[AMRadio] P.S. - you get to run 1000W input on AM up here
Ed, So how does Canada feel about ex-pats? I hear you need to have a job lined up, or at least be self-sufficient. Central heating, parkas, warm toques (?!) and gloves are great and all that but how good is the pizza and hot cocoa?? Inquiring minds wanna know. And so do I. And thanks. 73, Terry Bakowski KC9KEL ___ From: "Ed Sieb" <[EMAIL PROTECTED]> Subject: RE: [AMRadio] Re: AMRadio Digest, Vol 46, Issue 13 Yes, but we have perfected central heating, parkas, warm toques, and gloves. We can handle it. (P.S. - you get to run 1000W input on AM up here.) Ed, VA3ES** See what's new at http://www.aol.com __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
- Original Message - From: "Brett Gazdzinski" <[EMAIL PROTECTED]> To: "Discussion of AM Radio in the Amateur Service" Sent: Monday, November 12, 2007 8:42 PM Subject: Re: [AMRadio] Re:Reactor Wanted Modulator or linear amp tubes (I treat them the same here) are designed to operate within certain parameters to maximize plate efficiency while maintaining acceptable distortion levels. Operating above those specs will increase power at the expense of tube life and increased distortion. I am running them at 2000 volts which is where the books say to run them. No argument there, I wasnt implying that. I will be using 810's at 725W "advertised" audio to modulate a pair of 813's at 750W input. There will be a common PS providing ~ 2250V. Its a bit over spec for the 813's but nothing that a little air cant cure; the tubes hi-pot at well over modulation peak voltages. I have experimented with mine at 2500+ volts (the deck has filtered forced air cooling) and heavy modulation without problems. Glad to hear it. Ive got NOS 810's (same date codes that Ive had stashed for decades) and NOS carbon plate 813's. The problem with that theory is that tetrodes have a higher level of IMD increase than triodes when run above their spec. Feedback and a low impedence regulated screen and grid supplies can gain back some of that IMD. Another tetrode problem at over voltage is secondary screen emission which contributes to even more IMD. Used tubes and especially FM pulls almost always have screen emission. I worked extensively with the 4X150/250 family for decades on VHF where their cheap price resulted in high use in homebrew amps with resultant very poor IMD, often in the teens. It took several of us in the US and Europe to establish cause and effect and establish correct operating parameters. Good 4CX250B & R tubes operated at 2500V in SSB service can deliver 28-32 dB IMD with the above criteria. Thats about equal to an average run of the mill triode. It still requires careful tuning and heavy loading which equates to using a correct mod xfmr for both audio and RF loads. I dont see any published specs for 4X150A/7034 operation in either AB1 or AB2 at any voltage. Have you obtained that data in your actual setup? Youre not using the old glass 4X150A I hope. I have been using new 4x150a/7034's, which I thought were equal to a 4cx250 type tube except for the vhf/uhf zone where the ceramic did better then the glass 4x150's. The ceramic versions can withstand higher seal temperatures which could relax air flow a bit for less noise. Im building for silence; Ive enough blower noise on my regular amps from HF thru 2304 MHZ. All I want is glow, xfmr hum and relay clatter! The RCA book lists the 3rd order dist products level as 30db and 5th order as 35 db down, nor sure how that ties into THD or IM distortion. I dont see that with my 7034 spec sheet in RCA or Eimac. It is listed that way for the 4CX250B but I know nobody that has measured that using operating parameters of the 50's. Also realize that the SSB ratings are for AB1; if you are running 650W then that is AB2 which will increase IMD. How much I dont know; Ive only run 8122's in AB2 and they are in the mid 20's. How much that translates to actual signals on a crowded 75M with all the other crud on the band I dont know. Its probably no worse than most riceboxes. On a quiet VHF band poor IMD is very obvious and usually commented on. The distortion gets lower with higher plate voltages (in the book) up to 2000 volts, which is as high as I run them. The screen voltage and the bias voltage are regulated and adjustable. Except for the frequency ratings, both types seem the same. Switching between a pair of 4x150a's and 4cx250b's does not change anything as far as I can hear. This deck sounds cleaner then any class B deck I have built. I remember an article in CQ maybe bemoaning the lack of audio use of the 4X150 class and including a building article. Probably still have that issue in the attic. Has anyone run a more modern Class B tube such as the 3-500Z or one of the big ceramic tubes as modulators? Ive also thought of using 572B's running at 2250V since they were originally designed by Taylor (T-160L) as an audio tube. It would be interesting to compare with the 810's. Good performance comes by the pound. Tailoring the audio at low level is a seperate part of the problem and almost always inadequate in commercial ham rigs. My current rig is a Viking I but others will be homebrew using the best of the old designs and updated if necessary but not going overboard with high tech enhancements. The 813 rig takes up two 6 foot rack cabinets, its very heavy. The 4 UTC cg108's and 109's must weigh 100 pounds each, plus 2 large power transformers, 2 large variac's, all the oil filled caps, etc I have used and abused this rig for over 20 years without a crapout. (now havi
Re: [AMRadio] Re:Reactor Wanted
> Modulator or linear amp tubes (I treat them the same here) are designed to > operate within certain parameters to maximize plate efficiency while > maintaining acceptable distortion levels. Operating above those specs will > increase power at the expense of tube life and increased distortion. > I am running them at 2000 volts which is where the books say to run them. > > > I will be using 810's at 725W "advertised" audio to modulate a pair of 813's > at 750W input. There will be a common PS providing ~ 2250V. Its a bit over > spec for the 813's but nothing that a little air cant cure; the tubes hi-pot > at well over modulation peak voltages. > I have experimented with mine at 2500+ volts (the deck has filtered forced air cooling) and heavy modulation without problems. > > The problem with that theory is that tetrodes have a higher level of IMD > increase than triodes when run above their spec. Feedback and a low > impedence regulated screen and grid supplies can gain back some of that IMD. > Another tetrode problem at over voltage is secondary screen emission which > contributes to even more IMD. Used tubes and especially FM pulls almost > always have screen emission. > > I worked extensively with the 4X150/250 family for decades on VHF where > their cheap price resulted in high use in homebrew amps with resultant very > poor IMD, often in the teens. It took several of us in the US and Europe to > establish cause and effect and establish correct operating parameters. > > Good 4CX250B & R tubes operated at 2500V in SSB service can deliver 28-32 dB > IMD with the above criteria. Thats about equal to an average run of the mill > triode. It still requires careful tuning and heavy loading which equates to > using a correct mod xfmr for both audio and RF loads. > > I dont see any published specs for 4X150A/7034 operation in either AB1 or > AB2 at any voltage. Have you obtained that data in your actual setup? Youre > not using the old glass 4X150A I hope. I have been using new 4x150a/7034's, which I thought were equal to a 4cx250 type tube except for the vhf/uhf zone where the ceramic did better then the glass 4x150's. The RCA book lists the 3rd order dist products level as 30db and 5th order as 35 db down, nor sure how that ties into THD or IM distortion. The distortion gets lower with higher plate voltages (in the book) up to 2000 volts, which is as high as I run them. The screen voltage and the bias voltage are regulated and adjustable. Except for the frequency ratings, both types seem the same. Switching between a pair of 4x150a's and 4cx250b's does not change anything as far as I can hear. This deck sounds cleaner then any class B deck I have built. > Good performance comes by the pound. Tailoring the audio at low level is a > seperate part of the problem and almost always inadequate in commercial ham > rigs. My current rig is a Viking I but others will be homebrew using the > best of the old designs and updated if necessary but not going overboard > with high tech enhancements. The 813 rig takes up two 6 foot rack cabinets, its very heavy. The 4 UTC cg108's and 109's must weigh 100 pounds each, plus 2 large power transformers, 2 large variac's, all the oil filled caps, etc I have used and abused this rig for over 20 years without a crapout. (now having said that) Brett N2DTS __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
- Original Message - From: "Brett Gazdzinski" <[EMAIL PROTECTED]> To: "Ben Dover" <[EMAIL PROTECTED]>; "Discussion of AM Radio in the Amateur Service" Sent: Monday, November 12, 2007 6:36 PM Subject: Re: [AMRadio] Re:Reactor Wanted I suppose the added voltage makes the tubes run more as they like, and make much more power then needed. Modulator or linear amp tubes (I treat them the same here) are designed to operate within certain parameters to maximize plate efficiency while maintaining acceptable distortion levels. Operating above those specs will increase power at the expense of tube life and increased distortion. Really, the power needed seems to be much more than 50% plus the loss in the mod iron,, I would recomend the same power out of the modulator If you read design info from the 30's that was the norm in many books and it specifically stressed circuit losses and having sufficient overhead. In later years the norm drifted to running modulators at their maximum ratings. I can only guess that as RF tubes that had ever increasing power capabilities came along many tried to justify the bare minimum of audio under so called "ideal" conditions. I will be using 810's at 725W "advertised" audio to modulate a pair of 813's at 750W input. There will be a common PS providing ~ 2250V. Its a bit over spec for the 813's but nothing that a little air cant cure; the tubes hi-pot at well over modulation peak voltages. as RF input. The 4X150a deck can produce 650 watts of audio at 2000 volts and 500ma. I have done lots of expeiments over the years, with different mod iron, modified hysing, and since both the mod and rf deck are variac'd, lots of different power levels and voltages. Things always seem to work better reducing the RF current, and increasing the mod voltage. Its my theory that the extra mod voltage allows the tubes to run in the low distortion range, and the RF tubes have reserve emission for modulation peaks. The problem with that theory is that tetrodes have a higher level of IMD increase than triodes when run above their spec. Feedback and a low impedence regulated screen and grid supplies can gain back some of that IMD. Another tetrode problem at over voltage is secondary screen emission which contributes to even more IMD. Used tubes and especially FM pulls almost always have screen emission. I worked extensively with the 4X150/250 family for decades on VHF where their cheap price resulted in high use in homebrew amps with resultant very poor IMD, often in the teens. It took several of us in the US and Europe to establish cause and effect and establish correct operating parameters. Good 4CX250B & R tubes operated at 2500V in SSB service can deliver 28-32 dB IMD with the above criteria. Thats about equal to an average run of the mill triode. It still requires careful tuning and heavy loading which equates to using a correct mod xfmr for both audio and RF loads. I dont see any published specs for 4X150A/7034 operation in either AB1 or AB2 at any voltage. Have you obtained that data in your actual setup? Youre not using the old glass 4X150A I hope. I also dont take current design (or old designs) as the best way to do something, only the cheapest way of doing something, that is why I have nothing but home brew stuff left in the shack. Never had a commercial or ham piece of gear where they did not cut corners to reduce costs. WRL made that an art Good performance comes by the pound. Tailoring the audio at low level is a seperate part of the problem and almost always inadequate in commercial ham rigs. My current rig is a Viking I but others will be homebrew using the best of the old designs and updated if necessary but not going overboard with high tech enhancements. Carl KM1H Brett N2DTS - Original Message - From: "Ben Dover" <[EMAIL PROTECTED]> To: "Brett Gazdzinski" <[EMAIL PROTECTED]>; "Discussion of AM Radio in the Amateur Service" ; "Discussion of AM Radio in the Amateur Service" Sent: Monday, November 12, 2007 2:00 PM Subject: Re: [AMRadio] Re:Reactor Wanted -Original Message- >From: Brett Gazdzinski <[EMAIL PROTECTED]> >Sent: Nov 12, 2007 12:14 PM >To: Discussion of AM Radio in the Amateur Service >Subject: Re: [AMRadio] Re:Reactor Wanted > >I also run 2000 volts on the plates of the modulator, 4x150a's, and usualy >1500 >volts on the pair of 813's in the final. > >It seems to like it that way, i have done experiments as both supplies >have variacs, things always seem to modulate better, and sound better >with more mod voltage. > >Brett >N2DTS > Howdy, Brett! Interesting indeed. That approach flies in the face of decades of design convention; as a rule, AM rigs either use the same supply for mods and final, or as the rig gets bigger, the mod has it's own supply which is usually a lower voltage than the PA plate supply. The only reason I can see for improved
Re: [AMRadio] Re: AMRadio Digest, Vol 46, Issue 13
Brett Gazdzinski wrote: yeh, but its too cold! Brett N2DTS - Original Message - One of the things I am most thankfull is that I am living in Canada. You'll forgive a Texan ham for finding that statement 'funny', coming from New Jersey! ;-) -- Driving your AM Rig without a scope, is like driving your car at night, without headlights. (K4KYV) -- 73 = Best Regards, -Geoff/W5OMR __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Re: AMRadio Digest, Vol 46, Issue 13
Yes, but we have perfected central heating, parkas, warm toques, and gloves. We can handle it. (P.S. - you get to run 1000W input on AM up here.) Ed, VA3ES --- Brett Gazdzinski wrote: yeh, but its too cold! __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger 1 construction manual
Larry, I just bought a Ranger 1 this week and could use a copy of that file. Many thanks Best 73's Peter K2LRC www.k2lrc.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Larry WA9VRH Sent: Monday, November 12, 2007 5:19 PM To: "Undisclosed-Recipient:;"@mail.dishmail.net Subject: [AMRadio] Ranger 1 construction manual Hi all, I think someone was looking for the construction manual for a Ranger 1? If that was you please email me directly [EMAIL PROTECTED] and I will email you the PDF of it.I just found it this afternoon on another pc. I will also send it to BAMA ASAP. 73 Larry WA9VRH __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re: AMRadio Digest, Vol 46, Issue 13
yeh, but its too cold! Brett N2DTS - Original Message - From: <[EMAIL PROTECTED]> To: Sent: Monday, November 12, 2007 3:45 PM Subject: [AMRadio] Re: AMRadio Digest, Vol 46, Issue 13 > One of the things I am most thankfull is that I am living in Canada. This > country has the most liberal listening laws in the world. Plus Canadian hams no > longer have to pay each year for our ham licences. There are other reasons I > am thankfull but I hate to sound proud or arrogant due to an accident of > birth.You could do more wrong than having a DX camp over the border, especially > here in Quebec where you can buy beer in local convience stores, ha > > > > > __ > Our Main Website: http://www.amfone.net > AMRadio mailing list > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > To unsubscribe, send an email to [EMAIL PROTECTED] with > the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
I suppose the added voltage makes the tubes run more as they like, and make much more power then needed. Really, the power needed seems to be much more than 50% plus the loss in the mod iron,, I would recomend the same power out of the modulator as RF input. The 4X150a deck can produce 650 watts of audio at 2000 volts and 500ma. I have done lots of expeiments over the years, with different mod iron, modified hysing, and since both the mod and rf deck are variac'd, lots of different power levels and voltages. Things always seem to work better reducing the RF current, and increasing the mod voltage. Its my theory that the extra mod voltage allows the tubes to run in the low distortion range, and the RF tubes have reserve emission for modulation peaks. I also dont take current design (or old designs) as the best way to do something, only the cheapest way of doing something, that is why I have nothing but home brew stuff left in the shack. Never had a commercial or ham piece of gear where they did not cut corners to reduce costs. WRL made that an art Brett N2DTS - Original Message - From: "Ben Dover" <[EMAIL PROTECTED]> To: "Brett Gazdzinski" <[EMAIL PROTECTED]>; "Discussion of AM Radio in the Amateur Service" ; "Discussion of AM Radio in the Amateur Service" Sent: Monday, November 12, 2007 2:00 PM Subject: Re: [AMRadio] Re:Reactor Wanted > > > -Original Message- > >From: Brett Gazdzinski <[EMAIL PROTECTED]> > >Sent: Nov 12, 2007 12:14 PM > >To: Discussion of AM Radio in the Amateur Service > >Subject: Re: [AMRadio] Re:Reactor Wanted > > > >I also run 2000 volts on the plates of the modulator, 4x150a's, and usualy > >1500 > >volts on the pair of 813's in the final. > > > >It seems to like it that way, i have done experiments as both supplies > >have variacs, things always seem to modulate better, and sound better > >with more mod voltage. > > > >Brett > >N2DTS > > > > > Howdy, Brett! > > Interesting indeed. > > That approach flies in the face of decades of design convention; as a rule, AM > rigs either use the same supply for mods and final, or as the rig gets bigger, > the mod has it's own supply which is usually a lower voltage than the PA plate > supply. > > The only reason I can see for improved performance using this approach would be > that when used conventionally the modulator operating parameters were incorrectly > chosen for low distortion AT THE POWER LEVEL REQUIRED. I've noted over the years > that most ham designers tend to be very optimistic when it comes to estimating the > power that they'll get out of a modulator, and tend to not recognize what they'll > lose in the transformer, especially those losses that come from a significant > impedance mismatch between the mod plates and the PA load impedances. > > The usual result is that they can't get to 100% modulation, or if they're using a > pair of pentodes or tetrodes as modulators, they find it necessary to run the tubes > well into the nonlinear area of the curves caused by the action of the screen grid > in order to get enough power. > > Jacking up the plate voltage to the modulator is ONE way to get the additional watts > needed without correcting the design defects that caused the problems in the first > place. In addition to giving more audio power, raising mod plate voltage will also > increase the amount of low distortion headroom the modulator has available. > > Other than that, I can't see ANY reason, either in terms of physics or intuition, > for raising mod plate voltage above the PA causing an inherent increase in audio > quality. > > > On the other hand... if the modulator parameters have been properly chosen in the > design, AND losses in the mod transformer and due to the (almost inevitable) minor > impedance mismatch are taken into account (so that it's not necessary to drive the > mod tubes into nonlinearity) when the mod is run at the same B+ voltage as the PA > or less, jacking up modulator plate voltage shouldn't make ANY difference whatever > in resulting signal quality... except INCREASING the distortion, caused by the > change in mod tube plate to plate impedance creating a mismatch with the PA load! > > > > What it boils down to is this... > > It's GOOD to design a modulator that's capable of producing MORE than 50% of the PA's > input (i.e., a mod that has some headroom) no matter WHAT the plate voltage of the > modulator is relative to the PA. If it's got headroom, it's gonna distort less. > > It's BAD to underestimate mod transformer losses (figure 20% or more of the audio you > put into it ain't gonna come back out). It's even WORSE to pull another common ham > stunt, driving your mod transformer core toward saturation (face it... mod transformers > are getting harder and harder to find, and they AIN'T CHEAP anymore. Using too small > a transformer for the design is VERY tempting sometimes). > > > > 73's, > > Mr. T., W9LBB > _
[AMRadio] Ranger 1 construction manual
Hi all, I think someone was looking for the construction manual for a Ranger 1? If that was you please email me directly [EMAIL PROTECTED] and I will email you the PDF of it.I just found it this afternoon on another pc. I will also send it to BAMA ASAP. 73 Larry WA9VRH __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Best Heathkit AM Transmitter
I must agree. I have both rigs here, and the DX-100 is more flexible, and requires less audio work to sound good. The 160 band is a plus. It also runs 11M in case you want to be the "Channel Master". :-) Ed. VA3ES --- Bob Macklin wrote: Probably the DX-100 if you want one of the plate modulated ones. The only other plate modulated Heath AM trnasmitter is the Apache. And it's not much more than a repacakaged DX-100. The couple friends I have that have both the DX-100 and Apache prefer the DX-100. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re: AMRadio Digest, Vol 46, Issue 13
Better be careful Steve, if things go down the tubes in this country, many of us may want to join you. One of the things I am most thankfull is that I am living in Canada. This country has the most liberal listening laws in the world. Plus Canadian hams no longer have to pay each year for our ham licences. There are other reasons I am thankfull but I hate to sound proud or arrogant due to an accident of birth.You could do more wrong than having a DX camp over the border, especially here in Quebec where you can buy beer in local convience stores, ha __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Best Heathkit AM Transmitter
For me it is the DX-100B. I run one and you can really make them sound great. I have a W2IHY Audio Chain and a Heil PR40 and everyone says it sounds great... Very Best 73's Bob W1PE The Voice of Mesquite www.w1pe.com "Money is only temporary, but radios are forever" - Jim Little aka "the old dog"/K5BAI -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, November 12, 2007 2:36 PM To: amradio@mailman.qth.net Subject: [AMRadio] Best Heathkit AM Transmitter What would be Heathkits' best transmitter for AM HF? I am not partial to 160 so the DX-100 is not a factor neccessarily. 73, Steve VE2SWC __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Best Heathkit AM Transmitter
I would tend to agree with the comments about the DX-100. For an inexpensive transmitter it is easy to perform numerous modifications to improve the audio, regulation, PTT and you have a real work horse that sounds terrific. I sold my last one to a local Ham who is using it on 3870 in the evenings and he gets compliments on the audio all the time. Lots of room inside to work on them also. All the Best Ron Weaver W6OM www.qsl.net/w6om -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bob Macklin Sent: Monday, November 12, 2007 12:47 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Best Heathkit AM Transmitter Probably the DX-100 if you want one of the plate modulated ones. The only other plate modulated Heath AM trnasmitter is the Apache. And it's not much more than a repacakaged DX-100. The couple friends I have that have both the DX-100 and Apache prefer the DX-100. Bob Macklin K5MYJ Seattle, Wa, "Real Radios Glow in the Dark" - Original Message - From: <[EMAIL PROTECTED]> To: Sent: Monday, November 12, 2007 12:36 PM Subject: [AMRadio] Best Heathkit AM Transmitter > What would be Heathkits' best transmitter for AM HF? I am not partial to 160 > so the DX-100 is not a factor neccessarily. 73, Steve VE2SWC > > > > > __ > Our Main Website: http://www.amfone.net > AMRadio mailing list > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > To unsubscribe, send an email to [EMAIL PROTECTED] with > the word unsubscribe in the message body. > __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Central Electronics, etc
AND BIG PRICES if I remember - Original Message - From: "Barrie Smith" <[EMAIL PROTECTED]> To: "Discussion of AM Radio in the Amateur Service" Sent: Monday, November 12, 2007 2:18 PM Subject: Re: [AMRadio] Central Electronics, etc Still looking for big modulation xfmrs. Carl KM1H Still have a BIG PWD and a BIG reactor. Barrie, W7ALW __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Best Heathkit AM Transmitter
Probably the DX-100 if you want one of the plate modulated ones. The only other plate modulated Heath AM trnasmitter is the Apache. And it's not much more than a repacakaged DX-100. The couple friends I have that have both the DX-100 and Apache prefer the DX-100. Bob Macklin K5MYJ Seattle, Wa, "Real Radios Glow in the Dark" - Original Message - From: <[EMAIL PROTECTED]> To: Sent: Monday, November 12, 2007 12:36 PM Subject: [AMRadio] Best Heathkit AM Transmitter > What would be Heathkits' best transmitter for AM HF? I am not partial to 160 > so the DX-100 is not a factor neccessarily. 73, Steve VE2SWC > > > > > __ > Our Main Website: http://www.amfone.net > AMRadio mailing list > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > To unsubscribe, send an email to [EMAIL PROTECTED] with > the word unsubscribe in the message body. > __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] Re: AMRadio Digest, Vol 46, Issue 13
One of the things I am most thankfull is that I am living in Canada. This country has the most liberal listening laws in the world. Plus Canadian hams no longer have to pay each year for our ham licences. There are other reasons I am thankfull but I hate to sound proud or arrogant due to an accident of birth.You could do more wrong than having a DX camp over the border, especially here in Quebec where you can buy beer in local convience stores, ha __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Best Heathkit AM Transmitter
I know several people who use DX-100B's and really sound good after the audio mod's. Phil Philip LaMarche LaMarche Enterprises, Inc. www.instantgourmetspices.com www.w9dvm.com 800-395-7795 pin 02 727-944-3226 FAX 727-937-8834 NASFT 30210 W9DVM -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, November 12, 2007 3:36 PM To: amradio@mailman.qth.net Subject: [AMRadio] Best Heathkit AM Transmitter What would be Heathkits' best transmitter for AM HF? I am not partial to 160 so the DX-100 is not a factor neccessarily. 73, Steve VE2SWC __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] Best Heathkit AM Transmitter
What would be Heathkits' best transmitter for AM HF? I am not partial to 160 so the DX-100 is not a factor neccessarily. 73, Steve VE2SWC __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
> -Original Message- > Interesting indeed. > > That approach flies in the face of decades of design convention; as a rule, AM > rigs either use the same supply for mods and final, or as the rig gets bigger, > the mod has it's own supply which is usually a lower voltage than the PA plate > supply. > Greetings, Mr. T! Here are a few random thoughts of mine on this subject. First, I can think of the following arguments FOR using a common power supply. First, cost & space savings. Second, with a choke input supply, the class C final maintains a minimum load on the supply, reducing the size of the choke required to maintain critical inductance. Otherwise, the separate modulator PS would need to be capacitor input, or would have to waste a huge mount of power in a bleeder resistor to maintain the required minimum load on the filter. I think the historic reason for a lower-voltage modulator PS in the case when the supplies WERE separate originates from the conventional wisdom that the audio power required to 100% plate-modulate a class-C final is 50% of the class-C plate input power. But this (1) ignores losses, (2) ignores the "headroom" required for clean modulation, (3) ignores waveform asymettry, and (4) perhaps most importantly, assumes a modulation transformer of the correct turns/impedance ratio can be had. These days, we're lucky find whatever mod iron we can in the power class we need, and build around it. It is often the case we need to run a higher voltage on the modulators than on the final to achieve enough audio voltage at the mod tranny secondary to properly modulate the final, with the iron we are able to scrounge. 73, -Larry/NE1S __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Central Electronics, etc
> > Still looking for big modulation xfmrs. > > Carl > KM1H Still have a BIG PWD and a BIG reactor. Barrie, W7ALW __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] Central Electronics, etc
That 100V even had the 160M coils. Darn, now I want it back! I still have the 75A4 I used with it. If I remember I sold the 100V and 200V seperately for quite a bit more than I asked at Deerfield. Also sold off the 10A, 10B, 20A, VFO's, monitor and Slicer in that era. Never thought Id be going back to obsolete "junque" again. Recently picked up a HT32B and SX-115 for very short money and those will be my vintage SSB station into the NCL-2000 prototype Ive had since 63. But for now Im concentrating on 3 different era AM stations and a pair of 211's for CW. Still looking for big modulation xfmrs. Carl KM1H - Original Message - From: <[EMAIL PROTECTED]> To: "Discussion of AM Radio in the Amateur Service" ; "Discussion of AM Radio in the Amateur Service" Sent: Monday, November 12, 2007 12:47 PM Subject: Re: [AMRadio] 6U8 Subststute and the 20a - Original Message - Subject: Re: [AMRadio] 6U8 Subststute and the 20a Date: Mon, November 12, 2007 9:00 From: "jeremy-ca" Nice setup Jim. Ive had the full range of CE transmitters from 10A to 200V and everything in between. Yeah, Carl, I remember when you were selling a 100V and 200V for $150 for the pair at Deerfield back in the 80s or very early 90s. I'm STILL kicking myself for not buying them both, but that was a lot of money to me back then. I always wanted a 100V especially. I do, however, seem to have "cornered the market" on CE 20As (got four of 'em). 73, -Larry/NE1S __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
-Original Message- >From: Brett Gazdzinski <[EMAIL PROTECTED]> >Sent: Nov 12, 2007 12:14 PM >To: Discussion of AM Radio in the Amateur Service >Subject: Re: [AMRadio] Re:Reactor Wanted > >I also run 2000 volts on the plates of the modulator, 4x150a's, and usualy >1500 >volts on the pair of 813's in the final. > >It seems to like it that way, i have done experiments as both supplies >have variacs, things always seem to modulate better, and sound better >with more mod voltage. > >Brett >N2DTS > Howdy, Brett! Interesting indeed. That approach flies in the face of decades of design convention; as a rule, AM rigs either use the same supply for mods and final, or as the rig gets bigger, the mod has it's own supply which is usually a lower voltage than the PA plate supply. The only reason I can see for improved performance using this approach would be that when used conventionally the modulator operating parameters were incorrectly chosen for low distortion AT THE POWER LEVEL REQUIRED. I've noted over the years that most ham designers tend to be very optimistic when it comes to estimating the power that they'll get out of a modulator, and tend to not recognize what they'll lose in the transformer, especially those losses that come from a significant impedance mismatch between the mod plates and the PA load impedances. The usual result is that they can't get to 100% modulation, or if they're using a pair of pentodes or tetrodes as modulators, they find it necessary to run the tubes well into the nonlinear area of the curves caused by the action of the screen grid in order to get enough power. Jacking up the plate voltage to the modulator is ONE way to get the additional watts needed without correcting the design defects that caused the problems in the first place. In addition to giving more audio power, raising mod plate voltage will also increase the amount of low distortion headroom the modulator has available. Other than that, I can't see ANY reason, either in terms of physics or intuition, for raising mod plate voltage above the PA causing an inherent increase in audio quality. On the other hand... if the modulator parameters have been properly chosen in the design, AND losses in the mod transformer and due to the (almost inevitable) minor impedance mismatch are taken into account (so that it's not necessary to drive the mod tubes into nonlinearity) when the mod is run at the same B+ voltage as the PA or less, jacking up modulator plate voltage shouldn't make ANY difference whatever in resulting signal quality... except INCREASING the distortion, caused by the change in mod tube plate to plate impedance creating a mismatch with the PA load! What it boils down to is this... It's GOOD to design a modulator that's capable of producing MORE than 50% of the PA's input (i.e., a mod that has some headroom) no matter WHAT the plate voltage of the modulator is relative to the PA. If it's got headroom, it's gonna distort less. It's BAD to underestimate mod transformer losses (figure 20% or more of the audio you put into it ain't gonna come back out). It's even WORSE to pull another common ham stunt, driving your mod transformer core toward saturation (face it... mod transformers are getting harder and harder to find, and they AIN'T CHEAP anymore. Using too small a transformer for the design is VERY tempting sometimes). 73's, Mr. T., W9LBB __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] 6U8 Subststute and the 20a
Larry, CE equipment is wonderful although complicated circuitry in the 100 and 200. I have a completely restored 200V and am so proud of it. Owned one in 1960 including the 600L. May add a 20A just to look at. It was my first SSB station in 58 along with the 75A-4 and a amplifier with 10 6AG7's on a loaf pan. Memories. Phil Philip LaMarche LaMarche Enterprises, Inc. www.instantgourmetspices.com www.w9dvm.com 800-395-7795 pin 02 727-944-3226 FAX 727-937-8834 NASFT 30210 W9DVM -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, November 12, 2007 12:48 PM To: Discussion of AM Radio in the Amateur Service; Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] 6U8 Subststute and the 20a - Original Message - Subject: Re: [AMRadio] 6U8 Subststute and the 20a Date: Mon, November 12, 2007 9:00 From: "jeremy-ca" > Nice setup Jim. Ive had the full range of CE transmitters from 10A to > 200V and everything in between. > > Yeah, Carl, I remember when you were selling a 100V and 200V for $150 for the pair at Deerfield back in the 80s or very early 90s. I'm STILL kicking myself for not buying them both, but that was a lot of money to me back then. I always wanted a 100V especially. I do, however, seem to have "cornered the market" on CE 20As (got four of 'em). 73, -Larry/NE1S __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] 6U8 Subststute and the 20a
- Original Message From: jeremy-ca <[EMAIL PROTECTED]> How did you handle the 8877 conversion as far as mounting and cooling? The DTR-2000 had the tube horizontal and blowing all the heat right on the tank circuit. That caused a bit of tuning drift as the fixed caps for 80/160 were right in the path; more so when the PS was upgraded to 3500V. Ive a pair of MLA-2500's here being converted to 6M for customers, thankfully the 8875's are full power. But Ive been looking for tube swap ideas that get rid of the heat better. Carl KM1H Reply From Jim, WD5JKO, Carl, I have a couple of pictures at the following link, and I've pasted some text below that I've already written concerning the modification. Regards, Jim http://pages.prodigy.net/jcandela/Dentron/ >From Dentron Yahoo group post that I entered: Scott, I believe that one of the 8875 tube failures are the result of a parasitic. I bet it is usually localized to one socket too. The issue has to do with how the sockets are paralleled, and the blue ALC wire takes the tube input RF and then routes it near the plate circuit. This definitely creates a tendency towards a parasitic. One or more of the MLA-2500 Conversions address this Dentron design issue. I converted my MLA-2500 to a single 8877. I just added two pictures under the files section labeled, "another MLA-2500 conversion". I had to deal with the blue wire issue as well since the 8877 would take off on peaks. Actually I disabled the ALC function, and used the transformer ALC winding to "boost" the HV B+ (details upon request). The 8877 equipped MLA-2500 can peak 2kw PEP out on SSB(for 1-2 milliseconds until the B+ sags), or do 400 watts out on AM 100% modulated (1600 w PEP) with 20 watts carrier drive (80w pep). I did need to add an additional fan on the top cover to help exhaust all that heat from AM operation. The stock fan is blowing in from behind but is spaced back by the Hammond box (containing the socket). The Silastic RTV chimney was bought from the Alph folks. Dennis, Reread what I said. I stated that the amp would do ssb at 2kw pep out for 1-2 milliseconds or until the B+ sags. This is completely different from key down CW tune up for maximum power. The MLA-2500 power supply cannot maintain the B+ over 2250v at > 500ma CCS. My power supply modification boosts the B+ by ~ 150v under load. Even so, brief tune ups approaching 1 ampere result in the B+ sagging below 2 KV. As a driver during my testing I was limited to no more than 55 watts carrier (and 65w pep ssb), so I didn't worry about excessive grid current from over zealous drive beyond that. With my drive limited to 55 watts the maximum CW output is limited to 900 watts (B+ sags a lot). If I had a real power supply then things could would be different. So to answer your question, I can see ssb at 2kw PEP on an oscilloscope briefly (1-2 ms) from the idle B+ of about 2600vdc with about 65 watts pep drive. The scope shows uncompressed voice peaks over 316v peak (or 632v peak to peak) into a 50 ohm load. The only fire so far is an occasional tuning capacitor flash over. I did have to play some with those fixed loading capacitors that were used improperly and beyond ratings. I replaced some of them with 2 or 3 smaller values so as to lower the RF current through each capacitor. Using bypass capacitors in a hi-Q tuned circuit is not always a good thing. As they heat up the capacitance changes, and therefore the tuning changes. Not good. AM operation at 400 watts carrier out revealed the loading problem. Thanks for the feedback, Jim WD5JKO __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] 6U8 Subststute and the 20a
- Original Message - Subject: Re: [AMRadio] 6U8 Subststute and the 20a Date: Mon, November 12, 2007 9:00 From: "jeremy-ca" > Nice setup Jim. Ive had the full range of CE transmitters from 10A to 200V > and everything in between. > > Yeah, Carl, I remember when you were selling a 100V and 200V for $150 for the pair at Deerfield back in the 80s or very early 90s. I'm STILL kicking myself for not buying them both, but that was a lot of money to me back then. I always wanted a 100V especially. I do, however, seem to have "cornered the market" on CE 20As (got four of 'em). 73, -Larry/NE1S __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
Jim Wilhite wrote: Please Geoff keep the remarks respectful when you address someone. I wasn't being disrespectful. -- Driving your AM Rig without a scope, is like driving your car at night, without headlights. (K4KYV) -- 73 = Best Regards, -Geoff/W5OMR __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
Please Geoff keep the remarks respectful when you address someone. Jim/W5JO Moderator - Original Message - From: "Geoff/W5OMR" <[EMAIL PROTECTED]> To: "Ben Dover" <[EMAIL PROTECTED]>; "Discussion of AM Radio in the Amateur Service" Sent: Monday, November 12, 2007 10:43 AM Subject: Re: [AMRadio] Re:Reactor Wanted Ben Dover wrote: That's what it takes, to keep the audio from flat-topping, and distorting, causing a 'sloppy signal'. I disagree. then you'd be wrong. Did you see the scope video? No. Then future conversation with you is irrelevant. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
I also run 2000 volts on the plates of the modulator, 4x150a's, and usualy 1500 volts on the pair of 813's in the final. It seems to like it that way, i have done experiments as both supplies have variacs, things always seem to modulate better, and sound better with more mod voltage. Brett N2DTS - Original Message - From: "Geoff/W5OMR" <[EMAIL PROTECTED]> To: "Discussion of AM Radio in the Amateur Service" Sent: Monday, November 12, 2007 11:09 AM Subject: Re: [AMRadio] Re:Reactor Wanted > W9LBB wrote: > > It's interesting tho... I don't think I've ever heard of a rig that runs a > > much higher B+ on the modulator plates than it runs on the FINAL. > > > > John/WA5BXO runs 2400v on his (4) 813 (push-pull parallel) modulator, > and ~1200 on a pair of 250TH's. > > > He used to have a rig that ran a pair of 304TL's, that ran 1300 or 1400v > on the final, and the same modulator (same voltage). > > The voltage on the modulator is what's needed to properly modulate the > amount of carrier produced, without flat-topping or causing distortion. > > -- > Driving your AM Rig without a scope, > is like driving your car at night, without headlights. (K4KYV) > > -- > 73 = Best Regards, > -Geoff/W5OMR > > __ > Our Main Website: http://www.amfone.net > AMRadio mailing list > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > To unsubscribe, send an email to [EMAIL PROTECTED] with > the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
Ben Dover wrote: That's what it takes, to keep the audio from flat-topping, and distorting, causing a 'sloppy signal'. I disagree. then you'd be wrong. Did you see the scope video? No. Then future conversation with you is irrelevant. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
>> It's interesting tho... I don't think I've ever heard of a rig that runs a >> much higher B+ on the modulator plates than it runs on the FINAL. >> > >That's what it takes, to keep the audio from flat-topping, and >distorting, causing a 'sloppy signal'. I disagree. >Did you see the scope video? No. Mr. T., W9LBB __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
W9LBB wrote: It's interesting tho... I don't think I've ever heard of a rig that runs a much higher B+ on the modulator plates than it runs on the FINAL. John/WA5BXO runs 2400v on his (4) 813 (push-pull parallel) modulator, and ~1200 on a pair of 250TH's. He used to have a rig that ran a pair of 304TL's, that ran 1300 or 1400v on the final, and the same modulator (same voltage). The voltage on the modulator is what's needed to properly modulate the amount of carrier produced, without flat-topping or causing distortion. -- Driving your AM Rig without a scope, is like driving your car at night, without headlights. (K4KYV) -- 73 = Best Regards, -Geoff/W5OMR __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
Ben Dover wrote: If you have to keep your carrier below 100 watts to stay legal, then why do you need 250THs, with 3 grand on the plates no less, to begin with? That stage is MORE than capable of modulating a kilowatt final. Sort of a case of swatting a fly with a sledgehammer. It's interesting tho... I don't think I've ever heard of a rig that runs a much higher B+ on the modulator plates than it runs on the FINAL. That's what it takes, to keep the audio from flat-topping, and distorting, causing a 'sloppy signal'. Did you see the scope video? -- Driving your AM Rig without a scope, is like driving your car at night, without headlights. (K4KYV) -- 73 = Best Regards, -Geoff/W5OMR __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
> If I want to stay -legal-, I need to keep my carrier power just under >100w, because my rig -will- produce an SR of 4. Re-read that page >again, and then read it again, and let it soak in. >http://www.qsl.net/wa5bxo/asyam/aam3.html >Those 250TH's, with nearly 3kV on their plates, idle at 120mA, resting >current, when B+ is on. They are modulating another pair of 250TH's in >the final, with a max of 1500v (when the variac is cranked up) at around >250mA for max smoke (which I hardly ever run). The -normal- operation >of the final is 800~1000v @ 150mA for around 150w DC input, and 100w of >carrier output. With that light of a load on the final, there's -more- >audio available. Glad to say that I don't get an SR of 4, when running >250w carrier output, but it ain't 2, so I don't go higher. Geoff, If you have to keep your carrier below 100 watts to stay legal, then why do you need 250THs, with 3 grand on the plates no less, to begin with? That stage is MORE than capable of modulating a kilowatt final. Sort of a case of swatting a fly with a sledgehammer. It's interesting tho... I don't think I've ever heard of a rig that runs a much higher B+ on the modulator plates than it runs on the FINAL. Mr. T., W9LBB __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
-Original Message- >From: [EMAIL PROTECTED] >Sent: Nov 12, 2007 8:37 AM >To: amradio@mailman.qth.net >Subject: Re: [AMRadio] Re:Reactor Wanted > > >Another twist in measurement of peak output power is how you defining peak >duration. Test gear varies in short a peak it can respond to. > >We can split this hair pretty fine... but does it really matter? Do FCC >inspectors of amateur stations even exist any longer? It has been a lnng >time since I ran into one in professional circles, never in the amateur >realm... EXACTLY!!! As I once told you, my feeling is that the FCC long ago abdicated it's responsibilities for maintaining engineering standards and has become a lottery outfit for selling off the radio spectrum that isn't thiers to sell to begin with. The fact that we're now saddled with a 1500 watt PEP limit in itself shows that the FCC is now run by LAWYERS, and the Commissioners wouldn't recognize an engineering issue if it bit 'em right square in the butt!!! <> To be frank about it, I don't think that there's currently an engineer, qualified or otherwise, even sitting on the current Commission. The whole 1500 watt PEP thing is a simple matter of the incompetent being given an irrelevant bit of technical information, which they immediately misinterpret. Since ham radio isn't a potential multibillion dollar industrial interest, and regulation has become a bad joke these days, worrying about hair splitting on the peak power of an AM ham rig is pretty anal retentive, IMHO. We ain't big or important enough to attract Michael Powell's attention; he could give less than a rodent's rectum about such a tiny blip on the RADAR. > Twenty years ago I was involved in training Commission inspectors for >several services, and the most complicated test gear they had for measuring >power >was a Bird 43 or equivalent. Maybe now they've got a peak-reading Bird (since >lots of commercial stuff is multiple-carrier on one transmission line these >days). But quite often these guys were quite happy to use the existing >metering >in the station and just wrote down the reading. Yup... and I'd be REALLY surprised it they HAVE the peak reading version of the meter; once again, when you factor in variables like sampling time, it makes things too messy and subject to interpretation. FCC inspectors aren't geniuses, and just like the military the FCC rules cut down technical issues to the lowest common denominator, and leave as little room for creative interpretation as possible. They want thier inspectors to come up with cut and dried, yes or no answers to questions. To do that you eliminate variables, and go with hard, fast bureaucratic rules. >I'd think it more likely today they'd sit in the car and make field-strength >measurements of your signal at a given distance - a pretty rough gauge of >transmitter power in amateur stations. Good luck to you if you have an >extra-efficient antenna... Yeah, but if your rock crusher signal attracts the attention of a Fed, when he sticks the Bird in your feedline and you're lookin' good on it your problem goes away instantly. Mr. T., W9LBB __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
Another twist in measurement of peak output power is how you defining peak duration. Test gear varies in short a peak it can respond to. We can split this hair pretty fine... but does it really matter? Do FCC inspectors of amateur stations even exist any longer? It has been a lnng time since I ran into one in professional circles, never in the amateur realm... Twenty years ago I was involved in training Commission inspectors for several services, and the most complicated test gear they had for measuring power was a Bird 43 or equivalent. Maybe now they've got a peak-reading Bird (since lots of commercial stuff is multiple-carrier on one transmission line these days). But quite often these guys were quite happy to use the existing metering in the station and just wrote down the reading. I'd think it more likely today they'd sit in the car and make field-strength measurements of your signal at a given distance - a pretty rough gauge of transmitter power in amateur stations. Good luck to you if you have an extra-efficient antenna... Steve WD8DAS ** See what's new at http://www.aol.com __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] 6U8 Subststute and the 20a
Nice setup Jim. Ive had the full range of CE transmitters from 10A to 200V and everything in between. How did you handle the 8877 conversion as far as mounting and cooling? The DTR-2000 had the tube horizontal and blowing all the heat right on the tank circuit. That caused a bit of tuning drift as the fixed caps for 80/160 were right in the path; more so when the PS was upgraded to 3500V. Ive a pair of MLA-2500's here being converted to 6M for customers, thankfully the 8875's are full power. But Ive been looking for tube swap ideas that get rid of the heat better. Carl KM1H - Original Message - From: "Jim Candela" <[EMAIL PROTECTED]> To: "'Discussion of AM Radio in the Amateur Service'" Sent: Sunday, November 11, 2007 11:07 PM Subject: RE: [AMRadio] 6U8 Subststute and the 20a -Original Message- From: [EMAIL PROTECTED] [mailto:amradio- Glad to hear someone is still flogging those old CE's. I was always partial to phasing rigs and would love to find a 100V again. Carl KM1H Reply by Jim, WD5JKO: Carl, Yes I have been flogging the 20a's for about 5 years now... In fact I was on last night on 3890 LSB running legal limit SSB. The same setup can run about 300 watts AM. The tube lineup was: 1626 Osc 1625 Buffer 6MU8 9 Mc Osc and audio driver 6BA7 Mixer 1/2 12BH7 Driver 2 x 7591 Linear output tubes 8877 Dentron MLA-2500 substitute tube for a pair of dead 8875's Part of my QRO 20a campaign has been to settle down the stock 20A heat issue. Here is an excerpt of my report: The unregulated voltages +550, +290 are both from choke input circuits, so the regulation with these is decent. The Key up high B+ only rises to about 600 volts. Funny thing here is that with choke input filtering, the power transformer runs cooler than a stock 20A, which uses a capacitor input filter circuit. Lowering the B+ on the low level stages also cuts way back on the heat produced. Recall that a stock 20A will run the low level stuff at ~ 400 volts B+ (idle) with today's 120V + line voltages. QRO 7591 output tubes: http://pages.prodigy.net/jcandela/Central%20Electronics%2020a%20QRO%20%2 32/ QRO single E34L output tube: http://pages.prodigy.net/jcandela/CE20AQRO/ 73, Jim JKO __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Re:Reactor Wanted
Thomas Adams wrote: Howdy, Geoff! >>> Thomas Adams wrote: and maybe even make the legal limit output for AM (375 watts of carrier). Hi, Tom. This is an incorrect statement. There is no -legal limit carrier level- for AM. The legal limit on -any- mode is 1,500 watts -PEP -output-. Period. If you have a transmitter that has it's audio at the base-line on negative peaks and positive peaks that reach beyond a 2:1 ratio, then your 375w carrier is producing more than 1,500 watts PEP output. <<< In the (unlikely) event of an FCC inspection, I doubt that the inspecting engineer is going to go with that sort of reasoning and observe such niceties, even tho it IS correct. Man, I dunno... the -federal law- is pretty clear... The "right" answer in this case is the one that they tested me on for my (now defunct) 1st Class Radiotelephone license; the peak power of a carrier at 100 percent modulation is four times the carrier power. Anything else leaves too much wiggle room, and opens the door for lawsuits... especially if your rig doesn't use any sort of processing tricks like negative peak clippers. Which mine doesn't. I, too, have a modulation reactor (thanks, to Brett/N2DTS) that's 50Hy @ 400mA that I'm using to shunt the DC off of the secondary of the modulation transformer. My audio chain starts with a Shure SM-7 Mic, a Yamaha 31-band graphic EQ (balanced line in/out) into a Bogen 120w PA system, used as a speech-amp, and the audio comes straight off of the plates of the (4) 8417's in push-pull, parallel to a 1:1, 6k ohm isolation transformer. The secondary of the isolation transformer acts as a High Z choke, and then the audio goes to the bases of a pair of horizontal output transistors in emitter-follower configuration, which then directly drives the grids of the 250TH's in Class B. Those 250TH's, with nearly 3kV on their plates, idle at 120mA, resting current, when B+ is on. They are modulating another pair of 250TH's in the final, with a max of 1500v (when the variac is cranked up) at around 250mA for max smoke (which I hardly ever run). The -normal- operation of the final is 800~1000v @ 150mA for around 150w DC input, and 100w of carrier output. With that light of a load on the final, there's -more- audio available. Glad to say that I don't get an SR of 4, when running 250w carrier output, but it ain't 2, so I don't go higher. This is a matter of absolutes... and absolutes ONLY exist in bureaucracy and statutes. In those realms, reality means little or nothing. And the bureaucracy says that without processing, PEP equals four times the power of the unmodulated carrier. I read it differently, Tom... 1500w PEP output (regardless of mode) IS the absolute maximum legal output. Period. Punto. Absolutely. End of discussion. It's written in stone. She Retracted her Ball Point (that's all she wrote) If I want to stay -legal-, I need to keep my carrier power just under 100w, because my rig -will- produce an SR of 4. Re-read that page again, and then read it again, and let it soak in. http://www.qsl.net/wa5bxo/asyam/aam3.html Here's a scope video of my rig. Just slightly over 100% at times (and don't mind that 'hum' look on the carrier - that's just a noisy near-field transformer) but it describes my point dramatically. this is a 100w carrier, with an SR of -4-. The carrier consumes 2 divisions, and the peaks (from top to bottom) consume 8. 8:2 is reduced to 4:1. 100w at 2:1 = 400w PEP output. at 3:1, that's an increase of 3db, or 800w. You can see where this is going. *http://tinyurl.com/yvhqjr* No audio, but it's me, saying "hello, one, two thr, four five. -- Driving your AM Rig without a scope, is like driving your car at night, without headlights. (K4KYV) -- 73 = Best Regards, -Geoff/W5OMR __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
