[AMRadio] Re: AM Transmitter Advice??
To Jim, John and all: Jim: The URL you listed is a great site for information on the H&K type 5. It is quite true that the H&K type 5 never went much beyond the prototype stage and I have one of those "rare little puppies" in my collection. However, the larger transmitting gridless Gammatrons were used extensively in the west coast based Globe Wireless communication system built by H&K. The complete H&K gridless Gammatron story is about a 30-page article named "Defiance in the West, The Heintz and Kaufman Story" that was published in the "AWA Review", Volume X, 1996. It includes pictures of all the different gridless Gammatrons. John: The 6AX5GT and some Raytheon 6X5WGT's have the proper plate-cathode construction that makes them candidates for gridless Gammatron experimentation. I can not take credit for the initial idea of using the 6AX5GT. Reed Fisher, W2CQH, first introduced the use of the 6AX5GT as an experimental gridless Gammatron substitute in an article that appeared in the April, 2004 issue of the "Tube Collector". I refer to both his work and the above mentioned "AWA Review" article in my article that appears in the February, 2006 "Tube Collector". Using the above information, I further refined the 6AX5GT Gammatron operating conditions and developed the AM transmitter circuit. My article documents my experimental findings and includes the AM transmitter schematic. In a nutshell and just enough to peak your interest into pursuing the articles for all the details, I offer the brief description of operation: One must reduce the heater voltage of the 6AX5GT to a point the there is a limited flow of electrons between cathode and one of the two plates that has been selected to act as the anode. About 15 ma. appears to be optimum in my circuits with 75 volts on the anode. The second plate is then used as the Gamma or control plate which is synonymous with the grid connection in a triode circuit. Control potentials imposed on the designated Gamma plate diverts some of the cathode to anode electron flow to the Gamma plate therefore causing triode action. A word of caution! Since one has a forward biased diode across the power supply with only the cathode temperature limiting the electron flow, one must protect the power supply from the possibility of excessive current. Initially, I used a #47 lamp in series with the anode and the power supply. I got tired of replacing the lamps when I was experimenting with various Gamma currents or electron space charge buildup and resorted to a voltage divider setup allowing 75 volts at 15 ma. from a 180 volt supply. The design wattage of the voltage dropping resistor was selected so it could safely dissipate the entire 180 volts in conditions when the Gammatron currents became excessive either due to too high of a heater voltage or electron space charge buildup. I suggest that you visit http://www.tubecollectors.org/ for information regarding the tube collector. I just noticed that the editor has not listed the February, 2006 on the website yet. However, all previous issues are currently listed. Information on the most recent issue containing my article should be appearing in the next couple days. Have fun experimenting That is what ham radio is all about. Bob, K2GLO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Candela Sent: Friday, February 17, 2006 4:09 AM To: Discussion of AM Radio Subject: RE: [AMRadio] Re: AM Transmitter Advice?? John, Check this out: http://uv201.com/Tube_Pages/heintz-kaufman.htm Jim WD5JKO --- John Coleman ARS WA5BXO <[EMAIL PROTECTED]> wrote: > OK BOB! > You got my attention. Explain more. I hope I'm not > a sucker > here. I have seen and extremely low mu amplifier > circuit (common > cathode) made by reverse biasing the plate of a > triode and forward > biasing the grid where output is taken from the grid > and input is on the > plate. So I know that weird stuff does exist. > > John, WA5BXO > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of Bob Deuel > Sent: Thursday, February 16, 2006 6:05 PM > To: 'Discussion of AM Radio' > Subject: [AMRadio] Re: AM Transmitter Advice?? > > Hello Larry and all: > > Larry's tongue in cheek comment employing 866's as a > linear amplifier > tube > prompted me to contribute the following: Certain > full-wave rectifiers > can be > configured to amplify or oscillate. I have built > audio, Hartley and > Simpson > oscillators using only 6AX5GT's full-wave rectifiers > as the sole active > device. These were displayed at 2004 Mid-Atlantic > Antique Radio Club > Meet > and actually won a Blue Ribbon. > Late last year I built an AM transmitter consisting > of a Hartley > oscillator > modulated by an AM modulator using only 6AX5GT > full-wave rectifier tubes > as > the active devices. No solid-state magic, just > simple full-wave > rectifiers. > The basic concept is that of t
Re: [AMRadio] AM Transmitter Advice??
Wow. Well, 6 watts to 20 watts is about 5.2 dB of increase. One night someone switched from 350 watts to 80 watts, about a 6.4 dB signal reduction. What a difference, he really fell into the atmospheric static. I'm always surprised at what a few dB can do. I know it's not supposed to work that way... so it's suprising. I guess we work at pretty low s/n, so we really see the diffference. Bacon, WA3WDR - Original Message - From: "Gary Schafer" <[EMAIL PROTECTED]> To: "'Discussion of AM Radio'" Sent: Friday, February 17, 2006 11:36 AM Subject: RE: [AMRadio] AM Transmitter Advice?? > Actually the 10 watt ratting on the CE 10A/B is 10 watts PEP input. > That gives around 5 to 6 watts output PEP for available drive. > > 73 > Gary K4FMX
RE: [AMRadio] AM Transmitter Advice??
Actually the 10 watt ratting on the CE 10A/B is 10 watts PEP input. That gives around 5 to 6 watts output PEP for available drive. 73 Gary K4FMX > -Original Message- > From: [EMAIL PROTECTED] [mailto:amradio- > [EMAIL PROTECTED] On Behalf Of Bob Bruhns > Sent: Friday, February 17, 2006 11:23 AM > To: Discussion of AM Radio > Subject: Re: [AMRadio] AM Transmitter Advice?? > > 12AX7s have surprised me with their power > capabilities before, but 20 watts output with 30 > watts input is 67% efficiency, and that means that > the 20 watts output is the PEP output of the > 3-12AX7 linear. I think that the 10W rating with > a 6AG7 is PEP as well. > > Bacon, W3WDR > > > - Original Message - > From: "Jim Candela" <[EMAIL PROTECTED]> > To: "Discussion of AM Radio" > > Sent: Friday, February 17, 2006 7:29 AM > Subject: RE: [AMRadio] AM Transmitter Advice?? > > > > > > > > Hi All, > > > >I recently had a conversation with a ham in > San > > Antonio (forgot his call), and he told me that > he > > built a unique linear amplifier for his central > > electronics 10a, and for tubes he chose 3 type > 12AX7 > > in parallel grounded grid. He said he could run > 30 > > watts input (300v @ 100ma) with no problems, and > about > > 20 watts out. I find it odd though that a 10a > can do > > 10 watts with a single 6AG7, and 20 watts is > only a > > 3db boost. > > > > To my way of thinking, a linear amp needs to > boost > > your power at least 6 db (~1 'S' unit) to be > worth the > > trouble. For us AM'ers, going from 100 watts to > 375 > > watts carrier does not meet the 6 db boost > criteria, > > and that explains why a good antenna on a DX-100 > is > > better than a average antenna on a Globe King > 500. > > > > Still, as I once posted last year, a dual 304TL > > grounded grid linear seems to fit the bill as a > 6 db > > 'brick' capable of 400 watts AM carrier output > with > > 100 watts AM input, or said another way it takes > 400 > > watts PEP and boosts it to 1600 watts PEP. There > was > > an old W6SAI construction project about this > (single > > 304tl GG amp), and I recall that the setup in > class C > > could run 1 kw dc input with over 1 kw rf output > > because of the low gain, and massive amount of > > feedthrough power from the exciter that finds > it's way > > to the output. This was a way around the FCC > power > > rules of the day. > > > > Regards, > > Jim > > WD5JKO > > > > --- Donald Chester <[EMAIL PROTECTED]> wrote: > > > > > >Assuming one is going to build a linear, and > so > > > putting aside other issues > > > >such as linear vs plate modulation, why do > you > > > think it makes a difference > > > >what tube is used? Are you referring to > running a > > > linear at greater than > > > >legal limit?. > > > > > > Well, go ahead and try building a legal limit > linear > > > that runs a pair of > > > 807's in the final. > > > > > > > > > __ > _ > > > > > > This message was typed using the DVORAK > keyboard > > > layout. Try it - you'll > > > like it. > > > http://www.mwbrooks.com/dvorak/ > > > http://gigliwood.com/abcd/ > > > > > > > > > > > > __ > > > > AMRadio mailing list > > > Home: > > > > http://mailman.qth.net/mailman/listinfo/amradio > > > Help: http://mailman.qth.net/mmfaq.html > > > Post: mailto:AMRadio@mailman.qth.net > > > AMfone Website: http://www.amfone.net > > > AM List Admin: Brian Sherrod/w5ami, Paul > > > Courson/wa3vjb > > > > > > > > __ > > > AMRadio mailing list > > Home: > http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:AMRadio@mailman.qth.net > > AMfone Website: http://www.amfone.net > > AM List Admin: Brian Sherrod/w5ami, Paul > Courson/wa3vjb > > > > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] AM Transmitter Advice??
12AX7s have surprised me with their power capabilities before, but 20 watts output with 30 watts input is 67% efficiency, and that means that the 20 watts output is the PEP output of the 3-12AX7 linear. I think that the 10W rating with a 6AG7 is PEP as well. Bacon, W3WDR - Original Message - From: "Jim Candela" <[EMAIL PROTECTED]> To: "Discussion of AM Radio" Sent: Friday, February 17, 2006 7:29 AM Subject: RE: [AMRadio] AM Transmitter Advice?? > > > Hi All, > >I recently had a conversation with a ham in San > Antonio (forgot his call), and he told me that he > built a unique linear amplifier for his central > electronics 10a, and for tubes he chose 3 type 12AX7 > in parallel grounded grid. He said he could run 30 > watts input (300v @ 100ma) with no problems, and about > 20 watts out. I find it odd though that a 10a can do > 10 watts with a single 6AG7, and 20 watts is only a > 3db boost. > > To my way of thinking, a linear amp needs to boost > your power at least 6 db (~1 'S' unit) to be worth the > trouble. For us AM'ers, going from 100 watts to 375 > watts carrier does not meet the 6 db boost criteria, > and that explains why a good antenna on a DX-100 is > better than a average antenna on a Globe King 500. > > Still, as I once posted last year, a dual 304TL > grounded grid linear seems to fit the bill as a 6 db > 'brick' capable of 400 watts AM carrier output with > 100 watts AM input, or said another way it takes 400 > watts PEP and boosts it to 1600 watts PEP. There was > an old W6SAI construction project about this (single > 304tl GG amp), and I recall that the setup in class C > could run 1 kw dc input with over 1 kw rf output > because of the low gain, and massive amount of > feedthrough power from the exciter that finds it's way > to the output. This was a way around the FCC power > rules of the day. > > Regards, > Jim > WD5JKO > > --- Donald Chester <[EMAIL PROTECTED]> wrote: > > > >Assuming one is going to build a linear, and so > > putting aside other issues > > >such as linear vs plate modulation, why do you > > think it makes a difference > > >what tube is used? Are you referring to running a > > linear at greater than > > >legal limit?. > > > > Well, go ahead and try building a legal limit linear > > that runs a pair of > > 807's in the final. > > > > > __ _ > > > > This message was typed using the DVORAK keyboard > > layout. Try it - you'll > > like it. > > http://www.mwbrooks.com/dvorak/ > > http://gigliwood.com/abcd/ > > > > > > > __ > > AMRadio mailing list > > Home: > > http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:AMRadio@mailman.qth.net > > AMfone Website: http://www.amfone.net > > AM List Admin: Brian Sherrod/w5ami, Paul > > Courson/wa3vjb > > > > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb >
[AMRadio] FS: More Boatanchors
FOR SALE. Shipping extra. Homebrew crystal set with cats whisker and vertical tuning coil. About the size of a beer can. The parts used are obviously commercial. Very cute and well-made. $40 Homebrew "Versatile 70" 70 Watt AM Transmitter. This is a construction project from CQ Magazine, December, 1953. 70 watt bandswitching AM transmitter using single 6146 in final. I believe this is grid-modulated. Fabulously built with the best of components. Nice cosmetic condition. Untested. No restoration has been done. Some cold solder joints and loose connections are visible underneath. This is a 19" rackmount occupying 10-1/2" of rack space. Currently in nice black-wrinkle ex-military desktop cabinet. With original CQ article. Tube line-up is 1-6AG5, 5-6AQ5, 1-6146, 1-6AU6, 1-6C4, 1-0A2, 1-0B2, 1-6X4, 1-5R4GY. As-is. $105 RME 99 HF receiver. 1940-vintage ham bands receiver in nice black wrinkle desk cabinet. Oddly, the large dial in the center is bandspread, while the smaller dial at the right Is the main tuning. Triple conversion. Very good cosmetic condition with some small marks in paint. Some knobs may be wrong but they are so close that it's hard to tell. Untested. As-is. The tube line-up is locktals: 4-7A7, 1-7B8, 2-7A4, 1-7F7, 1-7C5, 1-7A6, 1-VR150, 1-80. With manual copy. $250 Meissner Signal Shifter EX--rackmount version. The rack panel was a separate option and is seldom seen. Looks great. Working. $125 Picture available. Tektronix 190B Constant Amplitude Signal Generator with the output cord and the 190B attenuator. 1957-vintage. This is a sine-wave generator with a range from 350kc to 50mc. Amplitude is variable from 40 millivolts to 10 volts peak to peak in 7 ranges. This seems to be working right. But it has a dirty meter zero adjust pot and bad contacts on the pilot lamp. Looks good but the pseudo-leather handle is crumbling. $40 HP 4265A Universal Bridge. This is a typical repair bench bridge from 1973. With original manual and sales receipt ($510 in 1973). Covers L C and R with mechanical digital readout. Has options for connecting HP VTVM etc on rear panel. Has DC bias for L and C measurements. Variable test frequency from 50hz to 10khz. Solid state with carry handle. Seems to be working correctly but switches and pots need cleaning. $95 RCA ACR-155 Receiver. This is a very uncommon 1936 ham receiver covering .55mc - 22mc in oversize desk cabinet. Styled to match RCA ACT-20 transmitter. Band switch moves complex mechanical linkage to change dial scales. Tuning knob looks like BC-348 (but it's not). It's in very good or excellent cosmetic condition. Electrically untested, but complete with no visible modifications--except that the original. BFO on/of switch has been changed to toggle instead of turn-type. I can supply the correct switch and knob with the radio. With original manual. The tube line-up is 2-6K7, 1-6L7, 2-6J7, 1-6H6, 1-6F5,1-6F6, 1-5W4. Unique BA in the long cabinet with the top corner beveled off. $350 Thanks for looking. 73, Don Merz, N3RHT The information contained in this e-mail may be confidential and is intended solely for the use of the named addressee. Access, copying or re-use of the e-mail or any information contained therein by any other person is not authorized. If you are not the intended recipient please notify us immediately by returning the e-mail to the originator.(17b)
RE: [AMRadio] AM Transmitter Advice??
Hi Jim, My understanding was. Under the old rules stage or stages, that provide output to the antenna, total power should not exceed 1000 watts DC input. This includes the sum of the driver and final in the case of GG output circuit. I think that rule was tested. John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Candela Sent: Friday, February 17, 2006 6:29 AM To: Discussion of AM Radio Subject: RE: [AMRadio] AM Transmitter Advice?? Hi All, There was an old W6SAI construction project about this (single 304tl GG amp), and I recall that the setup in class C could run 1 kw dc input with over 1 kw rf output because of the low gain, and massive amount of feedthrough power from the exciter that finds it's way to the output. This was a way around the FCC power rules of the day. Regards, Jim WD5JKO --- Donald Chester <[EMAIL PROTECTED]> wrote: > >Assuming one is going to build a linear, and so > putting aside other issues > >such as linear vs plate modulation, why do you > think it makes a difference > >what tube is used? Are you referring to running a > linear at greater than > >legal limit?. > > Well, go ahead and try building a legal limit linear > that runs a pair of > 807's in the final. > > ___ > > This message was typed using the DVORAK keyboard > layout. Try it - you'll > like it. > http://www.mwbrooks.com/dvorak/ > http://gigliwood.com/abcd/ > > > __ > AMRadio mailing list > Home: > http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul > Courson/wa3vjb > __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] AM Transmitter Advice??
Thats poppycock. Everyone knows if you reduce the output filtering, and use an all band, coax fed, off-center Windom it will be possible to transmit multi-band. If you have a 5 bands off the radiator that would, effectively, give you 150% efficiency. 5 bands x 30% = 150%. Think of the possibilities. Now who of then experts would dare say, "Theres no free lunch". The numbers dont lie. Brian Carling wrote: I bet you a BC610 will out-peg a DX100 any day! Don't care what the numbers say... Grin! That 12AX7 linear amplifier sounds like more of a FUN project than a useful station accessory! Just WAIT until the experts start telling you it can't be done, you will only get 30% efficiency and all that jazz! LOL. 73 de AF4K, Bry On 17 Feb 2006 at 4:29, Jim Candela wrote: Hi All, I recently had a conversation with a ham in San Antonio (forgot his call), and he told me that he built a unique linear amplifier for his central electronics 10a, and for tubes he chose 3 type 12AX7 in parallel grounded grid. He said he could run 30 watts input (300v @ 100ma) with no problems, and about 20 watts out. I find it odd though that a 10a can do 10 watts with a single 6AG7, and 20 watts is only a 3db boost. To my way of thinking, a linear amp needs to boost your power at least 6 db (~1 'S' unit) to be worth the trouble. For us AM'ers, going from 100 watts to 375 watts carrier does not meet the 6 db boost criteria, and that explains why a good antenna on a DX-100 is better than a average antenna on a Globe King 500. Still, as I once posted last year, a dual 304TL grounded grid linear seems to fit the bill as a 6 db 'brick' capable of 400 watts AM carrier output with 100 watts AM input, or said another way it takes 400 watts PEP and boosts it to 1600 watts PEP. There was an old W6SAI construction project about this (single 304tl GG amp), and I recall that the setup in class C could run 1 kw dc input with over 1 kw rf output because of the low gain, and massive amount of feedthrough power from the exciter that finds it's way to the output. This was a way around the FCC power rules of the day. Regards, Jim WD5JKO --- Donald Chester <[EMAIL PROTECTED]> wrote: Assuming one is going to build a linear, and so putting aside other issues such as linear vs plate modulation, why do you think it makes a difference what tube is used? Are you referring to running a linear at greater than legal limit?. Well, go ahead and try building a legal limit linear that runs a pair of 807's in the final. ___ This message was typed using the DVORAK keyboard layout. Try it - you'll like it. http://www.mwbrooks.com/dvorak/ http://gigliwood.com/abcd/ __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
RE: [AMRadio] AM Transmitter Advice??
I bet you a BC610 will out-peg a DX100 any day! Don't care what the numbers say... Grin! That 12AX7 linear amplifier sounds like more of a FUN project than a useful station accessory! Just WAIT until the experts start telling you it can't be done, you will only get 30% efficiency and all that jazz! LOL. 73 de AF4K, Bry On 17 Feb 2006 at 4:29, Jim Candela wrote: > > > Hi All, > >I recently had a conversation with a ham in San > Antonio (forgot his call), and he told me that he > built a unique linear amplifier for his central > electronics 10a, and for tubes he chose 3 type 12AX7 > in parallel grounded grid. He said he could run 30 > watts input (300v @ 100ma) with no problems, and about > 20 watts out. I find it odd though that a 10a can do > 10 watts with a single 6AG7, and 20 watts is only a > 3db boost. > > To my way of thinking, a linear amp needs to boost > your power at least 6 db (~1 'S' unit) to be worth the > trouble. For us AM'ers, going from 100 watts to 375 > watts carrier does not meet the 6 db boost criteria, > and that explains why a good antenna on a DX-100 is > better than a average antenna on a Globe King 500. > > Still, as I once posted last year, a dual 304TL > grounded grid linear seems to fit the bill as a 6 db > 'brick' capable of 400 watts AM carrier output with > 100 watts AM input, or said another way it takes 400 > watts PEP and boosts it to 1600 watts PEP. There was > an old W6SAI construction project about this (single > 304tl GG amp), and I recall that the setup in class C > could run 1 kw dc input with over 1 kw rf output > because of the low gain, and massive amount of > feedthrough power from the exciter that finds it's way > to the output. This was a way around the FCC power > rules of the day. > > Regards, > Jim > WD5JKO > > --- Donald Chester <[EMAIL PROTECTED]> wrote: > > > >Assuming one is going to build a linear, and so > > putting aside other issues > > >such as linear vs plate modulation, why do you > > think it makes a difference > > >what tube is used? Are you referring to running a > > linear at greater than > > >legal limit?. > > > > Well, go ahead and try building a legal limit linear > > that runs a pair of > > 807's in the final. > > > > > ___ > > > > This message was typed using the DVORAK keyboard > > layout. Try it - you'll > > like it. > > http://www.mwbrooks.com/dvorak/ > > http://gigliwood.com/abcd/ > > > > > > > __ > > AMRadio mailing list > > Home: > > http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:AMRadio@mailman.qth.net > > AMfone Website: http://www.amfone.net > > AM List Admin: Brian Sherrod/w5ami, Paul > > Courson/wa3vjb > > > > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb >
RE: [AMRadio] AM Transmitter Advice??
Hi All, I recently had a conversation with a ham in San Antonio (forgot his call), and he told me that he built a unique linear amplifier for his central electronics 10a, and for tubes he chose 3 type 12AX7 in parallel grounded grid. He said he could run 30 watts input (300v @ 100ma) with no problems, and about 20 watts out. I find it odd though that a 10a can do 10 watts with a single 6AG7, and 20 watts is only a 3db boost. To my way of thinking, a linear amp needs to boost your power at least 6 db (~1 'S' unit) to be worth the trouble. For us AM'ers, going from 100 watts to 375 watts carrier does not meet the 6 db boost criteria, and that explains why a good antenna on a DX-100 is better than a average antenna on a Globe King 500. Still, as I once posted last year, a dual 304TL grounded grid linear seems to fit the bill as a 6 db 'brick' capable of 400 watts AM carrier output with 100 watts AM input, or said another way it takes 400 watts PEP and boosts it to 1600 watts PEP. There was an old W6SAI construction project about this (single 304tl GG amp), and I recall that the setup in class C could run 1 kw dc input with over 1 kw rf output because of the low gain, and massive amount of feedthrough power from the exciter that finds it's way to the output. This was a way around the FCC power rules of the day. Regards, Jim WD5JKO --- Donald Chester <[EMAIL PROTECTED]> wrote: > >Assuming one is going to build a linear, and so > putting aside other issues > >such as linear vs plate modulation, why do you > think it makes a difference > >what tube is used? Are you referring to running a > linear at greater than > >legal limit?. > > Well, go ahead and try building a legal limit linear > that runs a pair of > 807's in the final. > > ___ > > This message was typed using the DVORAK keyboard > layout. Try it - you'll > like it. > http://www.mwbrooks.com/dvorak/ > http://gigliwood.com/abcd/ > > > __ > AMRadio mailing list > Home: > http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul > Courson/wa3vjb >
RE: [AMRadio] Re: AM Transmitter Advice??
John, Check this out: http://uv201.com/Tube_Pages/heintz-kaufman.htm Jim WD5JKO --- John Coleman ARS WA5BXO <[EMAIL PROTECTED]> wrote: > OK BOB! > You got my attention. Explain more. I hope I'm not > a sucker > here. I have seen and extremely low mu amplifier > circuit (common > cathode) made by reverse biasing the plate of a > triode and forward > biasing the grid where output is taken from the grid > and input is on the > plate. So I know that weird stuff does exist. > > John, WA5BXO > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of Bob Deuel > Sent: Thursday, February 16, 2006 6:05 PM > To: 'Discussion of AM Radio' > Subject: [AMRadio] Re: AM Transmitter Advice?? > > Hello Larry and all: > > Larry's tongue in cheek comment employing 866's as a > linear amplifier > tube > prompted me to contribute the following: Certain > full-wave rectifiers > can be > configured to amplify or oscillate. I have built > audio, Hartley and > Simpson > oscillators using only 6AX5GT's full-wave rectifiers > as the sole active > device. These were displayed at 2004 Mid-Atlantic > Antique Radio Club > Meet > and actually won a Blue Ribbon. > Late last year I built an AM transmitter consisting > of a Hartley > oscillator > modulated by an AM modulator using only 6AX5GT > full-wave rectifier tubes > as > the active devices. No solid-state magic, just > simple full-wave > rectifiers. > The basic concept is that of the Heintz and Kaufman > gridless Gammatron > circuits. The transmitter was set up for the > broadcast band and works > fine. > It has been publicly demonstrated a couple times now > and a write up > including the circuit was published in the February, > 2006 issue of the > "Tube > Collector" magazine which is the bi-monthly magazine > published by the > Tube > Collectors Association, Inc. It is fun to make > full-wave rectifiers do > more > than just rectify. > > Bob, K2GLO > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of ne1s > Sent: Thursday, February 16, 2006 10:36 AM > To: Discussion of AM Radio > Subject: [AMRadio] Re: AM Transmitter Advice?? > > Donald Chester writes: > > > > >> Assuming one is going to build a linear, and so > putting aside other > >> issues > >> such as linear vs plate modulation, why do you > think it makes a > >> difference > >> what tube is used? Are you referring to running a > linear at greater > than > >> legal limit?. > > > > Well, go ahead and try building a legal limit > linear that runs a pair > of > > 807's in the final. > > > > Yeah, or a pair of 866As > > Sorry (the devil made me do it). > > 73, > -Larry/NE1S > __ > AMRadio mailing list > Home: > http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul > Courson/wa3vjb > > __ > AMRadio mailing list > Home: > http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul > Courson/wa3vjb > > > > __ > AMRadio mailing list > Home: > http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul > Courson/wa3vjb >
Re: [AMRadio] Re: AM Transmitter Advice??
Reverse biasing the galena crystal was a stroke of genius. 100% negative side modulation with no need for clipping on the pos. side. Cleanest class C sine wave ever. Brilliant. Brian Carling wrote: I think that was the APRIL issue of Tube Collector magazine. The heck of it is, he used a galena crystal as a modulation transformer! On 16 Feb 2006 at 20:42, John Coleman ARS WA5BXO wrote: OK BOB! You got my attention. Explain more. I hope I'm not a sucker here. I have seen and extremely low mu amplifier circuit (common cathode) made by reverse biasing the plate of a triode and forward biasing the grid where output is taken from the grid and input is on the plate. So I know that weird stuff does exist. John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bob Deuel Sent: Thursday, February 16, 2006 6:05 PM To: 'Discussion of AM Radio' Subject: [AMRadio] Re: AM Transmitter Advice?? Hello Larry and all: Larry's tongue in cheek comment employing 866's as a linear amplifier tube prompted me to contribute the following: Certain full-wave rectifiers can be configured to amplify or oscillate. I have built audio, Hartley and Simpson oscillators using only 6AX5GT's full-wave rectifiers as the sole active device. These were displayed at 2004 Mid-Atlantic Antique Radio Club Meet and actually won a Blue Ribbon. Late last year I built an AM transmitter consisting of a Hartley oscillator modulated by an AM modulator using only 6AX5GT full-wave rectifier tubes as the active devices. No solid-state magic, just simple full-wave rectifiers. The basic concept is that of the Heintz and Kaufman gridless Gammatron circuits. The transmitter was set up for the broadcast band and works fine. It has been publicly demonstrated a couple times now and a write up including the circuit was published in the February, 2006 issue of the "Tube Collector" magazine which is the bi-monthly magazine published by the Tube Collectors Association, Inc. It is fun to make full-wave rectifiers do more than just rectify. Bob, K2GLO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of ne1s Sent: Thursday, February 16, 2006 10:36 AM To: Discussion of AM Radio Subject: [AMRadio] Re: AM Transmitter Advice?? Donald Chester writes: Assuming one is going to build a linear, and so putting aside other issues such as linear vs plate modulation, why do you think it makes a difference what tube is used? Are you referring to running a linear at greater than legal limit?. Well, go ahead and try building a legal limit linear that runs a pair of 807's in the final. Yeah, or a pair of 866As Sorry (the devil made me do it). 73, -Larry/NE1S __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb Reverse biasing the galena was a stroke of genius
RE: [AMRadio] Re: AM Transmitter Advice??
I think that was the APRIL issue of Tube Collector magazine. The heck of it is, he used a galena crystal as a modulation transformer! On 16 Feb 2006 at 20:42, John Coleman ARS WA5BXO wrote: > OK BOB! > You got my attention. Explain more. I hope I'm not a sucker > here. I have seen and extremely low mu amplifier circuit (common > cathode) made by reverse biasing the plate of a triode and forward > biasing the grid where output is taken from the grid and input is on the > plate. So I know that weird stuff does exist. > > John, WA5BXO > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Bob Deuel > Sent: Thursday, February 16, 2006 6:05 PM > To: 'Discussion of AM Radio' > Subject: [AMRadio] Re: AM Transmitter Advice?? > > Hello Larry and all: > > Larry's tongue in cheek comment employing 866's as a linear amplifier > tube > prompted me to contribute the following: Certain full-wave rectifiers > can be > configured to amplify or oscillate. I have built audio, Hartley and > Simpson > oscillators using only 6AX5GT's full-wave rectifiers as the sole active > device. These were displayed at 2004 Mid-Atlantic Antique Radio Club > Meet > and actually won a Blue Ribbon. > Late last year I built an AM transmitter consisting of a Hartley > oscillator > modulated by an AM modulator using only 6AX5GT full-wave rectifier tubes > as > the active devices. No solid-state magic, just simple full-wave > rectifiers. > The basic concept is that of the Heintz and Kaufman gridless Gammatron > circuits. The transmitter was set up for the broadcast band and works > fine. > It has been publicly demonstrated a couple times now and a write up > including the circuit was published in the February, 2006 issue of the > "Tube > Collector" magazine which is the bi-monthly magazine published by the > Tube > Collectors Association, Inc. It is fun to make full-wave rectifiers do > more > than just rectify. > > Bob, K2GLO > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of ne1s > Sent: Thursday, February 16, 2006 10:36 AM > To: Discussion of AM Radio > Subject: [AMRadio] Re: AM Transmitter Advice?? > > Donald Chester writes: > > > > >> Assuming one is going to build a linear, and so putting aside other > >> issues > >> such as linear vs plate modulation, why do you think it makes a > >> difference > >> what tube is used? Are you referring to running a linear at greater > than > >> legal limit?. > > > > Well, go ahead and try building a legal limit linear that runs a pair > of > > 807's in the final. > > > > Yeah, or a pair of 866As > > Sorry (the devil made me do it). > > 73, > -Larry/NE1S > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb > > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb > > > > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb >
Re: [AMRadio] Re: AM Transmitter Advice??
Dennis D. W7QHO Glendale, CA
