Re: [WISPA] OT amps and volts
Brian, Call me monday, but too many volts is what kills electronics. Blair Brian Rohrbacher wrote: I'm a little confused here. I'm working on a 300 ft run of cat5 and have a question. The radio is acting sparatic. The power supply has already been upped from a 18v to a 24v. Both 1 amp. Will it hurt to put a 24v 2 amp power supply in? If I over do on amps or volts, what blows a radio. One or both? I seem to remember being told that a radio only takes what amps it needs, so putting a higher amp power supply in won't hurt, but if you put too many volts in, that will fry them. Please clarify me on this. -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] OT amps and volts
It's not actually mine. It's another's from the list. We were talking about it. But I am sure that on my 230 ft run of cat 5 that I had to replace an 18v 1a with an 18v 2a to get the radio to stop rebooting. The individual I was talking to thought if you up the amps it will kill the radio. I thought if you up the volts it kills the radio. Who is right? Well, actually I know what the cat 5 is. It's comscope 25 pair. Which brings up another question. Who does this? Run a single bundle of 25 pair up towers and use punch down blocks. Any issues with this? Brian Sean S gayle wrote: Brian, I'm normally a lurker, but maybe your problem is in the 300' run of CAT5. What kind is it? You may be getting signal degradation which is causing the sporadic radio behavior. Sean JohnnyO's evil twin -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brian Rohrbacher Sent: Saturday, February 04, 2006 2:01 PM To: wireless@wispa.org Subject: [WISPA] OT amps and volts I'm a little confused here. I'm working on a 300 ft run of cat5 and have a question. The radio is acting sparatic. The power supply has already been upped from a 18v to a 24v. Both 1 amp. Will it hurt to put a 24v 2 amp power supply in? If I over do on amps or volts, what blows a radio. One or both? I seem to remember being told that a radio only takes what amps it needs, so putting a higher amp power supply in won't hurt, but if you put too many volts in, that will fry them. Please clarify me on this. -- Brian Rohrbacher Reliable Internet, LLC www.reliableinter.net Cell 269-838-8338 Caught up in the Air 1 Thess. 4:17 -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] OT amps and volts
Lets exaggerate here. I can plug a billion amps in and it will only draw what it wants, but if I go a volt or two over it fries. Chuckk wrote: Over voltage will kill the radio or board current is only drawn as needed. Chuckk Brian Rohrbacher wrote: It's not actually mine. It's another's from the list. We were talking about it. But I am sure that on my 230 ft run of cat 5 that I had to replace an 18v 1a with an 18v 2a to get the radio to stop rebooting. The individual I was talking to thought if you up the amps it will kill the radio. I thought if you up the volts it kills the radio. Who is right? Well, actually I know what the cat 5 is. It's comscope 25 pair. Which brings up another question. Who does this? Run a single bundle of 25 pair up towers and use punch down blocks. Any issues with this? Brian Sean S gayle wrote: Brian, I'm normally a lurker, but maybe your problem is in the 300' run of CAT5. What kind is it? You may be getting signal degradation which is causing the sporadic radio behavior. Sean JohnnyO's evil twin -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brian Rohrbacher Sent: Saturday, February 04, 2006 2:01 PM To: wireless@wispa.org Subject: [WISPA] OT amps and volts I'm a little confused here. I'm working on a 300 ft run of cat5 and have a question. The radio is acting sparatic. The power supply has already been upped from a 18v to a 24v. Both 1 amp. Will it hurt to put a 24v 2 amp power supply in? If I over do on amps or volts, what blows a radio. One or both? I seem to remember being told that a radio only takes what amps it needs, so putting a higher amp power supply in won't hurt, but if you put too many volts in, that will fry them. Please clarify me on this. -- Brian Rohrbacher Reliable Internet, LLC www.reliableinter.net Cell 269-838-8338 Caught up in the Air 1 Thess. 4:17 -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] OT amps and volts
That is correct. Now if you use a 10 amp supply and only need 2 amps and there is a short up top there is a good chance you will burn your cat 5 cable up. Chuckk Brian Rohrbacher wrote: Lets exaggerate here. I can plug a billion amps in and it will only draw what it wants, but if I go a volt or two over it fries. Chuckk wrote: Over voltage will kill the radio or board current is only drawn as needed. Chuckk Brian Rohrbacher wrote: It's not actually mine. It's another's from the list. We were talking about it. But I am sure that on my 230 ft run of cat 5 that I had to replace an 18v 1a with an 18v 2a to get the radio to stop rebooting. The individual I was talking to thought if you up the amps it will kill the radio. I thought if you up the volts it kills the radio. Who is right? Well, actually I know what the cat 5 is. It's comscope 25 pair. Which brings up another question. Who does this? Run a single bundle of 25 pair up towers and use punch down blocks. Any issues with this? Brian Sean S gayle wrote: Brian, I'm normally a lurker, but maybe your problem is in the 300' run of CAT5. What kind is it? You may be getting signal degradation which is causing the sporadic radio behavior. Sean JohnnyO's evil twin -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brian Rohrbacher Sent: Saturday, February 04, 2006 2:01 PM To: wireless@wispa.org Subject: [WISPA] OT amps and volts I'm a little confused here. I'm working on a 300 ft run of cat5 and have a question. The radio is acting sparatic. The power supply has already been upped from a 18v to a 24v. Both 1 amp. Will it hurt to put a 24v 2 amp power supply in? If I over do on amps or volts, what blows a radio. One or both? I seem to remember being told that a radio only takes what amps it needs, so putting a higher amp power supply in won't hurt, but if you put too many volts in, that will fry them. Please clarify me on this. -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] OT amps and volts
huh? I appologize if this was in-jest and I didn't recognize it. You apply a potential when you connect something (a voltage). You don't apply a current. Neither voltage nor current kill most things. There are a few kinds of things that are voltage sensitive but not typically found on the input of a commercial device. Power kills most things through direct conversion to heat. There's so many different powering circuits that's is just not possible to draw any across the board generalities. Some things have AC supplies and generate DC, some take DC and run through a regulator, some take DC and run it into an inverter and then generate their own DC. Depends on the radio and the powering circuitry. I know what's in the Motorola, and they have an inverter and regenerate their own DC. If you check the specs for some brand radio, if you see a voltage spec with a range of voltage (say 12v to 24v) its probably running an onboard inverter. These are pretty hardy (they naturally support a wide range of applied voltage). On the other hand, a radio with a voltage spec without a range may only have an onboard regulator, and these may be popped by overvoltage. Simple onboard regulators drop the input voltage down to whatever the board wants, and the dropped voltage x the radio current is power that is dissipated to heat in the regulator. Rich - Original Message - From: Brian Rohrbacher [EMAIL PROTECTED] To: WISPA General List wireless@wispa.org Sent: Saturday, February 04, 2006 2:53 PM Subject: Re: [WISPA] OT amps and volts Lets exaggerate here. I can plug a billion amps in and it will only draw what it wants, but if I go a volt or two over it fries. Chuckk wrote: Over voltage will kill the radio or board current is only drawn as needed. Chuckk Brian Rohrbacher wrote: It's not actually mine. It's another's from the list. We were talking about it. But I am sure that on my 230 ft run of cat 5 that I had to replace an 18v 1a with an 18v 2a to get the radio to stop rebooting. The individual I was talking to thought if you up the amps it will kill the radio. I thought if you up the volts it kills the radio. Who is right? Well, actually I know what the cat 5 is. It's comscope 25 pair. Which brings up another question. Who does this? Run a single bundle of 25 pair up towers and use punch down blocks. Any issues with this? Brian Sean S gayle wrote: Brian, I'm normally a lurker, but maybe your problem is in the 300' run of CAT5. What kind is it? You may be getting signal degradation which is causing the sporadic radio behavior. Sean JohnnyO's evil twin -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brian Rohrbacher Sent: Saturday, February 04, 2006 2:01 PM To: wireless@wispa.org Subject: [WISPA] OT amps and volts I'm a little confused here. I'm working on a 300 ft run of cat5 and have a question. The radio is acting sparatic. The power supply has already been upped from a 18v to a 24v. Both 1 amp. Will it hurt to put a 24v 2 amp power supply in? If I over do on amps or volts, what blows a radio. One or both? I seem to remember being told that a radio only takes what amps it needs, so putting a higher amp power supply in won't hurt, but if you put too many volts in, that will fry them. Please clarify me on this. -- Brian Rohrbacher Reliable Internet, LLC www.reliableinter.net Cell 269-838-8338 Caught up in the Air 1 Thess. 4:17 -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] OT amps and volts
YES ! On Sat, 2006-02-04 at 15:53 -0500, Brian Rohrbacher wrote: Lets exaggerate here. I can plug a billion amps in and it will only draw what it wants, but if I go a volt or two over it fries. Chuckk wrote: Over voltage will kill the radio or board current is only drawn as needed. Chuckk Brian Rohrbacher wrote: It's not actually mine. It's another's from the list. We were talking about it. But I am sure that on my 230 ft run of cat 5 that I had to replace an 18v 1a with an 18v 2a to get the radio to stop rebooting. The individual I was talking to thought if you up the amps it will kill the radio. I thought if you up the volts it kills the radio. Who is right? Well, actually I know what the cat 5 is. It's comscope 25 pair. Which brings up another question. Who does this? Run a single bundle of 25 pair up towers and use punch down blocks. Any issues with this? Brian Sean S gayle wrote: Brian, I'm normally a lurker, but maybe your problem is in the 300' run of CAT5. What kind is it? You may be getting signal degradation which is causing the sporadic radio behavior. Sean JohnnyO's evil twin -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Brian Rohrbacher Sent: Saturday, February 04, 2006 2:01 PM To: wireless@wispa.org Subject: [WISPA] OT amps and volts I'm a little confused here. I'm working on a 300 ft run of cat5 and have a question. The radio is acting sparatic. The power supply has already been upped from a 18v to a 24v. Both 1 amp. Will it hurt to put a 24v 2 amp power supply in? If I over do on amps or volts, what blows a radio. One or both? I seem to remember being told that a radio only takes what amps it needs, so putting a higher amp power supply in won't hurt, but if you put too many volts in, that will fry them. Please clarify me on this. -- Brian Rohrbacher Reliable Internet, LLC www.reliableinter.net Cell 269-838-8338 Caught up in the Air 1 Thess. 4:17 -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] OT amps and volts
Time for some ohm law here guys. The radio you are powering is a load in series with a transmission line that has resistance. The ohms of the line and the ohms of the load add together to determine the effective load for determining the amount of current flow that will be drawn. If you already know the number of amps that the radio draws then this gets easier to calculate. 24 AWG wire has a resistance of roughly .0302 ohms per foot. If you are going 300 foot to the load then you actually have 300 foot on the positive side and 300 foot on the negative side of the load. This yields 600 X .0302 = 18.12 ohms. Now here is where those with no electronics background may start to glaze over a bit. We actually have two lines for positive and two lines for negative when using two pairs of a 24 AWG cat 5 cable. When you have two identical loads in parallel the resistance gets cut in half. So the effective resistance of the transmission line for 300 feet of Cat 5 24 AWG cable is 9.06 ohms. Let's assume the radio being powered has a current draw of 1.2 amps. The current flow in a series circuit is the same throughout the circuit so the voltage drop across the transmission line would be determined by multiplying the amps of current times the ohms of resistance which means 1.2 amps X 9.06 ohms = 10.872 volts. This means that if a radio needs 12 volts with 1.2 amps current flow then you would need to supply a minimum of about 24 volts at the POE injector. This is because if we start with 24 volts and lose 10.872 across the transmission line this leaves about 13.128 volts to the radio. If you do not know ohms law then you need to do some reading on it. It is easier than I have described here once you play with it a bit and you really do use it in your life if you do anything at all with electricity. Here is a page I just Googled and seems to cover most of the basics: http://www.awrr.com/descorn.html Cheers, Scriv Brian Rohrbacher wrote: I'm a little confused here. I'm working on a 300 ft run of cat5 and have a question. The radio is acting sparatic. The power supply has already been upped from a 18v to a 24v. Both 1 amp. Will it hurt to put a 24v 2 amp power supply in? If I over do on amps or volts, what blows a radio. One or both? I seem to remember being told that a radio only takes what amps it needs, so putting a higher amp power supply in won't hurt, but if you put too many volts in, that will fry them. Please clarify me on this. -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
