Re: [AMRadio] Solid State 575 mercury vapor RectifierReplacementsneeded
Thanks to everyone for pointing out my brain lapse -grin- apparently I got confused in my calculations. I wrote: To calculate the value of resistor, use Ohms law R=E/I and P=IxE where R is in ohms, E is the desired drop in volts, and I is the current in amps, and P in watts For example, lets say your B+ is 50 volts too high. The load draws 0.250 amps. R= 50/.25 = 200 ohms. P= 0.25x200=50 watts. The last line should be P= 0.25x50=12.5 watts. When I came up with 50 watts, I thought to myself at the time, that seems like a big resistor, oh well... la-dee-dah... and I went about my business instead of checking my work. I should trust the Force when feel an error coming on like that. Steve WD8DAS sbjohns...@aol.com http://www.wd8das.net/ - Radio is your best entertainment value. - -Original Message- From: sbjohns...@aol.com To: amradio@mailman.qth.net Sent: Sun, Oct 4, 2009 3:17 pm Subject: Re: [AMRadio] Solid State 575 mercury vapor RectifierReplacementsneeded Jim W5JO wrote: What kind of resistor do you use in this type of rectifier build to simulate the voltage drop? I prefer cylindrical wirewound power resistors for this job (they seem to be able to take more surge20current than the sandy rectangular ones in case of a fault downstream). To calculate the value of resistor, use Ohms law R=E/I and P=IxEwhere R is in ohms, E is the desired drop in volts, and I is the current in amps, and P in watts For example, lets say your B+ is 50 volts too high. The load draws 0.250 amps. R= 50/.25 = 200 ohms. P= 0.25x200=50 watts. If the resistor ends up to be hard to find or expensive, it might be easier to eliminate the reasons why the higher B+ is a problem. And more efficient too. Upgrading some capacitors could be a reasonable approach. Steve WD8DAS sbjohns...@aol.com http://www.wd8das.net/ - Radio is your best entertainment value. - -Original Message- From: Jim Wilhite w...@brightok.net To: Discussion of AM Radio in the Amateur Service amradio@mailman.qth.net Sent: Sun, Oct 4, 2009 10:40 am Subject: Re: [AMRadio] Solid State 575 mercury vapor RectifierReplacementsneeded Steve, What kind of resistor do you use in this type of rectifier build to simulate the voltage drop? Jim/W 5JO - Original Message - I've made my own solid-state plug-in replacement rectifiers for a variety of tube types. I look up the tube specs and select solid-state diodes that stack up appropriately for current and forward and reverse voltages. I usually end up using either 1N4007s or 1N5408s. From on-lline sources like Digikey or Mouser or All Electronics the diodes are very inexpensive, ten cents to maybe 30 cents each. I put the diodes on a rectangular piece of perfboard sized to fit upright with its bottom end tucked within the sides of the base of the defunct tube it is replacing. A small L bracket holds it in place. If you use diodes from the same run (which is easy if they are sold on the paper tapes used by manufacturers today) then I find no equalizing components are needed. I add a few more diodes than the calculated voltage required for an extra measure of safety and have never had a failure, even in broadcast rigs on the air 24/7 with lots of lightning and power bumps to deal with. You can expect somewhat higher voltage from the new stack than the original tube rectifier - if that is a problem for the rig, then add aC2 series power resistor to simulate the internal voltage drop of the earlier tube. So far I've only needed to do that once when the new higher B+ exceeded the rating of the by-pass caps in the other sections of the rig. Otherwise the rigs seemed to thrive on the higher voltage. Steve WD8DAS __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: amra...@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home:
Re: [AMRadio] Solid State 575 mercury vaporRectifierReplacementsneeded
Thanks for the info Steve, but not quite what I had in mind. Is the resistor you use a wirewound (given the wattage, it must be)? Something many people overlook is the voltage value of resistors. Most carbon comp or film are good only up to ~500 volts and many of them only to 350. So in this particular application if one wants to build the rectifier circuit in a tube base, you should have room for a 15 watt resistor. Then on top of that you will have the heat dissipated by the resistor to contend with which is probably more than the tube. So the best situation would be to ignore the voltage drop and just put in modern diodes which have tighter specifications that don't require equalizing resistors and caps, then just work around the higher voltage in the circuit. Most tubes will withstand a much higher plate voltage than their specifications. Just off the top of my head I forget how the manufacturer determines maximum plate voltage, but tubes will withstand much more and operate fine. So if you add the resistor you have the heat but lower voltage, without it you have higher voltage but not the heat. So the easiest thing would be look at the capacitors in the circuit and see if you need to raise the voltage value of them and just leave the voltage dropping resistor out of the circuit. And given the price of ceramic coated wirewound resistors, much cheaper too. 73 Jim/W5JO - Original Message - I wrote: To calculate the value of resistor, use Ohms law R=E/I and P=IxE where R is in ohms, is the desired drop in volts, and I is the current in amps, and P in watts For example, lets say your B+ is 50 volts too high. The load draws 0.250 amps. R= 50/.25 = 200 ohms. P= 0.25x50=12.5 watts. Steve WD8DAS __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[AMRadio] Any amplifier suggestions?
I am interested is a simple design hf amplifier for am cw on 160-80/75-40. These are the bands i operate on where the extra power would help. Fewer parts count the better. Ultimately lower cost the better. I have power supply parts and believe that i can generate around 2000 volts. I am slowly researching tubes and am leaning toward 2 or 4 tubes that can basically generate lots of watts at half to two thirds their ratings to prolong their life span. Perhaps tubes such as 811's, 810's, 833's, 4-400's. I am open to suggestions. I will need to build or acquire a heavy duty matching system as part of the amp. My goal is at least 300 Watts AM. I do not want to mess with systems that require cooling other than fans. I am not interested in modes for this amp other than am and cw. It will almost exclusively be used for am as i rarely use more than 5 watts on cw any way. Simpler cheaper is better for me. I appreciate your suggestions. Todd __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] 575A's
Some of the older, built like a brick Scheiße-Haus kw broadcast transmitters, used 575A's to run 2500-3000 volts to 833A's. But the later Lite versions of the 833A kilowatt rigs by the same manufacturers used 872A's, which seemed to work OK up to 3 kv or so. IIRC, the PIV of 575A's is 15 kv, while that of 872A's is 10kv. 10kv piv should be ok up to 3100 volts DC using the full wave midtap circuit. Apparently when the manufacturers cheapened their rigs, they decided the extra 50% safety margin was unnecessary, and with good 872A's, rectifier flash-over was never a problem if they were operated properly. I believe 575's and 872's run at the same filament voltage, so they should be directy interchangeable. Four 872A's (or 4B32's) in a full wave bridge should be good for about 6 kv at 1 amp. I haven't tried to build my own solid state rectifier stacks for many years, but back in the 60's and 70's I never could get them to work very long before having a firework display, no matter what equalising resistors and by-pass capacitors I used, or how many extra diodes I included in the string for safety margin. So, with several bushels of mostly used 866A's, 3B28's, 872A's and 4B32's on hand and plenty of filament transformers to run them, I have always stuck with hollow state rectifiers. I use commercially built, direct replacement solid state 872A's and 866A's in my Gates BC1-T and after 5 years they have never given me any trouble. I replaced the 5R4 bias rectifier with diodes purchased brand new (don't recall if I used two in series for each leg or just one in each leg) but I used the highest piv diodes I could find and so far, no problem with those, either. I solid stated the bias rectifier to free up the octal socket, to hold the 6AS7G I use as a DC regulator to isolate the protective bias tap that allows me to run the Gates on CW. Don k4kyv ___ This message was typed using the DVORAK keyboard layout. http://www.mwbrooks.com/dvorak/ http://gigliwood.com/abcd/ __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] Any amplifier suggestions?
Todd, Typically the linear amp will be the fewer parts and expense but with less output than a full plate modulated class C rig per a given tube. One of the simplest tetrode linear systems is to put a 50 ohm load resistor right on the grid of a big jug like a 4-1000 or a pair of 4-400s and use a zener to bias the cathode circuit or fil return. It will also require a screen supply. The idea in all of this is that if the grid is loaded with a 50 ohm dummy load, then it will not require tuning. The small amount of input capacitance will be negligible on the lower freq bands. And it should not require neutralization. OTH, If you are going linear with a triode or triode connected tetrodes then you will want to go to a grounded grid linear. No screen supply, no neutralization, but does require more drive and/or may require drive tuning. You may expect very poor plate efficiency in any linier amp that is tuned properly to work with an AM input. If you're looking for old style circuits that are proven to have the most output with the least plate dissipation (smallest tubes) then plate modulated full class C finals with push pull class B modulators is best. More work more parts, but well worth the time and effort in the long run. My favorite in small legal limit stuff would be a pair of 812s push pull class C, modulated by a pair of 811a is class B. -Original Message- From: amradio-boun...@mailman.qth.net [mailto:amradio-boun...@mailman.qth.net] On Behalf Of Todd Carpenter Sent: Monday, October 05, 2009 9:30 AM To: AMRadio@mailman.qth.net Subject: [AMRadio] Any amplifier suggestions? I am interested is a simple design hf amplifier for am cw on 160-80/75-40. These are the bands i operate on where the extra power would help. Fewer parts count the better. Ultimately lower cost the better. I have power supply parts and believe that i can generate around 2000 volts. I am slowly researching tubes and am leaning toward 2 or 4 tubes that can basically generate lots of watts at half to two thirds their ratings to prolong their life span. Perhaps tubes such as 811's, 810's, 833's, 4-400's. I am open to suggestions. I will need to build or acquire a heavy duty matching system as part of the amp. My goal is at least 300 Watts AM. I do not want to mess with systems that require cooling other than fans. I am not interested in modes for this amp other than am and cw. It will almost exclusively be used for am as i rarely use more than 5 watts on cw any way. Simpler cheaper is better for me. I appreciate your suggestions. Todd __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] CCA am-1000d
Jim As has been pointed out by others that transmitter was made by a company that went under some time back and definitely not Collins. I have had to work on some of their AM and FM products in the course of my professional career and frankly can't say that I enjoyed it especially the FM ones but the AM-1000 might be good on 75. There was a company in Georgia that sold parts that was run by a gentleman with a very heavy Vietnamese accent, but I think they too went under. However!!! there is a company in Palestine, Texas that is now selling CCA parts. Go to www.vernonboyce.org telephone number is 903.729.6204 I've never talked to this guy, but the business manager of Broadcast Works who does deal with with him pointed me his way. He can probably help you with the documentation. I may and note the under line have a schematic left over from one I worked on in west Texas at KBST before it blew up one too many times and was replaced by a BE AM1A. Bill AD5OL From: KA4RFA - Jim Stewart ka4...@comporium.net To: amradio@mailman.qth.net Sent: Sunday, October 4, 2009 8:46:39 PM Subject: [AMRadio] CCA am-1000d rescued a continental am-1000d but have no documentation--can anyone help? want to put on 1885 thanks jim ka4rfa __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] Any amplifier suggestions?
Download the manual and schematic for Heathket SP-1000 or Ameritron AL-80. It's a pretty straight forward design running a single 3-500 in grounded grid and good for 160 thru 10M The earlier two 3-500 tube amps that heath sold might work better for AM as the final tubes won't have to work the duty cycle as long. Also check out back copies (pre 1960) of the Handbook for earlier designs. Good luck! Bill-WF1L --- On Mon, 10/5/09, Todd Carpenter n9...@yahoo.com wrote: From: Todd Carpenter n9...@yahoo.com Subject: [AMRadio] Any amplifier suggestions? To: AMRadio@mailman.qth.net Date: Monday, October 5, 2009, 10:29 AM I am interested is a simple design hf amplifier for am cw on 160-80/75-40. These are the bands i operate on where the extra power would help. Fewer parts count the better. Ultimately lower cost the better. I have power supply parts and believe that i can generate around 2000 volts. I am slowly researching tubes and am leaning toward 2 or 4 tubes that can basically generate lots of watts at half to two thirds their ratings to prolong their life span. Perhaps tubes such as 811's, 810's, 833's, 4-400's. I am open to suggestions. I will need to build or acquire a heavy duty matching system as part of the amp. My goal is at least 300 Watts AM. I do not want to mess with systems that require cooling other than fans. I am not interested in modes for this amp other than am and cw. It will almost exclusively be used for am as i rarely use more than 5 watts on cw any way. Simpler cheaper is better for me. I appreciate your suggestions. Todd __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] Any amplifier suggestions?
Hi Todd, A rough rule-of-thumb to help get you started in your choice of tube(s) is the following: your carrier OUTPUT---when the linear amplifier is used as such, i.e. to boost the AM signal driving it from your exciter---is equal to ONE HALF of the plate dissipation of your tubes... I have a pair of G-G 813s in my HB kilowatt: each 813 is good for 125 watts of plate dissipation, so one tube alone would be good for 62.5 watts of carrier output in AM linear mode...the pair of them gives me a total of 125-watts of carrier, with a drive of some modulated 15 watts, or so, at the linear's input jack... No, it may not be as good to the purists as a full-bore 200 watt plate carrier modulated by some 100 watts of P-P class B audio, but it'll STILL make your presence on the band known, and in pretty good fashion, too... Besides, have you seen many 100 watt plate modulation transformers for sale anywhere lately...?! ~73~ de Eddy VE3CUI - VE3XZ ** - Original Message - From: Todd Carpenter n9...@yahoo.com To: AMRadio@mailman.qth.net Sent: Monday, October 05, 2009 10:29 AM Subject: [AMRadio] Any amplifier suggestions? I am interested is a simple design hf amplifier for am cw on 160-80/75-40. These are the bands i operate on where the extra power would help. Fewer parts count the better. Ultimately lower cost the better. I have power supply parts and believe that i can generate around 2000 volts. I am slowly researching tubes and am leaning toward 2 or 4 tubes that can basically generate lots of watts at half to two thirds their ratings to prolong their life span. Perhaps tubes such as 811's, 810's, 833's, 4-400's. I am open to suggestions. I will need to build or acquire a heavy duty matching system as part of the amp. My goal is at least 300 Watts AM. I do not want to mess with systems that require cooling other than fans. I am not interested in modes for this amp other than am and cw. It will almost exclusively be used for am as i rarely use more than 5 watts on cw any way. Simpler cheaper is better for me. I appreciate your suggestions. Todd __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] Any amplifier suggestions?
I have a heath dx 60 and vfo to drive it with. Just have to find someone to help me fix the dx60. I am not sure which is better, but no tune would be a plus. I have 6 of the 1625 tubes as well. I also have a 1940 handbook with a single tube 4-400 amp in it. But i am looking for maximum am output. -Original Message- From: John Coleman j...@pctechref.com Sent: Monday, October 05, 2009 10:26 AM To: 'Discussion of AM Radio in the Amateur Service' amradio@mailman.qth.net Subject: Re: [AMRadio] Any amplifier suggestions? Todd, Typically the linear amp will be the fewer parts and expense but with less output than a full plate modulated class C rig per a given tube. One of the simplest tetrode linear systems is to put a 50 ohm load resistor right on the grid of a big jug like a 4-1000 or a pair of 4-400s and use a zener to bias the cathode circuit or fil return. It will also require a screen supply. The idea in all of this is that if the grid is loaded with a 50 ohm dummy load, then it will not require tuning. The small amount of input capacitance will be negligible on the lower freq bands. And it should not require neutralization. OTH, If you are going linear with a triode or triode connected tetrodes then you will want to go to a grounded grid linear. No screen supply, no neutralization, but does require more drive and/or may require drive tuning __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] Any amplifier suggestions?
Hi Todd: Sounds like a fun project. I use a Swan MK2 amplifier on am for 200 w out using two 3-500Zs, input is 30w from an Elmac AF 67. For 2 kvdc I think I would look into a pair of 813's running in grounded grid. The 813 is a very rugged tube and show up at the flea markets and at reasonable prices too. The 572B might be a good choice too but cost more. You said you needed a matching system and also that fewer parts is better. I recommend you avoid build an L tuner. That's the random wire tuner using one capacitor and one coil. I've used them before and they seem to put alot of RF in the shack. I got nipped a bunch of times using a metal D 104 mic. I switched to a T tuner - two caps, one coil and an a balun and the shack rf disappeared. Anyway, have fun! Greg WA7LYO Kinston NC - Original Message - From: Todd Carpenter n9...@yahoo.com To: AMRadio@mailman.qth.net Sent: Monday, October 05, 2009 10:29 AM Subject: [AMRadio] Any amplifier suggestions? I am interested is a simple design hf amplifier for am cw on 160-80/75-40. These are the bands i operate on where the extra power would help. Fewer parts count the better. Ultimately lower cost the better. I have power supply parts and believe that i can generate around 2000 volts. I am slowly researching tubes and am leaning toward 2 or 4 tubes that can basically generate lots of watts at half to two thirds their ratings to prolong their life span. Perhaps tubes such as 811's, 810's, 833's, 4-400's. I am open to suggestions. I will need to build or acquire a heavy duty matching system as part of the amp. My goal is at least 300 Watts AM. I do not want to mess with systems that require cooling other than fans. I am not interested in modes for this amp other than am and cw. It will almost exclusively be used for am as i rarely use more than 5 watts on cw any way. Simpler cheaper is better for me. I appreciate your suggestions. Todd __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[AMRadio] CCA First Wednesday AM Night Oct 7th!!!
FIRST WEDNESDAY AM NIGHT!!! Sponsored by the Collins Collectors Association. Wednesday October 7th, 2009 on 3880 kcs at 7:00 PM local East Coast time marks the start of the latest chapter of First Wednesday AM Night, drawing hundreds of vintage stations from across the country. The East Coast and Central sections run for 90 minutes in response to the tremendous participation in those time zones. The remaining time zones will be an hour. We encourage stations to check-in on AM using Collins and other AM transmitters, new and old. It's an opportunity to revel in this nostalgic mode, enjoy giving vintage equipment a run, and sharing some storytelling about classic vacuum tube homebrew and commercial designs. Typically more than a hundred stations take part in the evening's coast-to-coast AM event; by the time it concludes at 10:00 PM Local PST. LISTEN for the following anchors and stop by to say hello, won't you? You don't have to be running Collins or vintage gear to be welcomed into the group. 7:00 PM-8:30 PM Local East Coast Time Anchor: Bob W0YVA 7:30 PM-9:00 PM Local Central Time Anchor: Jim W0NKL and Brian K0EFJ 8:00 PM-9:00 PM Local Mountain Time Anchor: K0OJ Jim and Chuck KD0ZS 8:00 PM-9:00 PM Local West Coast Time Anchor: WA6FIZ Mickey We are still looking for additional anchors in the West Coast time zone. Please contact me if you are interested! comments please to wa9...@dishmail.net __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[AMRadio] amplifier question
I frequently see questions regarding building an amp and seeking a schematic or other information. I think there is only one answer, DO NOT DO IT WITH OUT A LOT OF HELP FROM SOMEONE THAT WILL BE THERE WITH YOU! If one has to seek a schematic they are simply not ready to work with high voltages, there is no such thing as a slight electrical shock when using the typical voltages in even a moderate power amp. these things will KILL YOU. When was the last time you saw a lineman working on power lines by himself? Never. There is an old verse that fits this there are only two types of motorcycle riders, those that have gone down and those that are going to go down. I was hit at about 16 years old, it was only 500 volts from my finger to my elbow, same arm, I thought my arm was broken, could not move it for probably 30 min. so now 50 + years later, I am still afraid of the stuff and that is a good thing. One has to hear a capacitor or major fault with with a 3kv + supply every now and then to realize that this is not something to be casual about. This is not meant to discourage, but it is a lot safer and probably cheaper to buy a manufactured amp unless you have a lot of experience. Please do not kill your self. Bernie W8RPW __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] CCA am-1000d
thanks correction from nameplate CCA ELECTRONICS CORP GLOUCESTER CITY, NEW JERSEY MODEL AM-1000D#23110/1/71 - Original Message - From: BILL GUYGER bguy...@sbcglobal.net To: Discussion of AM Radio in the Amateur Service amradio@mailman.qth.net Sent: Monday, October 05, 2009 11:28 AM Subject: Re: [AMRadio] CCA am-1000d Jim As has been pointed out by others that transmitter was made by a company that went under some time back and definitely not Collins. I have had to work on some of their AM and FM products in the course of my professional career and frankly can't say that I enjoyed it especially the FM ones but the AM-1000 might be good on 75. There was a company in Georgia that sold parts that was run by a gentleman with a very heavy Vietnamese accent, but I think they too went under. However!!! there is a company in Palestine, Texas that is now selling CCA parts. Go to www.vernonboyce.org telephone number is 903.729.6204 I've never talked to this guy, but the business manager of Broadcast Works who does deal with with him pointed me his way. He can probably help you with the documentation. I may and note the under line have a schematic left over from one I worked on in west Texas at KBST before it blew up one too many times and was replaced by a BE AM1A. Bill AD5OL From: KA4RFA - Jim Stewart ka4...@comporium.net To: amradio@mailman.qth.net Sent: Sunday, October 4, 2009 8:46:39 PM Subject: [AMRadio] CCA am-1000d rescued a continental am-1000d but have no documentation--can anyone help? want to put on 1885 thanks jim ka4rfa __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] CCA am-1000d
I used to raid their dumpster, as I hung out with a friend who lived in Gloucester city. I might still have some meters I think they moved to cherry hill just before they went bust, and knew people that worked there, who walked off with stuff because they did not get paid Brett - Original Message - From: KA4RFA - Jim Stewart ka4...@comporium.net To: Discussion of AM Radio in the Amateur Service amradio@mailman.qth.net Sent: Monday, October 05, 2009 7:24 PM Subject: Re: [AMRadio] CCA am-1000d thanks correction from nameplate CCA ELECTRONICS CORP GLOUCESTER CITY, NEW JERSEY MODEL AM-1000D#23110/1/71 - Original Message - From: BILL GUYGER bguy...@sbcglobal.net To: Discussion of AM Radio in the Amateur Service amradio@mailman.qth.net Sent: Monday, October 05, 2009 11:28 AM Subject: Re: [AMRadio] CCA am-1000d Jim As has been pointed out by others that transmitter was made by a company that went under some time back and definitely not Collins. I have had to work on some of their AM and FM products in the course of my professional career and frankly can't say that I enjoyed it especially the FM ones but the AM-1000 might be good on 75. There was a company in Georgia that sold parts that was run by a gentleman with a very heavy Vietnamese accent, but I think they too went under. However!!! there is a company in Palestine, Texas that is now selling CCA parts. Go to www.vernonboyce.org telephone number is 903.729.6204 I've never talked to this guy, but the business manager of Broadcast Works who does deal with with him pointed me his way. He can probably help you with the documentation. I may and note the under line have a schematic left over from one I worked on in west Texas at KBST before it blew up one too many times and was replaced by a BE AM1A. Bill AD5OL From: KA4RFA - Jim Stewart ka4...@comporium.net To: amradio@mailman.qth.net Sent: Sunday, October 4, 2009 8:46:39 PM Subject: [AMRadio] CCA am-1000d rescued a continental am-1000d but have no documentation--can anyone help? want to put on 1885 thanks jim ka4rfa __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [AMRadio] AMRadio Digest, Vol 69, Issue 4
Don wrote: That would be true only if the original rectifiers were high vacuum tube types. With mercury vapour or xenon gas rectifiers, the voltage drop across each tube is about 15 volts, regardless of the current. When you are talking about 2500 or 3000 volts total on the plate, the voltage drop across the rectifiers is insignificant. My experience has been that solid-state stacks cause the B+ to rise more when replacing vacuum rectifiers, but it also does it to a lesser extent with mercury vapor rectifiers. I don't think I've ever done it with a xenon-filled tube. Could also be something else at play in those cases, or faulty memory, I admit. I might have upgraded filter caps at the same time, for example. In any case, your observation indicates it is even easier to do the replacement for vapor/gas tubes. Mercury vapor tubes put on a very pretty light show, so they should be used if possible. -grin- How do xenon tubes look in action? Steve WD8DAS sbjohns...@aol.com http://www.wd8das.net/ - Radio is your best entertainment value. - -Original Message- From: D. Chester k4...@charter.net To: amradio@mailman.qth.net Sent: Sun, Oct 4, 2009 4:36 pm Subject: Re: [AMRadio] AMRadio Digest, Vol 69, Issue 4 You can expect somewhat higher voltage from the new stack than the original tube rectifier - if that is a problem for the rig, then add a series power resistor to simulate the internal voltage drop of the earlier tube. So far I've only needed to do that once when the new higher B+ exceeded the rating of the by-pass caps in the other sections of the rig. Otherwise the rigs seemed to thrive on the higher voltage. Steve WD8DAS That would be true only if the original rectifiers were high vacuum tube types. With mercury vapour or xenon gas rectifiers, the voltage drop across each tube is about 15 volts, regardless of the current. When you are talking about 2500 or 3000 volts total on the plate, the voltage drop across the rectifiers is insignificant. With solid state, the voltage drop across each diode is about 0.7 volts. So if you have 20 1kv diodes series strung to give 20kv p.i.v., you will have approximately the same rectifier voltage drop that you would have with a set of MV tubes. Don k4kyv ___ This message was typed using the DVORAK keyboard layout. http://www.mwbrooks.com/dvorak/ http://gigliwood.com/abcd/ __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
