHW> http://imagebin.org/45150
[17:13] <G8KHW> http://imagebin.org/45151
[17:14] <jcoxon> looks good
[17:21] <jcoxon> okay will be back on tomorrow morning
[17:21] <jcoxon> cya all
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[17:49] <rjharrison> .
[17:49] <rjharrison> Humm seem to loast and regain internet connection
[17:49] <rjharrison> lost
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[18:17] <rjharrison> shellevil: could you do a quick vnc test for me
[18:18] <rjharrison> .
[18:20] <shellevil> sure
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[19:53] <natrium42> ello
[19:58] <shellevil> o
[20:00] <natrium42>
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[20:39] <natrium42> hi rjharrison
[20:59] <natrium42> edmoore, you can !summon him :)
[21:04] <edmoore> wow
[21:10] <natrium42> does he have push email on his cell phone? :P
[21:15] <edmoore> not sure
[21:17] <natrium42> whoa, hawt
[21:18] <natrium42> there is a script for eagle to export PCB to solidworks
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[21:31] <natrium42> edmoore, do you know when the launch tomorrow is?
[21:32] <rjharrison> 8am bst
[21:32] <rjharrison> 7amn gmt
[21:33] <edmoore> ok cool
[21:33] <edmoore> rjharrison: I will be up for that
[21:33] <edmoore> I guess we won't be leaving till 11-ish
[21:33] <edmoore> so yes I can vnc
[21:34] <natrium42> early
[21:34] <natrium42> i guess i will catch the launch before going to bed :P
[21:35] <edmoore> that's commitment natrium42
[21:35] <natrium42> yesterday i went to bed at 4am
[21:35] <natrium42> which is 9am GMT
[21:36] <natrium42> so there :P
[21:39] <edmoore> I am going to re-kindle a CUSF desire from about 3 years ago
[21:39] <edmoore> a VW camper
[21:40] <edmoore> http://www.speedace.info/automotive_directory/car_images/vw_split_screen_coca_cola_camper_van.jpg
[21:40] <edmoore> navy blue, CUSF logo down the side, stack of tracking antennas on the roof
[21:41] <natrium42> haha\
[21:41] <natrium42> peace symbols also?
[21:42] <edmoore> why not
[21:43] <icez> then you can all dress up with dark blue suits and ties and sunglasses and scare the little kids at the park where you launch
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[21:45] <natrium42> yo hallam
[21:45] <natrium42> hallam, rjharrison is launching at 2am our time
[21:45] <natrium42> are you up for it? :)
[21:49] <hallam> hey
[21:49] <hallam> I might be
[21:49] <hallam> got a lot of revision to do
[21:49] <hallam> what's flying?
[21:56] <edmoore> hallam: rjharrison's icarus payload, + fm receiver and mp3 recorder onboard
[21:56] <edmoore> for testing uplinks
[21:57] <hallam> heh, that's cool
[21:57] <hallam> how bad is MP3 for destroying data transmissions?
[22:08] <edmoore> probably can deal with 50-baud rtty
[22:08] <edmoore> i'd have thought
[22:08] <hallam> yeah
[22:24] <rjharrison> Ok guys this is my last till tomorroe
[22:24] <rjharrison> Ok guys this is my last till tomorrow
[22:24] <rjharrison> Off to bed
[22:24] <rjharrison> Early start
[22:24] <hallam> good luck
[22:28] <rjharrison> thanks
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[22:35] <natrium42> nite rjharrison
[22:36] <rjharrison> nights
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[22:52] <Laurenceb> hello
[22:52] <shellevil> o
[22:55] <hallam> hi Laurenceb (and shellevil)
[22:55] <Laurenceb> anyone familiar with evince?
[22:55] <Laurenceb> hi hallam
[22:55] <shellevil> it's a book reader isn't it?
[22:55] <Laurenceb> yeah
[22:56] <Laurenceb> I'm trying to view bookmarks in a pdf
[22:56] <shellevil> not really
[22:56] <shellevil> I put everything into html
[22:56] <shellevil> then read it - often with lynx
[22:56] <shellevil> as I've got a nifty backreference script
[22:56] <Laurenceb> your just stupidly hardcore
[22:56] <Laurenceb> :P
[22:57] <shellevil> that backreferences every proper name to its first occurance.
[22:57] <Laurenceb> its annoying having to wade through hundereds of pages in a datasheet to find what your after
[22:58] <shellevil> yeah - this is mainly for text.
[23:03] <Laurenceb> I was looking at the radiometrix receiver - theres a 455KHz IF
[23:04] <Laurenceb> I'm thinking it should be possible to sample that
[23:04] <shellevil> hmm
[23:04] <shellevil> just amplify it a bit, and feed to a 2MHz ADC or somethign you mean?
[23:05] <shellevil> this is a UHF reciever?
[23:05] <Laurenceb> nope, I'm thinking about 16Ksps
[23:05] <Laurenceb> yes
[23:05] <shellevil> 16k?
[23:06] <shellevil> you mean subsampling?
[23:06] <Laurenceb> yes
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[23:07] <Jcoxon> Hey
[23:07] <Jcoxon> I was summoned
[23:07] <edmoore> yeah
[23:07] <edmoore> vnc?
[23:07] <Jcoxon> ?
[23:08] <edmoore> re: tomorrow
[23:08] <edmoore> oh was that text not from you
[23:08] <edmoore> no it wasn't
[23:08] <Jcoxon> I'll be tracking
[23:08] <edmoore> ok, I unsummon you
[23:08] <Laurenceb> another launch?
[23:09] <Laurenceb> its like very weekend now :P
[23:09] <Jcoxon> Rob will need someone to vnc into his machine
[23:09] <Jcoxon> At home
[23:09] <Jcoxon> I'm on the suffolk coast so should be able to get a good track
[23:10] <edmoore> cool
[23:10] <edmoore> he told me after i had gone home, otherwise I would have brough my kit with me and listened
[23:11] <Jcoxon> Oh well
[23:12] <Jcoxon> i sent the launch info to the big amateur radio balloon list
[23:12] <Jcoxon> Might get some new visitors
[23:12] <Jcoxon> Right i'll be on at 7 tomorrow
[23:12] <Laurenceb> 434MHz ?
[23:12] <Jcoxon> Night
[23:12] Action: shellevil should maybe be awake
[23:12] <Jcoxon> Yup
[23:12] <shellevil> 434.750
[23:12] Action: hallam is under the horizon, but might be online
[23:13] <Jcoxon> Check the wiki
[23:13] <shellevil> err
[23:13] <Jcoxon> The launch info is there
[23:13] <shellevil> 434.075
[23:13] <shellevil> sorry
[23:13] <Jcoxon> Regarding the freq
[23:13] <shellevil> ah
[23:13] <Jcoxon> Night
[23:13] <shellevil> ignt
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[23:16] <Laurenceb> hmm annoyingly the inbuilt adc on avrs has an input bandwidth of ~100KHz
[23:16] <hallam> those BASTARDS
[23:16] <hallam> how dare they keep it comparable to the sampling frequency
[23:17] <Laurenceb> hehe
[23:18] <Laurenceb> but with an external 8 bit adc an avr can easily decode 300 baud or 50 baud
[23:18] <Laurenceb> just a FLL and DLL
[23:20] <gordonjcp> Laurenceb: why not convert it down to a lower frequency?
[23:21] <Laurenceb> it might require AGC as well - the radiometrix datasheet just has a rough diagram
[23:21] <Laurenceb> you convert to lower frequency with the ADC sampling rate
[23:21] <Laurenceb> I intend to use two fixed frequency lookup tables to do the mark/space determination on the avr
[23:22] <Laurenceb> then the FLL changes the time between samples
[23:22] <Laurenceb> the DLL determines number of samples per integration bin
[23:23] <Laurenceb> sampling the 455KHz IF around 16KHz or similar
[23:24] <shellevil> Umm.
[23:24] <shellevil> Why not just a RCRCRC filter or so
[23:25] <Laurenceb> eh
[23:26] <shellevil> to filter the IF
[23:26] <shellevil> oh - FM
[23:34] <gordonjcp> Laurenceb: sampling the IF at 16kHz won't really work
[23:35] <Laurenceb> ADC081S021 looks nice
[23:35] <Laurenceb> why not?
[23:35] <gordonjcp> because you need to sample at approximately twice the highest frequency
[23:36] <gordonjcp> or more, if you want any definition in the sampled signal
[23:36] <Laurenceb> nope
[23:36] <Laurenceb> it'll downconvert it
[23:36] <gordonjcp> no
[23:36] <gordonjcp> you'll get aliasing, that's not the same
[23:36] <Laurenceb> theres a SAW filter that limits the bandwidth of the IF to 6KHz
[23:36] <gordonjcp> uh-huh
[23:37] <Laurenceb> so you only need to sample at around 12KHz or a bit more
[23:37] <gordonjcp> but that's a bandpass filter centred on a particular input frequency
[23:37] <gordonjcp> Laurenceb: yes, after the detector
[23:37] <Laurenceb> no
[23:37] <gordonjcp> you can't sample the IF at 12kHz
[23:37] <Laurenceb> before
[23:37] <gordonjcp> how's that supposed to work?
[23:37] <Laurenceb> the detector runs at 455KHz
[23:37] <gordonjcp> yup
[23:37] <Laurenceb> I want to extract it before the detector
[23:38] <shellevil> why?
[23:38] <gordonjcp> Laurenceb: right, so you need to sample at about 1MHz at least
[23:38] <Laurenceb> nope
[23:38] <gordonjcp> yes, you do
[23:38] <Laurenceb> 12KHz at least
[23:38] <gordonjcp> okay, let's try again
[23:39] <gordonjcp> you have a 455kHz IF
[23:39] <gordonjcp> you have a filter with 6kHz bandwidth
[23:39] <gordonjcp> what is the frequency of the signal you get out, when you pass the IF through the filter?
[23:39] <Laurenceb> 455
[23:39] <gordonjcp> right
[23:39] <gordonjcp> so what's the lowest sample rate that can accurately sample 455kHz?
[23:40] <Laurenceb> 455*2
[23:40] <gordonjcp> right
[23:40] <Laurenceb> but if you only want 6KHz bandwidth you can sample at lower rate and get an image
[23:40] <gordonjcp> not really, no
[23:40] <Laurenceb> its done all the time
[23:40] <gordonjcp> where is it done?
[23:41] <Laurenceb> lots of receivers use that technique
[23:41] <Laurenceb> most of the single chip gps receivers
[23:42] <gordonjcp> [citation needed]
[23:42] <gordonjcp> anyway, if you reckon it'll work, try it
[23:42] <gordonjcp> I don't think it will give reliable results for what you're trying to do
[23:42] <gordonjcp> and also, I don't see why you'd try and do that when you could just sample the output of the detector/discriminator
[23:43] <gordonjcp> and have it properly in the audio domain to begin with
[23:43] <Laurenceb> that lets in extra noise
[23:47] <Laurenceb> hmm MCP6G01T-E/OT and ADC081S021 then an atmega168
[23:47] <Laurenceb> nice and small - ~12mm square
[23:48] <shellevil> Could you explain why it lets in extra noise?
[23:48] <Laurenceb> for the pcb, so its fit inside the recess on the bottom of the receiver
[23:48] <Laurenceb> as you have 6KHz bandwidth into the descriminator
[23:49] <shellevil> you're trying to sample the IF, and recover the 441/441.8 (or whatever) tones that result from FM?
[23:49] <Laurenceb> wheras if you digitise it and look for the signal you have of the order of the baud rate of bandwidth for noise to get in
[23:49] <Laurenceb> I'm directly modulating
[23:49] <gordonjcp> Laurenceb: but to digitise it you need to digitise at twice the IF
[23:50] <Laurenceb> grrr this is the same point you keep making
[23:50] <Laurenceb> its not thecase
[23:50] <shellevil> I think you're assuming that the A/D has less noise than the demodulator
[23:50] <shellevil> You're modulating AM?
[23:50] <Laurenceb> FM
[23:50] <Laurenceb> with a radiometrix
[23:51] <shellevil> ah - do it before then you can ignore nearby stronger signals and stuff
[23:51] <shellevil> I see
[23:51] <Laurenceb> and decode other stuff like phase modulated data ect
[23:52] <gordonjcp> Laurenceb: okay, so if you sample it at a lower frequency, how will you get the IF?
[23:52] <shellevil> as long as the clock is jitter-free
[23:52] <gordonjcp> you'd have to have a perfect unmodulated carrier
[23:53] <shellevil> nyquist is only true for the information content of the signal
[23:53] <Laurenceb> yes
[23:53] <shellevil> you have to sample twice or more the information bandwidth of the signal
[23:53] <Laurenceb> and its limited to 6KHz bandwidth
[23:53] <Laurenceb> so you only need >12Ksps
[23:53] <shellevil> For a 455KHz IF, band-limited to 6KHz, that's only 6KHz
[23:54] <shellevil> in theory - with ideal clocks
[23:55] <gordonjcp> Laurenceb: but if you do that, you won't recover *any* usable signal
[23:56] <gordonjcp> which is the whole point of an FM discriminator
[23:56] <gordonjcp> I suggest a strong cup of tea and a wee read of the relevant parts of the RSGB handbook or equivalent, before bed
[23:57] <Laurenceb> its data modulated using two descreet frequencies
[23:57] <Laurenceb> not FM voice
[23:57] <gordonjcp> right, fine, well
[23:57] <gordonjcp> it's still FM
[23:57] <gordonjcp> it's not like it's a hard problem
[23:58] <gordonjcp> people have been using fsk for a long long time now
[23:59] <shellevil> You put it through a demodulator, and you've got FM capture happening
[23:59] <shellevil> Which means that any noise in the whole passband can make the thing lock to it.
[23:59] <shellevil> If you digitise it - or use two more conventional filters - you can ignore most of the noise
[00:00] --- Sun Apr 12 2009