00:00:00 --- log: started forth/03.06.03 00:32:20 --- join: Serg_Penguin (Serg_Pengu@212.34.52.142) joined #forth 00:32:32 hi 00:32:41 up just 4 a short while ;( 00:33:05 :( 00:33:10 Hi anyway, serg 00:33:20 heh 00:33:44 it's my birthday today, and my bed gave me a nasty gift - wrecked through ;) 00:34:00 Haopy birthday! 00:34:24 I know another person who has birthday today.. spent the night writing him a little birthday program in Minix. 00:34:41 Stupid Minix... for some wierd reason sleep() fucked things up. 00:35:59 Why a birthday program in Minix? 00:36:41 Why not? ;) 00:37:35 Hmm.. I guess the account is his birthday present from me. 00:37:52 ah 00:37:56 It's connected with a null-modem cable :D 00:38:12 A few kb/s from a 486 running Minix, that's a nice present! 00:38:24 Lots of downtime, too. 00:39:15 heh 00:39:24 why not just give him copy of minix? 00:40:55 Why would I give him that when he can download it everywhere? 00:41:26 heh 00:41:42 Thought it was still under commercial license or something 00:42:14 No. 00:42:25 Was released a few years ago. 00:43:14 --- join: rob_ert (~robert@h138n2fls31o965.telia.com) joined #forth 00:43:19 Hello from Minix :) 00:43:47 Yes, there is an IRC client for it... 00:44:19 * rob_ert leaves. 00:44:20 --- quit: rob_ert (Client Quit) 01:12:51 --- quit: Serg_Penguin () 01:13:08 --- part: bwb left #forth 02:15:39 --- join: deluxe (~deluxe@pD9E59276.dip.t-dialin.net) joined #forth 03:29:19 --- join: Serg_Penguin (Serg_Pengu@212.34.52.142) joined #forth 03:45:12 --- quit: Serg_Penguin () 03:46:33 --- quit: a7r (Read error: 113 (No route to host)) 03:59:11 --- join: Serg_Penguin (Serg_Pengu@212.34.52.142) joined #forth 04:17:18 --- quit: Serg_Penguin () 05:09:29 --- join: Serg_Penguin (Serg_Pengu@212.34.52.142) joined #forth 05:54:12 --- quit: Serg_Penguin () 07:32:25 --- join: sifbot (~sifforth@h003065f7146c.ne.client2.attbi.com) joined #forth 07:32:25 Type sifbot: (or /msg sifbot to play in private) 08:50:49 --- join: Serg_Penguin (Serg_Pengu@212.34.52.142) joined #forth 08:59:13 * Serg_Penguin is ear-deep in viruses and crashed computers 08:59:37 just uncrashed one, but another seems to be wormed 09:03:01 --- join: gengar (~ritchie@rsmith.ccc.ox.ac.uk) joined #forth 09:03:40 hi 09:04:03 'lo. 09:07:31 hope not at all down ;) 09:07:34 new here ? 09:07:59 Yeah. Just distracting myself from study. 09:08:12 forth expireince ? 09:08:32 mine - little games and utils 09:08:32 Minimal. I started playing with it as a distraction and quite liked it. 09:09:46 some elders of here wrote own Forths 09:10:04 --- join: futhin (futhin@dial-207.ocis.net) joined #forth 09:10:08 --- quit: futhin (Client Quit) 09:10:09 http://isforth.clss.net for example 09:12:21 looking ? it's for Linux 09:12:36 Yeah, I just took a look... 09:13:05 or look at http://robert.zizi.org 09:13:20 he wrote some too, but i didn't try 09:14:02 i440r's isforth is perfect by design concept but mega buggy (at least, in my hands it crashes much more than others) 09:14:37 I'm playing with gforth at the moment... like I said, I'm only really playing with it as a distraction. 09:15:21 what books have you read on it ? 09:15:53 None at all. I found a few tutorials and started playing with the exercises. 09:16:24 tutors - suxx, many ppl stumble over them 09:16:52 read Leo Broudie 'Starting Forth' and 'Thinking Forth' 09:16:59 Seems quite nice. I used to do Z80 assembler when I was a sprog, and got into perl a few years back. Now I'm just playing with different concepts. Trying to get back into programming. 09:17:09 Cheers.\ 09:17:30 I'll look 'em up in Blackwells when I've finshed exams. 09:17:46 the latter is a must for any progger - coz it's more on progging philosophy w/ Forth examples 09:18:26 Sounds interesting. 09:18:33 or even on design philosophy, not only progging (it has one wonderful example on complex prototype hardware) 09:19:02 i read both in RU only, some amateurs translated 09:19:22 Forth in RU has many wizards and zealots 09:19:32 look forth.org.ru 09:19:36 Cool. 09:20:09 I anticipate having lots of free time to play with forth after I get kicked out of university in two weeks. Hee! 09:20:46 it's driven by eserv - win32 HTTPD written in SPF4 - open src RU Forth 09:21:10 and trivial HTTPD in Forth is just few pages of code 09:22:07 brb 09:27:21 Interesting. 09:30:00 --- join: fridge (~matt@dsl-203-33-160-242.NSW.netspace.net.au) joined #forth 09:31:07 hello 09:34:58 Hello! 09:42:05 back 09:44:11 wb. 10:06:50 --- join: a7r (~a7r@206.72.82.135) joined #forth 10:09:55 --- quit: Serg_Penguin () 10:20:10 hey 11:01:24 --- quit: Fractal (Read error: 110 (Connection timed out)) 11:09:56 --- quit: a7r (Read error: 60 (Operation timed out)) 11:55:05 --- join: mur (murr@baana-62-165-184-61.phnet.fi) joined #forth 11:58:09 --- join: abcd (~efgh@pD9E59276.dip.t-dialin.net) joined #forth 11:58:58 --- part: abcd left #forth 12:01:32 --- join: g4lt_ (~galt@pD9E59276.dip.t-dialin.net) joined #forth 12:02:54 --- quit: fridge (Excess Flood) 12:02:59 --- join: fridge (~matt@dsl-203-33-160-242.NSW.netspace.net.au) joined #forth 12:05:18 --- part: g4lt_ left #forth 12:06:52 --- join: deluxe_ (~deluxe@pD9E59276.dip.t-dialin.net) joined #forth 12:07:04 --- part: Robert left #forth 12:07:11 --- join: Robert (~snofs@h138n2fls31o965.telia.com) joined #forth 12:07:12 Oops. 12:08:21 Oops i did it again 12:08:42 --- nick: deluxe_ -> g4lt_ 12:10:10 --- part: g4lt_ left #forth 12:15:53 excúse moi 12:16:17 mur what did you do again? 12:16:23 nah 12:16:29 it was ironical phrase 12:16:37 vote now your favourites!! http://www.adbusters.org/campaigns/dirty_dozen/ 12:25:39 --- join: kc5tja (~kc5tja@ip68-8-206-137.sd.sd.cox.net) joined #forth 12:25:39 --- mode: ChanServ set +o kc5tja 12:45:35 --- quit: mur (Read error: 104 (Connection reset by peer)) 12:46:02 --- join: mur (murr@baana-62-165-184-61.phnet.fi) joined #forth 12:59:51 --- join: tathi (~josh@pcp02123722pcs.milfrd01.pa.comcast.net) joined #forth 13:01:54 --- join: dan_ (dan@pcp053555pcs.brlngt01.nj.comcast.net) joined #forth 13:22:36 elo tathi 13:22:42 Hi :) 13:22:56 lo 13:23:28 elo Robert.# 13:23:32 elo Robert. 13:23:41 elo mur. 13:23:44 elo mur 13:23:52 elo # 13:23:55 :) 13:24:34 late night typos tztz 13:24:56 Hehe.. 13:25:11 Robert: how's your forthchip prj ;-) 13:25:11 It's not late :) 13:25:28 Not a forthchip.. and I haven't worked on it for a while. 13:25:29 optimist :-) 13:27:09 elo gengar 13:27:20 * deluxe curious :-) 13:27:48 --- join: thin (thin@bespin.org) joined #forth 13:28:15 howdy thin 13:29:41 heya delux 13:30:06 oh shit 13:30:07 --- quit: thin (Client Quit) 13:33:37 hi deluxe 13:33:44 seems to be a common form to say good bye over there.. 13:34:02 lol 13:34:02 :) 13:35:08 your ppc forthos is coded in asm? 13:35:41 well...I've sort of dropped the OS part for the time being. 13:35:54 but the ppc forths that I'm playing with are coded in asm, yes. 13:36:34 oh? why? (thought you were already right inbetween) 13:37:05 easier to debug etc. under Linux 13:37:29 it would probably only take me an hour or two to get it to run straight from OpenFirmware though 13:38:33 which asm do you use? 13:38:40 GNU as 13:38:49 I don't know of another assembler for Linux PPC 13:39:09 it's not actually that bad. 13:39:37 the macro facility seems to be buggy and incomplete still, but otherwise... 13:39:51 isn't nasm a metaassembler(assembles itself)? 13:40:06 nasm is only x86, AFAIK 13:41:04 probably yes 13:41:55 I just have a really minimal forth written in assembly language. 13:42:28 then I define the assembly instructions that I use as forth words 13:42:46 and I'm currently working on getting it to be able to write out ELF files. 13:43:29 and playing with optimizing code generation 13:43:34 do you know introspector? 13:43:41 no, what is it? 13:44:02 --- nick: dan_ -> jstahuman 13:44:33 in #tunes yesterday someone told me, idea is interesting 13:44:37 only place I've heard the term is in connection with an object browser/examiner facility for Java 13:44:52 s/object/class/ 13:45:25 gcc metadata(trees) exported to xml/rdf and back 13:46:21 was gcc only at start, now a palette of compilers etc more 13:46:41 gcc metadata? 13:47:33 actually all data streamed through gcc 13:47:41 hmm 13:48:20 so I suppose that's useful if you want to try and automatically translate to another programming language 13:48:24 or something? 13:49:15 for visualizing and modifying complex relations in general 13:49:49 tathi: I noticed that you're using Gnu as for the PowerPC assembler. What is your impression of it? 13:50:03 well, the TUNES project obviously needs that kind of thing 13:50:13 I can't see that it's at all useful for forth... 13:50:51 kc5tja: as I said a few minutes ago, the macro facility seems to be buggy, and doesn't do everything that the info page says it does. 13:51:03 tathi: I meant other than that. 13:51:06 kc5tja: otherwise it works fine. 13:51:44 Cool. I know that as' x86 syntax is really bizarre (AT&T syntax just doesn't "fit" with x86 assembly language), but for PowerPC, it looks to be rather natural. 13:51:45 kc5tja: you have to pass -mregnames so you can use r3 rather than just 3 13:52:04 kc5tja: and it just treats the register names as numbers 13:52:27 * kc5tja nods 13:52:40 so if you type 'cmpwi r3,r4' you don't get an error 13:52:42 Traditional PowerPC assembly does the same. 13:52:56 it just silently assembles cmpwi r3,4 13:53:05 (compare word with immediate) 13:53:25 tathi: for newbee's like me interesting, probably helpful. but Os'es might be complex enough for others.. ? 13:53:46 I'm just wondering, because there's a chance that I may be doing commercial development for a PowerPC platform, and a small chance within that that it will be in Forth. 13:53:51 * kc5tja can't go into details. 13:54:26 as in you may be _writing_ a forth to develop in? 13:55:14 Quite possible. But whether it is in C or Forth, I still will likely need to write custom assembly code. 13:55:29 yeah. 13:55:41 personally, I really like PowerPC assembly 13:56:02 it's pretty uniform 13:56:03 I've done MIPS coding -- I loved MIPS. PowerPC and MIPS are almost identical from a coding perspective. 13:56:07 yeah 13:56:22 * kc5tja has more than a decade of 68K experience though; that's a wonderful architecture. 13:56:41 And more than a decade of 32-bit x86 coding experience. IA16 sucks eggs, but IA32 isn't nearly as bad. 13:57:10 68K is great, though I really haven't done much 13:57:23 In fact, IA32 almost seems tailor made to do Forth coding in. The register set is just the right size to implement most any Forth environment, without wasting registers. 13:57:35 :) 13:57:58 yeah, on PPC you _need_ some kind of optimizing compiler that keeps things in registers when possible. 13:58:24 I was thinking of coding up a type of Machine Forth that kept a data stack of 16 elements in 16 GPRs. 13:58:50 This way, it'd be kept nice and fast. 13:58:55 I've never understood how that would work. 13:59:07 Stack canonicalization would occur only across basic block boundaries, which pretty much happens with C compilers too anyway. 13:59:09 wouldn't you have to shift all the values over every time you pushed or popped something? 13:59:14 oh, ok 13:59:15 No. 13:59:25 The compiler keeps track of which registers are allocated, which one is the current TOS, etc. 14:00:03 There is a worst-case performance where it does shuffle all the registers around. 14:00:17 But if your stack is kept relatively shallow, it's actually faster than C's parameter passing. :) 14:00:19 and you just put the stack back to a standard state when you call another word 14:00:26 oh, definitely 14:00:28 Yes. 14:00:45 C on PPC puts stuff in registers unless you get more than 8 operands to a function 14:01:04 but still 14:01:06 I experimented with this with x86 once (I might resurrect it again), using EAX, ECX, EDX, EBX, ESI and EDI as a 6-deep data stack. It worked amazingly well. 14:02:03 yup yup 14:02:25 I just don't know that it makes sense to ever have more than about 6 things in registers 14:05:30 I went over a bunch of my forth code a couple of weeks ago, and concluded that the canonical state should be two items in registers, and that most of the time, 4 was the most that I needed. 14:05:44 but I imagine that depends on your programming style 14:05:46 Interesting you came to that conclusion. 14:05:59 Anton Ertl did an experiment where the Forth allocated registers a la most C compilers. 14:06:12 His results were the same, for x86 and otherwise: TOS and NOS in registers, the rest in memory. 14:07:09 Neat. 14:07:16 It basically allowed him to ping-pong between the two registers when updating the TOS after some operation. 14:07:42 So while one instruction was updating one register, another was reloading the other register. Apparently made good use of pipelining. 14:07:49 I hadn't experimented with that much. 14:07:51 I know he has done some work on this, but I keep forgetting to go try and find it. 14:08:02 All of my modern Forth implementations are subroutine threaded because someday, I want to play with this stuff. 14:08:54 What I like about PowerPCs is the use of a link register to support subroutine returns. 14:09:01 yeah 14:09:12 This makes *calling* a primitive almost as fast as inlining it -- there's only a 2 cycle penalty (one for the call, one for the return). 14:09:25 "leaf" words don't have the overhead of pushing the return address to memory. 14:09:49 That, combined with having the bulk of the code you're using sitting in instruction cache, would make the system incredibly fast. 14:10:11 That's a critical problem I have with the people who insist that inlining is the solution to everything: they fail to consider bus bandwidth issues. 14:10:12 :) 14:10:23 I know. 14:10:55 Especially on PPC (and other RISC?), where every instruction is 4 bytes 14:11:03 * kc5tja nods 14:11:24 Most RISCs have 32-bit instructions. The exception is StrongARM (mixture of 16-bit and 32-bit). 14:11:31 oh right. 14:11:56 non-strong ARMs are pure 32-bit of course. :) 14:12:34 and with pipelining, if everything is in the cache, the call and return instructions are going to get sort of folded out, so they really shouldn't affect execution speed that much. 14:12:47 I think. 14:13:35 And Motorola's G4s have 32K/32K instruction/data caches... :) 14:14:54 Oh. That's one annoying thing about doing forth on PPC. Separate instruction and data caches. 14:15:46 You can't just shove instructions into memory and go. You have to flush and synchronize the relevant cache lines. 14:16:55 s/\.$/ first./ 14:25:58 --- nick: Robert -> rob_ert 14:26:08 --- nick: rob_ert -> Robert 14:26:34 Well, that's why I say just a two cycle penalty. 14:26:54 tathi: Yup. 14:26:59 68K had the same problem. 14:30:24 Hey, kc5tja... I'm staring to think ham radio seems more and more interesting. Do you know any good "START HERE" links? :) 14:32:58 Not links, but there is a good book called "Now You're Talking!", published by the ARRL. 14:33:05 Radio Shack carries copies, IIRC. 14:33:31 * kc5tja hasn't been very active with ham radio in a number of years though. 14:33:48 I haven't found much around here that really keeps me interested. 14:33:54 Back in Mississippi, there was a ton of stuff. 14:34:16 You might want to check with a local ham radio club to find out what activities are "happening" in your local area. 14:34:38 Okay... should do that. 14:35:00 First I'll practice some construction and general electronics. 14:35:10 Microwave, for example, is really big where I live. I'd like to get into it more, but it's a bit expensive, and grossly inconvenient where i live; hence my relative inactivity. 14:35:10 * Robert knows close to nothing. 14:36:00 brb -- ordering food. 14:36:00 inconvenient? 14:36:33 deluxe: Very. Microwave stations have highly directional antennas, and I live in a severely antenna restricted community. Hence, I can't put up towers or anything. 14:37:06 To participate on the microwave bands, I'd have to drive out somewhere that gives me line of sight access to my desired station, and do whatever from there. 14:37:11 E.g., inconvenient. :) 14:37:16 oh now.. thx 14:38:29 Note also that by microwave, I'm talking 2.4GHz and higher in frequency. 1.2GHz is just barely usable with omnidirectional antennas, and we use amateur television on that band. Works astonishingly well, but there's a lot of ghosting effects on the video (unless you're right next to the ATV repeater). 14:40:45 even 2.4 is not always that good afaik? 14:42:19 I think above 1.2GHz, you start to get a lot of atmospheric and weather-related absorption. 14:42:32 It works, but you need directional antennas to overcome the path losses. 14:43:24 I think this is one of the reasons why 2.4GHz and 5GHz are often used for part-15 devices -- with relatively little power used in the transmission, there's relatively little chance for interference with other devices that use the same frequencies, unless you're up close. 14:45:58 * deluxe listening :-) 14:46:59 :) 14:48:09 * mur moves ears forth and back 14:48:22 *twiggle twiggle twiggle* 14:54:11 ? 14:56:07 what do you call expensive btw. ? 15:00:14 Anything above $250 in total value. 15:00:38 (generally speaking) 15:00:56 For example, my Kenwood TS-2000 rig was *DAMN* expensive. I saved up a long, long, long, long time for that rig. 15:01:22 But I'm glad i got it. 15:01:52 some things are worth splashing out on 15:02:02 But, I can't use it to its fullest potential because of my location -- I can't erect any antennas that will radiate here. 15:02:19 So right now, it's a glorified 2m transceiver and shortwave receiver for me. 15:09:58 Crap . . . 30 minutes to get my food. >:0 I'm going to implode. 15:12:33 Heh. 15:13:08 Drink water and take some old bread if you want an instant meal... otherwise, waiting is unavoidable ;) 15:13:24 I've been drinking water all day. 15:13:38 Then eat some bread! 15:13:50 What bread? 15:13:55 That requires I go shopping. 15:14:02 And that, in turn, requires I leave IRC . . . 15:14:29 Actually, I've been hacking on my FS/Forth all day today. I should have its command-line text interpretter up fairly soon. 15:14:50 I don't know how I'm going to handle loading from files yet, though. So I'm not going to bother putting support in the code for it yet. 15:15:20 There's always some bread in the kitchen... but maybe that's just because of those magic "parents". :) 15:15:40 I actually had to rip some code OUT -- I was 'leaving hooks.' The problem is, the hooks left didn't address the problem I was trying to solve. If Moore or Beck were here, they'd both say, "I told ya so." 15:15:54 Robert: I live by myself now. :) 15:16:07 Yeah, I guessed so. 15:16:21 Big boy 15:16:54 Heh 15:17:11 10011 Robert! 15:17:17 I finished implementing COMPARE to compare two strings. Now I need to walk the Forth interpretter's vocabulary chain. 15:18:02 mur: Right.. 15:20:21 kc5tja: Uhm.. just a little question, there are lots of simple AM receivers out there, but all are assuming that I want to use frequencies around 1MHz, can I just use the same circuits for higher frequencies (high enough to use a simple air-wound coil)? 15:24:29 For receiving AM stations above 1MHz, yes. 15:24:35 These would most often be shortwave stations. 15:24:43 You might not get some of the weaker stations though. 15:24:46 brb 15:26:45 back 15:26:58 keep in mind that not all radio stations are AM stations either. 15:27:05 Some are morse code, some are single sideband, etc. 15:30:18 Yeah.. 15:30:26 But I thought about both sending/receiving myself. 15:31:03 Just wondered if there were any technical reasons why AM receivers are on relativley low frequencies. 15:31:44 More legal than technical. 15:32:03 OK, great. 15:32:15 570kHz to 1700kHz is the commercial AM band 15:32:37 Won't work with any powerful transmitters anyway, so I guess nobody will even notice it. 15:33:01 Heh, you'd be surprised. 15:33:11 Why? :) 15:33:26 My recommendation -- if you're planning on making a transmitter, *stick in the commercial AM band*. 15:33:40 It's not used here anyway. 15:33:48 The commercial AM band is also an FCC Part 15 band, which means that you are legal to transmit (even w/out a license) provided your total radiated power is less than 1W. 15:34:06 Besides, who (within 100 meters or so) would be disturbed? 15:34:16 That's not the point. 15:34:19 FCC doesn't really have much power here ;) 15:34:34 The FCC has several "observing stations" around the country, designed to monitor the bands for (il)legal activity. 15:34:44 Where is "here"? 15:34:46 Sweden. 15:34:53 Oooh, I thought you were in America. 15:34:57 Nope :) 15:34:59 Well, I can't speak for your country then. 15:35:25 But.. now you're almost scaring me. Do you mean that they would care about such small transmitters? 15:35:31 This is definitley below 1W. 15:35:41 For part 15 devices, no. 15:35:45 They don't care at all about those. 15:35:54 Ah, great :) 15:35:55 robert 15:35:55 But they DO care about part 15 devices that do go outside of a legal part 15 band. 15:36:06 Hmm.. how could they detect them? 15:36:07 Which is why I suggested you stay IN the broadcast spectrum. 15:36:18 They have what are called RDF stations -- Radio Direction Finding stations. 15:36:34 Fancy.. 15:36:44 And they can detect even weak transmitters? 15:36:44 see you behind swedish curtains ;-) 15:36:45 Not really. 15:36:49 deluxe: ? 15:36:49 Just basic geometry. :) 15:37:12 But again, I'm talking about AMERICAN rules here. Sweden might have something completely different. 15:37:49 Robert: nothing, just kidding 15:37:55 Probably... but if they can't detect it, they won't do anything. 15:38:12 Ah, well.. maybe I should check this up. 15:38:21 It's your Swedish Radio Authority (or whatever they might be called) you should be worried about. :) 15:38:48 I can't speak for them, I don't know what kind of enforcement bodies they have, if any. 15:38:52 Yes.. I'm looking for them. 15:39:30 Post- och telestyrelsen, they're called. PTS. Might be good to know ;) 15:39:49 Hehe :) 15:40:08 * Robert uses his one-transistor FM transmitter to enjoy Over The Rainbow with extraordinary low sound quality. 15:40:53 ONE transistor? 15:41:05 The smallest I've seen was 2-transistor. 15:41:25 All the 1-transistor transmitters I've seen have been AM. 15:42:08 http://w1.859.telia.com/~u85920178/tx/bug.htm 15:42:30 And it works quite well.. not TOO unstable :) 15:42:36 Cool 15:42:47 Only a 1MHz frequency change if you approach the transmitter ;) 15:43:48 Heheheh :) 15:44:10 Hey, that's an interesting point -- if you calibrated it, it could be used as a range finder for stuff. Maybe a metal detector. 15:44:40 Yeah, thought about that... but as it is now, it detects _anything_. 15:45:01 If I connect a voltmeter to it, I can check the signal strength going up and down when things are moving. 15:46:04 Yes! This way of listening to the old soviet national anthem gives you the right "low-quality recording from the 30s" feeling ;) 15:47:12 hehehe :) 15:48:47 The document describing the frequencies is 148 pages. Yay. 15:49:10 Egads. :) 15:49:35 SM0VPO's site is a really cool site. 15:49:45 It's clean, it's reasonably well organized, and extremely helpful. 15:50:38 Yeah. 15:50:41 I really like it. 15:50:55 btw, if I go below 9KHz, they won't arrest me! ;) 15:52:32 Heheh :) 15:52:49 Here, we have another part 15 band between 160kHz to 190kHz. 15:53:12 It's primarily used by garage door openers. :) 15:53:36 Is such very long-wave equipment hard to use? 15:54:25 To use, no. TO get any real distance, that's the hard part. 15:54:36 "real distance"? 15:54:43 They don't call it the 1750m band for nothing! :) 15:55:02 1750m is quite some distance, imo. 15:55:02 In other words, a large separation between transmitter and receiver. 15:55:10 No no no. You misunderstand. 15:55:25 1750m band means that the radio wavelength is 1750m long. 15:55:37 That doesn't mean that that's how far the signal will carry. 15:55:55 Yeah, but I must have misinterpreted your joke ;) 15:55:57 To make an ideal radiator for that band, you'll need an antenna that is 875m long. 15:56:06 Hehe, 15:56:13 minimum. 15:56:13 :) 15:56:17 Half wavelength = ideal antenna? 15:57:06 Mathematically speaking, a half-wave dipole is the closest thing to the ideal antenna that there is. 15:57:30 Hmm... so a 1.5m antenna is good for the 3m band? 15:57:38 * kc5tja nods 15:57:50 What difference does it make if it's, say, .5m instead? MUCH difference, or just a few percent? 15:57:59 My 2m antenna elements are just shy of 0.5m -- so the total antenna size is roughly 1m. 15:58:08 MUCH difference. 15:58:17 It has to do with whether or not the antenna resonates at the frequency. 15:58:23 Oh. 15:58:30 Neat :) 15:58:39 A smaller antenna can be used to receive signals, but with increased losses because it doesn't resonate. 15:59:01 A larger antenna may or may not be beneficial. Larger antennas can often yield "gain", but at the expense of directivity. 15:59:02 How about transmitting, is the antenna also important there? 15:59:20 Immensely important. It's actually more important when transmitting than when receiving, for a number of reasons. 15:59:30 How can you "direct" the waves? 15:59:37 Like a flashlight -- reflections. 16:00:00 Radio waves are light waves, and behave according to the same rules. It's just that reflectors and such just look different. 16:00:00 Hmm.. anything useful for a beginner with no equipment except what I can solder together? :) 16:00:11 Define "useful?" 16:00:24 That is, something I can build and not just dream of. ;) 16:00:43 Like... 1.5m of wire is "useful". A parabol is not... 16:01:07 Well, what frequency are you looking to build for? 16:01:44 Hmm.. I was thinking about ~27MHz, but 5m antennas is nothing I want :D 16:01:56 So maybe the 2m band or something... 16:02:10 Well, 2m is a ham band. And NOT a part 15 band. 16:02:10 :) 16:02:41 I'll find an empty spot ;) 16:02:51 For 27MHz, you needn't build one yourself. You can go down to your local radio store and pick up a "mag-mount" CB antenna. 16:02:52 Well, or use the 3m band 16:03:02 You can't just pick any ol' band you want. 16:03:07 For commercial FM radio. 16:03:11 Yeah, I know... 16:03:23 For now I'm using the outer regions of the commercial FM band. 16:03:42 well, HERE IN AMERICA, the FM band also happens to be a part 15 band. 16:03:47 Not sure if it's the case in Sweden as well. 16:04:07 But if it is, then your 3m antenna can be built using what's called a Quarter Wave Ground-plane antenna. 16:04:15 Nah, but the only thing I have any receiver for. 16:04:37 Any info on that? 16:04:39 I'm currently using a ground-plane antenna for my 2m requirements. :) 16:04:42 Yes. 16:04:48 You need three antenna elements. 16:04:59 Hold on a sec. 16:05:05 --- join: jdamisch (jdamisch@207.191.240.43) joined #forth 16:05:12 Sure :) Thanks alot for what you've told me so far, btw. 16:06:12 OK, this rule is for English units. I tried to derive it for metric but I get wrong numbers. So it's best if you just did it for English units, then converted it to metric afterwards. 16:06:34 Each element's length, in FEET, is 234/f, where f is the frequency you intend to receive/transmit on IN MEGAHERTZ. 16:06:37 i hope your kids aren't trying to launch any space probes :^) 16:06:39 I see 27MHz is free to use without any license here. 16:06:46 jdamisch: Not an issue. 16:06:59 just kidding 16:07:54 Let me find you an URL which can explain it better than I can. 16:08:12 Thanks :) 16:10:38 sifbot: : hi 0 do .( hi! ) cr loop ; 5 hi 16:10:39 jdamisch: hi! 16:11:06