Re: [AMRadio] Pw Supply
John E. Coleman (ARS WA5BXO) wrote: Good info Jim: Certainly something I never considered. You know, since I've been running the two power supplies in series, on my rig, I've noticed that when PS#2 is turned on, and the tubes re-biased for 150mA, the primary current -at least- doubles. I wouldn't have thought that to be the case, when the primaries were in parallel. -- -Geoff/W5OMR __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Pw Supply
Brett gazdzinski wrote: Looking for a transformer since 1955, or a power supply? Actually, my brain. But a pair 813's modulated by a pair of 811's was a sort of mantra in those days. As a teenager in high school, all I could afford was an 807 modulated by a key and an S38. Now I'm rich and want that mantra. In plate modulated AM service, the 813's will run nice at 2000 volts on the plates at 400ma for 2 tubes. Thank you. Lots of stuff is no longer in the fair radio catalog. But lots of people bought the stuff they used to have, so its floating around. Actually, I got an email back from them and they have something very close but it is only 110 but the price is right. Thanks for your thoughts, js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Pw Supply
Jack Schmidling wrote: In plate modulated AM service, the 813's will run nice at 2000 volts on the plates at 400ma for 2 tubes. Just looking at the spec's, Jack, for a single 813... in Ham service, they say you can run 2500v on the plates, at 225mA, but in the same chart, says the max is 450w max. Sorry... the math just don't add up. But, if you use a single 813 in the final, and modulate it with a pair of 811's, you'll be at, or over the 'legal limit' anyway. Either way, 1500w PEP is the Maximum Power Output we're allowed to run these days. Not like in the old days, when 1kW DC input, measured at the plate of the output tube(s) was the law (and a helluvalot easier to measure) -- 73 = Best Regards, -Geoff/W5OMR Every Day of Freedom is a Good day to Thank A Veteran. __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Pw Supply
Jack, I looked up the specs on the 813 that I have here, in a pdf file.. It says: Because of its high power sensitivity, the 813 requires very little driving power to give full power output. For example, in class C telegraph services under ICAS conditions, a single 813 is capable of giving a power outpuot of approximately 375 watts with a driving power of only about 4 watts. -- 73 = Best Regards, -Geoff/W5OMR __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] Pw Supply
Just looking at the spec's, Jack, for a single 813... in Ham service, they say you can run 2500v on the plates, at 225mA, but in the same chart, says the max is 450w max. Sorry... the math just don't add up. I think 2000 volts is max in plate modulated service. As long as you do not exceed the plate dissipation, you can run higher voltage or current, you could likely run a pair at 2500 volts and 300 ma, or 2000 volts at400ma, or 1750 volts at 450 or 500 ma. More voltage usually works better though, as you have to worry about cathode emission and current losses in things. Almost everything I ever used did better at higher voltage lighter current... But, if you use a single 813 in the final, and modulate it with a pair of 811's, you'll be at, or over the 'legal limit' anyway. A single 813 at 2000 volts and 200ma will give about 300 watts out. I don't usually get 4 times the carrier power on the pep watt meter, more like 3 times, so that is only 900 to 1000 watts. Depends on your voice maybe... A pair of 811A's wont do well enough to modulate 2 813's at full bore. Its good to have at least as much audio power as DC input to the RF deck, its clean that way. Either way, 1500w PEP is the Maximum Power Output we're allowed to run these days. Not like in the old days, when 1kW DC input, measured at the plate of the output tube(s) was the law (and a helluvalot easier to measure) With a pep reading watt meter, you don't even have to do any math. The meters read all over the place with a little swr though...and who knows about the calibration... Brett N2DTS __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] Pw Supply
I would not buy anything from MFJ! Why the big hurry, wait to find a good transformer, they are around. What ratings are you looking for? Is it supposed to fit on the deck over that big hole? Fair radio used to sell a nice oil filled Collins transformer, 2250 volt ct at 650ma, 110 or 220 primary. With a variac that would give 0 to 1500 volts. Its always much better to go with choke input, much better voltage regulation, much lower startup surge current. With a cap input, the voltage will increase quite a bit, but will sag big time under a load. For small supplies with steady loads, that is ok, but for big supplies with loads that vary its not good. On key up, a cap looks like a dead short till it charges up, a choke looks like a resistance in series with the voltage...a big difference... What are you going to run off the supply? 8UF is not very good for a modulator, I always go around 40UF for energy storage. The old Bill Orr handbooks have loads of great info about power supplies in them. Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling Sent: Tuesday, December 05, 2006 11:12 PM To: Discussion of AM Radio in the Amateur Service Subject: [AMRadio] Pw Supply I am not having much luck finding a HV xformer for my power supply so an idea occurred to me that I would like to pass around. MFJ has a 900v one for about $100. Is there any reason why I can not use two of these and tie one side of the secondaries together and call that the center tap and have an 1800v ct transformer/s? I am using 866's so I must have a center tap. Second question is: Mine has the HV going to the choke and then to two 4 mf 3kv caps in parallel. Is it not more conventional to put a cap on each side of the choke or two chokes for a choke input filter? What would I gain or lose by moving one of the caps to the HV side? Thanks, js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Pw Supply
Brett gazdzinski wrote: I would not buy anything from MFJ! The transformers are Ameritron for whatever that is worth. Why the big hurry, wait to find a good transformer, they are around. I have wanted one of these since 1955. I have waited long enough besides, at my age, time is at a premium. What ratings are you looking for? Good question. Actually, I was going to post a question so I could answer that one. I can't make any sense out of the 813 specs, either in the Handbook or the data sheet I got on line. As near as I can tell, the typical voltage for AM is about 1300 but I see the Maul talking about 2000. I see plate current at about 150 but I see elsewhere 250. I am sort of confused but think that 2000v ct at 1/2 amp would do the job. Is it supposed to fit on the deck over that big hole? Roger. Fair radio used to sell a nice oil filled Collins transformer, 2250 volt ct at 650ma, 110 or 220 primary. With a variac that would give 0 to 1500 volts. I don't see anything like that on their site but I will check further. Its always much better to go with choke input, much better voltage regulation, much lower startup surge current. With a cap input, the voltage will increase quite a bit, but will sag big time under a load. Good info. I read somewhere about needing some sort of step start and mine has a time delay relay but it doesn't seem to have anything to do with charging caps. It connects to something in the RF deck which I haven't run down yet. It has a high/low switch which applies either 110 or 220 to the primary of the HV trans. Would this be adequate step start? What are you going to run off the supply? 8UF is not very good for a modulator, I always go around 40UF for energy storage. Unfortunately, I want to run the modulator and rf deck from this supply. That would be 813's/811's. This package I bought was a linear so that could explain the too low cap? js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Pw Supply
MFJ has a 900v one for about $100. Is there any reason why I can not use two of these and tie one side of the secondaries together and call that the center tap and have an 1800v ct transformer/s? Reply from Jim, JKO: No you cannot do this. For full wave center-tap rectification the two windings must be on the same core. If you try this, it may appear to work, but the combined primary currents will be high by 2X from a single transformer. Those MFJ transformers are intended to work into a full wave voltage doubler circuit where 900 x 1.414 x 2 = 2545 volts unloaded, and about 2 kv loaded. This can work, but the capacitors need to be big, and a soft start circuit is needed. Not a good choice for Push To Talk B+. Take those two transformers, and with a full wave bridge on each one, series up the DC outputs. You will get the same unloaded voltage, but with MUCH better regulation. You could also run choke input filtering as well, but the output will drop to about 1600 volts. You are better off with better iron and just one transformer. Regards, Jim JKO __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Pw Supply
Jim Candela wrote: No you cannot do this. For full wave center-tap rectification the two windings must be on the same core. So much for that great idea. Thanks, js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] Pw Supply
Jim: (JKO) That is an interesting statement which I had never thought of before. Using two XFMRs like Jack said, seems at first to be a good theory but as you pointed out each transformer will be looking into a half rectifier circuit so that the duty cycle on each core and primary would be alternately 1/120 of a second. I'm just not sure how that computes to heat. The primary current of one XFMR would high for 1/2 of the cycle and low on the other half and alternating half cycles for the other XFMR if phase wiring was proper. If the primary windings were in parallel then the sum of the primary currents would equate to a proper sine wave and the total current of the two would be more that if there was one due to the losses being double but I wouldn't have thought it to be 2X more. This may seem like a dummy's question but is it the unbalanced magnetic swings and DC current through the secondary that would cause the extra loss? I can see where a full wave bridge circuit for each supply and connecting the two power supplies in series would solve this. Elucidated some more please! John, WA5BXO __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] Pw Supply
Good info Jim: Certainly something I never considered. John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Candela Sent: Wednesday, December 06, 2006 5:24 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Pw Supply John, I don't have a good explanation except I tried this once at a high power level, and the results worked until we put a clamp on Ammeter to look at the combined primary current. We needed 60 volts CT at 200 amperes with 208 vac primary. The secondary isolation from the primary had to withstand 200,000 volts DC. The core was a large 'C' core, and the whole thing sat in a oil tank. The layered layers of mylar insulation resulted in considerable leakage inductance within the transformer. Before we built the beast we tried two 30 volt @ 100 ampere standard transformers to power up a big electro-magnet. It worked but the primary I was 2X what it should have been. Maybe the Tripplett clamp on ammeter was miss-behaving from the every half cycle current draw, but I also recall blowing circuit breakers, and darkening portions of the building. The boss was concerned to say the least. After building the 60v CT transformer prototype, everything worked fine, and had expected primary current. So was it core saturation from high DC current one way only, a power factor issue, or something else? I really don't know, and since that was 1981, my recall could be put in question. After all , over 50 now, so CRS is a fact of being an OM! ;-) I had to make a 0-200amp DC linear series regulator for that supply. A large water cooled heatsink and 32 TO-3 2N6258's in parallel. What a monster that was! Regards, Jim JKO - Original Message From: John E. Coleman (ARS WA5BXO) [EMAIL PROTECTED] To: Discussion of AM Radio in the Amateur Service amradio@mailman.qth.net Sent: Wednesday, December 6, 2006 3:28:44 PM Subject: RE: [AMRadio] Pw Supply Jim: (JKO) That is an interesting statement which I had never thought of before. Using two XFMRs like Jack said, seems at first to be a good theory but as you pointed out each transformer will be looking into a half rectifier circuit so that the duty cycle on each core and primary would be alternately 1/120 of a second. I'm just not sure how that computes to heat. The primary current of one XFMR would high for 1/2 of the cycle and low on the other half and alternating half cycles for the other XFMR if phase wiring was proper. If the primary windings were in parallel then the sum of the primary currents would equate to a proper sine wave and the total current of the two would be more that if there was one due to the losses being double but I wouldn't have thought it to be 2X more. This may seem like a dummy's question but is it the unbalanced magnetic swings and DC current through the secondary that would cause the extra loss? I can see where a full wave bridge circuit for each supply and connecting the two power supplies in series would solve this. Elucidated some more please! John, WA5BXO __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] Pw Supply
Why the big hurry, wait to find a good transformer, they are around. I have wanted one of these since 1955. I have waited long enough besides, at my age, time is at a premium. Looking for a transformer since 1955, or a power supply? What ratings are you looking for? Good question. Actually, I was going to post a question so I could answer that one. I can't make any sense out of the 813 specs, either in the Handbook or the data sheet I got on line. As near as I can tell, the typical voltage for AM is about 1300 but I see the Maul talking about 2000. I see plate current at about 150 but I see elsewhere 250. I am sort of confused but think that 2000v ct at 1/2 amp would do the job. In plate modulated AM service, the 813's will run nice at 2000 volts on the plates at 400ma for 2 tubes. About 600 to 700 watts of carrier output, 3000 watts pep is easy if you have the audio power to drive them. You can drop the voltage or current and just get less power out. You can match them to the mod iron that way if you don't want maximum power out. The 813 is very rugged, I have run them at 2500 volts and 500 ma for short times, they run 2000 volts and 400 ma all day long without problems, and they don't seem to go bad or wear out, I have had the same pair in for the last 15 years... For the modulator I use a pair of 4x150a/4cx250b tubes, 600 watts of audio out at 2000 volts in AB1, no driving power needed, very clean audio.. Is it supposed to fit on the deck over that big hole? Roger. Fair radio used to sell a nice oil filled Collins transformer, 2250 volt ct at 650ma, 110 or 220 primary. With a variac that would give 0 to 1500 volts. I don't see anything like that on their site but I will check further. Lots of stuff is no longer in the fair radio catalog. But lots of people bought the stuff they used to have, so its floating around. The Collins iron would be on the low side voltage wise, and light on the current, but would work at lower powers. 1200 volts at 600ma, you could run 1200 volts at 300ma on the RF deck, and modulate it with 811A's in zero bias. But you would want a separate voltage output from the power supply, through a swinging choke for the modulator. Its always much better to go with choke input, much better voltage regulation, much lower startup surge current. With a cap input, the voltage will increase quite a bit, but will sag big time under a load. Good info. I read somewhere about needing some sort of step start and mine has a time delay relay but it doesn't seem to have anything to do with charging caps. It connects to something in the RF deck which I haven't run down yet. It has a high/low switch which applies either 110 or 220 to the primary of the HV trans. Would this be adequate step start? You can do that I suppose, a time delay relay that switches between 220/110, I just use a resistor, like 5 to 10 ohms, the relay shorts the resistor out. What are you going to run off the supply? 8UF is not very good for a modulator, I always go around 40UF for energy storage. Unfortunately, I want to run the modulator and rf deck from this supply. That would be 813's/811's. This package I bought was a linear so that could explain the too low cap? I don't think the supply would be big enough. ssb amps are light duty, even the real big ones are light duty. The peak current could be over 700 ma, constant current will be 400 ma for the RF deck, and the modulator resting current of about 40 ma, and the 811A pulls about 350ma peak. Plus the bleeder resistor, say 100ma, that's 850ma on peaks, 540 ma under no modulation. The transformer, choke, rectifiers have to be able to take that current and duty cycle. Its lots better to have separate supplies for rf and modulator. You can run different voltages, use a swinging choke on the modulator power supply, and parts are easier to get when they are not huge. With the parts you have, I suspect it would run a single 813 with 811A modulators at about 200 watts out. Amplifiers also tend to have low voltage plate tuning caps, but in AM service, the voltage doubles under modulation, and really, on peaks can get to 3 times the plate voltage. You can use a 2000 volt cap on an amp running 2000 volts, but need a 6000 volt one under plate modulation to be safe. Most amplifiers can run 1/4 the power of their ssb rating on AM, and I would guess that is so even if you plate modulate it, its just not good for the power. Brett N2DTS js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Pw Supply
On Tue, 5 Dec 2006, Jack Schmidling wrote: I am not having much luck finding a HV xformer for my power supply so an idea occurred to me that I would like to pass around. Answer one of my emails, if you're getting them If you're *not* getting them, well, hey: just use the Fahwce ;} Cheers John KB6SCO PS: Yo! Don't use the Reflector for private replies! PPS: But, but, but I... PPPS: Well, okay, just this once! __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] Pw Supply
John Lawson wrote: On Tue, 5 Dec 2006, Jack Schmidling wrote: I am not having much luck finding a HV xformer for my power supply so an idea occurred to me that I would like to pass around. Answer one of my emails, if you're getting them If you're *not* getting them, well, hey: just use the Fahwce Not sure what that is but I believe we are now connected. Thanks, I might also mention that the person who had 4 S38's for sale seems to have dropped of the radar also. If you is dare I am waiting with... yuck... bated breath. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] PW Supply
Brett gazdzinski wrote: All the homebrew power supply decks have voltage and current meters, then all the modulators and RF decks also have current meters. If you run both rf and modulator off one power supply, you get an indication on the power supply of the total current. Now that I am used to the Ranger, I kinda like having a separate modulation meter and this would be on the mod deck so I don't seem much point in having one on the supply. Well at least not enough point to add one if it's not already there. Having said that, I spent an hour milling a 3 window in the panel next to the voltmeter so I could watch the 866's glow. We all have our priorities, I guess. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] PW Supply
It looks nasty. I would never use something that looked so nasty and poorly made, and if building something, like to use parts that look like they match, use grommets, the correct wire, etc. Its likely a good idea to at least put a grounded power cord on the thing if you are going to use it... Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling Sent: Saturday, December 02, 2006 11:34 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] PW Supply Brett gazdzinski wrote: The power supply looks really nasty, it does not look like there are many good parts on it... Hopefully, looks are deceiving. I have checked every part in it with ohmeter, sig gen and scope and can find no faulty parts. That's not the same as applying voltage to it but it is comforting. One thing that bothers me is that the line cord is just a standard 110v type with two wires going to a screw terminal in the cabinet. The pw sup has a 3 wire cable with 3 lugs that would seem to go to this same terminal and the sup seems to be 220v. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] PW Supply
Maybe its to prevent some surge when the supply is powered on. If so, it's a dumb way to do it. The negative is through the rack (chassis ground) I would guess. I always run a negative directly, and don't rely on the rack, I think it would be poor practice to rely on the mounting of the front panel to provide a good connection. Its also poor practice to put the current meter on another deck, what happens when you want to use the power supply on something else? Brett N2DTS John Coleman ARS WA5BXO wrote: It may be the only path to ground for the power supply and measuring the voltage across it may be the way to measure current from the power supply. A 10 ohm resistor with 1 volt measure across it represents 100ma current. This is common practice for the way I measure power supply current. But there are no other connections to it or the metering circuit. The voltmeter has a 6 meg in series with the high voltage and the current meter is in the RF deck. It just seems to lift the negative side of the HV off ground and it's not clear where the negative side of the HV supply is that goes to the RF deck. I don't see what effect it would have as a short protection. BTW I found this really neat site with some good info on power supplies http://www.qsl.net/i0jx/supply.html Thanks but it seems to only apply to full wave bridges so it does not help me understand much. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] PW Supply
Brett gazdzinski wrote: I would never use something that looked so nasty and poorly made Actually, it is very will made, laid out and laced like mil spec. I haven't a clue what you are talking about. like to use parts that look like they match Just what is it that does not match? You sound like my wife when we are ready to go out. Are we looking at the same pics? use grommets There are grommets at every pass through.. the correct wire If anything, the wire is over kill. Its likely a good idea to at least put a grounded power cord on the thing if you are going to use it... That is pretty basic. What makes you think there is not one? Not sure what your problem is but I am not gonna let you spoil my fun. I like it a lot for what I paid and I expect to have a pretty decent powersupply when I get it all together. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] PW Supply
Brett gazdzinski wrote: Its also poor practice to put the current meter on another deck, what happens when you want to use the power supply on something else? Yes indeed! How convenient to tune the RF deck while watching the plate current meter about 3 feet below it. The idea of putting a meter in the something else is not exactly appalling. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] PW Supply
Ok, if you like it, that is what counts! I was looking at the picture links you posted, kind of small, so maybe it looks better in real life. Brett -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling Sent: Sunday, December 03, 2006 6:46 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] PW Supply Brett gazdzinski wrote: I would never use something that looked so nasty and poorly made Actually, it is very will made, laid out and laced like mil spec. I haven't a clue what you are talking about. like to use parts that look like they match Just what is it that does not match? You sound like my wife when we are ready to go out. Are we looking at the same pics? use grommets There are grommets at every pass through.. the correct wire If anything, the wire is over kill. Its likely a good idea to at least put a grounded power cord on the thing if you are going to use it... That is pretty basic. What makes you think there is not one? Not sure what your problem is but I am not gonna let you spoil my fun. I like it a lot for what I paid and I expect to have a pretty decent powersupply when I get it all together. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] PW Supply
All the homebrew power supply decks have voltage and current meters, then all the modulators and RF decks also have current meters. If you run both rf and modulator off one power supply, you get an indication on the power supply of the total current. I use the radio shack meters (they used to sell) because they take a small hole and used to cost $6.00. Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling Sent: Sunday, December 03, 2006 6:57 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] PW Supply Brett gazdzinski wrote: Its also poor practice to put the current meter on another deck, what happens when you want to use the power supply on something else? Yes indeed! How convenient to tune the RF deck while watching the plate current meter about 3 feet below it. The idea of putting a meter in the something else is not exactly appalling. js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] PW Supply
It may be the only path to ground for the power supply and measuring the voltage across it may be the way to measure current from the power supply. A 10 ohm resistor with 1 volt measure across it represents 100ma current. This is common practice for the way I measure power supply current. BTW I found this really neat site with some good info on power supplies http://www.qsl.net/i0jx/supply.html Hats off to Tony, I0JX John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling Sent: Saturday, December 02, 2006 7:12 PM To: Discussion of AM Radio in the Amateur Service Subject: [AMRadio] PW Supply I am having some quality time with my new supply and have lots of questions about things I do not understand. First one is, this is a choke input with a pair of 4mf's across the output of the choke and a monster 100k bleeder. What bothers me is that there is a 10 ohm, many watt resistor between the negative side of the caps and ground. What is this for? js -- PHOTO OF THE WEEK: http://schmidling.com/pow.htm Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.com __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
