Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
If you have RFI problems from a switching supply, it is not likely to show up on 70 CM, it is more likely to show up somewhere below 30 MHz. -- Original Message -- Received: Sat, 13 Jan 2007 01:49:42 PM CST From: "Tony L." <[EMAIL PROTECTED]> To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > We replaced our troublesome Astron 50 amp, linear, rack mounted supply > with a Duracomm switched mode model about a year ago. No problems > whatsoever thus far. No noise at all on 70cm. Much lighter too; I > didn't hurt my back lifting into the cabinet as I have with the Astron. > > > --- In Repeater-Builder@yahoogroups.com, "n9lv" <[EMAIL PROTECTED]> wrote: > > > > With all the talk about switching power supplies, I asked a question > > but did not really see my answer. Currently I have an Astron 70 Amp > > power supply on the repeater system. I have access to a 100 Amp > > Audiopipe DSPS10012 switching power supply available for the > > repeater. What would be the (dis)advantage of using this power > supply > > and release the 70 Amp Astron that is in line currently? > > > > Mathew > > > > >
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
Hi Skipp, I am concerned about noise from even the top line switching supplies to my equipment and the other equipment in the tower site. I have heard it said that placing a battery (over the supply, on the supply, somewhere) will remove any of the noise. In your experience does this work and if so how is the battery configured on say a 70 amp switching supply? Thanks JIM KA2AJH _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Sunday, January 14, 2007 12:10 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > If the supply you are using is fine why change? Yes, you > would gain some amperage capacity. Relative example... A room full of Motorola Repeater Stations in non constant service costs about $30/month each to operate. Put the repeater into lock to talk mode (IRLP or Echolink) and the energy cost rises by almost a third (typical). One of the energy soaks is the well designed and constructed transformers within the repeater power supplies. Replacing the hungry Motorhead Power Supplies cuts at least 1/2 off the power bill, which is much nicer when you're the one having to pay it. > However, switching supplies are inherently noisy. You > could experience problems from these noises. I realize > we are not talking about HF. But, it is possible to wind > up with a problem you don't have now. Many of the common 13.8 vdc switchers sold to the ham market will hose up at least the 160 meter ham band no problem, which is just above the am broadcast band I have on the shop when XM is stale. > If that 50 amp supply is fine, I see no advantage in the change. > Dave Cheers Dave, skipp
Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
The ojective is not gain amperage, I have plenty of that. This one is available for free to me, and is brand new. This would release the 70 amp Astron for use back in the ham shack for all the HF equipment, and would serve also as a standby. Since the repeater is the only unit in this shack, unless the noise was present on the repeater, there is nothing else to suffer noise. The answer to the question has come, however, the final result will be today when I switch them out and see if it brings any noises to the repeater. Mathew skipp025 <[EMAIL PROTECTED]> wrote: > If the supply you are using is fine why change? Yes, you > would gain some amperage capacity. Relative example... A room full of Motorola Repeater Stations in non constant service costs about $30/month each to operate. Put the repeater into lock to talk mode (IRLP or Echolink) and the energy cost rises by almost a third (typical). One of the energy soaks is the well designed and constructed transformers within the repeater power supplies. Replacing the hungry Motorhead Power Supplies cuts at least 1/2 off the power bill, which is much nicer when you're the one having to pay it. > However, switching supplies are inherently noisy. You > could experience problems from these noises. I realize > we are not talking about HF. But, it is possible to wind > up with a problem you don't have now. Many of the common 13.8 vdc switchers sold to the ham market will hose up at least the 160 meter ham band no problem, which is just above the am broadcast band I have on the shop when XM is stale. > If that 50 amp supply is fine, I see no advantage in the change. > Dave Cheers Dave, skipp - We won't tell. Get more on shows you hate to love (and love to hate): Yahoo! TV's Guilty Pleasures list.
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
Mathew, If you use a modern switch-mode power supply from a reputable manufacturer, you should not have any noise problems. Some of the postings allude to "noisy" switching power supplies, but those problems were common a decade or so ago, not today. I use a Yaesu-branded Samlex switch-mode power supply for my Yaesu FT-847 HF rig, and I have zero noise from it. My spectrum analyzer shows that it is clean on every Ham band. I also have several Astron and Duracomm switchers, and they, too, are free of measurable broadband noise. I got far more broadband noise out of my (former) 900 MHz desktop computer than I do now from any of my switch-mode power supplies, and that noise was enough to upset a nearby VHF radio. There have been several reviews of switch-mode power supplies published in QST Magazine, the most recent being in the July 2006 issue. Previous reviews appeared in the January 2000, September 2000, and September 2002 issues. Even the least-expensive switch-mode power supply showed no broadband noise in the Ham bands. As always, YMMV. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Mathew Quaife Sent: Sunday, January 14, 2007 10:22 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. The ojective is not gain amperage, I have plenty of that. This one is available for free to me, and is brand new. This would release the 70 amp Astron for use back in the ham shack for all the HF equipment, and would serve also as a standby. Since the repeater is the only unit in this shack, unless the noise was present on the repeater, there is nothing else to suffer noise. The answer to the question has come, however, the final result will be today when I switch them out and see if it brings any noises to the repeater. Mathew
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
That is perfectly understandable Plus, as someone else mentioned, the switcher will save you money. Richard, N7TGB -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of Mathew Quaife Sent: Sunday, January 14, 2007 10:22 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. The ojective is not gain amperage, I have plenty of that. This one is available for free to me, and is brand new. This would release the 70 amp Astron for use back in the ham shack for all the HF equipment, and would serve also as a standby. Since the repeater is the only unit in this shack, unless the noise was present on the repeater, there is nothing else to suffer noise. The answer to the question has come, however, the final result will be today when I switch them out and see if it brings any noises to the repeater. Mathew skipp025 <[EMAIL PROTECTED]> wrote: > If the supply you are using is fine why change? Yes, you > would gain some amperage capacity. Relative example... A room full of Motorola Repeater Stations in non constant service costs about $30/month each to operate. Put the repeater into lock to talk mode (IRLP or Echolink) and the energy cost rises by almost a third (typical). One of the energy soaks is the well designed and constructed transformers within the repeater power supplies. Replacing the hungry Motorhead Power Supplies cuts at least 1/2 off the power bill, which is much nicer when you're the one having to pay it. > However, switching supplies are inherently noisy. You > could experience problems from these noises. I realize > we are not talking about HF. But, it is possible to wind > up with a problem you don't have now. Many of the common 13.8 vdc switchers sold to the ham market will hose up at least the 160 meter ham band no problem, which is just above the am broadcast band I have on the shop when XM is stale. > If that 50 amp supply is fine, I see no advantage in the change. > Dave Cheers Dave, skipp -- We won't tell. Get more on shows you hate to love (and love to hate): Yahoo! TV's Guilty Pleasures list.
Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
Would I gain any advantage by changing out my Motorola MICOR Repeater TPN1110B supplies (the ones with the constant-voltage transformer) to the TPN1151A Switching power supply? I have a few spares of each type, but most of my MICOR Repeaters came with the 1110B supply installed. I don't know why there were two types of supplies offered with the MICOR Repeater/Base Station radios. The switching supplies seem to be very quiet (even around an HF radio), as far as I have been able to determine. Some of the MICOR service manuals have sections for both supplies, to cover the particular unit that was supplied with the user's station. LJ -Original Message- >From: skipp025 <[EMAIL PROTECTED]> >Sent: Jan 14, 2007 9:09 AM >To: Repeater-Builder@yahoogroups.com >Subject: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > > >> If the supply you are using is fine why change? Yes, you >> would gain some amperage capacity. > >Relative example... >A room full of Motorola Repeater Stations in non constant >service costs about $30/month each to operate. Put the repeater >into lock to talk mode (IRLP or Echolink) and the energy cost >rises by almost a third (typical). > >One of the energy soaks is the well designed and constructed >transformers within the repeater power supplies. > >Replacing the hungry Motorhead Power Supplies cuts at least >1/2 off the power bill, which is much nicer when you're the one >having to pay it. > >> However, switching supplies are inherently noisy. You >> could experience problems from these noises. I realize >> we are not talking about HF. But, it is possible to wind >> up with a problem you don't have now. > >Many of the common 13.8 vdc switchers sold to the ham market >will hose up at least the 160 meter ham band no problem, which >is just above the am broadcast band I have on the shop when >XM is stale. > >> If that 50 amp supply is fine, I see no advantage in the change. >> Dave > >Cheers Dave, >skipp > >
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
Larry, You have a golden opportunity to provide an extremely valuable service to the radio community! If you can obtain the use of a wattmeter, you can make a comparison between the two power supplies. One such meter is the "KILL A WATT" meter that is sold under several brand names. It is inexpensive, and accurate enough for our purposes. Try measuring the power- both real and apparent- drawn by the same equipment while operating on the TPN1110B supply, and again while operating on the TPN1151A supply. Make a note of all parameters in both the idle state and while transmitting. I'll be surprised if the energy used by the switcher is not much less than the ferro-resonant unit. Keep in mind that the utility charges its customers for the consumption of real power in watts over time, in kWh. In an AC circuit, the independent measurement of volts and amperes does not equal watts unless the load is resistive, which is definitely not the case with a power supply. Therefore, the measurement of current drawn by each power supply is meaningless, since it is not in phase with the voltage. The product of unsynchronized measurements of volts and amps in an AC circuit is VA, not watts, and will differ from watts depending upon the power factor. But, I digress... Just the watts consumed by each power supply in standby and transmit modes will be important to know. Once you see the difference, you may be inclined to stick with the switch-mode power supply- especially if you are paying for power. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Sunday, January 14, 2007 11:28 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. Would I gain any advantage by changing out my Motorola MICOR Repeater TPN1110B supplies (the ones with the constant-voltage transformer) to the TPN1151A Switching power supply? I have a few spares of each type, but most of my MICOR Repeaters came with the 1110B supply installed. I don't know why there were two types of supplies offered with the MICOR Repeater/Base Station radios. The switching supplies seem to be very quiet (even around an HF radio), as far as I have been able to determine. Some of the MICOR service manuals have sections for both supplies, to cover the particular unit that was supplied with the user's station. LJ
Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
At 11:28 AM 1/14/2007, you wrote: >Would I gain any advantage by changing out my Motorola MICOR >Repeater TPN1110B supplies (the ones with the constant-voltage >transformer) to the TPN1151A Switching power supply? <---What makes you think the TPN1151A is a switcher? Ken -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.ah6le.net/arcom/index.html Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
How clean are they in the AM broadcast band? -- Original Message -- Received: Sun, 14 Jan 2007 12:55:55 PM CST From: "Eric Lemmon" <[EMAIL PROTECTED]> To: Subject: RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > Mathew, > > If you use a modern switch-mode power supply from a reputable manufacturer, > you should not have any noise problems. > > Some of the postings allude to "noisy" switching power supplies, but those > problems were common a decade or so ago, not today. I use a Yaesu-branded > Samlex switch-mode power supply for my Yaesu FT-847 HF rig, and I have zero > noise from it. My spectrum analyzer shows that it is clean on every Ham > band. I also have several Astron and Duracomm switchers, and they, too, are > free of measurable broadband noise. I got far more broadband noise out of > my (former) 900 MHz desktop computer than I do now from any of my > switch-mode power supplies, and that noise was enough to upset a nearby VHF > radio. > > There have been several reviews of switch-mode power supplies published in > QST Magazine, the most recent being in the July 2006 issue. Previous > reviews appeared in the January 2000, September 2000, and September 2002 > issues. Even the least-expensive switch-mode power supply showed no > broadband noise in the Ham bands. As always, YMMV. > > 73, Eric Lemmon WB6FLY > > > -Original Message- > From: Repeater-Builder@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of Mathew Quaife > Sent: Sunday, January 14, 2007 10:22 AM > To: Repeater-Builder@yahoogroups.com > Subject: Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > > The ojective is not gain amperage, I have plenty of that. This one is > available for free to me, and is brand new. This would release the 70 amp > Astron for use back in the ham shack for all the HF equipment, and would > serve also as a standby. Since the repeater is the only unit in this shack, > unless the noise was present on the repeater, there is nothing else to > suffer noise. The answer to the question has come, however, the final > result will be today when I switch them out and see if it brings any noises > to the repeater. > > Mathew > > >
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
> You have a golden opportunity to provide an extremely > valuable service to the radio community! If you can obtain > the use of a wattmeter, you can make a comparison between the > two power supplies. One such meter is the "KILL A WATT" > meter that is sold under several brand names. It is > inexpensive, and accurate enough for our purposes. Unless I'm remembering wrong, the TPN1151A was still a ferro supply just like a TPN1110B. It had some kind of a switching circuit that was specific to that model (which was the battery backup version power supply for the Micor), but the main high current supply was still a ferro. At least that's how I remember it. I can't remember ever having either of those supplies fail (not even filter caps!) that I've never had to spend much time inside them, nor their respective manual pages. If there's really interest in something like this, I can take both types of Micor supplies, a GE M2 ferro, an Astron linear, a Duracomm/Iota switcher, and maybe a few other things I have around and load test them at a few different current draw points (something like no load, standby @2A, mid-power transmit @ 15A, and high-power transmit @ 30A) and come up with a table. I have a Transistor Devices electronic load good for 1000 watts so I can do this with a fairly high degree of accuracy. I also have a Kill-A-Watt along with traditional RMS-reading DVM's and amp-clamps too. If there's interest email me and I'll put it on the ham projects to-do list. I'm thinking of a tabulation of input E/I/PF/VA/watts, output E/I/watts, and efficiency (watts out vs watts out). Would that cover it? --- Jeff
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
Jeff, That sounds like a plan! And I agree with your and Ken's comment about the TPN1151A being a linear supply- I checked a MICOR manual to be sure. I seem to recall that there was a MICOR switch-mode supply, but I can't remember which Compa-Stations had it installed, or what model number it bore. Old age is affecting my memory, I guess... 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo Sent: Sunday, January 14, 2007 3:21 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > You have a golden opportunity to provide an extremely > valuable service to the radio community! If you can obtain > the use of a wattmeter, you can make a comparison between the > two power supplies. One such meter is the "KILL A WATT" > meter that is sold under several brand names. It is > inexpensive, and accurate enough for our purposes. Unless I'm remembering wrong, the TPN1151A was still a ferro supply just like a TPN1110B. It had some kind of a switching circuit that was specific to that model (which was the battery backup version power supply for the Micor), but the main high current supply was still a ferro. At least that's how I remember it. I can't remember ever having either of those supplies fail (not even filter caps!) that I've never had to spend much time inside them, nor their respective manual pages. If there's really interest in something like this, I can take both types of Micor supplies, a GE M2 ferro, an Astron linear, a Duracomm/Iota switcher, and maybe a few other things I have around and load test them at a few different current draw points (something like no load, standby @2A, mid-power transmit @ 15A, and high-power transmit @ 30A) and come up with a table. I have a Transistor Devices electronic load good for 1000 watts so I can do this with a fairly high degree of accuracy. I also have a Kill-A-Watt along with traditional RMS-reading DVM's and amp-clamps too. If there's interest email me and I'll put it on the ham projects to-do list. I'm thinking of a tabulation of input E/I/PF/VA/watts, output E/I/watts, and efficiency (watts out vs watts out). Would that cover it? --- Jeff
Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
Erick, I agree with you! The only difference will be any increased efficiencies in the switcher over the mag and that will be small. I have had a Master Electrical License for 38 years. A physical law of science says that 746 watts equal 1 horsepower> There is no deviation from that scientific fact. In addition, if the equipment that is powered by the astron, draws 30 amps, it's going to draw 30 amps on the switcher. THAT CANNOT CHANGE> The power supply, both switcher and mag type, will draw the required line current that is demanded by that load. Ohm's law says P=E/I (power ((wattage)) = E((voltage)) divided by the amperage ((I)). If 30 amps are required at 13.8 volts the resultant power consumed will REMAIN THE SAME POWERED BY THE MAG OR SWITCHER SUPPLY. Since this physical law cannot change, then the efficiency differences between the two types of supply will be the ONLY POSSIBLE DECREASE IN CONSUMED ELECTRICITY. Since efficiency is the ONLY POSSIBLE GAIN and the switcher cannot generate electricity and there is no perpetual motion, needed magnetizing current decrease and possible utility current power factor improvements are the ONLY POSSIBLE IMPROVEMENTS THAT CAN OCCUR. If you consider these facts, you will instantly see that utility cost reductions will be minimal at best. Electrical company power charges are calculated in KWH (kilowatt hours). That is calculated by the formula KHW (killer what hours ((hi hi)) = wattage load (both apparent and actual) multiplied by the time used and divided by one thousand. Since the inefficiencies are these SMALL differences, any real electrical cost savings will be in pennies on the monthly bill and that is if the utility apparent wattage is in line with actual use (power factor corrected). As you can see, the only real advantage to the switching supplies are mostly physical. By the way. Accurately measuring these electrical differences with metering equipment can get quite complicated since ac power factor is involved. To correctly measure this you need to correct power factor by using correction capacitors. That is why utility meters have a designed and approved accuracy of 1.5 to 2 percent (this is national standard and regulation required). If anyone believes they are going to save any substantial amount of money by converting to switchers, they are going to be rudely awakened. It would take decades to recoup the cost of such equipment replacements based upon utility savings. One last myth left to clear up. A power supply connected to ac current and left turned on 24/7/365 is the way to insure increased equipment longevity. I have heard many people say they must "turn their power supply off when equipment is not being used to save electricity." NOTHING COULD BE MORE ERRONEOUS. The ONLY electricity being consumed when the load is switched off, is magnetizing current and voltage correction current from leakage etc. Since this is relatively minute, those "significant savings" are nonexistent. Once again we speak of pennies. If you consider the stress caused by switching the power supply on and off many times, in the end you loose. Life expectancy is decreased by in rush, each time the unit is re-energized. I have had Astron mag. supplies functioning for DECADES with no failure. As long as the input is protected by GOOD electronic spike suppression, failure is mostly limited to age or abuse (possible load shorts). I can only hope this helps clear up confusion and to eliminate conjecture regarding these subjects. David R. Henry LME - Original Message - From: "Eric Lemmon" <[EMAIL PROTECTED]> To: Sent: Sunday, January 14, 2007 3:07 PM Subject: RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > Larry, > > You have a golden opportunity to provide an extremely valuable service to > the radio community! If you can obtain the use of a wattmeter, you can > make > a comparison between the two power supplies. One such meter is the "KILL > A > WATT" meter that is sold under several brand names. It is inexpensive, > and > accurate enough for our purposes. > > Try measuring the power- both real and apparent- drawn by the same > equipment > while operating on the TPN1110B supply, and again while operating on the > TPN1151A supply. Make a note of all parameters in both the idle state and > while transmitting. I'll be surprised if the energy used by the switcher > is > not much less than the ferro-resonant unit. > > Keep in mind that the utility charges its customers for the consumption of > real power in watts over time, in kWh. In an AC circuit, the independent > measurement of volts and amperes does not equal watts unless the load is > resistive, which is definitely not the case with a power supply. > Therefo
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
I was wrong about the MICOR Power Supply number. I went by the number of the other supply shown in the MICOR UHF Repeater manual, instead of actually going out across the snow into the COLD garage to visibly look at the Supply. Its number is TPN1095A (also has a TLN4731A number on it). It's quite different than the TPN1110B with its big transformer and capacitor. We always referred to the TPN1095A as "The Switching Supply", but we might have been wrong all along! LJ -Original Message- >From: Eric Lemmon <[EMAIL PROTECTED]> >Sent: Jan 14, 2007 3:44 PM >To: Repeater-Builder@yahoogroups.com >Subject: RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > >Jeff, > >That sounds like a plan! And I agree with your and Ken's comment about the >TPN1151A being a linear supply- I checked a MICOR manual to be sure. I seem >to recall that there was a MICOR switch-mode supply, but I can't remember >which Compa-Stations had it installed, or what model number it bore. Old >age is affecting my memory, I guess... > >73, Eric Lemmon WB6FLY > > >-Original Message- >From: Repeater-Builder@yahoogroups.com >[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo >Sent: Sunday, January 14, 2007 3:21 PM >To: Repeater-Builder@yahoogroups.com >Subject: RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > >> You have a golden opportunity to provide an extremely >> valuable service to the radio community! If you can obtain >> the use of a wattmeter, you can make a comparison between the >> two power supplies. One such meter is the "KILL A WATT" >> meter that is sold under several brand names. It is >> inexpensive, and accurate enough for our purposes. > >Unless I'm remembering wrong, the TPN1151A was still a ferro supply just >like a TPN1110B. It had some kind of a switching circuit that was specific >to that model (which was the battery backup version power supply for the >Micor), but the main high current supply was still a ferro. At least that's >how I remember it. I can't remember ever having either of those supplies >fail (not even filter caps!) that I've never had to spend much time inside >them, nor their respective manual pages. > >If there's really interest in something like this, I can take both types of >Micor supplies, a GE M2 ferro, an Astron linear, a Duracomm/Iota switcher, >and maybe a few other things I have around and load test them at a few >different current draw points (something like no load, standby @2A, >mid-power transmit @ 15A, and high-power transmit @ 30A) and come up with a >table. I have a Transistor Devices electronic load good for 1000 watts so I >can do this with a fairly high degree of accuracy. I also have a Kill-A-Watt >along with traditional RMS-reading DVM's and amp-clamps too. If there's >interest email me and I'll put it on the ham projects to-do list. > >I'm thinking of a tabulation of input E/I/PF/VA/watts, output E/I/watts, and >efficiency (watts out vs watts out). Would that cover it? > >--- Jeff > >
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
I'd like to pose a question here regarding only a portion of the discussion. This pertains to the "cleanliness" of the power received. I understand that the voltage can fluctuate widely when the utility switches on and out various circuits to meet demand. Skipp mentions that this can cause nasty things to happen to power supplies in equipment racks and cabinets in transmitter rooms, among other items of equipment. My question is this: is it worthwhile to install a variac on the mains for the item in question to "stabilize" the voltage? Or will this not work as I envision it might/should? Mark - N9WYS -Original Message- (much text snippage) I'll take the turn it off when not needed/used gamble because I've seen first hand what can and does come down the power line quite a bit more often that one would expect. It's not pretty, nor is it clean or stable 100% of the time. Our local utility does a big grid switch every weekday morning about 8am and that event alone is a huge glitch generator.
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
Mark, Sudden and regular changes in voltage levels on long lines are normally caused by the switching in and out of capacitor banks that are used to improve voltage regulation on long distribution lines. This is most commonly used on lines carrying 4,160 to 22,000 volts. In areas where light industrial loads are common, the power factor is lagging during most of the day, due to the number of motors and other inductive loads connected. To counteract this lagging power factor, capacitor banks are switched in and out by either a timer or a voltage sensor. In my area, the nominal voltage jumped from about 119 volts to 123 volts in the morning, and dropped back in the late afternoon. This practice is very important in rural areas, where a 12kV line might run 20 miles to a farm. If regulators or capacitor banks were not used to stabilize the voltage, there would be large excursions each time the farmer started his irrigation pumps. Motors, being inductive, cause a lagging power factor that results in an increased voltage drop on the distribution circuit. The capacitors supply capacitive reactance that cancels the inductive reactance and, when properly applied, will improve the power factor to near unity and minimize the voltage drop. Most well-designed power supplies, both linear and switch-mode, will maintain a relatively stable output voltage despite wide variations in AC input voltage. Some designs are nearly immune to step-voltage changes resulting from capacitor switching. I don't think it's necessary to employ a Variac or similar variable transformer to adjust the voltage. If the measured AC voltage at the repeater site is not within the IEEE standard of 120 +/- 5%, then the utility should be contacted to change the transformer taps to bring the voltage within tolerance. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of N9WYS Sent: Monday, January 15, 2007 8:43 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. I'd like to pose a question here regarding only a portion of the discussion. This pertains to the "cleanliness" of the power received. I understand that the voltage can fluctuate widely when the utility switches on and out various circuits to meet demand. Skipp mentions that this can cause nasty things to happen to power supplies in equipment racks and cabinets in transmitter rooms, among other items of equipment. My question is this: is it worthwhile to install a variac on the mains for the item in question to "stabilize" the voltage? Or will this not work as I envision it might/should? Mark - N9WYS -Original Message- (much text snippage) I'll take the turn it off when not needed/used gamble because I've seen first hand what can and does come down the power line quite a bit more often that one would expect. It's not pretty, nor is it clean or stable 100% of the time. Our local utility does a big grid switch every weekday morning about 8am and that event alone is a huge glitch generator.
RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
Thanks for the fine explanation, Eric! My main concern/wonder was in regard to the issue mentioned by Skipp, and a perceived concern over damage that might occur as a result of the voltage fluctuations. I've even noticed dimming and brightening of the lights in my house when this apparently occurs - I guess the issue is not as serious as I thought. Just trying to be cautions - maybe overly so. ;-) Thanks again! Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of Eric Lemmon Mark, Sudden and regular changes in voltage levels on long lines are normally caused by the switching in and out of capacitor banks that are used to improve voltage regulation on long distribution lines. This is most commonly used on lines carrying 4,160 to 22,000 volts. In areas where light industrial loads are common, the power factor is lagging during most of the day, due to the number of motors and other inductive loads connected. To counteract this lagging power factor, capacitor banks are switched in and out by either a timer or a voltage sensor. In my area, the nominal voltage jumped from about 119 volts to 123 volts in the morning, and dropped back in the late afternoon. This practice is very important in rural areas, where a 12kV line might run 20 miles to a farm. If regulators or capacitor banks were not used to stabilize the voltage, there would be large excursions each time the farmer started his irrigation pumps. Motors, being inductive, cause a lagging power factor that results in an increased voltage drop on the distribution circuit. The capacitors supply capacitive reactance that cancels the inductive reactance and, when properly applied, will improve the power factor to near unity and minimize the voltage drop. Most well-designed power supplies, both linear and switch-mode, will maintain a relatively stable output voltage despite wide variations in AC input voltage. Some designs are nearly immune to step-voltage changes resulting from capacitor switching. I don't think it's necessary to employ a Variac or similar variable transformer to adjust the voltage. If the measured AC voltage at the repeater site is not within the IEEE standard of 120 +/- 5%, then the utility should be contacted to change the transformer taps to bring the voltage within tolerance. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of N9WYS Sent: Monday, January 15, 2007 8:43 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. I'd like to pose a question here regarding only a portion of the discussion. This pertains to the "cleanliness" of the power received. I understand that the voltage can fluctuate widely when the utility switches on and out various circuits to meet demand. Skipp mentions that this can cause nasty things to happen to power supplies in equipment racks and cabinets in transmitter rooms, among other items of equipment. My question is this: is it worthwhile to install a variac on the mains for the item in question to "stabilize" the voltage? Or will this not work as I envision it might/should? Mark - N9WYS -Original Message- (much text snippage) I'll take the turn it off when not needed/used gamble because I've seen first hand what can and does come down the power line quite a bit more often that one would expect. It's not pretty, nor is it clean or stable 100% of the time. Our local utility does a big grid switch every weekday morning about 8am and that event alone is a huge glitch generator. Yahoo! Groups Links
Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
At 10:12 AM 1/16/2007, you wrote: > and if you're stuck paying really high "rack-space rent" >inside some of those almost empty commercial repeater sites... > >It's prudent to think how "size does matter". > >Don't get me wrong... I respect and like the Motorhead (motorola) >and GE Ferroresonant type supplies. It takes nearly an act of god >to kill one... I also understand the typical MSR-2000 power supply >costs about $15 to $25 min each per month to space heat the cabinet >and call out for field mice to sleep on (and pee up). Where and >when I'm not paying the bill... heck plug 25 of them in just to >keep the room warm and run cabinet fans all day long.
