My vacuum tube homebrew transmitter
FYI, FWIW... As I recently became retired my interests have evolved towards building homebrew tube gear. Reasons: i) simplicity in circuitry, ii) comparatively large tubes & sockets make soldering easier, iii) accidental slip of the test prod might not kill a tube but might a transistor, iv) yeah, I like to see those filaments glow, too, v) can still get those tubes but some transistors you can't find anywhere, v) throw-away technology (boards) is bad ecology...give me discrete devices any day, and vi) with high power heat sinks, silicon compound for conduction of heat (if it gets on your fingers, its hard to get it off) is needed and that damned metal can getdamned hot. I've been building a tube SSB transmitter for about 1-2 years now (parts of it can be seen at http://www.panix.com/~asd) and ends up with a pair of 813s in grounded-grid, driven by a single 811a in G-G, lots of home brew antenna tuners, and Icom 707 for the moment SSB transciever. The homebrew SSB exciter lineup is not yet pictured, but at its current stage of construction is almost ready to go on the air. Generate DSB at 2 mHz with 6AL5 balanced modulator, upconvert by mixing with 7 mHz to 9 mHz (6BE6), use McCoy 9 mHz crystal filter (somebody gave it to me 25 years ago) to shave off the desired sideband, mix (6SA7) with 5 mHz local oscilator (by doubled 2.5 mHz from old war surplus Collins 70H3 VFO [from Fair Radio Sales when they had them, they ran out years ago]) to get 4 mHz (75 meters, my favorite ragchew band) which the scope shows to be about 5-10 mv, and goes into two 6C4s (triodes, grounded cathode) and then into a 6AG7 & 6146. I am at the point where I need to make a RF transformer to take the output of the 6146 to drive two more 6146s in parallel to get the ten watts I need to drive the G-G 811a. Yes, if I could optimize everything better, I could use less tubes. But, I preferred to make modules (lots of stages are built inside of old computer power supply cabinets (they are about 6x6x4 or so, and nice to work with, cheap at hamfests at $1 each or so). All the gear is full of those old D'arsonval "Frankenstein"-type (real) meters (not this LED crap), so I can keep monitoring practically all the voltages on anything. Its not very pretty to look at, but its a whole lot easier to work on than any of that new gear out that surely has thousands of transistors and hundreds of chips (?). I chose the 813s and 811 and GG amps because both the 813 and 811 don't really need cooling fans (I hate blower/fan noises) and grounded-grid amps are notoriously stable (no neutralization headaches), and they are pretty cheap. I have several 813s, some made in China; one of the Chinese 813s had a filament that opened up on me all by itself after very little use (don't know if that is THEIR quality control or just a statistical fluke, but I thought I'd pass that along to y'all). I also manage filament warmup and cooldown on the 813s with a variac (up and down over abut 5-10 seconds), but not on the 811 amp. Been using the 813s + 811 for over a year (using the Icom 707 as driver) and just love how nice and quiet it is without fans/blower noise. Almost all of my old rigs are also pictured on that URL, and a couple of pictures of my "secret lab" out in the garage (heated with a space heater in the winter, cooled with a small airconditioner in the summer). I started as a novice in 1959. Had a Knight kit T-50 and Knight R-100 receiver, later got a DX-40. Mostly liked to ragchew with locals on ten meters AM at the time. Lots of find memories. Lots of SWLing. I'd like to hear from other homebrewers, HFers, ragchewers and learn if ther are any 75 meter nets for homebrewers/tubers/etc. I look at all this new gear coming out (for thousands of dollars) with hundreds of buttons, knobs, and "thangs" on them, and big thick manuals you have to read to figure out how to push the buttons (once, press twice, press and hold?, press and hold one, then turn on the power switch? Etc? Secret "reboot" buttons hidden somewhere. Built in DRM, DCMA, spyware? Too?). What happened to old-fashioned skill? 50 years ago guys worked the world with a crystal and a single 6L6 and straight key. Now, they are all couch potatoes in front of a black box that looks like its from outer space. ;-) I figure I'm within a week or two of getting the homebrew SSB exciter actually on the air. I've been testing the outputs of various stages either using the Icom 707 as general coverage receiver, one or two oscilloscopes to check generated signals, etc. Still have a lot of tweaking to do. Its been a ton of work, debugging and rebuilding when something doesn't work, but its also been an incomparable sense of accomplishment, too, when I get a stage to work and make progress (four steps forward, three steps backwards). Its also nice to have some test equipment (generators, meters, a good oscilloscope [had a Tektronix 922 that gave up and I tossed, then a heathkit which had a dead vertical amp that I fixed, and a BK-1420? very nice but now the horizontal sweep died but vertical amp still good, so I can probe at least for RF which gives me a vertical line [keeping the test equipment going is also a problem], and all of that stuff is also 30+ years old). After that, I plan to build a tube receiver and maybe even build a crystal lattice filter, and try to build a stable VFO. Art, W4PON Member, QCWA ~99.9% of my time with soldering iron & screwdriver, 0.1% of my time in ragchewing. |
My vacuum tube homebrew transmitter
Might not kill a tube, but it could kill a builder! Be careful!!
Scott N0EDV Straydog wrote: FYI, FWIW... As I recently became retired my interests have evolved towards building homebrew tube gear. Reasons: iii) accidental slip of the test prod might not kill a tube but might a transistor, |
My vacuum tube homebrew transmitter
It is great to know that I am not the last dinosaur left on the planet.
Although my call goes back to the 1950's when I was very active with all home brew equipment, there has been a period of inactivity with family and other hobby interests (such as aviation) and I have kept amateur radio as my real retirement activity. With commercially manufactured equipment now mandated here for foundation licence applicants my greatest fear is that we will lose our greatest priviledge of being able to design and build our own transmitting equipment. My first SSB transmitter was, of course, all valve. It started at 483Khz with a phasing system followed by two half lattice crystal filter sections. Output started as a 6146 and then grew to 4x811A's in parallel. One of the real problems was getting the VFO really stable and the best I came up with used the worm drive capacitor out of one of those TU6 tuning boxes with the tuned circuits connected remotely via coax lines to the oscillator stage which was on the main chassis. All a long time ago but I still believe that such experiments were a good way to learn and am also of the opinion that the newcomers who simply purchase a commercial rig are missing out on a lot of the basic fun that we had when a piece of junk disposals equipment could be transformed into something useful. Good luck to you Art, hope you continue to enjoy the hobby George "Straydog" wrote in message .com... FYI, FWIW... As I recently became retired my interests have evolved towards building homebrew tube gear. Reasons: i) simplicity in circuitry, ii) comparatively large tubes & sockets make soldering easier, iii) accidental slip of the test prod might not kill a tube but might a transistor, iv) yeah, I like to see those filaments glow, too, v) can still get those tubes but some transistors you can't find anywhere, v) throw-away technology (boards) is bad ecology...give me discrete devices any day, and vi) with high power heat sinks, silicon compound for conduction of heat (if it gets on your fingers, its hard to get it off) is needed and that damned metal can getdamned hot. I've been building a tube SSB transmitter for about 1-2 years now (parts of it can be seen at http://www.panix.com/~asd) and ends up with a pair of 813s in grounded-grid, driven by a single 811a in G-G, lots of home brew antenna tuners, and Icom 707 for the moment SSB transciever. The homebrew SSB exciter lineup is not yet pictured, but at its current stage of construction is almost ready to go on the air. Generate DSB at 2 mHz with 6AL5 balanced modulator, upconvert by mixing with 7 mHz to 9 mHz (6BE6), use McCoy 9 mHz crystal filter (somebody gave it to me 25 years ago) to shave off the desired sideband, mix (6SA7) with 5 mHz local oscilator (by doubled 2.5 mHz from old war surplus Collins 70H3 VFO [from Fair Radio Sales when they had them, they ran out years ago]) to get 4 mHz (75 meters, my favorite ragchew band) which the scope shows to be about 5-10 mv, and goes into two 6C4s (triodes, grounded cathode) and then into a 6AG7 & 6146. I am at the point where I need to make a RF transformer to take the output of the 6146 to drive two more 6146s in parallel to get the ten watts I need to drive the G-G 811a. Yes, if I could optimize everything better, I could use less tubes. But, I preferred to make modules (lots of stages are built inside of old computer power supply cabinets (they are about 6x6x4 or so, and nice to work with, cheap at hamfests at $1 each or so). All the gear is full of those old D'arsonval "Frankenstein"-type (real) meters (not this LED crap), so I can keep monitoring practically all the voltages on anything. Its not very pretty to look at, but its a whole lot easier to work on than any of that new gear out that surely has thousands of transistors and hundreds of chips (?). I chose the 813s and 811 and GG amps because both the 813 and 811 don't really need cooling fans (I hate blower/fan noises) and grounded-grid amps are notoriously stable (no neutralization headaches), and they are pretty cheap. I have several 813s, some made in China; one of the Chinese 813s had a filament that opened up on me all by itself after very little use (don't know if that is THEIR quality control or just a statistical fluke, but I thought I'd pass that along to y'all). I also manage filament warmup and cooldown on the 813s with a variac (up and down over abut 5-10 seconds), but not on the 811 amp. Been using the 813s + 811 for over a year (using the Icom 707 as driver) and just love how nice and quiet it is without fans/blower noise. Almost all of my old rigs are also pictured on that URL, and a couple of pictures of my "secret lab" out in the garage (heated with a space heater in the winter, cooled with a small airconditioner in the summer). I started as a novice in 1959. Had a Knight kit T-50 and Knight R-100 receiver, later got a DX-40. Mostly liked to ragchew with locals on ten meters AM at the time. Lots of find memories. Lots of SWLing. I'd like to hear from other homebrewers, HFers, ragchewers and learn if ther are any 75 meter nets for homebrewers/tubers/etc. I look at all this new gear coming out (for thousands of dollars) with hundreds of buttons, knobs, and "thangs" on them, and big thick manuals you have to read to figure out how to push the buttons (once, press twice, press and hold?, press and hold one, then turn on the power switch? Etc? Secret "reboot" buttons hidden somewhere. Built in DRM, DCMA, spyware? Too?). What happened to old-fashioned skill? 50 years ago guys worked the world with a crystal and a single 6L6 and straight key. Now, they are all couch potatoes in front of a black box that looks like its from outer space. ;-) I figure I'm within a week or two of getting the homebrew SSB exciter actually on the air. I've been testing the outputs of various stages either using the Icom 707 as general coverage receiver, one or two oscilloscopes to check generated signals, etc. Still have a lot of tweaking to do. Its been a ton of work, debugging and rebuilding when something doesn't work, but its also been an incomparable sense of accomplishment, too, when I get a stage to work and make progress (four steps forward, three steps backwards). Its also nice to have some test equipment (generators, meters, a good oscilloscope [had a Tektronix 922 that gave up and I tossed, then a heathkit which had a dead vertical amp that I fixed, and a BK-1420? very nice but now the horizontal sweep died but vertical amp still good, so I can probe at least for RF which gives me a vertical line [keeping the test equipment going is also a problem], and all of that stuff is also 30+ years old). After that, I plan to build a tube receiver and maybe even build a crystal lattice filter, and try to build a stable VFO. Art, W4PON Member, QCWA ~99.9% of my time with soldering iron & screwdriver, 0.1% of my time in ragchewing. |
My vacuum tube homebrew transmitter
What happened to old-fashioned skill? 50 years ago guys worked the world with a crystal
and a single 6L6 and straight key. Now, they are all couch potatoes in front of a black box that looks like its from outer space. ;-) ============================== 50 years ago the bands were sooooo quiet (relatively speaking) that you didn't need today's sophistication Although even today ,by using QRP equipment ....and Morse telegraphy.........simple gear can still give a lot of enjoyment, but in 20 - 30 years time ,how many hams will then still be using Morse code? But as far as 'local ragchew' is concerned , I agree with you ,simple homebrew gear will still do the trick . Frank GM0CSZ / KN6WH north of Scotland |
My vacuum tube homebrew transmitter
With commercially manufactured equipment now mandated here for foundation
licence applicants my greatest fear is that we will lose our greatest priviledge of being able to design and build our own transmitting equipment. My first SSB transmitter was, of course, all valve. It started at 483Khz with a phasing system followed by two half lattice crystal filter sections. Output started as a 6146 and then grew to 4x811A's in parallel. One of the real problems was getting the VFO really stable and the best I came up with used the worm drive capacitor out of one of those TU6 tuning boxes with the tuned circuits connected remotely via coax lines to the oscillator stage which was on the main chassis. All a long time ago but I still believe that such experiments were a good way to learn and am also of the opinion that the newcomers who simply purchase a commercial rig are missing out on a lot of the basic fun that we had when a piece of junk disposals equipment could be transformed into something useful. ============================================= Firstly , Foundation Licensees in the UK are permitted to use self-constructed transmitting equipment from an 'approved kit' , whatever that 'approved' means. The younger generation(s) are no longer interested in our hobby for all the well known reasons, Internet- Mobile Phones - Sat TV - iPod etc. Their first priority is 'socialising' and a 'nerd' sitting in a shack soldering and using test equipment is NOT socialising. Moreover ,homebrew equipment is NOT necessarily cheaper than off-the-shelf stuff (with the exception of very basic equipment and peripherals). Being involved in assisting people to get a Ham licence , most if not all recruits are retired or are about to retire. We now live in 2007 and beyond ............that's the reality . However ,being an old fogy myself .....I still do enjoy home-brewing. Frank GM0CSZ / KN6WH north of Scotland |
My vacuum tube homebrew transmitter
On Aug 23, 9:17 pm, Scott wrote:
Might not kill a tube, but it could kill a builder! Be careful!! Oh, come on. How could anyone have not touched a low-kilovolt B+ and call himself a ham? We've all touched a kilovolt or two, probably as young kids, and we're all perfectly normal! Tim. |
My vacuum tube homebrew transmitter
Well, all humor aside, I stand by my original answer to BE CAREFUL.
True, a KV might not kill you, but if you start out being careless, when you progress up to tubes like a 4-1000A, the B+ will most certainly kill you. The pile of ashes on the floor will be proof enough ;) Again, humor aside, I pride myself on NOT having hit a KV...that takes more skill than hitting it ;) Scott N0EDV Tim Shoppa wrote: On Aug 23, 9:17 pm, Scott wrote: Might not kill a tube, but it could kill a builder! Be careful!! Oh, come on. How could anyone have not touched a low-kilovolt B+ and call himself a ham? We've all touched a kilovolt or two, probably as young kids, and we're all perfectly normal! Tim. -- Scott http://corbenflyer.tripod.com/ Gotta Fly or Gonna Die Building RV-4 (Super Slow Build Version) |
My vacuum tube homebrew transmitter
See quoted material at end. When I was a kid, I and the guys I hung out with were always playing with high voltage. We all built Tesla coils (12-15" sparks), played with Model T Ford spark coils (2" sparks), neon sign transformers that weighed 50 pounds and put out 15,000 volts at 30 to 50 milliamps, and Frankenstein-type "jacobs ladders." We made sparks. We made arcs. We made noise. We made smoke. We blew fuses. One more thing we all made was an old fashioned "repulsion coil" (coat hangers, wire, copper or alluminum ring that would jump up a foot when you threw the switch). We all made crystal sets, too. Made one transistor radios, too. Built Knight kits and heathkits. Yes, you do NOT want to be a _klutz_ and goof off like we did. Yes, you do not want to play "electric chair" with yourself, and yes, its a very good idea when working with lethal voltage to keep one hand in your pocket when anything is "live". Repeat: if you are a klutz, or accident-prone, then do not mess around with this stuff. Beyond that, yes, I got a few shocks. I even felt current from a 12 volt car battery (moist hands, large metal electrods, and use one hand on each, squeeze tight, I felt a mini-tingle). Got a nast RF burn by accidentally touching the plate cap of a 6146 with 50 watts of 10 meters carrier. It hurts and burnt flesh (part of my thumb) stinks like hell. I got a few more shocks, all minor, and whenever I'm around serious voltage and power, I definitely look twice at everything. Most scandalous shock: Outside the house. Rainstorm coming and lightning and thunder comes 10 seconds later, means its all about two miles away, and I'm playing with the feedline on a 75 meter dipole with my hands, and then the next flash of light from the lightning and--dang it--I felt that "needle" in my hand from a pulse of electricity. Hmmmm...better get inside the house. So, next time you are listening on HF and when the lightning and thunder are close, and your S-meter needle is bouncing all the way to the top, you can be thiking about 100-200 volt pulses, eh? Anyway, just think about Ben Franklin who was flying his kites in the rain (in my case, I was dry and the rain wasn't falling yet where I was). W4PON ===== no change to below, included for reference and context ===== On Fri, 24 Aug 2007, Scott wrote: Might not kill a tube, but it could kill a builder! Be careful!! Scott N0EDV Straydog wrote: FYI, FWIW... As I recently became retired my interests have evolved towards building homebrew tube gear. Reasons: iii) accidental slip of the test prod might not kill a tube but might a transistor, |
My vacuum tube homebrew transmitter
On Fri, 24 Aug 2007, George McLeod wrote: It is great to know that I am not the last dinosaur left on the planet. Jeeze, what is it, you and me against the world? ;-) Although my call goes back to the 1950's when I was very active with all home brew equipment, there has been a period of inactivity with family and other hobby interests (such as aviation) and I have kept amateur radio as my real retirement activity. Yeah, I go to the local QCWA monthly lunches and what does everyone talk about? Not ham radio (but everyone has a ricebox), but their medical problems. Lots of them. With commercially manufactured equipment now mandated here for foundation licence applicants my greatest fear is that we will lose our greatest priviledge of being able to design and build our own transmitting equipment. That is really sad. So, along with Microsoft as ultimate software robber-barron, we all become slaves to "commercial" interests. My first SSB transmitter was, of course, all valve. It started at 483Khz with a phasing system followed by two half lattice crystal filter sections. Output started as a 6146 and then grew to 4x811A's in parallel. One of the real problems was getting the VFO really stable and the best I came up with used the worm drive capacitor out of one of those TU6 tuning boxes with the tuned circuits connected remotely via coax lines to the oscillator stage which was on the main chassis. Soon I will approach this problem. I may end up with a bank of crystals with a small variable capacitor to "warp" the crystal frequency. Free running oscillators are very hard to stabilize. The other option is to just leave them turned on, 24/7, so they are always warmed up. All a long time ago but I still believe that such experiments were a good way to learn and am also of the opinion that the newcomers who simply purchase a commercial rig are missing out on a lot of the basic fun that we had when a piece of junk disposals equipment could be transformed into something useful. I agree 100%. I grew up in the 1950s and we had Popular Science, Popular Mechanics, and Mechanics Illustrated magazines. All kinds of do-it-yourself projects, diagrams, how-tos, everything. I loved it. Today, its all "appliance operator" stuff in a throw away economy. It makes no sense to me. Good luck to you Art, hope you continue to enjoy the hobby Thanks for all the good words. One more thing: "Long live dinosaurs!" W4PON ===== no change to below, included for reference and context ===== George "Straydog" wrote in message .com... FYI, FWIW... As I recently became retired my interests have evolved towards building homebrew tube gear. Reasons: i) simplicity in circuitry, ii) comparatively large tubes & sockets make soldering easier, iii) accidental slip of the test prod might not kill a tube but might a transistor, iv) yeah, I like to see those filaments glow, too, v) can still get those tubes but some transistors you can't find anywhere, v) throw-away technology (boards) is bad ecology...give me discrete devices any day, and vi) with high power heat sinks, silicon compound for conduction of heat (if it gets on your fingers, its hard to get it off) is needed and that damned metal can getdamned hot. I've been building a tube SSB transmitter for about 1-2 years now (parts of it can be seen at http://www.panix.com/~asd) and ends up with a pair of 813s in grounded-grid, driven by a single 811a in G-G, lots of home brew antenna tuners, and Icom 707 for the moment SSB transciever. The homebrew SSB exciter lineup is not yet pictured, but at its current stage of construction is almost ready to go on the air. Generate DSB at 2 mHz with 6AL5 balanced modulator, upconvert by mixing with 7 mHz to 9 mHz (6BE6), use McCoy 9 mHz crystal filter (somebody gave it to me 25 years ago) to shave off the desired sideband, mix (6SA7) with 5 mHz local oscilator (by doubled 2.5 mHz from old war surplus Collins 70H3 VFO [from Fair Radio Sales when they had them, they ran out years ago]) to get 4 mHz (75 meters, my favorite ragchew band) which the scope shows to be about 5-10 mv, and goes into two 6C4s (triodes, grounded cathode) and then into a 6AG7 & 6146. I am at the point where I need to make a RF transformer to take the output of the 6146 to drive two more 6146s in parallel to get the ten watts I need to drive the G-G 811a. Yes, if I could optimize everything better, I could use less tubes. But, I preferred to make modules (lots of stages are built inside of old computer power supply cabinets (they are about 6x6x4 or so, and nice to work with, cheap at hamfests at $1 each or so). All the gear is full of those old D'arsonval "Frankenstein"-type (real) meters (not this LED crap), so I can keep monitoring practically all the voltages on anything. Its not very pretty to look at, but its a whole lot easier to work on than any of that new gear out that surely has thousands of transistors and hundreds of chips (?). I chose the 813s and 811 and GG amps because both the 813 and 811 don't really need cooling fans (I hate blower/fan noises) and grounded-grid amps are notoriously stable (no neutralization headaches), and they are pretty cheap. I have several 813s, some made in China; one of the Chinese 813s had a filament that opened up on me all by itself after very little use (don't know if that is THEIR quality control or just a statistical fluke, but I thought I'd pass that along to y'all). I also manage filament warmup and cooldown on the 813s with a variac (up and down over abut 5-10 seconds), but not on the 811 amp. Been using the 813s + 811 for over a year (using the Icom 707 as driver) and just love how nice and quiet it is without fans/blower noise. Almost all of my old rigs are also pictured on that URL, and a couple of pictures of my "secret lab" out in the garage (heated with a space heater in the winter, cooled with a small airconditioner in the summer). I started as a novice in 1959. Had a Knight kit T-50 and Knight R-100 receiver, later got a DX-40. Mostly liked to ragchew with locals on ten meters AM at the time. Lots of find memories. Lots of SWLing. I'd like to hear from other homebrewers, HFers, ragchewers and learn if ther are any 75 meter nets for homebrewers/tubers/etc. I look at all this new gear coming out (for thousands of dollars) with hundreds of buttons, knobs, and "thangs" on them, and big thick manuals you have to read to figure out how to push the buttons (once, press twice, press and hold?, press and hold one, then turn on the power switch? Etc? Secret "reboot" buttons hidden somewhere. Built in DRM, DCMA, spyware? Too?). What happened to old-fashioned skill? 50 years ago guys worked the world with a crystal and a single 6L6 and straight key. Now, they are all couch potatoes in front of a black box that looks like its from outer space. ;-) I figure I'm within a week or two of getting the homebrew SSB exciter actually on the air. I've been testing the outputs of various stages either using the Icom 707 as general coverage receiver, one or two oscilloscopes to check generated signals, etc. Still have a lot of tweaking to do. Its been a ton of work, debugging and rebuilding when something doesn't work, but its also been an incomparable sense of accomplishment, too, when I get a stage to work and make progress (four steps forward, three steps backwards). Its also nice to have some test equipment (generators, meters, a good oscilloscope [had a Tektronix 922 that gave up and I tossed, then a heathkit which had a dead vertical amp that I fixed, and a BK-1420? very nice but now the horizontal sweep died but vertical amp still good, so I can probe at least for RF which gives me a vertical line [keeping the test equipment going is also a problem], and all of that stuff is also 30+ years old). After that, I plan to build a tube receiver and maybe even build a crystal lattice filter, and try to build a stable VFO. Art, W4PON Member, QCWA ~99.9% of my time with soldering iron & screwdriver, 0.1% of my time in ragchewing. |
My vacuum tube homebrew transmitter
On Fri, 24 Aug 2007, Highland Ham wrote: What happened to old-fashioned skill? 50 years ago guys worked the world with a crystal and a single 6L6 and straight key. Now, they are all couch potatoes in front of a black box that looks like its from outer space. ;-) ============================== 50 years ago the bands were sooooo quiet (relatively speaking) that you didn't need today's sophistication I am retired out in the country (nearest town is 7 miles away, nearest traffic light is 2.2 miles away). here, now, in the summertime, my background static noise on 75 meters, believe it or not, is usually about S 1 to S3. Only when we have thunderstorms does it get up to S 9 or more. Yes. Believe it or not. A guy I ragchew with on 75 meters lives in the city. His noise is never less than S8 and quite often 20-40 db over S 9, and he can't find the source. Although even today ,by using QRP equipment ....and Morse telegraphy.........simple gear can still give a lot of enjoyment, but in 20 - 30 years time ,how many hams will then still be using Morse code? It will be like slide rules and logarithms: forgotten. If teh kids can't find the answers on the internet, then the project just will not be done. And, they are still trying to figure out how the Egyptians built the pyramids. But as far as 'local ragchew' is concerned , I agree with you ,simple homebrew gear will still do the trick . Yep. Frank GM0CSZ / KN6WH north of Scotland Good luck with Gordon Brown!!! |
My vacuum tube homebrew transmitter
On Fri, 24 Aug 2007, Highland Ham wrote: With commercially manufactured equipment now mandated here for foundation licence applicants my greatest fear is that we will lose our greatest priviledge of being able to design and build our own transmitting equipment. My first SSB transmitter was, of course, all valve. It started at 483Khz with a phasing system followed by two half lattice crystal filter sections. Output started as a 6146 and then grew to 4x811A's in parallel. One of the real problems was getting the VFO really stable and the best I came up with used the worm drive capacitor out of one of those TU6 tuning boxes with the tuned circuits connected remotely via coax lines to the oscillator stage which was on the main chassis. All a long time ago but I still believe that such experiments were a good way to learn and am also of the opinion that the newcomers who simply purchase a commercial rig are missing out on a lot of the basic fun that we had when a piece of junk disposals equipment could be transformed into something useful. ============================================= Firstly , Foundation Licensees in the UK are permitted to use self-constructed transmitting equipment from an 'approved kit' , whatever that 'approved' means. The younger generation(s) are no longer interested in our hobby for all the well known reasons, Internet- Mobile Phones - Sat TV - iPod etc. Their first priority is 'socialising' and a 'nerd' sitting in a shack soldering and using test equipment is NOT socialising. Right. Today's business model is profits. You don't need brains, knowleddge, or skill to _buy_ an already assembled gadget. Just money (or debt). Moreover ,homebrew equipment is NOT necessarily cheaper than off-the-shelf stuff (with the exception of very basic equipment and peripherals). Best to look at hamfests (don't know if you have these over where you are), used equipment, and war surplus (we have a few left here in US). Being involved in assisting people to get a Ham licence , most if not all recruits are retired or are about to retire. We now live in 2007 and beyond ............that's the reality . Frightening, isn't it? However ,being an old fogy myself .....I still do enjoy home-brewing. So do I. Frank GM0CSZ / KN6WH north of Scotland |
My vacuum tube homebrew transmitter
On Fri, 24 Aug 2007, Tim Shoppa wrote: On Aug 23, 9:17 pm, Scott wrote: Might not kill a tube, but it could kill a builder! Be careful!! Oh, come on. How could anyone have not touched a low-kilovolt B+ and call himself a ham? Right on!! We've all touched a kilovolt or two, probably as young kids, and we're all perfectly normal! Just don't let the current path include your heart/chest. Tim. |
My vacuum tube homebrew transmitter
On Fri, 24 Aug 2007, Scott wrote: Well, all humor aside, I stand by my original answer to BE CAREFUL. True, a KV might not kill you, but if you start out being careless, when you progress up to tubes like a 4-1000A, the B+ will most certainly kill you. The pile of ashes on the floor will be proof enough ;) Again, humor aside, I pride myself on NOT having hit a KV...that takes more skill than hitting it ;) Knights of Olde Times had scars to prove their courage, bravery, and skills and slain dragons. ;-) (or foolheartiness?) Then thee can speak of "experience." ;-) And, once burned, you learn and remember better, too!!! :-) Memory is wonderful: You recognize when you made that same mistake before! ;-) And, of course, you get bragging rights if you can talk about a smoke test where you really did get the smoke (yeah, I had one and that burnt rubber stank, too). 73 Art, W4PON ===== no change to below, included for reference and context ===== Scott N0EDV Tim Shoppa wrote: On Aug 23, 9:17 pm, Scott wrote: Might not kill a tube, but it could kill a builder! Be careful!! Oh, come on. How could anyone have not touched a low-kilovolt B+ and call himself a ham? We've all touched a kilovolt or two, probably as young kids, and we're all perfectly normal! Tim. -- Scott http://corbenflyer.tripod.com/ Gotta Fly or Gonna Die Building RV-4 (Super Slow Build Version) |
My vacuum tube homebrew transmitter
On Fri, 24 Aug 2007 23:51:36 -0400, Straydog wrote:
On Fri, 24 Aug 2007, George McLeod wrote: It is great to know that I am not the last dinosaur left on the planet. Jeeze, what is it, you and me against the world? ;-) Oh, there's more of us :-) At 39, I'm a dinosaur at heart with barely a transistor in stock. A couple thousand tubes though! Cheers, __ Gregg |
My vacuum tube homebrew transmitter
On Sat, 25 Aug 2007 00:09:47 -0400, Straydog wrote:
On Fri, 24 Aug 2007, Scott wrote: Well, all humor aside, I stand by my original answer to BE CAREFUL. True, a KV might not kill you, but if you start out being careless, when you progress up to tubes like a 4-1000A, the B+ will most certainly kill you. The pile of ashes on the floor will be proof enough ;) Again, humor aside, I pride myself on NOT having hit a KV...that takes more skill than hitting it ;) Knights of Olde Times had scars to prove their courage, bravery, and skills and slain dragons. ;-) (or foolheartiness?) Then thee can speak of "experience." ;-) And, once burned, you learn and remember better, too!!! :-) Memory is wonderful: You recognize when you made that same mistake before! ;-) And, of course, you get bragging rights if you can talk about a smoke test where you really did get the smoke (yeah, I had one and that burnt rubber stank, too). At least in Europe AC/DC radio and television receivers were common, in which you could have the 220 V mains directly in the chassis. You learned quite quicly to check the polarity of the mains plug before starting serving such equipment. There was a golden rule of always keeping your left hand in your pocket while working with your right hand inside a mains powered or high voltage device. An AC/DC powered device could deliver quite a lot current through the mains fuse and rectifier. If you touched some high voltage part (possibly causing a cramp in your hand), the current would not go through your hart and you would have the other hand operational to pull the plug. --- When testing a new power supply, I was sniffing around to detect any overheating components, my nouse touched the mains transformer primary and got an electric shock in my nouse. I did not notice anything special after that, but driving a car immediately after that proved to be difficult, since I really had to concentrate to stay in the lane. So if you get an electric shock in the head, nouse or ears, please avoid driving a car for a few hours, at least for the safety of others using the road :-). Paul OH3LWR |
My vacuum tube homebrew transmitter
There was a golden rule of always keeping your left hand in your
pocket while working with your right hand inside a mains powered or high voltage device. An AC/DC powered device could deliver quite a lot current through the mains fuse and rectifier. If you touched some high voltage part (possibly causing a cramp in your hand), the current would not go through your hart and you would have the other hand operational to pull the plug. ============================== Being left handed I now realise that I must be very happy to be alive ;) Frank GM0CSZ |
My vacuum tube homebrew transmitter
On Fri, 24 Aug 2007, geek wrote: On Fri, 24 Aug 2007 23:51:36 -0400, Straydog wrote: On Fri, 24 Aug 2007, George McLeod wrote: It is great to know that I am not the last dinosaur left on the planet. Jeeze, what is it, you and me against the world? ;-) Oh, there's more of us :-) At 39, I'm a dinosaur at heart with barely a transistor in stock. A couple thousand tubes though! Three of us? Could we form a club? "The dinosaur club"? ;-) I'm kinda half serious, though. I go through QST and they have this "Old Radio" department now. But its also almost all old _commercial_ gear. I'm looking for those guys who built all those rigs that appeared in QSTs, CQs, etc. If they are still alive. I've got probably 100+ myself. Constantly looking at my tube manual and dreaming about the next project(s), whether I should use some tube or a different one, or maybe even something else. I started out with mostly 7 pin and 9 pin miniatures, but now I'm pushing myself towards octals just for the ease of handling. The "key" means its very easy to get into the socket (get key in hole, rotate and ...click..push in). Besides, the socket pins are bigger, easier to solder. And, since the heat is spread out more, the tube runs cooler so you don't burn yourself when you go to pull out a hot tube to check another of the same kind. Takes up more volume, but, what the hey, I build this stuff spread out for ease of repair, ease of construction, modification. Cheers, __ Gregg |
My vacuum tube homebrew transmitter
Good comments, Paul. I'll keep the extended story in mind. On Sat, 25 Aug 2007, Paul Keinanen wrote: On Sat, 25 Aug 2007 00:09:47 -0400, Straydog wrote: On Fri, 24 Aug 2007, Scott wrote: Well, all humor aside, I stand by my original answer to BE CAREFUL. True, a KV might not kill you, but if you start out being careless, when you progress up to tubes like a 4-1000A, the B+ will most certainly kill you. The pile of ashes on the floor will be proof enough ;) Again, humor aside, I pride myself on NOT having hit a KV...that takes more skill than hitting it ;) Knights of Olde Times had scars to prove their courage, bravery, and skills and slain dragons. ;-) (or foolheartiness?) Then thee can speak of "experience." ;-) And, once burned, you learn and remember better, too!!! :-) Memory is wonderful: You recognize when you made that same mistake before! ;-) And, of course, you get bragging rights if you can talk about a smoke test where you really did get the smoke (yeah, I had one and that burnt rubber stank, too). At least in Europe AC/DC radio and television receivers were common, in which you could have the 220 V mains directly in the chassis. You learned quite quicly to check the polarity of the mains plug before starting serving such equipment. There was a golden rule of always keeping your left hand in your pocket while working with your right hand inside a mains powered or high voltage device. An AC/DC powered device could deliver quite a lot current through the mains fuse and rectifier. If you touched some high voltage part (possibly causing a cramp in your hand), the current would not go through your hart and you would have the other hand operational to pull the plug. --- When testing a new power supply, I was sniffing around to detect any overheating components, my nouse touched the mains transformer primary and got an electric shock in my nouse. I did not notice anything special after that, but driving a car immediately after that proved to be difficult, since I really had to concentrate to stay in the lane. So if you get an electric shock in the head, nouse or ears, please avoid driving a car for a few hours, at least for the safety of others using the road :-). Paul OH3LWR |
My vacuum tube homebrew transmitter
snip
Oh, there's more of us :-) At 39, I'm a dinosaur at heart with barely a transistor in stock. A couple thousand tubes though! Three of us? Could we form a club? "The dinosaur club"? ;-) Behold - http://geek.scorpiorising.ca/GeeK_ZonE Some of the tube lovers are even mid-teenagers :-) Cheers, __ Gregg |
My vacuum tube homebrew transmitter
On Sun, 26 Aug 2007, geek wrote: snip Oh, there's more of us :-) At 39, I'm a dinosaur at heart with barely a transistor in stock. A couple thousand tubes though! Three of us? Could we form a club? "The dinosaur club"? ;-) Behold - http://geek.scorpiorising.ca/GeeK_ZonE How about that... I had a quick look, and cracked up over that one abut getting 500 watts out of a 6L6. Didn't read deeply, but saw a few links I'll have a read later. Thanks. Some of the tube lovers are even mid-teenagers :-) There ae also guys out there that, for wacko (?) reasons, like to restore old cars (eg. Model T fords) and drive them around, too. ;-) Cheers, __ Gregg |
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