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Repeater experts....HELP!
Hi guys. Thanks in advance for any help. Please post
responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
Double shielded jumpers. And the length may be a component of what
exact frequency, so you may have to get with Telewave for advice on that. RG8 is not in my opinion good for the run from duplexer to antenna either. I would look for (depending on length of run) 1/2" or 7/8" hardline. How did you "tweak" the duplexer? With two service monitors or, one with a tracking generator? I'd replace the jumpers and feedline. de WA2MCT "me" wrote: Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
Double shielded jumpers. And the length may be a component of what
exact frequency, so you may have to get with Telewave for advice on that. RG8 is not in my opinion good for the run from duplexer to antenna either. I would look for (depending on length of run) 1/2" or 7/8" hardline. How did you "tweak" the duplexer? With two service monitors or, one with a tracking generator? I'd replace the jumpers and feedline. de WA2MCT "me" wrote: Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
1st Use superflex 1/4 - 3/8 hardline jumpers between duplexer and repeater.... 2nd Make sure that if the duplexers are in the same cabinet as repeater,put some sort of shield between the two... 3rd Use at least 1/2 inch, preferrably 7/8 hardline from cans to antenna, as even the LMR coax is still more lossy at 2M... 4th Make sure all connecters cables are solidly connected. 5th Use a poly phaser lightning arrester as it will ground cable, and make sure cabinet(s) are/is grounded, with a good earth ground. Get rid of the RG8 superfoam and go with hardline!!!!!! That's causing a lot of your problem..... too much loss of signal. I used to run a 2M repeater, and I found that the above are a must for good reception.. Also Hamtronics is correct, you should have a better set of duplexers, my old set was around 105db isolation( 6 can set about 30" tall) and I put them in thier own metal cabinet. Good luck Bob N9LVU Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
1st Use superflex 1/4 - 3/8 hardline jumpers between duplexer and repeater.... 2nd Make sure that if the duplexers are in the same cabinet as repeater,put some sort of shield between the two... 3rd Use at least 1/2 inch, preferrably 7/8 hardline from cans to antenna, as even the LMR coax is still more lossy at 2M... 4th Make sure all connecters cables are solidly connected. 5th Use a poly phaser lightning arrester as it will ground cable, and make sure cabinet(s) are/is grounded, with a good earth ground. Get rid of the RG8 superfoam and go with hardline!!!!!! That's causing a lot of your problem..... too much loss of signal. I used to run a 2M repeater, and I found that the above are a must for good reception.. Also Hamtronics is correct, you should have a better set of duplexers, my old set was around 105db isolation( 6 can set about 30" tall) and I put them in thier own metal cabinet. Good luck Bob N9LVU Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
As the others already said, you MUST have very well shielded jumpers. RG-214
will do if you have some, otherwise go with super-flex hard line. Both are often available on eBay. Try to stay away from the LMR coax, as it consists of a braid and foil shield which expand at different rates and cause all sorts of noise problems. Great as far as shielding goes, however. Super-flex cable is corrugated and has just a copper outer conductor so no metal expansion to worry about, but it can't be bent too many times. Excellent for use in and around repeaters and will work well outside if you tie it down properly. You may want something larger than 1/2 inch depending on the loss your system can tolerate. Depending on your Tx/Rx spacing, you could get away with less than 95 dB of isolation in the duplexer, but a 4-cavity unit will give you about 80 dB at best, so you really want a 6-cavity unit. Alternatively, a very tight receiver might help you, such as a Motorola Micor or MSF5000. The antenna could also be a source of desense. There aren't many ways to prove where the desense is coming from, but a good spectrum analyzer on the receiver's antenna input might tell you if you're getting signal directly from the transmitter, through the duplexer, or back from the antenna. Connect a dummy load to the output of the duplexer and use a signal generator to key the repeater. Check if you still have desense that way. If so, the problem is in your cables and/or duplexer and/or repeater. If not, it's a function of the antenna and feed line. A friend of mine is having a similar problem and he has gone through all the appropriate steps. His desense appears to be coming down from the antenna, and in his case it takes an additional 15-20 dB of signal (using a signal generator) to keep the repeater open once the transmitter comes on. I can't tell you how many S-units that is, but it's still a lot of signal, and he has a 4-cavity duplexer and is running a 1 MHz split. Operation with a dummy load is 100% perfect, so his problem is external to the equipment. Unfortunately, if the signal is coming down from the antenna, then you could have a 60-cavity duplexer and it wouldn't eliminate the desense. Bob M. ====== "Robert Kubichek" wrote in message ... 1st Use superflex 1/4 - 3/8 hardline jumpers between duplexer and repeater.... 2nd Make sure that if the duplexers are in the same cabinet as repeater,put some sort of shield between the two... 3rd Use at least 1/2 inch, preferrably 7/8 hardline from cans to antenna, as even the LMR coax is still more lossy at 2M... 4th Make sure all connecters cables are solidly connected. 5th Use a poly phaser lightning arrester as it will ground cable, and make sure cabinet(s) are/is grounded, with a good earth ground. Get rid of the RG8 superfoam and go with hardline!!!!!! That's causing a lot of your problem..... too much loss of signal. I used to run a 2M repeater, and I found that the above are a must for good reception.. Also Hamtronics is correct, you should have a better set of duplexers, my old set was around 105db isolation( 6 can set about 30" tall) and I put them in thier own metal cabinet. Good luck Bob N9LVU Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
As the others already said, you MUST have very well shielded jumpers. RG-214
will do if you have some, otherwise go with super-flex hard line. Both are often available on eBay. Try to stay away from the LMR coax, as it consists of a braid and foil shield which expand at different rates and cause all sorts of noise problems. Great as far as shielding goes, however. Super-flex cable is corrugated and has just a copper outer conductor so no metal expansion to worry about, but it can't be bent too many times. Excellent for use in and around repeaters and will work well outside if you tie it down properly. You may want something larger than 1/2 inch depending on the loss your system can tolerate. Depending on your Tx/Rx spacing, you could get away with less than 95 dB of isolation in the duplexer, but a 4-cavity unit will give you about 80 dB at best, so you really want a 6-cavity unit. Alternatively, a very tight receiver might help you, such as a Motorola Micor or MSF5000. The antenna could also be a source of desense. There aren't many ways to prove where the desense is coming from, but a good spectrum analyzer on the receiver's antenna input might tell you if you're getting signal directly from the transmitter, through the duplexer, or back from the antenna. Connect a dummy load to the output of the duplexer and use a signal generator to key the repeater. Check if you still have desense that way. If so, the problem is in your cables and/or duplexer and/or repeater. If not, it's a function of the antenna and feed line. A friend of mine is having a similar problem and he has gone through all the appropriate steps. His desense appears to be coming down from the antenna, and in his case it takes an additional 15-20 dB of signal (using a signal generator) to keep the repeater open once the transmitter comes on. I can't tell you how many S-units that is, but it's still a lot of signal, and he has a 4-cavity duplexer and is running a 1 MHz split. Operation with a dummy load is 100% perfect, so his problem is external to the equipment. Unfortunately, if the signal is coming down from the antenna, then you could have a 60-cavity duplexer and it wouldn't eliminate the desense. Bob M. ====== "Robert Kubichek" wrote in message ... 1st Use superflex 1/4 - 3/8 hardline jumpers between duplexer and repeater.... 2nd Make sure that if the duplexers are in the same cabinet as repeater,put some sort of shield between the two... 3rd Use at least 1/2 inch, preferrably 7/8 hardline from cans to antenna, as even the LMR coax is still more lossy at 2M... 4th Make sure all connecters cables are solidly connected. 5th Use a poly phaser lightning arrester as it will ground cable, and make sure cabinet(s) are/is grounded, with a good earth ground. Get rid of the RG8 superfoam and go with hardline!!!!!! That's causing a lot of your problem..... too much loss of signal. I used to run a 2M repeater, and I found that the above are a must for good reception.. Also Hamtronics is correct, you should have a better set of duplexers, my old set was around 105db isolation( 6 can set about 30" tall) and I put them in thier own metal cabinet. Good luck Bob N9LVU Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
"me" wrote in message news:01c3a9ed$368f2540$82878685@clip... Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick Why ask for help here when you will not follow simple instructions ? You must use double shielded cable or beter (solid shielding like heliax) to the duplexer. Many times to the antenna also. The ringo is a terrable antenna to use in repeater service due to the coupling to the feedline. The ammount of duplexer isolation is determimed by how much trash the transmitter puts out for one thing. A good clean transmitter (usually one using tubes for the amplifiers) can get away with less than the comsumer grade trtansmitters. Go here and pay attention to what is being said. http://www.repeater-builder.com/rbtip/ |
"me" wrote in message news:01c3a9ed$368f2540$82878685@clip... Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick Why ask for help here when you will not follow simple instructions ? You must use double shielded cable or beter (solid shielding like heliax) to the duplexer. Many times to the antenna also. The ringo is a terrable antenna to use in repeater service due to the coupling to the feedline. The ammount of duplexer isolation is determimed by how much trash the transmitter puts out for one thing. A good clean transmitter (usually one using tubes for the amplifiers) can get away with less than the comsumer grade trtansmitters. Go here and pay attention to what is being said. http://www.repeater-builder.com/rbtip/ |
The Hamtronics manual says you HAVE to use a
duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation Rick- I would guess your duplexer was intended for a commercial repeater that had greater separation than 600 KHz. You are kidding yourself if you think you can make it work. Those other repeaters with old duplexers either have desense or have some kind of super filters in the transmitter and receiver chains. About the only thing that might help you (after you get that double-shielded co-ax) would be adding a couple extra cavities. Although that approach will probably have a higher insertion loss, it may be possible to tune the resulting set for sufficient isolation. If you can't fix the cavities, then all you can do is reduce transmit power out of the repeater. If you reduce from one hundred to one watt, you pick up the equivalent of 20 dB of isolation. (A four-cavity duplexer with 95 dB isolation may be possible, but the cavities will be big ones.) 73, Fred, K4DII |
The Hamtronics manual says you HAVE to use a
duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation Rick- I would guess your duplexer was intended for a commercial repeater that had greater separation than 600 KHz. You are kidding yourself if you think you can make it work. Those other repeaters with old duplexers either have desense or have some kind of super filters in the transmitter and receiver chains. About the only thing that might help you (after you get that double-shielded co-ax) would be adding a couple extra cavities. Although that approach will probably have a higher insertion loss, it may be possible to tune the resulting set for sufficient isolation. If you can't fix the cavities, then all you can do is reduce transmit power out of the repeater. If you reduce from one hundred to one watt, you pick up the equivalent of 20 dB of isolation. (A four-cavity duplexer with 95 dB isolation may be possible, but the cavities will be big ones.) 73, Fred, K4DII |
Well you gave the problem in the 1st couple of lines
1) USE Double shielded coax between duplexer and repeater...throw out the RG 8 foam stuff...NEVER use RG 8 in a rptr install... 2) Hamtronics....enough said 3) Ringo Ranger antenna...if it's loose in any place, it will cause problems....need to get a real repeater antenna....One without a ring that depends on a cheap ring connection for matching. Depending on the cleaness of the RF output, and how good is the rcvr in overload conditions is what determines the isolation you need in the duplexer....95db isolation is easy to find...WACOM WP641s, 642, and other makes!! Get your isolation better than 80db and get rid of the crap coax...and you'll be a lot better off! Chris WB5ITT at arrl . net me wrote: Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick -- Replace NOSPAM with 1st initial and last name for direct reply! |
Well you gave the problem in the 1st couple of lines
1) USE Double shielded coax between duplexer and repeater...throw out the RG 8 foam stuff...NEVER use RG 8 in a rptr install... 2) Hamtronics....enough said 3) Ringo Ranger antenna...if it's loose in any place, it will cause problems....need to get a real repeater antenna....One without a ring that depends on a cheap ring connection for matching. Depending on the cleaness of the RF output, and how good is the rcvr in overload conditions is what determines the isolation you need in the duplexer....95db isolation is easy to find...WACOM WP641s, 642, and other makes!! Get your isolation better than 80db and get rid of the crap coax...and you'll be a lot better off! Chris WB5ITT at arrl . net me wrote: Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick -- Replace NOSPAM with 1st initial and last name for direct reply! |
I agree with Chris, RG8 is mainly good stuff, but it is intended for
more two way radio and not full duplex systems. I also recommend the best coax to the antenna from duplexer as well, may not affect it much, but even if it helps the slightest, it helps. The Hantronics is a good starter repeater to learn with, but you will notice as you get better equipment, the quality of the system will greatly improve. Look into a Yeaseu or Kenwood repeater or commercial repeater. Cheap is good, but like they say, you get what you pay for. Look inside the case and make sure that the transmitter and receiver are completely shielded from each other as well. You are getting a RF leak into the receiver is what is causing the choppy affect if it isnt shielded. The duplexer should be at least 80% or better. 80% being bare minimum. Wacom as recommended below will be the right choices. Some duplexers are used in different types of systems. The frequency spread determines the amount of isolation needed in a duplexer. 77% may be just good enough on a 440 system because of the 5 Mhz spread between TX and RX frequency. Since 2 meters is 600khz difference, a tighter duplexer is needed. In most cases, a clean 100 watt repeater will work great with a 90% duplexer. any more than 100 watts would require a tighter isolation in my experiences with commercial gear. Definately a repeater antenna. Depending on the coverage area, A ringo ranger may be fine, but a repeater antenna is what it is intended for, a repeater! Also make sure the repeater case has no exposed openings. Some people dont realize that when they are tuning the repeater with the lid off for some reason, that the RF leaks out easily. The better the shielding on all of your equipment, the better the quality. Also make sure everything is grounded properly. One case not being grounded could be severe enough to kill a 4-5 S-Unit signal. Reducing the sensitivity of the reciever would be pointless. That would be gaining nothing. If anything, reduce the output power if necessary. I usually only run my repeater at 75% of what it says for continuous duty. So if my repeater was 100 watts Continuous Duty, I would turn it down to 75 watts thus increasing its life, stays cooler and my receiver isnt affected at all by it, in fact I notice that the receiver actually doesnt receive as much garbage from the other systems on the hill while in use and I did notice that distant users were able to get in the squelch easier this way. On Tue, 24 Feb 2004 13:39:34 GMT, Chris Boone wrote: Well you gave the problem in the 1st couple of lines 1) USE Double shielded coax between duplexer and repeater...throw out the RG 8 foam stuff...NEVER use RG 8 in a rptr install... 2) Hamtronics....enough said 3) Ringo Ranger antenna...if it's loose in any place, it will cause problems....need to get a real repeater antenna....One without a ring that depends on a cheap ring connection for matching. Depending on the cleaness of the RF output, and how good is the rcvr in overload conditions is what determines the isolation you need in the duplexer....95db isolation is easy to find...WACOM WP641s, 642, and other makes!! Get your isolation better than 80db and get rid of the crap coax...and you'll be a lot better off! Chris WB5ITT at arrl . net me wrote: Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
I agree with Chris, RG8 is mainly good stuff, but it is intended for
more two way radio and not full duplex systems. I also recommend the best coax to the antenna from duplexer as well, may not affect it much, but even if it helps the slightest, it helps. The Hantronics is a good starter repeater to learn with, but you will notice as you get better equipment, the quality of the system will greatly improve. Look into a Yeaseu or Kenwood repeater or commercial repeater. Cheap is good, but like they say, you get what you pay for. Look inside the case and make sure that the transmitter and receiver are completely shielded from each other as well. You are getting a RF leak into the receiver is what is causing the choppy affect if it isnt shielded. The duplexer should be at least 80% or better. 80% being bare minimum. Wacom as recommended below will be the right choices. Some duplexers are used in different types of systems. The frequency spread determines the amount of isolation needed in a duplexer. 77% may be just good enough on a 440 system because of the 5 Mhz spread between TX and RX frequency. Since 2 meters is 600khz difference, a tighter duplexer is needed. In most cases, a clean 100 watt repeater will work great with a 90% duplexer. any more than 100 watts would require a tighter isolation in my experiences with commercial gear. Definately a repeater antenna. Depending on the coverage area, A ringo ranger may be fine, but a repeater antenna is what it is intended for, a repeater! Also make sure the repeater case has no exposed openings. Some people dont realize that when they are tuning the repeater with the lid off for some reason, that the RF leaks out easily. The better the shielding on all of your equipment, the better the quality. Also make sure everything is grounded properly. One case not being grounded could be severe enough to kill a 4-5 S-Unit signal. Reducing the sensitivity of the reciever would be pointless. That would be gaining nothing. If anything, reduce the output power if necessary. I usually only run my repeater at 75% of what it says for continuous duty. So if my repeater was 100 watts Continuous Duty, I would turn it down to 75 watts thus increasing its life, stays cooler and my receiver isnt affected at all by it, in fact I notice that the receiver actually doesnt receive as much garbage from the other systems on the hill while in use and I did notice that distant users were able to get in the squelch easier this way. On Tue, 24 Feb 2004 13:39:34 GMT, Chris Boone wrote: Well you gave the problem in the 1st couple of lines 1) USE Double shielded coax between duplexer and repeater...throw out the RG 8 foam stuff...NEVER use RG 8 in a rptr install... 2) Hamtronics....enough said 3) Ringo Ranger antenna...if it's loose in any place, it will cause problems....need to get a real repeater antenna....One without a ring that depends on a cheap ring connection for matching. Depending on the cleaness of the RF output, and how good is the rcvr in overload conditions is what determines the isolation you need in the duplexer....95db isolation is easy to find...WACOM WP641s, 642, and other makes!! Get your isolation better than 80db and get rid of the crap coax...and you'll be a lot better off! Chris WB5ITT at arrl . net me wrote: Hi guys. Thanks in advance for any help. Please post responses in NG as my email 'reply' address is fake since some don't know how to mind their manners. I recently put back into service a Hamtronics REP100 two meter repeater with a new Telewave Duplexer and the antenna is a Ringo Ranger II with radials. Coax to the antenna is RG8 superfoam and jumpers between repeater and duplexer are RG8 superfoam. Here is the problem. I am experiencing 'desense' on the repeater to the point where it takes a signal of S5 or better to get in. A lesser signal just makes the repeater "chop" (continually opens and closes the transmit side. The Duplexer was factory tuned (for what it was worth) and I did 'tweak' it and got a much noticible improvement. Before tweaking, it took an S9 or better to get in. I realize I should be running (supposedly) double shielded jumpers from repeater to the Duplexer, but I can't imagine they are going to make that much difference. I am also told to mount the duplexer in it's own enclosure (it's rack mount so that would be cute) to keep it away from the repeater. The Hamtronics manual says you HAVE to use a duplexer with at least 95 db of isolation (try to find one) and mine is 77db. I really can't imagine there is not enough isolation, because I know where there are other machines running with old duplexers with much less than 77db of isolation. Just to add to the mix, I sent the repeater up to Hamtronics and had it tuned and checked out and it is 100 percent, so I *suspect* it is not a repeater problem. (Someone suggested to try killing some of the sensitivity of the reciever). So....looking for ideas and suggestions on what to try next (other than double shielded jumpers to the duplexer). Thanks for any help or ideas... 73's Rick |
The Hantronics is a good starter repeater to learn with, but you will notice as you get better equipment, the quality of the system will greatly improve. Look into a Yeaseu or Kenwood repeater or commercial repeater. Cheap is good, but like they say, you get what you pay for. Look inside the case and make sure that the transmitter and receiver are completely shielded from each other as well. You are getting a RF leak into the receiver is what is causing the choppy affect if it isnt shielded. To go cheap and really good quality get a comercial transceiver or two. The GE Mastr ll is one of the best ways to go. Well shielded and sharp tuning receiver. They can be had for less than $ 100 and about half that much more for a set of crystals. Then add a controler such as a Cat 300 and you have less than $ 500 in the basic unit. Then you add the expensive stuff such as a duplexer, feedline, and antenna. |
The Hantronics is a good starter repeater to learn with, but you will notice as you get better equipment, the quality of the system will greatly improve. Look into a Yeaseu or Kenwood repeater or commercial repeater. Cheap is good, but like they say, you get what you pay for. Look inside the case and make sure that the transmitter and receiver are completely shielded from each other as well. You are getting a RF leak into the receiver is what is causing the choppy affect if it isnt shielded. To go cheap and really good quality get a comercial transceiver or two. The GE Mastr ll is one of the best ways to go. Well shielded and sharp tuning receiver. They can be had for less than $ 100 and about half that much more for a set of crystals. Then add a controler such as a Cat 300 and you have less than $ 500 in the basic unit. Then you add the expensive stuff such as a duplexer, feedline, and antenna. |
Along with the GE Master II check out the Motorola Micor Repeater,
(not the mobiles converted to repeaters, alhough they work too) They are cheap also and as with the GE, and you can't kill them!! These are commercial repeaters and built to last almost forever. Both are excellent! 73 Ralph Mowery wrote: The Hantronics is a good starter repeater to learn with, but you will notice as you get better equipment, the quality of the system will greatly improve. Look into a Yeaseu or Kenwood repeater or commercial repeater. Cheap is good, but like they say, you get what you pay for. Look inside the case and make sure that the transmitter and receiver are completely shielded from each other as well. You are getting a RF leak into the receiver is what is causing the choppy affect if it isnt shielded. To go cheap and really good quality get a comercial transceiver or two. The GE Mastr ll is one of the best ways to go. Well shielded and sharp tuning receiver. They can be had for less than $ 100 and about half that much more for a set of crystals. Then add a controler such as a Cat 300 and you have less than $ 500 in the basic unit. Then you add the expensive stuff such as a duplexer, feedline, and antenna. |
Along with the GE Master II check out the Motorola Micor Repeater,
(not the mobiles converted to repeaters, alhough they work too) They are cheap also and as with the GE, and you can't kill them!! These are commercial repeaters and built to last almost forever. Both are excellent! 73 Ralph Mowery wrote: The Hantronics is a good starter repeater to learn with, but you will notice as you get better equipment, the quality of the system will greatly improve. Look into a Yeaseu or Kenwood repeater or commercial repeater. Cheap is good, but like they say, you get what you pay for. Look inside the case and make sure that the transmitter and receiver are completely shielded from each other as well. You are getting a RF leak into the receiver is what is causing the choppy affect if it isnt shielded. To go cheap and really good quality get a comercial transceiver or two. The GE Mastr ll is one of the best ways to go. Well shielded and sharp tuning receiver. They can be had for less than $ 100 and about half that much more for a set of crystals. Then add a controler such as a Cat 300 and you have less than $ 500 in the basic unit. Then you add the expensive stuff such as a duplexer, feedline, and antenna. |
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