Re: [Repeater-Builder] Two Repeaters, One Antenna
It can be done. I used to work with a UHF commercial system which combined multiple repeaters to a common antenna. The cans were built tuned by TxRx; rather expensive in terms of money and insertion loss. At 01:38 PM 2/20/2008, you wrote: Guys, I've found a site for my most recent Ham repeater project. Nice farm tower on a hill, clean of RF colo, etc. The farm repeater is a 463.xxx + machine and I'm on 444.825. It is set up with nice hardline and a 16 bay folded dipole antenna (not sure the mfg., but he thinks it's DB). Anyway, assuming that thing has useable SWR on my TX frequency (I've had that happen before, not holding my breath), does anyone have any ideas about the viability of running both repeaters on the same antenna but connecting the duplexer outputs together in to the common feedline? I've done no math, and not a lot of thinking, but is this one of those times when I might run odd multiples of 1/4 wave coax to a T at the hardline or something? Both repeaters have BpBr duplexers and both have isolators on their outputs. 73 DE N0MJS -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206 Yahoo! Groups Links Thanks, Robin Midgett K4IDC 615-322-5836 office - rolls to pager 615-835-7699 pager 615-301-1642 home [EMAIL PROTECTED] Radio Gear For Sale: http://www.people.vanderbilt.edu/~robin.midgett/index.htm
Re: [Repeater-Builder] Two Repeaters, One Antenna
At 08:43 AM 2/21/2008, you wrote: It can be done. I used to work with a UHF commercial system which combined multiple repeaters to a common antenna. The cans were built tuned by TxRx; rather expensive in terms of money and insertion loss. -One comment for what it's worth. Transmitter combiners are generally quite lossy. And that loss can increase to prohibitive amounts the closer in frequency adjacent ports are. In other words, there is a point of diminishing returns IMHO Ken -- President and CTO - Arcom Communications Makers of repeater controllers and accessories. http://www.arcomcontrollers.com/ Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net We don't just make 'em. We use 'em!
RE: [Repeater-Builder] Two Repeaters, One Antenna
I agree with Ken. On an 800 Mhz system I maintain, 100 watts into the combiner yields about 16 watts at the antenna. This is a 10 channel combiner with 250khz spacing and 320 ft of 1 5/8 Heliax. We have actually installed a second antenna and feedline and have plans to split the combiner but just haven't gotten around to it yet. Kinda sucks but there's always a warm spot in the room in the winter. Jamey Wright Systems Analyst/EDACS Administrator Morgan County EMCD 911 Decatur, AL 256-552-0911 -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Ken Arck Sent: Thursday, February 21, 2008 10:51 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Two Repeaters, One Antenna At 08:43 AM 2/21/2008, you wrote: It can be done. I used to work with a UHF commercial system which combined multiple repeaters to a common antenna. The cans were built tuned by TxRx; rather expensive in terms of money and insertion loss. -One comment for what it's worth. Transmitter combiners are generally quite lossy. And that loss can increase to prohibitive amounts the closer in frequency adjacent ports are. In other words, there is a point of diminishing returns IMHO Ken -- President and CTO - Arcom Communications Makers of repeater controllers and accessories. http://www.arcomcontrollers.com/ Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net We don't just make 'em. We use 'em! Yahoo! Groups Links
RE: [Repeater-Builder] Two Repeaters, One Antenna
Transmitter combiners are not always high loss, avoid like the plague kind of thing. 10 channels at 250 Khz spacing on 800 does give you quite a hit but it is still better than the alternative. The cavity on each transmitter must give at least 10 db of attenuation at the other frequencies in the combined system. So for close spaced frequencies the cavity insertion loss must be increased in order to obtain the proper skirt selectivity of the cavity so that 10 db can be met. With wider spacing there is much less insertion loss needed to obtain the required isolation. Also as frequency comes down, UHF or VHF the selectivity of the cavity gets better and less insertion loss is required for that same 10 db needed for isolation. So don't overlook transmitter combining as a high loss thing. It may not be. When spacing gets real close then hybrid combiners are needed and losses really get high there especially with several channels. These are quite common on 900 MHz and 220 MHz ACSB systems where channel spacing is very close. Sometimes combined channels can be split up with 2 antennas putting half the channels on each antenna and staggering their frequencies so you can use minimum loss. Also sometimes receive channels can be on those same antennas with 1 or 2 receiver multicouplers and appropriate filters. It all depends on what frequencies are involved. In regard to the two repeaters on one antenna, Jeff summed it up very well. 73 Gary K4FMX -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Jamey Wright Sent: Thursday, February 21, 2008 12:12 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Two Repeaters, One Antenna I agree with Ken. On an 800 Mhz system I maintain, 100 watts into the combiner yields about 16 watts at the antenna. This is a 10 channel combiner with 250khz spacing and 320 ft of 1 5/8 Heliax. We have actually installed a second antenna and feedline and have plans to split the combiner but just haven't gotten around to it yet. Kinda sucks but there's always a warm spot in the room in the winter. Jamey Wright Systems Analyst/EDACS Administrator Morgan County EMCD 911 Decatur, AL 256-552-0911 -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Ken Arck Sent: Thursday, February 21, 2008 10:51 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Two Repeaters, One Antenna At 08:43 AM 2/21/2008, you wrote: It can be done. I used to work with a UHF commercial system which combined multiple repeaters to a common antenna. The cans were built tuned by TxRx; rather expensive in terms of money and insertion loss. -One comment for what it's worth. Transmitter combiners are generally quite lossy. And that loss can increase to prohibitive amounts the closer in frequency adjacent ports are. In other words, there is a point of diminishing returns IMHO Ken -- President and CTO - Arcom Communications Makers of repeater controllers and accessories. http://www.arcomcontrollers.com/ Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net We don't just make 'em. We use 'em! Yahoo! Groups Links Yahoo! Groups Links
RE: [Repeater-Builder] Two Repeaters, One Antenna
Also for what's its worth when combining units together a good IM study might not be a bad idea. _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jamey Wright Sent: Thursday, February 21, 2008 11:12 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Two Repeaters, One Antenna I agree with Ken. On an 800 Mhz system I maintain, 100 watts into the combiner yields about 16 watts at the antenna. This is a 10 channel combiner with 250khz spacing and 320 ft of 1 5/8 Heliax. We have actually installed a second antenna and feedline and have plans to split the combiner but just haven't gotten around to it yet. Kinda sucks but there's always a warm spot in the room in the winter. Jamey Wright Systems Analyst/EDACS Administrator Morgan County EMCD 911 Decatur, AL 256-552-0911 -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] mailto:Builder%40yahoogroups.com .com] On Behalf Of Ken Arck Sent: Thursday, February 21, 2008 10:51 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] Two Repeaters, One Antenna At 08:43 AM 2/21/2008, you wrote: It can be done. I used to work with a UHF commercial system which combined multiple repeaters to a common antenna. The cans were built tuned by TxRx; rather expensive in terms of money and insertion loss. -One comment for what it's worth. Transmitter combiners are generally quite lossy. And that loss can increase to prohibitive amounts the closer in frequency adjacent ports are. In other words, there is a point of diminishing returns IMHO Ken -- President and CTO - Arcom Communications Makers of repeater controllers and accessories. http://www.arcomcon http://www.arcomcontrollers.com/ trollers.com/ Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp. http://www.irlp.net net We don't just make 'em. We use 'em! Yahoo! Groups Links
RE: [Repeater-Builder] Two Repeaters, One Antenna
Jamey, Same here. I have the same thing I have to do with my Tetra system(s) just have not done so yet, that is split the the combiner in two, or four sections, cause as it stands 100 in and 36 out is not that good but that's the price to pay. I push about 100watts a channel into the combiner 10 cavities and get about 54watts well more like 48 have to tune them to the lowest power make to make things optimized on my 406 system _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jamey Wright Sent: Thursday, February 21, 2008 11:12 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Two Repeaters, One Antenna I agree with Ken. On an 800 Mhz system I maintain, 100 watts into the combiner yields about 16 watts at the antenna. This is a 10 channel combiner with 250khz spacing and 320 ft of 1 5/8 Heliax. We have actually installed a second antenna and feedline and have plans to split the combiner but just haven't gotten around to it yet. Kinda sucks but there's always a warm spot in the room in the winter. Jamey Wright Systems Analyst/EDACS Administrator Morgan County EMCD 911 Decatur, AL 256-552-0911 -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] mailto:Builder%40yahoogroups.com .com] On Behalf Of Ken Arck Sent: Thursday, February 21, 2008 10:51 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] Two Repeaters, One Antenna At 08:43 AM 2/21/2008, you wrote: It can be done. I used to work with a UHF commercial system which combined multiple repeaters to a common antenna. The cans were built tuned by TxRx; rather expensive in terms of money and insertion loss. -One comment for what it's worth. Transmitter combiners are generally quite lossy. And that loss can increase to prohibitive amounts the closer in frequency adjacent ports are. In other words, there is a point of diminishing returns IMHO Ken -- President and CTO - Arcom Communications Makers of repeater controllers and accessories. http://www.arcomcon http://www.arcomcontrollers.com/ trollers.com/ Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp. http://www.irlp.net net We don't just make 'em. We use 'em! Yahoo! Groups Links
Re: [Repeater-Builder] Two Repeaters, One Antenna
This is where you use a combiner... Cort Buffington wrote: Guys, I've found a site for my most recent Ham repeater project. Nice farm tower on a hill, clean of RF colo, etc. The farm repeater is a 463.xxx + machine and I'm on 444.825. It is set up with nice hardline and a 16 bay folded dipole antenna (not sure the mfg., but he thinks it's DB). Anyway, assuming that thing has useable SWR on my TX frequency (I've had that happen before, not holding my breath), does anyone have any ideas about the viability of running both repeaters on the same antenna but connecting the duplexer outputs together in to the common feedline? I've done no math, and not a lot of thinking, but is this one of those times when I might run odd multiples of 1/4 wave coax to a T at the hardline or something? Both repeaters have BpBr duplexers and both have isolators on their outputs. 73 DE N0MJS -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206 -- Jay Urish W5GM ex. KB5VPS ARRL Life MemberDenton County ARRL VEC N5ERS VP/Trustee Monitoring 444.850 PL-88.5 146.92 PL-110.9
Re: [Repeater-Builder] Two Repeaters, One Antenna
give TX RX a call and they can fix you up. Ask for Bob, have used them many time and very happy with them. John - Original Message - From: Cort Buffington To: Repeater-Builder@yahoogroups.com Sent: Wednesday, February 20, 2008 2:38 PM Subject: [Repeater-Builder] Two Repeaters, One Antenna Guys, I've found a site for my most recent Ham repeater project. Nice farm tower on a hill, clean of RF colo, etc. The farm repeater is a 463.xxx + machine and I'm on 444.825. It is set up with nice hardline and a 16 bay folded dipole antenna (not sure the mfg., but he thinks it's DB). Anyway, assuming that thing has useable SWR on my TX frequency (I've had that happen before, not holding my breath), does anyone have any ideas about the viability of running both repeaters on the same antenna but connecting the duplexer outputs together in to the common feedline? I've done no math, and not a lot of thinking, but is this one of those times when I might run odd multiples of 1/4 wave coax to a T at the hardline or something? Both repeaters have BpBr duplexers and both have isolators on their outputs. 73 DE N0MJS -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206
RE: [Repeater-Builder] Two Repeaters, One Antenna
I will offer another option, Telewave. Their combining equipment does not take up two footprints in the tower shack! The combiner that was just installed in my building is over 43 inches wide! The owner of the tower will thank you, I would. I will also warn you, when you have to duplex, combine and multicouple to get two systems on one antenna you are looking at a lot of loss, it would be better to install two antennas. With two antennas you would not be affecting the host radio system, in fact you may help his range a bit depending on how much loss is in his duplexer. Just my 2 cents, Paul _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Maire-Radios Sent: Wednesday, February 20, 2008 5:05 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Two Repeaters, One Antenna give TX RX a call and they can fix you up. Ask for Bob, have used them many time and very happy with them. John - Original Message - From: HYPERLINK mailto:[EMAIL PROTECTED]Cort Buffington To: HYPERLINK mailto:Repeater-Builder@yahoogroups.comRepeater-Builder@yahoogroups.com Sent: Wednesday, February 20, 2008 2:38 PM Subject: [Repeater-Builder] Two Repeaters, One Antenna Guys, I've found a site for my most recent Ham repeater project. Nice farm tower on a hill, clean of RF colo, etc. The farm repeater is a 463.xxx + machine and I'm on 444.825. It is set up with nice hardline and a 16 bay folded dipole antenna (not sure the mfg., but he thinks it's DB). Anyway, assuming that thing has useable SWR on my TX frequency (I've had that happen before, not holding my breath), does anyone have any ideas about the viability of running both repeaters on the same antenna but connecting the duplexer outputs together in to the common feedline? I've done no math, and not a lot of thinking, but is this one of those times when I might run odd multiples of 1/4 wave coax to a T at the hardline or something? Both repeaters have BpBr duplexers and both have isolators on their outputs. 73 DE N0MJS -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206 HYPERLINK http://rover.ebay.com/rover/1/711-1751-2978-238/1?aid=10356774pid=2316294; REMEMBER - You can find it on ebaY No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.8/1288 - Release Date: 2/19/2008 8:47 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.8/1288 - Release Date: 2/19/2008 8:47 PM
Re: [Repeater-Builder] Two Repeaters, One Antenna
yes we mostly one TX antenna and one RX antenna with pre amp on it and notch filter for 465 to 469.9 - Original Message - From: Paul Finch To: Repeater-Builder@yahoogroups.com Sent: Wednesday, February 20, 2008 9:37 PM Subject: RE: [Repeater-Builder] Two Repeaters, One Antenna I will offer another option, Telewave. Their combining equipment does not take up two footprints in the tower shack! The combiner that was just installed in my building is over 43 inches wide! The owner of the tower will thank you, I would. I will also warn you, when you have to duplex, combine and multicouple to get two systems on one antenna you are looking at a lot of loss, it would be better to install two antennas. With two antennas you would not be affecting the host radio system, in fact you may help his range a bit depending on how much loss is in his duplexer. Just my 2 cents, Paul -- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Maire-Radios Sent: Wednesday, February 20, 2008 5:05 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Two Repeaters, One Antenna give TX RX a call and they can fix you up. Ask for Bob, have used them many time and very happy with them. John - Original Message - From: Cort Buffington To: Repeater-Builder@yahoogroups.com Sent: Wednesday, February 20, 2008 2:38 PM Subject: [Repeater-Builder] Two Repeaters, One Antenna Guys, I've found a site for my most recent Ham repeater project. Nice farm tower on a hill, clean of RF colo, etc. The farm repeater is a 463.xxx + machine and I'm on 444.825. It is set up with nice hardline and a 16 bay folded dipole antenna (not sure the mfg., but he thinks it's DB). Anyway, assuming that thing has useable SWR on my TX frequency (I've had that happen before, not holding my breath), does anyone have any ideas about the viability of running both repeaters on the same antenna but connecting the duplexer outputs together in to the common feedline? I've done no math, and not a lot of thinking, but is this one of those times when I might run odd multiples of 1/4 wave coax to a T at the hardline or something? Both repeaters have BpBr duplexers and both have isolators on their outputs. 73 DE N0MJS -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206 REMEMBER - You can find it on ebaY No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.8/1288 - Release Date: 2/19/2008 8:47 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.8/1288 - Release Date: 2/19/2008 8:47 PM REMEMBER - You can find it on ebaY
RE: [Repeater-Builder] Two Repeaters, One Antenna
What you want to do has been done before. I believe the documents in the link below has information on this. I used to have a big foldout document from moto on the 1500 duplexers and it showed a configuration you describe. I hope the PDF documents on this like are the same I am thinking of. http://www.repeater-builder.com/motorola/t1500.html -Kevin -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Cort Buffington Sent: Wednesday, February 20, 2008 2:39 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Two Repeaters, One Antenna Guys, I've found a site for my most recent Ham repeater project. Nice farm tower on a hill, clean of RF colo, etc. The farm repeater is a 463.xxx + machine and I'm on 444.825. It is set up with nice hardline and a 16 bay folded dipole antenna (not sure the mfg., but he thinks it's DB). Anyway, assuming that thing has useable SWR on my TX frequency (I've had that happen before, not holding my breath), does anyone have any ideas about the viability of running both repeaters on the same antenna but connecting the duplexer outputs together in to the common feedline? I've done no math, and not a lot of thinking, but is this one of those times when I might run odd multiples of 1/4 wave coax to a T at the hardline or something? Both repeaters have BpBr duplexers and both have isolators on their outputs. 73 DE N0MJS -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206 Yahoo! Groups Links
