Re: [WISPA] 1 AP and 2 antennas
Good explanation, Tom. This will help many of us understand a little more about RF propagation behavior and challenges. Tom DeReggi wrote: Adam, It can work, but there are a couple notes and problems Its probably not a good idea to do with 900Mhz. However, it has been done, examples are Hyperlinktech's quad or Maxrad's tri antenna arrays for 2.4g and 5.8G. First, you'd be violating FCC regs, as that combination would not be certified. Second, you'll need a Coax splitter. M2INC has one for 900Mhz that they sell for their stacking Yagi Kits. (I think around 40 bucks) Third, the cable lengths to each antenna from splitter should each be the EXACT same length. Their are two immediate problem... Both antennas would act as a single radiating element if they were to close together, and it could change the beamwidth and radiating power of the antenna combination. Meaning it is not guaranteed that the end result would be two antennas pointing opposite directions with their spec'd beam. If they are back to back and spaced wrong, meaning out of phase, the signals will cancel each other out degrating the other. (Note that split signal cut power by 3 db, and adding two antennas of the same type adds 6 db, for a 3db gain, IF there is not cancellation or interference between the two elements. This is why stacking antennas work when properly spaced.) So, you'd need to have the two antennas spaced an exact calculated distance (both horizontally and vertically) for them to be in phase, with the wave length of the other, or have enough F/B isolation. Tough for 900Mhz Even with an antenna with high F/B ratio, and back to back, there is a chance a percent of the power will go back into the other antenna, so the signal comming out of the back would need to be in phase with the other antenna's signal or ot would interfere with it. If the spacing was correct, you could make it work. The other approach is to have adequate isolation from the two antennas, but that is hard with 900Mhz. But if you mounting to opposite sides/walls of a brick penthouse, that would create the needed isolation, where the two antennas would not interfere with each other, nor act as a single antenna. But if you were trying to moutn to a common mast, I'd say more trouble than worth. You'd probably be better off using an Omni with the adequate electronic downtilt, and mounted lower to ground. Remember with 2.4 and 5.8 the wve lengths are short and the ability to penetrate back plates is low. But 900Mhz has much larger wavelength and much harder to isolate. Not an easy task. In a nut shell I'd highy advise against it for 900Mhz. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Adam Goodman a...@wispring.com To: WISPA General List wireless@wispa.org Sent: Friday, April 24, 2009 9:49 AM Subject: [WISPA] 1 AP and 2 antennas Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.287 / Virus Database: 270.12.4/2080 - Release Date: 04/25/09 08:29:00 -- Scott Reed Sr. Systems Engineer GAB Midwest 1-800-363-1544 x4000 Cell: 260-273-7239 WISPA Wants You! Join today! http://signup.wispa.org
[WISPA] 1 AP and 2 antennas
Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] 1 AP and 2 antennas
When you use a splitter you loose 3dB in signal (hal you power since it's being split). If that is ok then you could do so. /Eje --Original Message-- From: Adam Goodman Sender: wireless-boun...@wispa.org To: WISPA General List ReplyTo: WISPA General List Subject: [WISPA] 1 AP and 2 antennas Sent: Apr 24, 2009 08:49 Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ Sent via BlackBerry from T-Mobile WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] 1 AP and 2 antennas
Device would be called a splitter/combiner. Just remember, power to each antenna will be 1/2 of the output of the radio. Adam Goodman wrote: Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.287 / Virus Database: 270.12.4/2078 - Release Date: 04/24/09 07:54:00 -- Scott Reed Sr. Systems Engineer GAB Midwest 1-800-363-1544 x4000 Cell: 260-273-7239 WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] 1 AP and 2 antennas
Thanks guys. Loosing 3db is probably not an issue since I was going to lower the tx power anyway doe to the distance to the subs. found this for $50. says its good for 0-6ghz. does it need to be tuned to a specific freq? http://www.l-com.com/item.aspx?id=20865 Now all I need to do is test and see how it works out. On Fri, Apr 24, 2009 at 9:49 AM, Adam Goodman a...@wispring.com wrote: Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] 1 AP and 2 antennas
One thing you need to be careful of is both pieces of coax need to be tuned to the proper length so that the antennas are in-phase with each other. Otherwise you will have multiple signals hitting the receivers of your clients and AP at different times. Kurt Fankhauser WAVELINC P.O. Box 126 Bucyrus, OH 44820 419-562-6405 www.wavelinc.com -Original Message- From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Adam Goodman Sent: Friday, April 24, 2009 10:41 AM To: WISPA General List Subject: Re: [WISPA] 1 AP and 2 antennas Thanks guys. Loosing 3db is probably not an issue since I was going to lower the tx power anyway doe to the distance to the subs. found this for $50. says its good for 0-6ghz. does it need to be tuned to a specific freq? http://www.l-com.com/item.aspx?id=20865 Now all I need to do is test and see how it works out. On Fri, Apr 24, 2009 at 9:49 AM, Adam Goodman a...@wispring.com wrote: Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] 1 AP and 2 antennas
Use a standoff bracket to mount an omni. Scriv On Fri, Apr 24, 2009 at 8:49 AM, Adam Goodman a...@wispring.com wrote: Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] 1 AP and 2 antennas
Plus the actual loss in the splitter. It's going to eat some of the signal. Greg On Apr 24, 2009, at 10:04 AM, e...@wisp-router.com wrote: When you use a splitter you loose 3dB in signal (hal you power since it's being split). If that is ok then you could do so. /Eje --Original Message-- From: Adam Goodman Sender: wireless-boun...@wispa.org To: WISPA General List ReplyTo: WISPA General List Subject: [WISPA] 1 AP and 2 antennas Sent: Apr 24, 2009 08:49 Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ Sent via BlackBerry from T-Mobile WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] 1 AP and 2 antennas
Adam, It can work, but there are a couple notes and problems Its probably not a good idea to do with 900Mhz. However, it has been done, examples are Hyperlinktech's quad or Maxrad's tri antenna arrays for 2.4g and 5.8G. First, you'd be violating FCC regs, as that combination would not be certified. Second, you'll need a Coax splitter. M2INC has one for 900Mhz that they sell for their stacking Yagi Kits. (I think around 40 bucks) Third, the cable lengths to each antenna from splitter should each be the EXACT same length. Their are two immediate problem... Both antennas would act as a single radiating element if they were to close together, and it could change the beamwidth and radiating power of the antenna combination. Meaning it is not guaranteed that the end result would be two antennas pointing opposite directions with their spec'd beam. If they are back to back and spaced wrong, meaning out of phase, the signals will cancel each other out degrating the other. (Note that split signal cut power by 3 db, and adding two antennas of the same type adds 6 db, for a 3db gain, IF there is not cancellation or interference between the two elements. This is why stacking antennas work when properly spaced.) So, you'd need to have the two antennas spaced an exact calculated distance (both horizontally and vertically) for them to be in phase, with the wave length of the other, or have enough F/B isolation. Tough for 900Mhz Even with an antenna with high F/B ratio, and back to back, there is a chance a percent of the power will go back into the other antenna, so the signal comming out of the back would need to be in phase with the other antenna's signal or ot would interfere with it. If the spacing was correct, you could make it work. The other approach is to have adequate isolation from the two antennas, but that is hard with 900Mhz. But if you mounting to opposite sides/walls of a brick penthouse, that would create the needed isolation, where the two antennas would not interfere with each other, nor act as a single antenna. But if you were trying to moutn to a common mast, I'd say more trouble than worth. You'd probably be better off using an Omni with the adequate electronic downtilt, and mounted lower to ground. Remember with 2.4 and 5.8 the wve lengths are short and the ability to penetrate back plates is low. But 900Mhz has much larger wavelength and much harder to isolate. Not an easy task. In a nut shell I'd highy advise against it for 900Mhz. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Adam Goodman a...@wispring.com To: WISPA General List wireless@wispa.org Sent: Friday, April 24, 2009 9:49 AM Subject: [WISPA] 1 AP and 2 antennas Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
Re: [WISPA] 1 AP and 2 antennas
Assuming you plan to use sectors, make sure that the sectors are very isolated from each other... But, with the ranges you are talking about, why bother with 2 antennas? one good omni should do fine... Adam Goodman wrote: Hi, I would like to set up 2 antennas (East and West more or less) but will not get more than 30 subs between the 2. I would like to connect both antennas to one AP. Normally, I would not even dream of doing this. However this is a small valey with low interferance. And all the subs will be very clse, peobably less than a quarter mile from the AP. I am planning to use 900MHz for this. So I guess this would be a device that would connect to the AP with one COAX and then connect to each antenna with a COAX. So, 3 N connectors. Has any of you done this, did you have success, and what is the device called, and where would I get it? Thank you, Adam WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ WISPA Wants You! Join today! http://signup.wispa.org/ WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
