[Repeater-Builder] Re: RadioShack Recalls Power Supplies
Then call the stinking things 12 amp and 16 amp circuits; for crying out loud!!! The United States is FULL of examples of this type of DISHONESTY (can you say horsepower?). No wonder the US has become a third rate country and their products (those that ARE still made here) have no credibility in the world market. Just like the half gallon of ice cream that now weighs 48 ounces; and I could go on and on! ONLY in the US. Tom 1 -- In Repeater-Builder@yahoogroups.com, Eric Lemmon [EMAIL PROTECTED] wrote: Ron, That is a good question. The answer is that one is not supposed to connect any load greater than 12 amperes to an outlet rated at 15 amperes, that is, a NEMA 5-15R receptacle. The NEC allows two or more 15-ampere-rated outlets to be installed on a 20-ampere branch circuit (wired with 12 AWG conductors and a 20A fuse or circuit breaker), but the limit of 12 amperes on each outlet still applies. Proof of this restriction is evident in the vacuum cleaner wars of a decade or so ago. Hoover came out with a vacuum cleaner with 7 amperes of cleaning power. Then Bissel came out with a unit claiming 9 amperes of cleaning power. Other vacuum cleaner makers entered the fray until all of the brands had units with 12 amperes of cleaning power. The reason that nobody offered a unit with 13 amperes of cleaning power is because they would then have to equip that unit with a NEMA 5-20P plug and at least a 14/3 power cord. Most older homes do not have NEMA 5-20R outlets, so such a vacuum cleaner could not be plugged in to the outlets in most homes. Besides, there is no credibility to a laughable rating of cleaning power expressed in amperes! That is about as silly as claiming that a mobile radio has 13.8 volts of talk power! Back to your second question. By definition, a 15-ampere-rated branch circuit has circuit conductors of #14 AWG or larger, and is protected by a fuse or circuit breaker rated at 15 amperes. The fuse or circuit breaker should hold indefinitely at 15 amperes, but the NEC recognizes that allowing 100% of rated current is never a good idea, since wiring in attics may already be in a very hot environment. Therefore, the NEC requires that no ordinary branch circuit be permitted to be loaded more than 80% of the circuit rating. That's where the 12 and 16 ampere limits come from. Another issue is voltage drop, which is directly proportional to circuit loading. Circuits that are loaded to 100% of rating will probably have excessive voltage drop, which leads to inefficient operation. Good electrical design dictates that the wire size be increased for long runs, to keep the voltage drop below 3%. Moreover, an adequate electrical supply system should never experience more than 80% loading of any circuit. Very heavy single loads should have a dedicated branch circuit of suitable capacity, with a single outlet. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Thursday, July 17, 2008 8:07 PM To: Repeater-Builder@yahoogroups.com Subject: Re: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Eric, Question about the outlets. Is the only reason one cannot get more than 12 amp from a 15 amp outlet is the rules so if one is designing a power system if more than 12 amps is required one has to put in 20 amp outlet to meet code??? I would think one could get 15 amps due to the breaker able to handle it or are 15 amp breakers designed to trip at just above 12 amps??? 73, ron, n9ee/r From: Eric Lemmon [EMAIL PROTECTED] mailto:wb6fly%40verizon.net Date: 2008/07/17 Thu PM 11:00:53 EDT To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Wayne, That is not exactly true. An outlet rated at 15 amperes cannot have any load greater than 12 amperes plugged into it. An outlet rated at 20 amperes cannot have any load greater than 16 amperes plugged into it. This is clearly stated in Article 210.21(B)(2) of the National Electrical Code. A device that actually draws 20 amperes at 120 VAC must be plugged into an outlet and branch circuit rated at 30 amperes. When load currents exceed 16 amperes at 120 VAC, it's time to consider a branch circuit rated at 208 or 240 VAC. Most repeaters and high-power PAs have optional connections to enable operation on 208 or 240 VAC. Keep in mind that there is no such voltage as 220 although that obsolete figure is still in common usage. The nominal single-phase voltage supplied to residences is 120/240 VAC, while the electrical supply to light commercial, apartment complexes, and condos is usually 120/208 VAC derived from two phases of a three-phase distribution system. I mention this because a fellow Ham who now lives in a large apartment complex mentioned to me
[Repeater-Builder] Re: RadioShack Recalls Power Supplies
That's the problem. Nothing/nobody delivers what it/they're rated/expected to deliver. I do not consider it acceptable for shysters to shirk their responsibility by citing engineering practice as an excuse. Tom --- In Repeater-Builder@yahoogroups.com, Gerald Pelnar [EMAIL PROTECTED] wrote: Eric, Nice explanation. Good engineering practice. However, circuits can be loaded 100% as long as it is not a continuous load (operated for more than 4 hours). Vacuum cleaners (not likely to run 4 hours at a time) are more likely limited to 12 amps due to minimum circuit opacity for motor loads requiring an additional 25% of the load, so as to not overload a 15 amp circuit. I apologize to all the non electricians reading this. Due to the amazingly confusing way the NEC is written, it's hard for electricians to pass up a good code argument. :) Once again, very good engineering practice, Eric, in spite of the code details. Gerald Pelnar WD0FYF McPherson, Ks - Original Message - From: Eric Lemmon [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Thursday, July 17, 2008 10:47 PM Subject: RE: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Ron, That is a good question. The answer is that one is not supposed to connect any load greater than 12 amperes to an outlet rated at 15 amperes, that is, a NEMA 5-15R receptacle. The NEC allows two or more 15-ampere-rated outlets to be installed on a 20-ampere branch circuit (wired with 12 AWG conductors and a 20A fuse or circuit breaker), but the limit of 12 amperes on each outlet still applies. Proof of this restriction is evident in the vacuum cleaner wars of a decade or so ago. Hoover came out with a vacuum cleaner with 7 amperes of cleaning power. Then Bissel came out with a unit claiming 9 amperes of cleaning power. Other vacuum cleaner makers entered the fray until all of the brands had units with 12 amperes of cleaning power. The reason that nobody offered a unit with 13 amperes of cleaning power is because they would then have to equip that unit with a NEMA 5-20P plug and at least a 14/3 power cord. Most older homes do not have NEMA 5-20R outlets, so such a vacuum cleaner could not be plugged in to the outlets in most homes. Besides, there is no credibility to a laughable rating of cleaning power expressed in amperes! That is about as silly as claiming that a mobile radio has 13.8 volts of talk power! Back to your second question. By definition, a 15-ampere-rated branch circuit has circuit conductors of #14 AWG or larger, and is protected by a fuse or circuit breaker rated at 15 amperes. The fuse or circuit breaker should hold indefinitely at 15 amperes, but the NEC recognizes that allowing 100% of rated current is never a good idea, since wiring in attics may already be in a very hot environment. Therefore, the NEC requires that no ordinary branch circuit be permitted to be loaded more than 80% of the circuit rating. That's where the 12 and 16 ampere limits come from. Another issue is voltage drop, which is directly proportional to circuit loading. Circuits that are loaded to 100% of rating will probably have excessive voltage drop, which leads to inefficient operation. Good electrical design dictates that the wire size be increased for long runs, to keep the voltage drop below 3%. Moreover, an adequate electrical supply system should never experience more than 80% loading of any circuit. Very heavy single loads should have a dedicated branch circuit of suitable capacity, with a single outlet. 73, Eric Lemmon WB6FLY
Re: [Repeater-Builder] Motorola High band base (tube type)
Poor choice of words. I visited my aunt and uncle in Evanston most summers. My uncle was a physician and my aunt a volunteer at the local hospital. There were some interesting stories told over dinner As to radio, I understood it the 10-85 repeater dated back to pre-600KHz days, and when the split was standardized on 600KHz they just added a 6.25 receiver. A bunch of the regular users were from Moto. There were voting receivers all over the place. One comment was that some day they would put up a second repeater in Schamburg just to normalize the pairs. Mike WA6ILQ At 05:22 PM 07/17/08, you wrote: Mike Are you saying that a bunch of techs and engineers from Motoroa used to hang out at your aunt's house? in Evanston? Strange. First I ever heard of that. AC George Henry [EMAIL PROTECTED] wrote: - Original Message - From: Mike Morris WA6ILQ mailto:wa6ilq%40arrl.net[EMAIL PROTECTED] To: mailto:Repeater-Builder%40yahoogroups.comRepeater-Builder@yahoogroups.com Sent: Thursday, July 17, 2008 1:55 PM Subject: Re: [Repeater-Builder] Motorola High band base (tube type) At 11:05 AM 07/17/08, you wrote: [snip] Is the 146.85 repeater still there in Chicago? With the 146.10 input? Bach in my teenage years I used to visit my aunt in Evanston for a week or two every summer, and a bunch of techs and engineers from Motorola hung out there. Mike WA6ILQ I'd have to check... there's a 146.85 (MAPS) repeater listed on the CARMA site, but it doesn't list the input frequency. I'll check the IL Repeater Association website see if it's listed. 73, George, KA3HSW / WQGJ413
[Repeater-Builder] Re: RadioShack Recalls Power Supplies
Besides, there is no credibility to a laughable rating of cleaning power expressed in amperes! That is about as silly as claiming that a mobile radio has 13.8 volts of talk power Not exactly. You can see that the vacuum is designed for 120 volt operation (plus or minus) and they tell you the maximum current, therefore you have an approximate volt-amp rating for the motor. Assuming the power factor of the small motors is fairly similar (I don't know that but I would guess they are) you now have an APPROXIMATION of the amount of work the motor can do. In the case of the 13.8 volts, no other information is given. You therefore have NO idea of the input power of the transmitter, etc. Of course, in the case of the vacuum, impeller design, housing design, air flow routing, and numerous other factors come in to play but, short of an industry standard rating, it's better than nothing. Tom -- In Repeater-Builder@yahoogroups.com, Eric Lemmon [EMAIL PROTECTED] wrote: Ron, That is a good question. The answer is that one is not supposed to connect any load greater than 12 amperes to an outlet rated at 15 amperes, that is, a NEMA 5-15R receptacle. The NEC allows two or more 15-ampere-rated outlets to be installed on a 20-ampere branch circuit (wired with 12 AWG conductors and a 20A fuse or circuit breaker), but the limit of 12 amperes on each outlet still applies. Proof of this restriction is evident in the vacuum cleaner wars of a decade or so ago. Hoover came out with a vacuum cleaner with 7 amperes of cleaning power. Then Bissel came out with a unit claiming 9 amperes of cleaning power. Other vacuum cleaner makers entered the fray until all of the brands had units with 12 amperes of cleaning power. The reason that nobody offered a unit with 13 amperes of cleaning power is because they would then have to equip that unit with a NEMA 5-20P plug and at least a 14/3 power cord. Most older homes do not have NEMA 5-20R outlets, so such a vacuum cleaner could not be plugged in to the outlets in most homes. Besides, there is no credibility to a laughable rating of cleaning power expressed in amperes! That is about as silly as claiming that a mobile radio has 13.8 volts of talk power! Back to your second question. By definition, a 15-ampere-rated branch circuit has circuit conductors of #14 AWG or larger, and is protected by a fuse or circuit breaker rated at 15 amperes. The fuse or circuit breaker should hold indefinitely at 15 amperes, but the NEC recognizes that allowing 100% of rated current is never a good idea, since wiring in attics may already be in a very hot environment. Therefore, the NEC requires that no ordinary branch circuit be permitted to be loaded more than 80% of the circuit rating. That's where the 12 and 16 ampere limits come from. Another issue is voltage drop, which is directly proportional to circuit loading. Circuits that are loaded to 100% of rating will probably have excessive voltage drop, which leads to inefficient operation. Good electrical design dictates that the wire size be increased for long runs, to keep the voltage drop below 3%. Moreover, an adequate electrical supply system should never experience more than 80% loading of any circuit. Very heavy single loads should have a dedicated branch circuit of suitable capacity, with a single outlet. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Thursday, July 17, 2008 8:07 PM To: Repeater-Builder@yahoogroups.com Subject: Re: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Eric, Question about the outlets. Is the only reason one cannot get more than 12 amp from a 15 amp outlet is the rules so if one is designing a power system if more than 12 amps is required one has to put in 20 amp outlet to meet code??? I would think one could get 15 amps due to the breaker able to handle it or are 15 amp breakers designed to trip at just above 12 amps??? 73, ron, n9ee/r From: Eric Lemmon [EMAIL PROTECTED] mailto:wb6fly%40verizon.net Date: 2008/07/17 Thu PM 11:00:53 EDT To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Wayne, That is not exactly true. An outlet rated at 15 amperes cannot have any load greater than 12 amperes plugged into it. An outlet rated at 20 amperes cannot have any load greater than 16 amperes plugged into it. This is clearly stated in Article 210.21(B)(2) of the National Electrical Code. A device that actually draws 20 amperes at 120 VAC must be plugged into an outlet and branch circuit rated at 30 amperes. When load currents exceed 16 amperes at 120 VAC, it's time to consider a branch circuit rated at 208 or 240 VAC. Most repeaters and high-power PAs have optional connections to enable operation on 208 or
Re: RE: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies
Eric, Thanks for the info. Yes we all went thru the vacuum cleaner current junk days. I guess was good marketing tool. Now it is how quiet and how it will clean your home air. Still little about how well it will clean what you want it for except for picking up MMs and bolts. The bowling ball pick up is still hanging in there, hi. So we can get 15 Amps out of a 15 amp 14-2 w/G circuit if needed. That was my question. The safety factor is my concern. We all know we should normally not load 100%, but how does one know in typical life. Most users don't even know what load is let alone how much it is. That is where the NEC comes in to give some assurance it is safe, not workable, but safe and that is how it should be. 73, ron, n9ee/r From: Eric Lemmon [EMAIL PROTECTED] Date: 2008/07/17 Thu PM 11:47:03 EDT To: Repeater-Builder@yahoogroups.com Subject: RE: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Ron, That is a good question. The answer is that one is not supposed to connect any load greater than 12 amperes to an outlet rated at 15 amperes, that is, a NEMA 5-15R receptacle. The NEC allows two or more 15-ampere-rated outlets to be installed on a 20-ampere branch circuit (wired with 12 AWG conductors and a 20A fuse or circuit breaker), but the limit of 12 amperes on each outlet still applies. Proof of this restriction is evident in the vacuum cleaner wars of a decade or so ago. Hoover came out with a vacuum cleaner with 7 amperes of cleaning power. Then Bissel came out with a unit claiming 9 amperes of cleaning power. Other vacuum cleaner makers entered the fray until all of the brands had units with 12 amperes of cleaning power. The reason that nobody offered a unit with 13 amperes of cleaning power is because they would then have to equip that unit with a NEMA 5-20P plug and at least a 14/3 power cord. Most older homes do not have NEMA 5-20R outlets, so such a vacuum cleaner could not be plugged in to the outlets in most homes. Besides, there is no credibility to a laughable rating of cleaning power expressed in amperes! That is about as silly as claiming that a mobile radio has 13.8 volts of talk power! Back to your second question. By definition, a 15-ampere-rated branch circuit has circuit conductors of #14 AWG or larger, and is protected by a fuse or circuit breaker rated at 15 amperes. The fuse or circuit breaker should hold indefinitely at 15 amperes, but the NEC recognizes that allowing 100% of rated current is never a good idea, since wiring in attics may already be in a very hot environment. Therefore, the NEC requires that no ordinary branch circuit be permitted to be loaded more than 80% of the circuit rating. That's where the 12 and 16 ampere limits come from. Another issue is voltage drop, which is directly proportional to circuit loading. Circuits that are loaded to 100% of rating will probably have excessive voltage drop, which leads to inefficient operation. Good electrical design dictates that the wire size be increased for long runs, to keep the voltage drop below 3%. Moreover, an adequate electrical supply system should never experience more than 80% loading of any circuit. Very heavy single loads should have a dedicated branch circuit of suitable capacity, with a single outlet. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Thursday, July 17, 2008 8:07 PM To: Repeater-Builder@yahoogroups.com Subject: Re: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Eric, Question about the outlets. Is the only reason one cannot get more than 12 amp from a 15 amp outlet is the rules so if one is designing a power system if more than 12 amps is required one has to put in 20 amp outlet to meet code??? I would think one could get 15 amps due to the breaker able to handle it or are 15 amp breakers designed to trip at just above 12 amps??? 73, ron, n9ee/r From: Eric Lemmon [EMAIL PROTECTED] mailto:wb6fly%40verizon.net Date: 2008/07/17 Thu PM 11:00:53 EDT To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Wayne, That is not exactly true. An outlet rated at 15 amperes cannot have any load greater than 12 amperes plugged into it. An outlet rated at 20 amperes cannot have any load greater than 16 amperes plugged into it. This is clearly stated in Article 210.21(B)(2) of the National Electrical Code. A device that actually draws 20 amperes at 120 VAC must be plugged into an outlet and branch circuit rated at 30 amperes. When load currents exceed 16 amperes at 120 VAC, it's time to consider a branch circuit rated at 208 or 240 VAC. Most repeaters and high-power PAs have optional connections to enable operation on 208 or 240 VAC. Keep in mind that there is no such voltage as 220 although that obsolete figure is
Re: [Repeater-Builder] Re: RadioShack Recalls Power Supplies
Well stated Ron! Ron Wright wrote: Eric, Thanks for the info. Yes we all went thru the vacuum cleaner current junk days. I guess was good marketing tool. Now it is how quiet and how it will clean your home air. Still little about how well it will clean what you want it for except for picking up MMs and bolts. The bowling ball pick up is still hanging in there, hi. So we can get 15 Amps out of a 15 amp 14-2 w/G circuit if needed. That was my question. The safety factor is my concern. We all know we should normally not load 100%, but how does one know in typical life. Most users don't even know what load is let alone how much it is. That is where the NEC comes in to give some assurance it is safe, not workable, but safe and that is how it should be. 73, ron, n9ee/r From: Eric Lemmon [EMAIL PROTECTED] Date: 2008/07/17 Thu PM 11:47:03 EDT To: Repeater-Builder@yahoogroups.com Subject: RE: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Ron, That is a good question. The answer is that one is not supposed to connect any load greater than 12 amperes to an outlet rated at 15 amperes, that is, a NEMA 5-15R receptacle. The NEC allows two or more 15-ampere-rated outlets to be installed on a 20-ampere branch circuit (wired with 12 AWG conductors and a 20A fuse or circuit breaker), but the limit of 12 amperes on each outlet still applies. Proof of this restriction is evident in the vacuum cleaner wars of a decade or so ago. Hoover came out with a vacuum cleaner with 7 amperes of cleaning power. Then Bissel came out with a unit claiming 9 amperes of cleaning power. Other vacuum cleaner makers entered the fray until all of the brands had units with 12 amperes of cleaning power. The reason that nobody offered a unit with 13 amperes of cleaning power is because they would then have to equip that unit with a NEMA 5-20P plug and at least a 14/3 power cord. Most older homes do not have NEMA 5-20R outlets, so such a vacuum cleaner could not be plugged in to the outlets in most homes. Besides, there is no credibility to a laughable rating of cleaning power expressed in amperes! That is about as silly as claiming that a mobile radio has 13.8 volts of talk power! Back to your second question. By definition, a 15-ampere-rated branch circuit has circuit conductors of #14 AWG or larger, and is protected by a fuse or circuit breaker rated at 15 amperes. The fuse or circuit breaker should hold indefinitely at 15 amperes, but the NEC recognizes that allowing 100% of rated current is never a good idea, since wiring in attics may already be in a very hot environment. Therefore, the NEC requires that no ordinary branch circuit be permitted to be loaded more than 80% of the circuit rating. That's where the 12 and 16 ampere limits come from. Another issue is voltage drop, which is directly proportional to circuit loading. Circuits that are loaded to 100% of rating will probably have excessive voltage drop, which leads to inefficient operation. Good electrical design dictates that the wire size be increased for long runs, to keep the voltage drop below 3%. Moreover, an adequate electrical supply system should never experience more than 80% loading of any circuit. Very heavy single loads should have a dedicated branch circuit of suitable capacity, with a single outlet. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Thursday, July 17, 2008 8:07 PM To: Repeater-Builder@yahoogroups.com Subject: Re: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Eric, Question about the outlets. Is the only reason one cannot get more than 12 amp from a 15 amp outlet is the rules so if one is designing a power system if more than 12 amps is required one has to put in 20 amp outlet to meet code??? I would think one could get 15 amps due to the breaker able to handle it or are 15 amp breakers designed to trip at just above 12 amps??? 73, ron, n9ee/r From: Eric Lemmon [EMAIL PROTECTED] mailto:wb6fly%40verizon.net Date: 2008/07/17 Thu PM 11:00:53 EDT To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Wayne, That is not exactly true. An outlet rated at 15 amperes cannot have any load greater than 12 amperes plugged into it. An outlet rated at 20 amperes cannot have any load greater than 16 amperes plugged into it. This is clearly stated in Article 210.21(B)(2) of the National Electrical Code. A device that actually draws 20 amperes at 120 VAC must be plugged into an outlet and branch circuit rated at 30 amperes. When load currents exceed 16 amperes at 120 VAC, it's time to consider a branch circuit rated at 208 or 240 VAC. Most repeaters and high-power PAs have optional connections to enable operation on 208 or 240 VAC. Keep in
Re: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies
breakers are ratedat '80%' it's not the wire or outlets that determine load allowed, but (breaker rating) x 80% - Original Message - From: Ron Wright To: Repeater-Builder@yahoogroups.com Sent: Thursday, July 17, 2008 10:07 PM Subject: Re: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Eric, Question about the outlets. Is the only reason one cannot get more than 12 amp from a 15 amp outlet is the rules so if one is designing a power system if more than 12 amps is required one has to put in 20 amp outlet to meet code??? I would think one could get 15 amps due to the breaker able to handle it or are 15 amp breakers designed to trip at just above 12 amps??? 73, ron, n9ee/r From: Eric Lemmon [EMAIL PROTECTED] Date: 2008/07/17 Thu PM 11:00:53 EDT To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: RadioShack Recalls Power Supplies Wayne, That is not exactly true. An outlet rated at 15 amperes cannot have any load greater than 12 amperes plugged into it. An outlet rated at 20 amperes cannot have any load greater than 16 amperes plugged into it. This is clearly stated in Article 210.21(B)(2) of the National Electrical Code. A device that actually draws 20 amperes at 120 VAC must be plugged into an outlet and branch circuit rated at 30 amperes. When load currents exceed 16 amperes at 120 VAC, it's time to consider a branch circuit rated at 208 or 240 VAC. Most repeaters and high-power PAs have optional connections to enable operation on 208 or 240 VAC. Keep in mind that there is no such voltage as 220 although that obsolete figure is still in common usage. The nominal single-phase voltage supplied to residences is 120/240 VAC, while the electrical supply to light commercial, apartment complexes, and condos is usually 120/208 VAC derived from two phases of a three-phase distribution system. I mention this because a fellow Ham who now lives in a large apartment complex mentioned to me that his 500 watt rig that worked fine in his former home was not putting out full power at his new location. The cause was revealed when he measured his line-to-line voltage as close to 208 VAC. His power amplifier was rated for 240 VAC, but was starving when fed 87% of its design voltage. A commercially-available boost transformer was installed to give him a true 240 VAC supply. Problem solved. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Wayne Sent: Thursday, July 17, 2008 11:01 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: RadioShack Recalls Power Supplies To properly plug in an item that is a 20 amp draw. etc., one should install a 20 amp outlet. This can be single or duplex, and is readily spotted (if dual purpose) by the fact that one side will be flat instead of vertical, or have both horizontal and vertical on that side. the flat/horizontal is on the neutral side. Not to be confused with a similar looking outlet for 250 volts, which has two flats , and one has vertical as well on the left side, looking at the front with the ground hole down. Anyway, there are oulets made for 20 or more amps, which are different than the 15 amp common outlets. local ordinances can often be more stringent than even the NEC codes. of course, if you are running a high power repeater, you would probably wish to put it on a circuit breaker by itself. But ordinary house wiring normally has several outlets wired in series from one breaker, and is NEC approved that way. Shop and Industrial become another matter, ha ha ha... Wayne WA2YNE On Sun, 06 Jul 2008 20:08:33 -0500, Bruce Bagwell [EMAIL PROTECTED] wrote: I figured that was A local code, not NEC. The only reason I can think of for that requirement is the ampacity of the 12 or 14 ga wires. While we all know, in actual use, 2 or more outlets strung along will not all have 15 amp or higher loads in EACH outlet. However, theoretically, each outlet could have A 20 amp load plugged into it.That is probably why some pencil pusher decided each outlet needs its own wire. (Never mind the fact the breaker would trip regardless of what is plugged into each outlet or the number of wires leading to said outlets, but that's another crazy thread) As for the Breaker Box, I would assume each also has its own breaker. Trying to stuff more than one wire into A breaker would more fun than I care to have. Bruce KE5TPN -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ Yahoo! Groups Links Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. No virus
[Repeater-Builder] PL Problem
I need some suggestions. It seems that my users that have newer Motorola Astro series radios have a problem on my Micor UHF repeater where the PL does not always open up their radios. It seems that it's only Astro type radios that have the problem. I have the PL Deveation set at 1K. It's generated internally on the uni-chassis TX PL board. I have 2 GP-300's, 1 MAxtrac, 1GM300, a Yeasu dual band Mobile and a Radio Shack HTX-404 (With an MDC board installed it in! I actually love that little radio) and None of them have any problems decoding the PL. So what's up with the new stuff? It it really picky? what else should I check? Thanks!! Tom W9SRV P.S.- I told them all to buy old radios and be done with it. Besides the TX audio out of the new stuff sucks anyways, IMHO, unless you like listening to over-processed crap ;)
[Repeater-Builder] Motorola GM340 Rear ACC connector
Hi everyone, I am trying to source a couple of connectors that will fit the rear acc connector of a Motorola GM340, and find the pinout details, as I am looking to use one of these radio's to provide an internet link into our local repeater. Would be grateful if anyone could give me details of where I could source a couple from, and also the pinout details. Thanks Allan MM1BJP
Re: [Repeater-Builder] FT-857 Remote Base w/o Control Head, Control Head Available?
Hi Robin, You should be able to get the control head as a spare part from any Vertex Standard dealer. Let me know if you have any problems. Regards _ Gareth Bennett (Technical Operations Manager) Signals New Zealand Ltd Direct Dial: (++64) 34 250 895 Freephone: (0800) 4 VERTEX Cellular: (0274) 588 377 [EMAIL PROTECTED] This email is confidential, if you received this message in error, or you are not the intended recipient, please return it to the sender and destroy any copies. Thank you. - Original Message - From: Robin Midgett To: Repeater-Builder@yahoogroups.com Sent: Saturday, July 19, 2008 2:32 AM Subject: [Repeater-Builder] FT-857 Remote Base w/o Control Head, Control Head Available? Hi, Do any of you know if a Yaesu FT-857D will operate as a remote base without the control head? The control head of my 857 was stolen from my vehicle last week; just exploring options. If any of you know of a control head that may be available, perhaps from a damaged 857, I'd like to acquire it. Yaesu doesn't sell the control heads separately. Thanks, Robin
Re: [Repeater-Builder] FT-857 Remote Base w/o Control Head, Control Head Available?
From what I know about that rig (i own and use one) it must have head to function. Robin Midgett wrote: Hi, Do any of you know if a Yaesu FT-857D will operate as a remote base without the control head? The control head of my 857 was stolen from my vehicle last week; just exploring options. If any of you know of a control head that may be available, perhaps from a damaged 857, I'd like to acquire it. Yaesu doesn't sell the control heads separately. Thanks, Robin Yahoo! Groups Links
RE: [Repeater-Builder] Switching a Repeater Betwen AC Sources
The primary purpose of the equipment grounding conductor (green wire) is to provide a low-impedance path for fault current on a branch circuit. The lowest-possible impedance is realized only when the EGC is routed alongside the phase conductor. Article 250.24(C)(1) states: This conductor shall be routed with the phase conductor... I didn't quote the entire sentence, because it is very long. I understand that. What I was saying is that isn't the *only* ground path. You're almost guaranteed to have multiple ground fault paths, therefore EGC's from both systems are already tied together by virtue of those other paths. Even if you didn't intentionally jumper the EGC's together, if you had one device plugged into one outlet and another plugged into another outlet and both devices mounted in the same rack (or, even just sitting on top of each other), the EGC's will be electrically joined through the units' metal cabinet exteriors. The reason for keeping the equipment grounding conductors separate is very simple; we are talking about a hospital, not some ordinary radio shack. The critical (red) buss likely feeds catheter labs, dialysis machines, mechanical respirators, and similar equipment that is connected to human bodies. Even a few milliamperes of stray current flowing through a grounding conductor may take a side trip through a patient's heart and kill them. Well, now we're getting into a completely different topic. Line powered medical equipment is wholly isolated from the patient. While I'm no expert on the subject, there's something called the isolation barrier which wholly isolates the patient from the electrical system. One of the previous posters suggested putting the computer on the white buss, with the repeater on the red buss. That's a good idea, but be careful to use a fiber-optic link to pass data between them, else the two devices will have a common ground connection through the data cable's shield. Depending on what the interface is between the two, that may or may not be necessary. Twisted pair Ethernet is transformer-coupled, so no additional isolation is necessary (just don't use shielded cable). For simple things like control logic (PTT, COR, whatever), just use an optocoupler. For audio, transformers. --- Jeff WN3A
[Repeater-Builder] Andrews jumpers and connectors
I've just gotten a SUV load of Andrews jumpers and some connectors. Email off list with your needs and we will see if it's in stock.Ronny K4RJJ
[Repeater-Builder] Mastr Professional Strip Covers
I want to locate the station Tx and Rx top and bottom strip covers with the meter plug on the top cover of each for a 150 MHz Tx and Rx and a 450 MHz Tx and Rx. If anybody has these 4 covers and would be willing to pitch them my way, please contact me direct. I do not want the Tx or Rx strips, just the covers that are used in the base station configuration. Thanks Fred W5VAY
Re: [Repeater-Builder] PL Problem
tgundo2003 wrote: It seems that my users that have newer Motorola Astro series radios have a problem on my Micor UHF repeater where the PL does not always open up their radios. It seems that it's only Astro type radios that have the problem. Do they decode PL properly from anything other than your repeater? (Simplex -- have someone transmit on the output with the right tone so they're not changing channels, in case they programmed the rigs wrong.) I have the PL Deveation set at 1K. It's generated internally on the uni-chassis TX PL board. Sounds kinda high to me. Who wants to listen to CTCSS on all the rigs that don't filter it well/or at all? Many radios I've tested with will open consistently as low as 300, but for most rigs to decode, 650 seems a good compromise. Maybe you're flat-topping something in the PL-generation circuit and the newer rigs are looking for the whole waveform instead of zero-crossings. Have you looked at it on a scope? I'd start with proving their radios work correctly on the programmed channel for your repeater first. Nate WY0X
RE: [Repeater-Builder] PL Problem
Isn't 1K a little hot for PL tone? David -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of tgundo2003 Sent: Friday, July 18, 2008 7:56 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] PL Problem I need some suggestions. It seems that my users that have newer Motorola Astro series radios have a problem on my Micor UHF repeater where the PL does not always open up their radios. It seems that it's only Astro type radios that have the problem. I have the PL Deveation set at 1K. It's generated internally on the uni-chassis TX PL board. I have 2 GP-300's, 1 MAxtrac, 1GM300, a Yeasu dual band Mobile and a Radio Shack HTX-404 (With an MDC board installed it in! I actually love that little radio) and None of them have any problems decoding the PL. So what's up with the new stuff? It it really picky? what else should I check? Thanks!! Tom W9SRV P.S.- I told them all to buy old radios and be done with it. Besides the TX audio out of the new stuff sucks anyways, IMHO, unless you like listening to over-processed crap ;)
Re: RE: [Repeater-Builder] PL Problem
PL is usually aroung 800 Hz. 1 K little high, but should not cause a problem unless the problem radio's PL circuits are being over driven. I would get the problem radios on a service monitor. Some of the IC PL units, which probably is what is in these radios, and there might be a problem with them not being on PL freq. Generate the input rcv signal with PL from the service monitor and see how far off PL tone freq you can be. Might find they are on the edge decoding sometimes and not others. Also could verify if receivers have a sen problem. With radios in PL it is often harder to tell if signal is fading since PL cuts in and out and cannot open sq for this test. I would want to verify problem receivers are working before I tore into the base/repeater. 73, ron, n9ee/r From: David Murman [EMAIL PROTECTED] Date: 2008/07/18 Fri PM 07:49:19 EDT To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] PL Problem Isn’t1K a little hot for PL tone? David -Original Message- From:Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of tgundo2003 Sent: Friday, July 18, 2008 7:56AM To:Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] PLProblem I need some suggestions. It seems that my users that have newer Motorola Astro series radios have a problem on my Micor UHF repeater where the PL does not always open up their radios. It seems that it's only Astro type radios that have the problem. I have the PL Deveation set at 1K. It's generated internally on the uni-chassis TX PL board. I have 2 GP-300's, 1 MAxtrac, 1GM300, a Yeasu dual band Mobile and a Radio Shack HTX-404 (With an MDC board installed it in! I actually love that little radio) and None of them have any problems decoding the PL. So what's up with the new stuff? It it really picky? what else should I check? Thanks!! Tom W9SRV P.S.- I told them all to buy old radios and be done with it. Besides the TX audio out of the new stuff sucks anyways, IMHO, unless you like listening to over-processed crap ;) Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
[Repeater-Builder] NBC Dateline story on Tower Climbers
For those interested in seeing what tower climbers go through. DATELINE NBC ANNOUNCEMENT - final.doc DATELINE PRESENTS TOWER DOGS - MONDAY, JULY 21 July 16, 2008 DATELINE PRESENTS TOWER DOGS -- A NEVER-BEFORE- SEEN LOOK AT THE MOST DANGEROUS JOB IN AMERICA -- MONDAY, JULY 21 AT 10 PM (New York) - July 16, 2008 - An upcoming Dateline Presents takes a never-before-seen journey into the perilous world of the tower climbers who work on the frontlines of America's high-tech communications system. They scale heights of up to 2,000 feet, in all types of weather, to install, maintain, and upgrade cell phone, Internet, and broadcast towers coast to coast. And according to figures cited by OSHA, these so-called tower dogs have the highest death rate per capita of any occupation in the country. The hour-long broadcast goes up close and personal to give a no- holds-barred look at tower dogs' lives - up in the air and on the ground. We experience their on-the-job tension and watch them work hard, play hard, and mourn when they lose one of their own. In a twist on all the dangerous-job programs viewers have already seen, Tower Dogs follows an unusual subcontract crew boss: a woman named X XXX, a single mom, former cheerleader, and the person keeping her tough-guy charges in one piece. There are approximately 9,500 tower climbers working at any given time, and they spend about 300 days per year on the road. A Dateline team worked with veteran tower dog Doug Delaney for four months documenting this group of tower climbers as they worked their way through 40 towns and cities in 24 states. During this time there were seven fatalities nationwide, including five deaths in a 12-day period in April. Tower Dogs airs on Monday, July 21st at 10:00 PM/ET. David Corvo is the executive producer.
Re: RE: [Repeater-Builder] PL Problem
I second the service monitor check and further suggest that one have the software to program the radio and the tuner software on standby in the PC. While 1K of PL deviation is high it should be decoded unless the radio has been programmed for say, 12.5k bandwidth. Have a look at the programming and you will probably be able to find more of what is going on. Milt N3LTQ - Original Message - From: Ron Wright [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Friday, July 18, 2008 8:10 PM Subject: Re: RE: [Repeater-Builder] PL Problem PL is usually aroung 800 Hz. 1 K little high, but should not cause a problem unless the problem radio's PL circuits are being over driven. I would get the problem radios on a service monitor. Some of the IC PL units, which probably is what is in these radios, and there might be a problem with them not being on PL freq. Generate the input rcv signal with PL from the service monitor and see how far off PL tone freq you can be. Might find they are on the edge decoding sometimes and not others. Also could verify if receivers have a sen problem. With radios in PL it is often harder to tell if signal is fading since PL cuts in and out and cannot open sq for this test. I would want to verify problem receivers are working before I tore into the base/repeater. 73, ron, n9ee/r From: David Murman [EMAIL PROTECTED] Date: 2008/07/18 Fri PM 07:49:19 EDT To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] PL Problem Isn’t1K a little hot for PL tone? David -Original Message- From:Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of tgundo2003 Sent: Friday, July 18, 2008 7:56AM To:Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] PLProblem I need some suggestions. It seems that my users that have newer Motorola Astro series radios have a problem on my Micor UHF repeater where the PL does not always open up their radios. It seems that it's only Astro type radios that have the problem. I have the PL Deveation set at 1K. It's generated internally on the uni-chassis TX PL board. I have 2 GP-300's, 1 MAxtrac, 1GM300, a Yeasu dual band Mobile and a Radio Shack HTX-404 (With an MDC board installed it in! I actually love that little radio) and None of them have any problems decoding the PL. So what's up with the new stuff? It it really picky? what else should I check? Thanks!! Tom W9SRV P.S.- I told them all to buy old radios and be done with it. Besides the TX audio out of the new stuff sucks anyways, IMHO, unless you like listening to over-processed crap ;) Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. Yahoo! Groups Links
Re: [Repeater-Builder] PL Problem
I believe the Motorola standard is 750 Hz for deviation on PL for MICORS. That's what I use on my system, and it hasn't failed me yet. YMMV. Don, KD9PT - Original Message - From: David Murman To: Repeater-Builder@yahoogroups.com Sent: Friday, July 18, 2008 6:49 PM Subject: RE: [Repeater-Builder] PL Problem Isn't 1K a little hot for PL tone? David -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of tgundo2003 Sent: Friday, July 18, 2008 7:56 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] PL Problem I need some suggestions. It seems that my users that have newer Motorola Astro series radios have a problem on my Micor UHF repeater where the PL does not always open up their radios. It seems that it's only Astro type radios that have the problem. I have the PL Deveation set at 1K. It's generated internally on the uni-chassis TX PL board. I have 2 GP-300's, 1 MAxtrac, 1GM300, a Yeasu dual band Mobile and a Radio Shack HTX-404 (With an MDC board installed it in! I actually love that little radio) and None of them have any problems decoding the PL. So what's up with the new stuff? It it really picky? what else should I check? Thanks!! Tom W9SRV P.S.- I told them all to buy old radios and be done with it. Besides the TX audio out of the new stuff sucks anyways, IMHO, unless you like listening to over-processed crap ;) !DSPAM:1016,48812b3f932333712038390!
Re: [Repeater-Builder] NBC Dateline story on Tower Climbers
A single Mom and a former cheerleader climbing 2000 foot towers? So, what happens when she gets to the top of the tower? A cheer? And at 200 feet, how does she keep tough-guy charges in one piece? This I gotta see. If she's pretty, maybe I'll consider joining her. Don, KD9PT - Original Message - From: Chris Huber [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Friday, July 18, 2008 7:26 PM Subject: [Repeater-Builder] NBC Dateline story on Tower Climbers For those interested in seeing what tower climbers go through. DATELINE NBC ANNOUNCEMENT - final.doc DATELINE PRESENTS TOWER DOGS - MONDAY, JULY 21 July 16, 2008 DATELINE PRESENTS TOWER DOGS -- A NEVER-BEFORE- SEEN LOOK AT THE MOST DANGEROUS JOB IN AMERICA -- MONDAY, JULY 21 AT 10 PM (New York) - July 16, 2008 - An upcoming Dateline Presents takes a never-before-seen journey into the perilous world of the tower climbers who work on the frontlines of America's high-tech communications system. They scale heights of up to 2,000 feet, in all types of weather, to install, maintain, and upgrade cell phone, Internet, and broadcast towers coast to coast. And according to figures cited by OSHA, these so-called tower dogs have the highest death rate per capita of any occupation in the country. The hour-long broadcast goes up close and personal to give a no- holds-barred look at tower dogs' lives - up in the air and on the ground. We experience their on-the-job tension and watch them work hard, play hard, and mourn when they lose one of their own. In a twist on all the dangerous-job programs viewers have already seen, Tower Dogs follows an unusual subcontract crew boss: a woman named X XXX, a single mom, former cheerleader, and the person keeping her tough-guy charges in one piece. There are approximately 9,500 tower climbers working at any given time, and they spend about 300 days per year on the road. A Dateline team worked with veteran tower dog Doug Delaney for four months documenting this group of tower climbers as they worked their way through 40 towns and cities in 24 states. During this time there were seven fatalities nationwide, including five deaths in a 12-day period in April. Tower Dogs airs on Monday, July 21st at 10:00 PM/ET. David Corvo is the executive producer. Yahoo! Groups Links !DSPAM:1016,488134af970771644115261!
Re: [Repeater-Builder] Mastr Professional Strip Covers
Fred, I have a complete Mastr Pro UHF repeater...I'd like to get rid of but it's in a desk mate cabinet and I want to keep the cabinet. This one has all the extra shielding for repeater use.. It can be had for the cost of the shippingprobably a transport truck or similar would be the best. 73 John VE3AMZ Waterloo, Ont - Original Message - From: Fred Seamans To: Repeater-Builder@yahoogroups.com Sent: Friday, July 18, 2008 5:03 PM Subject: [Repeater-Builder] Mastr Professional Strip Covers I want to locate the station Tx and Rx top and bottom strip covers with the meter plug on the top cover of each for a 150 MHz Tx and Rx and a 450 MHz Tx and Rx. If anybody has these 4 covers and would be willing to pitch them my way, please contact me direct. I do not want the Tx or Rx strips, just the covers that are used in the base station configuration. Thanks Fred W5VAY
RE: [Repeater-Builder] Switching a Repeater Betwen AC Sources
Jeff, Whether multiple ground paths exist is irrelevant. What the NEC requires is a direct, low-impedance fault return path for each branch circuit, considered individually. You cannot dispense with any ground paths because you think there exists alternate paths. While it is true that parallel paths may decrease the total impedance to a fault on any one branch circuit, that in no way constitutes license to eliminate a required grounding connection. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo Sent: Friday, July 18, 2008 7:50 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Switching a Repeater Betwen AC Sources The primary purpose of the equipment grounding conductor (green wire) is to provide a low-impedance path for fault current on a branch circuit. The lowest-possible impedance is realized only when the EGC is routed alongside the phase conductor. Article 250.24(C)(1) states: This conductor shall be routed with the phase conductor... I didn't quote the entire sentence, because it is very long. I understand that. What I was saying is that isn't the *only* ground path. You're almost guaranteed to have multiple ground fault paths, therefore EGC's from both systems are already tied together by virtue of those other paths. Even if you didn't intentionally jumper the EGC's together, if you had one device plugged into one outlet and another plugged into another outlet and both devices mounted in the same rack (or, even just sitting on top of each other), the EGC's will be electrically joined through the units' metal cabinet exteriors. The reason for keeping the equipment grounding conductors separate is very simple; we are talking about a hospital, not some ordinary radio shack. The critical (red) buss likely feeds catheter labs, dialysis machines, mechanical respirators, and similar equipment that is connected to human bodies. Even a few milliamperes of stray current flowing through a grounding conductor may take a side trip through a patient's heart and kill them. Well, now we're getting into a completely different topic. Line powered medical equipment is wholly isolated from the patient. While I'm no expert on the subject, there's something called the isolation barrier which wholly isolates the patient from the electrical system. One of the previous posters suggested putting the computer on the white buss, with the repeater on the red buss. That's a good idea, but be careful to use a fiber-optic link to pass data between them, else the two devices will have a common ground connection through the data cable's shield. Depending on what the interface is between the two, that may or may not be necessary. Twisted pair Ethernet is transformer-coupled, so no additional isolation is necessary (just don't use shielded cable). For simple things like control logic (PTT, COR, whatever), just use an optocoupler. For audio, transformers. --- Jeff WN3A
RE: [Repeater-Builder] PL Problem
Tom, The TIA-recommended standard deviation for CTCSS is 500 Hz on a 16K0F3E or 20K0F3E emission. Most CTCSS decoders can reliably detect tone deviated as low as 100 Hz. Any deviation greater than 500 Hz can be considered excessive. The HTX-404 is known for somewhat distorted (raspy) CTCSS tones, and that may be part of the problem. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of tgundo2003 Sent: Friday, July 18, 2008 5:56 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] PL Problem I need some suggestions. It seems that my users that have newer Motorola Astro series radios have a problem on my Micor UHF repeater where the PL does not always open up their radios. It seems that it's only Astro-type radios that have the problem. I have the PL deviation set at 1K. It's generated internally on the uni-chassis TX PL board. I have 2 GP-300's, 1 MaxTrac, 1 GM300, a Yaesu dual-band mobile and a Radio Shack HTX-404 (with an MDC board installed in it! I actually love that little radio) and none of them have any problems decoding the PL. So what's up with the new stuff? It it really picky? what else should I check? Thanks!! Tom W9SRV P.S.- I told them all to buy old radios and be done with it. Besides the TX audio out of the new stuff sucks anyways, IMHO, unless you like listening to over-processed crap ;)
RE: [Repeater-Builder] Harmoinic products
Hi Ron, and thanks for the reply. First off, the 904 signal is always there - and about 100kHz wide... A WIDE signal. Second, his machine is on 927.600/902.600. As you can see, the signal is 2 MHz up and still clobbering his receiver. Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of Ron Wright Mark, Usually desense is not harmonic or intermod related. It is caused by wide band noise from a transmitter. For harmonic it is just 2,3,4, etc times a frequency. For intermod it is nF1 +/- mF2 = your receive freq. In either case the problem will be there only when the offending txs are keyed up. Is the 904 tx keyed all the time? If not then you can determine if coming from it. Listen when it is unkeyed for the problem. If it is keyed all the time then I would put your friends tx on a dummy load with the remaining parts of the repeater, duplexer antenna receiver, connected. This can aid in determining if your tx is part of the problem. What are the freqs of your friends repeater? 73, ron, n9ee/r From: Mark OK, it’s been a while since I’ve had to compute this, so if my question seems a bit “trivial” or elementary in nature I apologize in advance. Yes, my math is rusty. ;-) Having said that, I’m trying to assist another ham with a desense problem he is experiencing on his 900 MHz ham-band repeater. He is experiencing about 10dB of receiver desense because of a signal centered at 904 MHz. He tells me this is verified with a Spectrum Analyzer and it is about 100 kHz wide... I take him at his word. The site he is at has no other 900 MHz at all, but it is a commercial site with other “stuff”, including various government and commercial frequencies, in use. What I am trying to do is see if we can figure out whether this might be a spur, or maybe some harmonic, that is being generated as the result of a mix of other products there. Can anyone provide me with the math necessary to try to determine whether this is a harmonic, using very rudimentary figures? (For example, I want to be able to use basic freqs like 150 MHz, 450 MHz, etc, to at least get us in the ball park.) Once we get close, then we can fine-tune the freq combinations to see if it is a mix product. Or if anyone has any ideas, I’m certainly open to suggestions. Thanks, Mark – N9WYS Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database: 270.5.1/1560 - Release Date: 7/18/2008 6:47 AM
RE: [Repeater-Builder] Switching a Repeater Betwen AC Sources
Jeff, Whether multiple ground paths exist is irrelevant. What the NEC requires is a direct, low-impedance fault return path for each branch circuit, considered individually. You cannot dispense with any ground paths because you think there exists alternate paths. While it is true that parallel paths may decrease the total impedance to a fault on any one branch circuit, that in no way constitutes license to eliminate a required grounding connection. 73, Eric Lemmon WB6FLY I KNOW! I'm not trying to eliminate the required EGC run along with the current-carrying conductors. What I'm asking is why you originally said that you should switch the EGC supplied by the two outlets rather than tying the two together. I had asked if there were any provisions in NEC that allowed for EGC's (whether from two different SDS's or otherwise) to ever be switched, as I can't recall there being any such case allowed in NEC. You replied that by tying EGC's together that you would create a new path whereby new, harful currents could flow. I replied that there always exist multiple EGC paths, whether desired or not, and in the instant case, there are, or would be, paths between the EGC's of the two systems whether or not you tied them together. So, my question remains, is there a case to be made where it is desirable, or even allowable, that the EGC can or should be switched? Let's assume that in the instant case (the hospital) that they are SDS's. --- Jeff WN3A
[Repeater-Builder] Re: NBC Dateline story on Tower Climbers
--- In Repeater-Builder@yahoogroups.com, Gmail - Kevin, Natalia, Stacey Rochelle [EMAIL PROTECTED] wrote: Just a shame some of us won't be able to see this interesting doco, not in the cont USA. Kevin, why would we not be able to see this in the USA? It's on NBC's Dateline, and I watch it often... VCR rolling (I still have one...!) Laryn K8TVZ
Re: [Repeater-Builder] Duplexer Tuning / Desense
Mike, that RG-8X is the first thing I would get rid of. It is typically only %95 covered in shield braid, and that is a path for a lot of leakage. The rule of thumb in the whole repeater cabinet is double shielded RG-214 or RG-142. That takes away a lot of paths for leakage to bypass your duplexer. 73 - Jim W5ZIT --- On Fri, 7/18/08, Mike Besemer (WM4B) [EMAIL PROTECTED] wrote: From: Mike Besemer (WM4B) [EMAIL PROTECTED] Subject: [Repeater-Builder] Duplexer Tuning / Desense To: Repeater-Builder@yahoogroups.com Date: Friday, July 18, 2008, 9:33 PM My club has been offered a sweet deal on a repeater site (free rent, free electricity, free antenna and feedline) and I’m trying to hurry to get a repeater on the air. We have a Kendecom Mark IV which was hit by lightning (through the phone line, not the antenna) which I’ve resurrected and interfaced with a CAT-1000 controller. The old cans (Decibel DB4060 – 4 cans total) had been in storage and were apparently used by another ham for experimentation after they were taken off line. I’d replaced the notch caps a couple of years ago because whoever was experimenting with them tightened them until they cracked. I’ve also disassembled them and made sure they were clean and had no signs of arching or other damage. They were originally tuned on 146.25/85 (but as I said, they’d been ‘played’ with) and I’m moving them to 145.11 (minus 600 KHz). I first tuned them with a signal generator per the DB Products instructions and they tuned in very well. The peaks were good on both sides and the notches were about -85 db, using my crude measuring system. Losses on the pass-band were less then 2 db (probably more like 1 db). This pre-tuning was done with an HP-8640 signal generator, a scope, and other miscellaneous goodies. Tonight I got a service monitor (HP-8920) from a buddy who works for the FAA. I set it to duplex and checked my peaks. They were very close to perfect already, but I managed to get the last little bit of RF through the pass-cavities. Next I set out to tune the notches. I was able to get decent notches, but apparently they are not deep enough (despite having measured -85 with the signal generator) because I still have about 15 db of desense. I’ve been through them 4 or 5 times tonight (until I’m sick of them) but that’s the best I can do. (I did discover that if I tune the receiver notch enough, I can pull the transmitter down to nothing!) I just reviewed (again) Kevin’s article on Repeater-Builder entitled ‘Getting the most from your Repeater System’, and the one thing I need to do yet is check for internal desense. I had to replace the Teflon-type cable which leads from the Mark IV transmitter to the back panel, and when I replaced it, all I had was some RG-8X. I’m (sort of) hoping that’s the problem, but I won’t know until I check. I can’t see where I’ve missed anything obvious, although tuning these types of duplexers is new to me. I spent 17 years in the Air Force working navigation and comm gear, so I’m pretty well versed in what I’m doing, but since this is a new venture for me, I’m certainly open to suggestions. I’ll check for internal desense tomorrow, but in the meantime if anybody has anything to add, please chime in. TIA, Mike WM4B Kathleen, GA ._,___
RE: [Repeater-Builder] Switching a Repeater Betwen AC Sources
Jeff, I understand and appreciate the nuances of your question. I guess what I am trying to convey, perhaps unsuccessfully, is that it is unwise to attempt to make a case for an exception to the NEC based upon conventional wisdom. I guess I'm not explaining myself well either then. I'm trying NOT to go against NEC. I don't believe NEC allows you to switch EGC as you originally proposed - that's the issue at hand. I'm not proposing that you eliminate the NEC-required EGC in any way, shape, or form, even though there likely exist many alternative ground paths capable of tripping the overcurrent device in the event of a fault even if the hard-wired EGC didn't exist. I was just pointing out that even if the two outlets are on two different SDS's, that the EGC's are already effectively tied together whether or not you hard-wired them together in the switching gizmo in the repeater rack. I believe that you are saying that if we assume that we have two SDS's, then we have two totally independent EGC's, and the two EGC's must not be allowed to be tied together, hence the need to switch the EGC's (as well as the hot and neutral) when switching between the sources, for if you don't, you will create a hazardous condition. That's where I started to disagree, which is what prompted me to ask if there is *any* situation where switching EGC is allowed in NEC, because I can't recall ever seeing anything like that in the past but I thought maybe you knew something I didn't. My advice is to always ask the AHJ (Authority Having Jurisdiction) to provide an interpretation in writing. His or her interpretation of the NEC will always trump that of a hospital electrician, or even a consulting engineer. The answer to your specific question varies, depending upon the opinion of the AHJ, and nothing I or you say or think will change that, I agree that the AHJ is the final word. But it's not necessarily an issue of the AHJ official's *interpretation* of NEC. There are plenty of AHJ's that have regulations that are more stringent than NEC, or less stringent than NEC, or in some cases, completely contradictory to NEC. --- Jeff WN3A
[Repeater-Builder] Re: Duplexer Tuning / Desense (DB-4060)
Preamp on the Receiver? Was the Receiver front-end aligned on the specific new frequency? Specific Receiver Model? Were the transmitter and any power amplifiers properly aligned? [The big questions...] Transmitter Power Output? Insertion loss setting on the duplexer probes? Were the duplexer cable harness lengths changed? What was the default/original factory set duplexer frequency? cheers, s. The old cans (Decibel DB4060 - 4 cans total) had been in storage and were apparently used by another ham for experimentation after they were taken off line. I'd replaced the notch caps a couple of years ago because whoever was experimenting with them tightened them until they cracked. I've also disassembled them and made sure they were clean and had no signs of arching or other damage. They were originally tuned on 146.25/85 (but as I said, they'd been 'played' with) and I'm moving them to 145.11 (minus 600 KHz). I first tuned them with a signal generator per the DB Products instructions and they tuned in very well. The peaks were good on both sides and the notches were about -85 db, using my crude measuring system. Losses on the pass-band were less then 2 db (probably more like 1 db). This pre-tuning was done with an HP-8640 signal generator, a scope, and other miscellaneous goodies. Tonight I got a service monitor (HP-8920) from a buddy who works for the FAA. I set it to duplex and checked my peaks. They were very close to perfect already, but I managed to get the last little bit of RF through the pass-cavities. Next I set out to tune the notches. I was able to get decent notches, but apparently they are not deep enough (despite having measured -85 with the signal generator) because I still have about 15 db of desense. I've been through them 4 or 5 times tonight (until I'm sick of them) but that's the best I can do. (I did discover that if I tune the receiver notch enough, I can pull the transmitter down to nothing!) I just reviewed (again) Kevin's article on Repeater-Builder entitled 'Getting the most from your Repeater System', and the one thing I need to do yet is check for internal desense. I had to replace the Teflon-type cable which leads from the Mark IV transmitter to the back panel, and when I replaced it, all I had was some RG-8X. I'm (sort of) hoping that's the problem, but I won't know until I check. I can't see where I've missed anything obvious, although tuning these types of duplexers is new to me. I spent 17 years in the Air Force working navigation and comm gear, so I'm pretty well versed in what I'm doing, but since this is a new venture for me, I'm certainly open to suggestions. I'll check for internal desense tomorrow, but in the meantime if anybody has anything to add, please chime in. TIA, Mike WM4B Kathleen, GA
