Article: 93924 of rec.radio.amateur.homebrew Date: Mon, 01 Aug 2005 22:28:51 -0400 From: -ex- Subject: Re: Crystal Shortwave? References: <1VzHe.1415$jq.1107@bignews3.bellsouth.net> Message-ID: <10a22$42eeda67$4232bd8a$7187@COQUI.NET> Franklin Jennings wrote: > I apologise if this is not the proper group, and will greatly appreciate > direction to the proper one. > > I would like to build the EconOceanic at > http://antiqueradio.org/econmain.htm but the plans call for a dual vari-cap > from an old superhet (using the RF section and Oscillator sections > seperately to tune through the five coil pairs.) But I cannot find this > vari-cap anywhere! > > > > This is fine by me since I live five miles from WSB, the local blowtorch > transmitter siting at AM 750. > > Alternatively, if someone can reccomend a different radio schematic that can > tune 5810, 5850, 9955, 9975, and 13615, that too would be appreciated. > > (The above freqs are for EWTN broadcasts throughout the day and night.) Hi, I'm a crystal radio fanatic. First I'd recommend checking in with the guys at http://www.midnightscience.com/rapntap/ I see two bigger problems than finding the cap. With WSB 5 miles away you are going to literally be swamped with RF and may not be able to hear much SW at all. Secondly, hearing ANY SW on a crystal set is kinda hit and miss in the best of circumstances. The signal needs to be VERY strong and remember that you'll have very little selectivity. As for finding the cap...just find an old $2 plastic clock radio at a yard sale or Goodwill store. There's some guys on Rap-n-Tap who could probably get into more detail about a xtal shortwave set. I built one once - with an audio amp - and yes I heard some wispy traces of SW signals. Its anybody's guess what frequency - or even what band - they were on. I'd recommend building something like a 2-tube regen set - or even a one tuber using something like a 6SN7 (dual triodes). On the same site where you found the xtal plans I think he also has a 2-tube Doerle receiver. Thats a good performer and if you're not into vintage tubes thats where you can replace the two #30s with a 6SN7 or even 12AU7. You'll find lots of these project on the web. Good luck and see you over on R-n-T. -Bill Article: 93925 of rec.radio.amateur.homebrew From: Tim Wescott Subject: Re: Crystal Shortwave? Date: Mon, 01 Aug 2005 23:07:32 -0700 Message-ID: <11eu3cs1fcfrmfb@corp.supernews.com> References: <1VzHe.1415$jq.1107@bignews3.bellsouth.net> Franklin Jennings wrote: > I apologise if this is not the proper group, and will greatly appreciate > direction to the proper one. > > I have just gotten into crystal sets after years away from the electronics > feild (studied at Nuke ET "A" School and FC "A" School in the Navy in > 1995-1996). > > I would like to build the EconOceanic at > http://antiqueradio.org/econmain.htm but the plans call for a dual vari-cap > from an old superhet (using the RF section and Oscillator sections > seperately to tune through the five coil pairs.) But I cannot find this > vari-cap anywhere! > > Here the designer shows the coverage of the various circuits in a graph. I > am quite rusty (I never really worked on Comm equipment, I am a gunfire > control technician by training) but if I understand this, I should be able > to tune all but the lowest frequencies (.50-.75 or so) without the RF > section cap (40-460pF). Again, IF I COMREHEND THIS PROPERLY, I should be > able to substitute a single 365pF vari-cap for the oscillator section, > ommitting the higher RF cap section, and tune all but the lowest BC > frequencies. > > This is fine by me since I live five miles from WSB, the local blowtorch > transmitter siting at AM 750. > > I just wanted to run my plans by the experts before I wind the two biggest > coil pairs for this radio. > > If someone wants to take the time to answer, even via email, I'll be happy > to figure out how to ship a 6-pack of homemade apple cider in appreciation. > > Alternatively, if someone can reccomend a different radio schematic that can > tune 5810, 5850, 9955, 9975, and 13615, that too would be appreciated. > > (The above freqs are for EWTN broadcasts throughout the day and night.) > > Thanks > > Franklin Jennings > Atlanta,GA > > http://www.tubesandmore.com There are plenty others if you dig a bit. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Article: 93928 of rec.radio.amateur.homebrew From: "N9WOS" References: Subject: Re: VFD as an audio/RF amplifier? Message-ID: <6kHHe.531094$cg1.236987@bgtnsc04-news.ops.worldnet.att.net> Date: Tue, 02 Aug 2005 09:48:50 GMT > Hmm... The second idea would also work with standard vacuum tubes that > have more than one anode. Or even two or more electrodes of any type that > is separated from each other by a small amout, that can be used as anodes. > The magnetic field would shift the electron flow from one electrode to the > other. I'll have to do some experiments on that subject. I have looked at over a 100 different tube types that I have on had. Ranging >from the 4 pin 01A to a bunch of different compactatrons. I haven't found one with the correct electrode structure to do a good job at detecting polarity and intensity. The only two that I found, that would possibly make a good intensity detector is the 6AV6, and the 6JH8. You would have to have a tube with two anodes about the same distance from the cathode, with both anodes on the same side of the cathode. (ie) the electrons leave the cathode in one direction, headed for the group of two electrodes. The amount of current arriving at each electrode will be a function of the magnetic field along the path. The magnetic field will curve the path to one electrode, or the other, depending on magnetic polarity. And the current distribution between the two electrodes would indicate intensity. The only thing that draws even close to that is a cathode ray tube with deflection plates. Operate it with the focus out of adjustment enough that the deflection plates are pulling a measurable current. Then the current distribution between the plates will depend on how the magnetic field is shifting the electron beam. Article: 93929 of rec.radio.amateur.homebrew From: "Kimmo Yliskoski" References: <42ea2dd0$0$27392$9b536df3@news.fv.fi> <42ea2e18$0$27392$9b536df3@news.fv.fi> Subject: Re: homebrew car antenna Date: Tue, 2 Aug 2005 12:56:59 +0300 Message-ID: <42ef4369$0$12789$9b536df3@news.fv.fi> Mike Andrews wrote: > TJ wrote: >> On Fri, 29 Jul 2005 16:24:42 +0300, "Kimmo Yliskoski" >> wrote: > >>> Kimmo Yliskoski wrote: >>>> Anyone have good tips to homebrew car antenna? No 1" pipe... just >>>> whip... that stays with me when driving > 60mph. I'm going to use >>>> magnet mount on my car roof. About 1,5m to 2m would be nice length. >>>> Any advice or site where can find something about it? >>> >>> Forget to mention that it is going to be used at CB-channels. 11m >>> band. > >> Why not go to RS and buy one?? >> A lot easier than building one for 27Mhz. > > Only if he's somewhere that has RS or equivalent, which isn't true all > places. I don't find Mr. Yliskoski in the FCC or RAC databases, which > leads me to believe he's not on the North American continent. The name > has a Slavic feel, and anyone, anywhere in the world, can have a gmail > address. It's entirely possible that there's no place near him that > sells brown-n-serve antennas. > > Kimmo, > > An efficient 11m whip probably is going to be a bit longer than 1.5m; > the rear bumper might be a better choice. > > If you really want to do a roof- or trunk- (boot-) mount, there is a > rather sturdy-looking magnetic mount described in the web page at > . The page at > discusses mobile antenna > design and construction of a bumper-mounted whip that works from 20m > through 6m and will handle 100W output. > > It's 99" (2.5m) long at max extension, and is retracted about 60 cm > (to about 1.9m) for 10m. I think that it would need to be just about > 2m long to work 11m, and that's pretty long for a roof-mounted whip. > With the coil in the center, it really would be difficult to keep it > in place on the roof, because of the rotational moment from the > forces on the coil, and it would be a real danger to traffic if it > came loose. > > Boot lid would be a little safer, but not much: a magnetic mount just > is not as secure as a real mechanical fastening. Please consider the > bumper mount. > > Good luck! > > 73, de Yes I'm not north american. I'm Finnish and comp. science student. Everything that i make myself gives extra pleasure to me. :) Now car antenna is next goal. Because i have made simple dipole antenna to my home use. I also found one that is made from fishing rod. http://home.att.net/~wizardoz/cbmw/antenna_fabri.html#fish going to try that one. 73's to all from Finland -- Kimmo Yliskoski Article: 93936 of rec.radio.amateur.homebrew From: flipper Subject: Re: VFD as an audio/RF amplifier? Date: Wed, 03 Aug 2005 05:36:24 -0500 Message-ID: References: <6kHHe.531094$cg1.236987@bgtnsc04-news.ops.worldnet.att.net> On Tue, 02 Aug 2005 09:48:50 GMT, "N9WOS" wrote: >> Hmm... The second idea would also work with standard vacuum tubes that >> have more than one anode. Or even two or more electrodes of any type that >> is separated from each other by a small amout, that can be used as anodes. >> The magnetic field would shift the electron flow from one electrode to the >> other. I'll have to do some experiments on that subject. > >I have looked at over a 100 different tube types that I have on had. Ranging >from the 4 pin 01A to a bunch of different compactatrons. I haven't found >one with the correct electrode structure to do a good job at detecting >polarity and intensity. The only two that I found, that would possibly make >a good intensity detector is the 6AV6, and the 6JH8. > >You would have to have a tube with two anodes about the same distance from >the cathode, with both anodes on the same side of the cathode. > >(ie) the electrons leave the cathode in one direction, headed for the group >of two electrodes. The amount of current arriving at each electrode will be >a function of the magnetic field along the path. The magnetic field will >curve the path to one electrode, or the other, depending on magnetic >polarity. And the current distribution between the two electrodes would >indicate intensity. > >The only thing that draws even close to that is a cathode ray tube with >deflection plates. Operate it with the focus out of adjustment enough that >the deflection plates are pulling a measurable current. Then the current >distribution between the plates will depend on how the magnetic field is >shifting the electron beam. > The Trochotron has multiple plates, e.g. 10, circularly around a central cathode with an outer magnet ring causing a spiral like trochotron electron pattern that's electrostatically deflected, by the "spades," to one of the plates as a nixie driver. It might be possible to adjust the normal operating parameters/ring magnet so it's sensitive to outside magnetic fields distorting the intended pattern, with the spades as a sensitivity/balance adjustment, and the operating instructions do warn about not mounting it near something magnetic or MuMetal. This site has data on them http://www.redremote.co.uk/electricstuff/count.html Article: 93940 of rec.radio.amateur.homebrew From: "xpyttl" References: <1123046267.850747.50510@z14g2000cwz.googlegroups.com> Subject: Re: PSpice help needed Message-ID: <6QaIe.2247$qv2.991@fe07.lga> Date: Wed, 3 Aug 2005 17:39:08 -0400 Chuck Adams has a lot of spice models for typical homebrew components available on his web site, www.k7qo.net. He has a nice tutorial in the QRP Homebrewer, I think you can still get issue number 5. Also, the QRP-L archives CD has a lot of models (they may be mostly the same as Chuck though). The CD is available through QRP-ARCI. Most manufacturers provide models of their parts, so often googling the part number will land you on a spice model. .. wrote in message news:1123046267.850747.50510@z14g2000cwz.googlegroups.com... > I've started using PSpice as part homebrewing and design efforts. It > is very interesting, and a great way to check out ideas before > committing them to actual PC boards. > > Some questions: > > The version I downloaded has some limitations in the parts libraries. > For example, I can't find many of the common parts used by ham > homebrewers: MPf102 JFETS, NE602 mixers, etc. Where can I find the > PSpice models of these parts? Has anyone developed a library of ham > homebrew .MOD files for the parts we use? > > I've (sort of) figured out how to put an impedance matching transformer > into the circuits. I select what they call a "non-linear" transformer > (bad name I think) and this allows me to set the coupling coefficient > and the turns on the primary and the secondary. But what about the > core material, toroid vice no-toried, bifilar windings, etc. Is there > a way of plugging in the kinds of toroids we use? > > Also, I'd be interested in hearing from other amateur homebrewers who > are using Pspice in their solder-melting activities. > > Thanks and 73 > > Bill N2CQR M0HBR CU2JL > http://www.qsl.net/n2cqr > Article: 93942 of rec.radio.amateur.homebrew From: "Joel" References: <4f408$42ea9582$943f9237$32491@STARBAND.NET> Subject: Re: Pool leak detector? Date: Thu, 4 Aug 2005 02:29:35 -0500 Message-ID: The problem is it could be on the bottom or sides and I need something better then my eyes to find it. It certainly is leaking as I have standing water all around the pool. The pool is 27 foot round, so a hole in the bottom could show most anyplace on any or all sides. I am hoping to measure 'something' resistance seems to make senses.. But something to lead me to the leaking location. The resistance is high between the water and the ground but measurable. I'm not sure I can see the resistance change to direct me in the right direction. I'm hoping to build or even buy something that would be maybe a bridge that would zero out or null on the restiance and then show minor changes. Something like that makes sense to me. But I can't believe someone hasn't already built something like this. Joe "Wim Ton" wrote in message news:HTQHe.70317$dN6.35281@fe1.news.blueyonder.co.uk... >> Has anyone had any experience with some sort of above ground pool leak >> detector? I figures if I could connect one probe to some sort of > sensitive >> restiance (ohm) meter and put it in the water, I could maybe read the >> resistance between the probe and ground and then as I got closer to the > leak >> the restiance would go down. But the restiance is WAY high.. But seems to > me >> something like that would work. Any ideas? > > Maybe look only outside the pool for the wettest area. The keywords to > look > for are in the direction of geophysics. These electrical methods are also > used to find subsurface water (e.g. where to drill wells) > > Wim > > Article: 93943 of rec.radio.amateur.homebrew Date: Thu, 04 Aug 2005 04:01:33 -0400 From: -ex- Subject: Re: Pool leak detector? References: <4f408$42ea9582$943f9237$32491@STARBAND.NET> Message-ID: <97e36$42f1cb60$4232bd45$19084@COQUI.NET> Joel wrote: > The problem is it could be on the bottom or sides and I need something > better then my eyes to find it. It certainly is leaking as I have standing > water all around the pool. The pool is 27 foot round, so a hole in the > bottom could show most anyplace on any or all sides. I am hoping to measure > 'something' resistance seems to make senses.. But something to lead me to > the leaking location. The resistance is high between the water and the > ground but measurable. I'm not sure I can see the resistance change to > direct me in the right direction. I'm hoping to build or even buy something > that would be maybe a bridge that would zero out or null on the restiance > and then show minor changes. Something like that makes sense to me. But I > can't believe someone hasn't already built something like this. > > Joe This is a crazy idea...I had one of those moisture indicators like you use with watering indoor house plants. Cost about 10 bux. Pretty sensitive but i don't know if it would help in pinpointing anything in your case. But...if you've got standing water all around the pool it would seem to me that you need to call a pool guy. They have experience in locating these problems and you'll likely need them to come fix the problem anyway. They won't be very impressed by having to slosh thru water to view the results of your homebrew leak detector. -Bill Article: 93946 of rec.radio.amateur.homebrew From: "William E. Sabin" Subject: My Homebrew gear Message-ID: <1GpIe.236642$xm3.51767@attbi_s21> Date: Thu, 04 Aug 2005 14:32:29 GMT A picture and brief discussion of my homebrew HF receiver and transmitter are on QRZ.COM. Bill W0IYH Article: 93947 of rec.radio.amateur.homebrew From: "Harold E. Johnson" References: <1GpIe.236642$xm3.51767@attbi_s21> Subject: Re: My Homebrew gear Message-ID: Date: Thu, 04 Aug 2005 14:40:13 GMT "William E. Sabin" wrote in message news:1GpIe.236642$xm3.51767@attbi_s21... >A picture and brief discussion of my homebrew HF receiver and transmitter >are on QRZ.COM. > > Bill W0IYH Very handsome Bill. Is that 40+ volt supply internal to the transmitter cabinet? Any blowers involved? Regards W4ZCB Article: 93949 of rec.radio.amateur.homebrew From: "Harold E. Johnson" References: <1GpIe.236642$xm3.51767@attbi_s21> Subject: Re: My Homebrew gear Message-ID: Date: Thu, 04 Aug 2005 17:01:25 GMT "Harold E. Johnson" wrote in message news:hNpIe.220263$_o.151253@attbi_s71... > > "William E. Sabin" wrote in message > news:1GpIe.236642$xm3.51767@attbi_s21... >>A picture and brief discussion of my homebrew HF receiver and transmitter >>are on QRZ.COM. >> >> Bill W0IYH > > Very handsome Bill. Is that 40+ volt supply internal to the transmitter > cabinet? Any blowers involved? Belay the last, just remembered the blower on the MRF-150's! > > Regards > W4ZCB > Article: 93950 of rec.radio.amateur.homebrew From: "William E. Sabin" References: <1GpIe.236642$xm3.51767@attbi_s21> Subject: Re: My Homebrew gear Message-ID: <6TrIe.237307$xm3.27399@attbi_s21> Date: Thu, 04 Aug 2005 17:02:58 GMT Yes, the 47 V 8A series regulator supply is in the big cabinet. It also has all of the protections for the MRF150 transistors. Also a fan for the 100W amplifier module. The transmitter is completely self-contained. There is no attempt at miniaturization. I don't have the time or patience for that level of effort. Each radio is a "test bed" and not a finished product. Just this morning I made two circuit improvements in the receiver. I recently rebuilt the 3.395 MHz IF amp module and the AGC processor module to get rid of a rat's nest of "fixups" and haywire. It looks pretty good now. I do admire the tremendous effort that goes into the compact transceivers, but I don't want to duplicate it. It is the basic radio communications functionality that I care about. Bill W0IYH "Harold E. Johnson" wrote in message news:hNpIe.220263$_o.151253@attbi_s71... > > "William E. Sabin" wrote in message > news:1GpIe.236642$xm3.51767@attbi_s21... >>A picture and brief discussion of my homebrew HF receiver and transmitter >>are on QRZ.COM. >> >> Bill W0IYH > > Very handsome Bill. Is that 40+ volt supply internal to the transmitter > cabinet? Any blowers involved? > > Regards > W4ZCB > Article: 93951 of rec.radio.amateur.homebrew From: fmmck@aol.com (Fred McKenzie) Subject: Re: Pool leak detector? Date: Thu, 04 Aug 2005 14:37:32 -0400 Message-ID: References: <4f408$42ea9582$943f9237$32491@STARBAND.NET> In article , "Joel" wrote: > The problem is it could be on the bottom or sides and I need something > better then my eyes to find it. It certainly is leaking as I have standing > water all around the pool. Joe- I've never had a pool, but it seems to me that standing water could only be the result of a gross leak. You should be able to see it with the naked eye. Isn't it more likely that a leak would be in the external plumbing associated with the pool? How else could the pool have a water level lower than the surrounding standing water, unless it is located in a swamp? 73, Fred, K4DII Article: 93953 of rec.radio.amateur.homebrew From: mcalhoun@ksu.edu Subject: Re: Crystal Shortwave? Date: 4 Aug 2005 17:14:45 -0500 Message-ID: References: <1VzHe.1415$jq.1107@bignews3.bellsouth.net> <10a22$42eeda67$4232bd8a$7187@COQUI.NET> >Franklin Jennings wrote: >> ... I would like to build the EconOceanic at.... -ex- writes: >.... Secondly, hearing ANY SW on a crystal set is kinda >hit and miss in the best of circumstances. The signal needs to be VERY >strong and remember that you'll have very little selectivity. >....[snip].... Unless something has really changed, you shouldn't be so negative about hearing SW on a crystal set. About 1958, on a simple xtal set (antenna, coil, capacitor, diode, phones) although I don't remember the exact stations (Quito and Radio Moscow?), I do remember hearing LOUD shortwave signals. At the time, my antenna was the top strand of a barbed-wire fence on wooden posts (length UNknown, but probably less that a couple-hundred feet) and the ground was the guy- wire to our house's power pole. -- --Myron A. Calhoun. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) Article: 93954 of rec.radio.amateur.homebrew From: "amdxjunk" References: <1VzHe.1415$jq.1107@bignews3.bellsouth.net> <10a22$42eeda67$4232bd8a$7187@COQUI.NET> Subject: Re: Crystal Shortwave? Date: Thu, 4 Aug 2005 19:15:11 -0500 Message-ID: > I see two bigger problems than finding the >cap. With WSB 5 miles away > you are going to literally be swamped with >RF and may not be able to > hear much SW at all. Secondly, hearing >ANY SW on a crystal set is kinda > hit and miss in the best of circumstances. >The signal needs to be VERY > strong and remember that you'll have very >little selectivity.store. Build a tuned circuit for WSB and use the voltage generated as the power supply for a transistor amplifier for your SW listening. You will find info on the web. Mike Article: 93955 of rec.radio.amateur.homebrew Subject: Re: Crystal Shortwave? From: Ed References: <1VzHe.1415$jq.1107@bignews3.bellsouth.net> <10a22$42eeda67$4232bd8a$7187@COQUI.NET> Message-ID: Date: Fri, 05 Aug 2005 01:26:24 GMT > > Build a tuned circuit for WSB and use the voltage generated as the > power > supply for a transistor amplifier for your SW listening. > You will find info on the web. > Mike > > That's a great concept.... I'd like more specific info on WEB sites. Can't quite figure what to type in the Google search box for this. Ed Article: 93956 of rec.radio.amateur.homebrew From: "Joel" References: <4f408$42ea9582$943f9237$32491@STARBAND.NET> Subject: Re: Pool leak detector? Date: Thu, 4 Aug 2005 22:35:38 -0500 Message-ID: This is a above ground pool with a vinyl liner.. about 27 feet in diameter, we had a special liner installed in it so we have the ground dug out so the deep end is about 6 and half feet deep. The bottom is cement as it's the only way to keep the sand from migrating along the bottom to the deep end. So a leak is a bugger to find as the liner leaks and the cement bottom send the water in all directions. I had another leak a year or so ago and I ended up draining the pool and finely found it and repaired it. In this case I can't drain the pool again, as the line probably won't take another streaching. And -ex- your probably right, I need to get a expert out here.. I live about 200 miles from Nashville and 150 from Memphis, and that's where these 'experts' probably would have to come. So if I could find this thing it would be great. I know they make some sort of electronic gismos for finding leaks, I just have no idea how they work. Joe AG4QC "Fred McKenzie" wrote in message news:fmmck-0408051437330001@aca32f66.ipt.aol.com... > In article , "Joel" > wrote: > >> The problem is it could be on the bottom or sides and I need something >> better then my eyes to find it. It certainly is leaking as I have >> standing >> water all around the pool. > > Joe- > > I've never had a pool, but it seems to me that standing water could only > be the result of a gross leak. You should be able to see it with the > naked eye. > > Isn't it more likely that a leak would be in the external plumbing > associated with the pool? How else could the pool have a water level > lower than the surrounding standing water, unless it is located in a > swamp? > > 73, Fred, K4DII Article: 93957 of rec.radio.amateur.homebrew From: biascomms Subject: Re: Crystal Shortwave? References: <1VzHe.1415$jq.1107@bignews3.bellsouth.net> <10a22$42eeda67$4232bd8a$7187@COQUI.NET> Message-ID: Date: Fri, 05 Aug 2005 05:34:34 GMT mcalhoun@ksu.edu wrote: > Unless something has really changed, you shouldn't be so negative about > hearing SW on a crystal set. > > About 1958, on a simple xtal set (antenna, coil, capacitor, diode, phones) > although I don't remember the exact stations (Quito and Radio Moscow?), I > do remember hearing LOUD shortwave signals. At the time, my antenna was > the top strand of a barbed-wire fence on wooden posts (length UNknown, > but probably less that a couple-hundred feet) and the ground was the guy- > wire to our house's power pole. Unfortunately, things /really/ have changed in the intervening years. The shortwave bands have become /much/ more crowded, and the general noise levels have increased radically - almost /every/ piece of domestic or commercial electronics radiates RF noise these days. Bob -- Everything gets easier with practice, except getting up in the morning! Article: 93958 of rec.radio.amateur.homebrew From: "William E. Sabin" References: <1GpIe.236642$xm3.51767@attbi_s21> <1123213736.998245.249570@g43g2000cwa.googlegroups.com> Subject: Re: My Homebrew gear Message-ID: Date: Fri, 05 Aug 2005 08:29:38 GMT Thanks Bill and 73 Bill W0IYH wrote in message news:1123213736.998245.249570@g43g2000cwa.googlegroups.com... > Bill: Very nice! It was a pleasure to look at the pictures and read > about your work. Very FB! 73 > Bill > M0HBR N2CQR CU2JL > http://planeta.clix.pt/n2cqr > Article: 93960 of rec.radio.amateur.homebrew From: "Heytubeguy" Subject: FA: Original Manuals:TWE 500+1000, HRO-50-1, 1 day Message-ID: Date: Fri, 05 Aug 2005 14:14:47 GMT See these original manuals at: http://search.ebay.com/_W0QQfgtpZ1QQfrppZ25QQsassZheytubeguy Tnx for looking heytubeguy Article: 93961 of rec.radio.amateur.homebrew From: "Ralph Mowery" References: <1123249370.681543.216960@f14g2000cwb.googlegroups.com> Subject: Re: Rules-of-thumb for RF variable cap plate spacing? Message-ID: Date: Fri, 05 Aug 2005 14:22:31 GMT "Tim Shoppa" wrote in message news:1123249370.681543.216960@f14g2000cwb.googlegroups.com... > Are there any generic rules-of-thumb for what variable cap (tune and > load) spacing is necessary for RF amps in a certain power class? > > For example, "if you're building a 80W amp with a single 6146B the > plate spacing should be x inches". > > Wasn't there a table in the ARRL handbook along these lines? > > I'm guessing it depends on both the DC plate voltage and the power > level and maybe how mismatched the antenna is. > > Of course, I could just buy bigger and bigger spacing surplus variable > caps until they don't arc over when I key up! Sort of how like they > put the weight limit on a bridge by building the bridge, driving bigger > and bigger trucks over it until it collapses, and then rebuild it with > the weight of the last truck that made it over :-). > The handbook lists peak voltages for the plate capacitor spacings. 1000 volts .015 inch spacing 2000 .05 3000 .07 4500 .125 6000 .15 9000 .25 13000 .5 Also it states that is for peak RF volts, if the DC plate voltage is across the capacitor it must be added. Plate modulated finals take about 4 times the plate voltage. Article: 93962 of rec.radio.amateur.homebrew From: "Mike Andrews" Subject: Re: Rules-of-thumb for RF variable cap plate spacing? Date: Fri, 5 Aug 2005 16:01:10 +0000 (UTC) Message-ID: References: <1123249370.681543.216960@f14g2000cwb.googlegroups.com> Ralph Mowery wrote: > The handbook lists peak voltages for the plate capacitor spacings. > 1000 volts .015 inch spacing > 2000 .05 > 3000 .07 > 4500 .125 > 6000 .15 > 9000 .25 > 13000 .5 > Also it states that is for peak RF volts, if the DC plate voltage is across > the capacitor it must be added. Plate modulated finals take about 4 times > the plate voltage. The rule of thumb I learned for HV conductor spacing is 30 KV per inch in dry air with smooth surfaces. Rough surfaces, points, sharp edges, etc. all reduce the arc-over voltage, as does increasing humidity. I'd go with the handbook's table above, as it allows a safety factor and probably will prevent embarrassing events involving smoke. -- I, for one, do not like to damage my precious equipment, especially when it involves repeatedly hitting it with a computer. -- Peter Corlett, about his hammer Article: 93964 of rec.radio.amateur.homebrew From: "amdxjunk" References: <1VzHe.1415$jq.1107@bignews3.bellsouth.net> <10a22$42eeda67$4232bd8a$7187@COQUI.NET> Subject: Re: Crystal Shortwave? Date: Fri, 5 Aug 2005 19:48:16 -0500 Message-ID: <7f6fb$42f408e1$18d6b479$19518@KNOLOGY.NET> "Ed" wrote in message news:Xns96A8BBB32AD5spectrumhogstarbandn@207.106.93.175... > > > > Build a tuned circuit for WSB and use the voltage generated as the > > power > > supply for a transistor amplifier for your SW listening. > > You will find info on the web. > > Mike > That's a great concept.... I'd like more specific info on WEB sites. > Can't quite figure what to type in the Google search box for this. > Ed I looked for a while and found many dead sites. I did find this one, this guy has done some serious research on crystal radios. You might recognize the name. http://www.bentongue.com/ Look at #25 Article: 93965 of rec.radio.amateur.homebrew Subject: Re: Crystal Shortwave? From: Ed References: <1VzHe.1415$jq.1107@bignews3.bellsouth.net> <10a22$42eeda67$4232bd8a$7187@COQUI.NET> <7f6fb$42f408e1$18d6b479$19518@KNOLOGY.NET> Message-ID: Date: Sat, 06 Aug 2005 05:57:56 GMT > I looked for a while and found many dead sites. I did find this one, > this > guy has done some serious research on crystal radios. > You might recognize the name. > http://www.bentongue.com/ > Look at #25 > Great! That site I had missed in my searching. Probably my best reference, now. Thanks. Ed Article: 93966 of rec.radio.amateur.homebrew From: To Lose Lautrec Subject: Re: 6m or 10m CW RX Kit Message-ID: References: Date: Sat, 06 Aug 2005 13:30:59 GMT RAMSEY and TENTEC might be two sources... On Fri, 05 Aug 2005 06:43:34 GMT, Andy Ball wrote: > >Is anyone here able to point me in the direction of a 10m or >6m CW receiver kit? I would like something that's fairly >simple to build (I don't have a lot of test equipment) but >would perform well enough to let me monitor a few beacons >and perhaps some fairly local CW activity (if there is any). > >Thanks, > - Andy, KB9YLW