Re: [Repeater-Builder] Re: Isolator vs intermod panel?
At 02:11 PM 07/24/09, you wrote: >Thanks everyone for the education on this subject. I'm sorry I >didn't reply sooner. I had a problem with my yahoo groups settings >and then a situation come up that took me away for a few days. I do >appreciate each and every reply! > >An intermod situation cropped up when a new WISP went on a nearby >tower. Whenever their 900 MHz stuff is activated and my 147.105 >transmitter comes up I have a strong intermod product on my 147.705 >input. Anyway thanks for the educational reading. Hopefully we will >be able to get this sorted out soon. > >Paul N1BUG Look for a 600 KHz based switching supply. I found that situation at one location by unplugging the RF stuff from the power supply and the crud was still there. Unplugged the PS and the problem went away. The ISP replaced the switcher with a linear and the problem was solved (at least THAT problem). Mike WA6ILQ
[Repeater-Builder] Re: Isolator vs intermod panel?
Thanks everyone for the education on this subject. I'm sorry I didn't reply sooner. I had a problem with my yahoo groups settings and then a situation come up that took me away for a few days. I do appreciate each and every reply! An intermod situation cropped up when a new WISP went on a nearby tower. Whenever their 900 MHz stuff is activated and my 147.105 transmitter comes up I have a strong intermod product on my 147.705 input. Anyway thanks for the educational reading. Hopefully we will be able to get this sorted out soon. Paul N1BUG
[Repeater-Builder] Re: Isolator vs intermod panel?
Re: Isolator vs intermod panel? The basic difference... a common Intermod Panel is often considered a complete or mostly complete hardware assembly, which (in the Land Mobile Radio World) should include one or more isolator or circulator devices. A single Isolator unit can be a one or dual port device... so the number and combination of isolator/circulator devices used can vary to obtain a more common desired dual port function. i.e. a quantity of two single port isolators placed in series versus one dual port device. A typical Land Mobile Radio Intermod panel will have one or two isolators trailed by a low pass filter and the rejection ports have proper size 50 ohm terminations (dummy load). Newer IMD Panels often have RF Sample Ports included on the 50 ohm terminations. Some IMD Panels might include metering sample functions. Typical Land Mobile (Two-way) Radio IMD Panels don't have on- board cavity filters. One or more Band Pass Cavities are placed on/after the IMD Panel output connection. * A single Isolator is just the "RF Check Valve" device often seen as a stand alone part (but often includes one or two screw on 50 ohm terminations. One will often see an Isolator connected to a trailing Low Pass Filter, which is good practice but not written in stone as a must have addition. Each case differs so some of you should not start jumping up and down about Low Pass Filters being a "must have". As many hams do... I used to squeak by without Isolators and IMD Panels. After a number of lucky breaks and train wrecks I now include them to fault protect the RF Power Amplifier and Receiver. I see them being sold fairly cheap on Ebay. cheers, s. > Paul Kelley N1BUG wrote: > > I guess I was lucky in my first few years as a repeater owner. > Lately I have nothing but grief in many forms. (Yeah I know, welcome > to the real world!) > > Can someone tell me in basic terms what is the difference between an > isolator and an intermod suppression panel which contains an isolator? > > If one has a high power tube PA on a repeater, I assume he would > need to use a high power isolator or intermod panel after the PA? Or > would it be sufficient to use a lower power one between the solid > state exciter and tube PA? > > Thanks... > > Paul N1BUG >
[Repeater-Builder] Re: Isolator vs intermod panel?
--- In Repeater-Builder@yahoogroups.com, Paul Kelley N1BUG wrote: > > I guess I was lucky in my first few years as a repeater owner. > Lately I have nothing but grief in many forms. (Yeah I know, welcome > to the real world!) > > Can someone tell me in basic terms what is the difference between an > isolator and an intermod suppression panel which contains an isolator? > > If one has a high power tube PA on a repeater, I assume he would > need to use a high power isolator or intermod panel after the PA? Or > would it be sufficient to use a lower power one between the solid > state exciter and tube PA? > > Thanks... > > Paul N1BUG The isolator prevents power from the antenna from entering your transmitter where it can mix with your output and cause intermod products. In the process of doing this the isolator also generates harmonics of your transmitter output so you *MUST* also use a cavity between the isolator and the antenna to suppress the harmonics. An additional benefit of an isolator is that it protects your transmitter from a damaged antenna system. If the antenna has 100% reflected power all of that power will end up in the isolators load so plan accordingly. So no isolator between the exciter and the PA does no good at all in preventing intermod. 73's Skip WB6YMH
Re: [Repeater-Builder] Re: Isolator Loss
I think that you better consider putting harmonic filters on your repeaters. Doing the math, your 2nd harmonics fall on 294.00MHz and 294.45MHz. A quick search on the Internet shows that the US Air Force has a frequency allocation of 291.800 to 296.650MHz. The least that you should do is check and see if you have a 2nd harmonic radiating when one or both of your repeaters are keyed. A visit from the USAF may not make the tower owner happy and would put you in a bad situation. 73, Joe, K1ike NORM KNAPP wrote: > Thanks so much for the inFo. I have seeb them on some transmit combiners for > UHF and 800mhz, but a VHF one is rare. > I don't think I need one however. I have 2 VHF (2m) ham repeaters on an old > AT&T microwave tower. One is 147.225 and the other is 147.000.
Re: [Repeater-Builder] Re: Isolator Loss
Thanks so much for the inFo. I have seeb them on some transmit combiners for UHF and 800mhz, but a VHF one is rare. I don't think I need one however. I have 2 VHF (2m) ham repeaters on an old AT&T microwave tower. One is 147.225 and the other is 147.000. The 225 is a 100watt Mastr II. The 147.000 is a paiR of Maxon SM4150's. The antennas are just inches apart, one over the other and so far, no problems with interference. I am using sinclair cans on both. Didn't know if I needed a circulator or isolator for this situation or not. I guess not sinc there seems to be no issues. No one else on tower. Nearest repeater is probably at least 10 miles away. 73 de N5NPO Norman Knapp - Original Message - From: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Sent: Sun May 17 09:23:25 2009 Subject: RE: [Repeater-Builder] Re: Isolator Loss Norm, A collection of very informative information is available here: As for what an isolator does, it ensures that your PA is working into a good 50 ohm load. If the antenna or feedline breaks, the power that would have been radiated is now reflected back to the PA- causing all sorts of problems. But an isolator shunts the reflected power into the attached 50 ohm load, thereby protecting the PA from a load mismatch. A circulator is the ferrite device that routes forward power to the antenna, but routes reverse (reflected) power to the dummy load. An isolator is the name given to a circulator that is packaged with one, two, or even three dummy loads. If you have a simple repeater that uses a single transistor PA that has no power control or high-SWR protection- such as a Hamtronics, RF Engineering, or Maggiore unit- an isolator on the output is necessary to keep the PA from burning up if the antenna or feedline faults. The other primary purpose of an isolator is to prevent mixing (intermodulation) in your PA of carriers from other nearby transmitters. Most commercial PAs have power available to them all the time, and only amplify when the exciter is providing an input. Being Class C, there is no amplification during idle periods. But, if other carriers can sneak into your PA through your duplexer, they can mix and be amplified to create new IM products. Keep in mind that most BpBr duplexers have a rather broad bandpass response, and can allow carriers far removed from your operating frequency to pass with ease. An isolator shunts such rogue carriers to the dummy load, thereby preventing the generation of spurious IM products. A ferrite isolator has a tendency to generate a second harmonic of the fundamental transmitted carrier, so it should be followed by a simple harmonic notch filter or a low-pass filter. As for the Kenwood TKR-750, I leave it to other and better-informed folks to respond to Item 2. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> [mailto:Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of NORM KNAPP Sent: Saturday, May 16, 2009 10:42 AM To: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> Subject: RE: [Repeater-Builder] Re: Isolator Loss Kinda OT, but not entirely 1) What does the isolator do, and why would I need one? 2) I work for a Kenwood dealer. Kenwood has admitted to our company that the TKR-750 is rife with internal desense caused mainly by synthesizer birdies. Supposedly no two will have exactly the same birdies or desense on the same freqs. They have told us that there is a fix under warrantee but it has to go to them for the fix and you must provide freq info for custom fix. Has anyone else seen this problem or heard of this? 73 de N5NPO Norman knapp
RE: [Repeater-Builder] Re: Isolator Loss
Norm, A collection of very informative information is available here: As for what an isolator does, it ensures that your PA is working into a good 50 ohm load. If the antenna or feedline breaks, the power that would have been radiated is now reflected back to the PA- causing all sorts of problems. But an isolator shunts the reflected power into the attached 50 ohm load, thereby protecting the PA from a load mismatch. A circulator is the ferrite device that routes forward power to the antenna, but routes reverse (reflected) power to the dummy load. An isolator is the name given to a circulator that is packaged with one, two, or even three dummy loads. If you have a simple repeater that uses a single transistor PA that has no power control or high-SWR protection- such as a Hamtronics, RF Engineering, or Maggiore unit- an isolator on the output is necessary to keep the PA from burning up if the antenna or feedline faults. The other primary purpose of an isolator is to prevent mixing (intermodulation) in your PA of carriers from other nearby transmitters. Most commercial PAs have power available to them all the time, and only amplify when the exciter is providing an input. Being Class C, there is no amplification during idle periods. But, if other carriers can sneak into your PA through your duplexer, they can mix and be amplified to create new IM products. Keep in mind that most BpBr duplexers have a rather broad bandpass response, and can allow carriers far removed from your operating frequency to pass with ease. An isolator shunts such rogue carriers to the dummy load, thereby preventing the generation of spurious IM products. A ferrite isolator has a tendency to generate a second harmonic of the fundamental transmitted carrier, so it should be followed by a simple harmonic notch filter or a low-pass filter. As for the Kenwood TKR-750, I leave it to other and better-informed folks to respond to Item 2. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of NORM KNAPP Sent: Saturday, May 16, 2009 10:42 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Isolator Loss Kinda OT, but not entirely 1) What does the isolator do, and why would I need one? 2) I work for a Kenwood dealer. Kenwood has admitted to our company that the TKR-750 is rife with internal desense caused mainly by synthesizer birdies. Supposedly no two will have exactly the same birdies or desense on the same freqs. They have told us that there is a fix under warrantee but it has to go to them for the fix and you must provide freq info for custom fix. Has anyone else seen this problem or heard of this? 73 de N5NPO Norman knapp
Re: [Repeater-Builder] Re: Isolator Loss
You better check for harmonics. You probably need a harmonic filter. What frequency is your repeater on? Joe offtrack wrote: > Do not, just the Isolator then the Telwave TPRD 1556 Pass-Reject Duplexer. > > Scott > KB7DZR >
[Repeater-Builder] Re: Isolator Loss
Do not, just the Isolator then the Telwave TPRD 1556 Pass-Reject Duplexer. Scott KB7DZR --- In Repeater-Builder@yahoogroups.com, "Gary Schafer" wrote: > > Do you have a low pass filter after the isolator? > > 73 > Gary K4FMX > > > -Original Message- > > From: Repeater-Builder@yahoogroups.com [mailto:Repeater- > > buil...@yahoogroups.com] On Behalf Of offtrack > > Sent: Saturday, May 16, 2009 11:19 AM > > To: Repeater-Builder@yahoogroups.com > > Subject: [Repeater-Builder] Re: Isolator Loss > > > > Eric > > > > Thanks for the confirmation on this. Its an older one that was tuned for > > me its a T-2200 that was replaced by the T-1530 I think, if I read > > correctly at the telwave site. > > > > I notice that the TKR 750 is running fine with no intermod issues ect. > > > > I was not sure about adding that meter in line and only did a quick check. > > Thanks for the warning on that one. > > > > The Diamond is so far working ok. I soldered all the parts in the antenna > > and sealed up all the possible leak points with a compound call "through > > the roof" This stuff stays semi flexible and is clear. Its located at my > > home and has been in service for about 2 years for my Simplex Echolink > > node I replaced with the repeater. Works pretty good, but that said I > > would never put it on a remote site as your correct not at all heavy duty. > > the radome is egg shell thin, I worry about it at the house as I am on a > > hill and get hit with some good winds/icing. So the Isolator in line helps > > ease my mind a bit. > > > > Thanks > > KB7DZR > > Scott > > > > --- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" wrote: > > > > > > Scott, > > > > > > I must assume that you purchased a Telewave T-1530 Isolator, and its > > > specified insertion loss is 0.4 dB. The readings you took indicate that > > the > > > isolator is working properly. However, it is not a good idea to insert > > a > > > meter between the isolator and the dummy load. The correct operation of > > the > > > isolator depends upon a stable 50 ohm impedance at the dummy load port. > > > > > > I think you made some good choices for the duplexer, feedline, and > > isolator. > > > The Diamond F22 is perhaps not the most rugged antenna for 2m repeater > > use, > > > but YMMV. > > > > > > 73, Eric Lemmon WB6FLY > > > > > > > > > > > > > > > > > > -Original Message- > > > From: Repeater-Builder@yahoogroups.com > > > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of offtrack > > > Sent: Friday, May 15, 2009 7:27 PM > > > To: Repeater-Builder@yahoogroups.com > > > Subject: [Repeater-Builder] Isolator Loss > > > > > > > > > > > > Hi all, > > > > > > Thanks for the group it has helped me out a bunch. > > > My system here is a Kenwood TRK K2 and Telewave TPRD-1556 6 can set. > > > Feed line is Heliax LDF4-50A about 70 feet and the antenna is a Diamond > > F22 > > > that has been worked over and sealed up better. > > > > > > The system is new and today I added a Telewave Isolator to the PA output > > > before the duplexer TX input. With my meter I got about 28 watts out of > > > antenna side of the duplexer set when connected to my antenna with out > > the > > > isolator. With the Isolator I am getting about 26 watts out now. This > > seems > > > good to me but I am new to an Isolator. Putting the meter between the > > > isolator and the dummy load it is showing around 1.6 watts going to the > > > dummy load. > > > > > > Just want to see if this is ok for this? > > > > > > KB7DZR > > > Scott > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > >
RE: [possible spam] RE: [Repeater-Builder] Re: Isolator Loss
Norm, A collection of very informative information is available here: As for what an isolator does, it ensures that your PA is working into a good 50 ohm load. If the antenna or feedline breaks, the power that would have been radiated is now reflected back to the PA- causing all sorts of problems. But an isolator shunts the reflected power into the attached 50 ohm load, thereby protecting the PA from a load mismatch. A circulator is the ferrite device that routes forward power to the antenna, but routes reverse (reflected) power to the dummy load. An isolator is the name given to a circulator that is packaged with one, two, or even three dummy loads. If you have a simple repeater that uses a single transistor PA that has no power control or high-SWR protection- such as a Hamtronics, RF Engineering, or Maggiore unit- an isolator on the output is necessary to keep the PA from burning up if the antenna or feedline faults. The other primary purpose of an isolator is to prevent mixing (intermodulation) in your PA of carriers from other nearby transmitters. Most commercial PAs have power available to them all the time, and only amplify when the exciter is providing an input. Being Class C, there is no amplification during idle periods. But, if other carriers can sneak into your PA through your duplexer, they can mix and be amplified to create new IM products. Keep in mind that most BpBr duplexers have a rather broad bandpass response, and can allow carriers far removed from your operating frequency to pass with ease. An isolator shunts such rogue carriers to the dummy load, thereby preventing the generation of spurious IM products. A ferrite isolator has a tendency to generate a second harmonic of the fundamental transmitted carrier, so it should be followed by a simple harmonic notch filter or a low-pass filter. As for the Kenwood TKR-750, I leave it to other and better-informed folks to respond to Item 2. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of NORM KNAPP Sent: Saturday, May 16, 2009 10:42 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [possible spam] RE: [Repeater-Builder] Re: Isolator Loss Kinda OT, but not entirely 1) What does the isolator do and why would I need one? 2) I work for a Kenwood dealer. Kenwood has admitted to our company that the TKR-750 is rife with internal desense caused mainly by synthesizer birdies. Supposedly no two will have exactly the same birdies or desense on the same freqs. They have told us that there is a fix under warrantee but it has to go to them for the fix and you must provide freq info for custom fix. Has anyone else seen this problem or heard of this? 73 de N5NPO Norman knapp - Original Message - From: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> mailto:Repeater-Builder%40yahoogroups.com> > To: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> mailto:Repeater-Builder%40yahoogroups.com> > Sent: Sat May 16 11:02:44 2009 Subject: [possible spam] RE: [Repeater-Builder] Re: Isolator Loss Do you have a low pass filter after the isolator? 73 Gary K4FMX > -Original Message- > From: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> <mailto:Repeater-Builder%40yahoogroups.com> [mailto:Repeater- > buil...@yahoogroups.com <mailto:Builder%40yahoogroups.com> <mailto:Builder%40yahoogroups.com> ] On Behalf Of offtrack > Sent: Saturday, May 16, 2009 11:19 AM > To: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> <mailto:Repeater-Builder%40yahoogroups.com> > Subject: [Repeater-Builder] Re: Isolator Loss > > Eric > > Thanks for the confirmation on this. Its an older one that was tuned for > me its a T-2200 that was replaced by the T-1530 I think, if I read > correctly at the telwave site. > > I notice that the TKR 750 is running fine with no intermod issues ect. > > I was not sure about adding that meter in line and only did a quick check. > Thanks for the warning on that one. > > The Diamond is so far working ok. I soldered all the parts in the antenna > and sealed up all the possible leak points with a compound call "through > the roof" This stuff stays semi flexible and is clear. Its located at my > home and has been in service for about 2 years for my Simplex Echolink > node I replaced with the repeater. Works pretty good, but that said I > would never put it on a remote site as your correct not at all heavy duty. > the radome is egg shell thin, I worry about it at the house as I am on a > hill and get hit with some good winds/icing. So the Isolator in line helps > ease my mind a bit. > > Thanks > KB7DZR >
Re: [possible spam] RE: [Repeater-Builder] Re: Isolator Loss
Go here: http://www.repeater-builder.com/antenna/ant-sys-index.html for a boatload of info, including isolators. Chuck WB2EDV - Original Message - From: "NORM KNAPP" To: Sent: Saturday, May 16, 2009 1:41 PM Subject: Re: [possible spam] RE: [Repeater-Builder] Re: Isolator Loss > Kinda OT, but not entirely > 1) What does tHe isolator do and why would I need one? > > 2) I work for a Kenwood dealer. Kenwood has admitted to our company that > the TKR-750 is rife with internal desense caused mainly by synthesizer > birdies. Supposedly no two will have exactly the same birdies or desense > on the same freqs. They have told us that there is a fix under warrantee > but it has to go to them for the fix and you must provide freq info for > custom fix. > Has anyone else seen this problem or heard of this? > > 73 de N5NPO > Norman knapp > > - Original Message - > From: Repeater-Builder@yahoogroups.com > To: Repeater-Builder@yahoogroups.com > Sent: Sat May 16 11:02:44 2009 > Subject: [possible spam] RE: [Repeater-Builder] Re: Isolator Loss > > > > Do you have a low pass filter after the isolator? > > 73 > Gary K4FMX > >> -Original Message- >> From: Repeater-Builder@yahoogroups.com >> <mailto:Repeater-Builder%40yahoogroups.com> [mailto:Repeater- >> buil...@yahoogroups.com <mailto:Builder%40yahoogroups.com> ] On Behalf Of >> offtrack >> Sent: Saturday, May 16, 2009 11:19 AM >> To: Repeater-Builder@yahoogroups.com >> <mailto:Repeater-Builder%40yahoogroups.com> >> Subject: [Repeater-Builder] Re: Isolator Loss >> >> Eric >> >> Thanks for the confirmation on this. Its an older one that was tuned for >> me its a T-2200 that was replaced by the T-1530 I think, if I read >> correctly at the telwave site. >> >> I notice that the TKR 750 is running fine with no intermod issues ect. >> >> I was not sure about adding that meter in line and only did a quick >> check. >> Thanks for the warning on that one. >> >> The Diamond is so far working ok. I soldered all the parts in the antenna >> and sealed up all the possible leak points with a compound call "through >> the roof" This stuff stays semi flexible and is clear. Its located at my >> home and has been in service for about 2 years for my Simplex Echolink >> node I replaced with the repeater. Works pretty good, but that said I >> would never put it on a remote site as your correct not at all heavy >> duty. >> the radome is egg shell thin, I worry about it at the house as I am on a >> hill and get hit with some good winds/icing. So the Isolator in line >> helps >> ease my mind a bit. >> >> Thanks >> KB7DZR >> Scott >> >> --- In Repeater-Builder@yahoogroups.com >> <mailto:Repeater-Builder%40yahoogroups.com> , "Eric Lemmon" >> wrote: >> > >> > Scott, >> > >> > I must assume that you purchased a Telewave T-1530 Isolator, and its >> > specified insertion loss is 0.4 dB. The readings you took indicate that >> the >> > isolator is working properly. However, it is not a good idea to insert >> a >> > meter between the isolator and the dummy load. The correct operation of >> the >> > isolator depends upon a stable 50 ohm impedance at the dummy load port. >> > >> > I think you made some good choices for the duplexer, feedline, and >> isolator. >> > The Diamond F22 is perhaps not the most rugged antenna for 2m repeater >> use, >> > but YMMV. >> > >> > 73, Eric Lemmon WB6FLY >> > >> > >> > >> > >> > >> > -Original Message- >> > From: Repeater-Builder@yahoogroups.com >> > <mailto:Repeater-Builder%40yahoogroups.com> >> > [mailto:Repeater-Builder@yahoogroups.com >> > <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of offtrack >> > Sent: Friday, May 15, 2009 7:27 PM >> > To: Repeater-Builder@yahoogroups.com >> > <mailto:Repeater-Builder%40yahoogroups.com> >> > Subject: [Repeater-Builder] Isolator Loss >> > >> > >> > >> > Hi all, >> > >> > Thanks for the group it has helped me out a bunch. >> > My system here is a Kenwood TRK K2 and Telewave TPRD-1556 6 can set. >> > Feed line is Heliax LDF4-50A about 70 feet and the antenna is a Diamond >> F22 >> > that has been worked over and sealed up better. >> > >> > The system is new and today I added a Telewave Isolator to the PA >> > output >> > before the duplexer TX input. With my meter I got about 28 watts out of >> > antenna side of the duplexer set when connected to my antenna with out >> the >> > isolator. With the Isolator I am getting about 26 watts out now. This >> seems >> > good to me but I am new to an Isolator. Putting the meter between the >> > isolator and the dummy load it is showing around 1.6 watts going to the >> > dummy load. >> > >> > Just want to see if this is ok for this? >> > >> > KB7DZR >> > Scott >> > >> >> >> >> >> >> >> >> >> Yahoo! Groups Links >> >> >> > > > > > > > > > > > Yahoo! Groups Links > > >
Re: [possible spam] RE: [Repeater-Builder] Re: Isolator Loss
Kinda OT, but not entirely 1) What does tHe isolator do and why would I need one? 2) I work for a Kenwood dealer. Kenwood has admitted to our company that the TKR-750 is rife with internal desense caused mainly by synthesizer birdies. Supposedly no two will have exactly the same birdies or desense on the same freqs. They have told us that there is a fix under warrantee but it has to go to them for the fix and you must provide freq info for custom fix. Has anyone else seen this problem or heard of this? 73 de N5NPO Norman knapp - Original Message - From: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Sent: Sat May 16 11:02:44 2009 Subject: [possible spam] RE: [Repeater-Builder] Re: Isolator Loss Do you have a low pass filter after the isolator? 73 Gary K4FMX > -Original Message- > From: Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> [mailto:Repeater- > buil...@yahoogroups.com <mailto:Builder%40yahoogroups.com> ] On Behalf Of > offtrack > Sent: Saturday, May 16, 2009 11:19 AM > To: Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > Subject: [Repeater-Builder] Re: Isolator Loss > > Eric > > Thanks for the confirmation on this. Its an older one that was tuned for > me its a T-2200 that was replaced by the T-1530 I think, if I read > correctly at the telwave site. > > I notice that the TKR 750 is running fine with no intermod issues ect. > > I was not sure about adding that meter in line and only did a quick check. > Thanks for the warning on that one. > > The Diamond is so far working ok. I soldered all the parts in the antenna > and sealed up all the possible leak points with a compound call "through > the roof" This stuff stays semi flexible and is clear. Its located at my > home and has been in service for about 2 years for my Simplex Echolink > node I replaced with the repeater. Works pretty good, but that said I > would never put it on a remote site as your correct not at all heavy duty. > the radome is egg shell thin, I worry about it at the house as I am on a > hill and get hit with some good winds/icing. So the Isolator in line helps > ease my mind a bit. > > Thanks > KB7DZR > Scott > > --- In Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> , "Eric Lemmon" > wrote: > > > > Scott, > > > > I must assume that you purchased a Telewave T-1530 Isolator, and its > > specified insertion loss is 0.4 dB. The readings you took indicate that > the > > isolator is working properly. However, it is not a good idea to insert > a > > meter between the isolator and the dummy load. The correct operation of > the > > isolator depends upon a stable 50 ohm impedance at the dummy load port. > > > > I think you made some good choices for the duplexer, feedline, and > isolator. > > The Diamond F22 is perhaps not the most rugged antenna for 2m repeater > use, > > but YMMV. > > > > 73, Eric Lemmon WB6FLY > > > > > > > > > > > > -Original Message- > > From: Repeater-Builder@yahoogroups.com > > <mailto:Repeater-Builder%40yahoogroups.com> > > [mailto:Repeater-Builder@yahoogroups.com > > <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of offtrack > > Sent: Friday, May 15, 2009 7:27 PM > > To: Repeater-Builder@yahoogroups.com > > <mailto:Repeater-Builder%40yahoogroups.com> > > Subject: [Repeater-Builder] Isolator Loss > > > > > > > > Hi all, > > > > Thanks for the group it has helped me out a bunch. > > My system here is a Kenwood TRK K2 and Telewave TPRD-1556 6 can set. > > Feed line is Heliax LDF4-50A about 70 feet and the antenna is a Diamond > F22 > > that has been worked over and sealed up better. > > > > The system is new and today I added a Telewave Isolator to the PA output > > before the duplexer TX input. With my meter I got about 28 watts out of > > antenna side of the duplexer set when connected to my antenna with out > the > > isolator. With the Isolator I am getting about 26 watts out now. This > seems > > good to me but I am new to an Isolator. Putting the meter between the > > isolator and the dummy load it is showing around 1.6 watts going to the > > dummy load. > > > > Just want to see if this is ok for this? > > > > KB7DZR > > Scott > > > > > > > > > > > Yahoo! Groups Links > > >
RE: [Repeater-Builder] Re: Isolator Loss
Do you have a low pass filter after the isolator? 73 Gary K4FMX > -Original Message- > From: Repeater-Builder@yahoogroups.com [mailto:Repeater- > buil...@yahoogroups.com] On Behalf Of offtrack > Sent: Saturday, May 16, 2009 11:19 AM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] Re: Isolator Loss > > Eric > > Thanks for the confirmation on this. Its an older one that was tuned for > me its a T-2200 that was replaced by the T-1530 I think, if I read > correctly at the telwave site. > > I notice that the TKR 750 is running fine with no intermod issues ect. > > I was not sure about adding that meter in line and only did a quick check. > Thanks for the warning on that one. > > The Diamond is so far working ok. I soldered all the parts in the antenna > and sealed up all the possible leak points with a compound call "through > the roof" This stuff stays semi flexible and is clear. Its located at my > home and has been in service for about 2 years for my Simplex Echolink > node I replaced with the repeater. Works pretty good, but that said I > would never put it on a remote site as your correct not at all heavy duty. > the radome is egg shell thin, I worry about it at the house as I am on a > hill and get hit with some good winds/icing. So the Isolator in line helps > ease my mind a bit. > > Thanks > KB7DZR > Scott > > --- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" wrote: > > > > Scott, > > > > I must assume that you purchased a Telewave T-1530 Isolator, and its > > specified insertion loss is 0.4 dB. The readings you took indicate that > the > > isolator is working properly. However, it is not a good idea to insert > a > > meter between the isolator and the dummy load. The correct operation of > the > > isolator depends upon a stable 50 ohm impedance at the dummy load port. > > > > I think you made some good choices for the duplexer, feedline, and > isolator. > > The Diamond F22 is perhaps not the most rugged antenna for 2m repeater > use, > > but YMMV. > > > > 73, Eric Lemmon WB6FLY > > > > > > > > > > > > -Original Message- > > From: Repeater-Builder@yahoogroups.com > > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of offtrack > > Sent: Friday, May 15, 2009 7:27 PM > > To: Repeater-Builder@yahoogroups.com > > Subject: [Repeater-Builder] Isolator Loss > > > > > > > > Hi all, > > > > Thanks for the group it has helped me out a bunch. > > My system here is a Kenwood TRK K2 and Telewave TPRD-1556 6 can set. > > Feed line is Heliax LDF4-50A about 70 feet and the antenna is a Diamond > F22 > > that has been worked over and sealed up better. > > > > The system is new and today I added a Telewave Isolator to the PA output > > before the duplexer TX input. With my meter I got about 28 watts out of > > antenna side of the duplexer set when connected to my antenna with out > the > > isolator. With the Isolator I am getting about 26 watts out now. This > seems > > good to me but I am new to an Isolator. Putting the meter between the > > isolator and the dummy load it is showing around 1.6 watts going to the > > dummy load. > > > > Just want to see if this is ok for this? > > > > KB7DZR > > Scott > > > > > > > > > > > Yahoo! Groups Links > > >
[Repeater-Builder] Re: Isolator Loss
Eric Thanks for the confirmation on this. Its an older one that was tuned for me its a T-2200 that was replaced by the T-1530 I think, if I read correctly at the telwave site. I notice that the TKR 750 is running fine with no intermod issues ect. I was not sure about adding that meter in line and only did a quick check. Thanks for the warning on that one. The Diamond is so far working ok. I soldered all the parts in the antenna and sealed up all the possible leak points with a compound call "through the roof" This stuff stays semi flexible and is clear. Its located at my home and has been in service for about 2 years for my Simplex Echolink node I replaced with the repeater. Works pretty good, but that said I would never put it on a remote site as your correct not at all heavy duty. the radome is egg shell thin, I worry about it at the house as I am on a hill and get hit with some good winds/icing. So the Isolator in line helps ease my mind a bit. Thanks KB7DZR Scott --- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" wrote: > > Scott, > > I must assume that you purchased a Telewave T-1530 Isolator, and its > specified insertion loss is 0.4 dB. The readings you took indicate that the > isolator is working properly. However, it is not a good idea to insert a > meter between the isolator and the dummy load. The correct operation of the > isolator depends upon a stable 50 ohm impedance at the dummy load port. > > I think you made some good choices for the duplexer, feedline, and isolator. > The Diamond F22 is perhaps not the most rugged antenna for 2m repeater use, > but YMMV. > > 73, Eric Lemmon WB6FLY > > > > > > -Original Message- > From: Repeater-Builder@yahoogroups.com > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of offtrack > Sent: Friday, May 15, 2009 7:27 PM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] Isolator Loss > > > > Hi all, > > Thanks for the group it has helped me out a bunch. > My system here is a Kenwood TRK K2 and Telewave TPRD-1556 6 can set. > Feed line is Heliax LDF4-50A about 70 feet and the antenna is a Diamond F22 > that has been worked over and sealed up better. > > The system is new and today I added a Telewave Isolator to the PA output > before the duplexer TX input. With my meter I got about 28 watts out of > antenna side of the duplexer set when connected to my antenna with out the > isolator. With the Isolator I am getting about 26 watts out now. This seems > good to me but I am new to an Isolator. Putting the meter between the > isolator and the dummy load it is showing around 1.6 watts going to the > dummy load. > > Just want to see if this is ok for this? > > KB7DZR > Scott >
[Repeater-Builder] Re: isolator
Bob, Yes, I looked for better than hour and did find some good info. I am sure not all for it seems hard to locate some items after having to read thru tons of titles, but then again one learns about other things, hi. 73, ron, n9ee/r ps Thanks to all who replied with real information. --- In Repeater-Builder@yahoogroups.com, "Bob M." <[EMAIL PROTECTED]> wrote: > > Have you checked the web site that accompanies this Yahoo! Group? > > Bob M. > == > --- On Wed, 11/12/08, Ron Wright <[EMAIL PROTECTED]> wrote: > > > From: Ron Wright <[EMAIL PROTECTED]> > > Subject: [Repeater-Builder] isolator > > To: Repeater-Builder@yahoogroups.com > > Date: Wednesday, November 12, 2008, 11:01 PM > > Hi all, > > > > I have aquired a EMR Isolator, model 7450/4 for 150-170 Mhz > > and tuned > > to 155 MHz. > > > > It has 3 tuning adjustments so need to retune it. > > > > Can anyone give info as to how to tune it or where I can > > get info. EMR > > has good info on what it does and how it works, but found > > nothing at > > their site on tuning. Tune for low SWR, max power out, min > > smoke, > > etc??? > > > > 73, ron, n9ee/r >
[Repeater-Builder] Re: isolator
Its all spelled out here: http://www.repeater-builder.com/antenna/care-and-feeding-of-the-rf-isolator.pdf --- In Repeater-Builder@yahoogroups.com, "Ron Wright" <[EMAIL PROTECTED]> wrote: > > Hi all, > > I have aquired a EMR Isolator, model 7450/4 for 150-170 Mhz and tuned > to 155 MHz. > > It has 3 tuning adjustments so need to retune it. > > Can anyone give info as to how to tune it or where I can get info. EMR > has good info on what it does and how it works, but found nothing at > their site on tuning. Tune for low SWR, max power out, min smoke, > etc??? > > 73, ron, n9ee/r >
[Repeater-Builder] Re: isolator - circulator loss
Might have been better to run more than one transmit antenna... that's what I try to do in similar applications. There are also quite a few different types of close spaced combiners... cheers, skipp > Jamey Wright <[EMAIL PROTECTED]> wrote: > > I'd love to only have 2.5 dB loss. We're over 5 dB here on our 10 channel site but some of our freqs are 250 kHz apart too (800 MHz Trunked). > > 100W through the combiner and through 300 Ft of 1 5/8 cable (plus Polyphaser, jumpers, connectors, etc) yields between 15 and 20 watts (calculated) at the top of the tower. > > Jamey Wright > Systems Analyst/EDACS Administrator > Morgan County EMCD 911 > Decatur, AL > 256-552-0911 > > > Amen Paul, > > > > In the real commercial radio world... when working on or into > > combiner systems... some people would give their first born to > > have less than 2.5 dB loss per channel. > > > > Although the entire path to the antenna can be a lossy son of > > a gun, it is the only real game in town worth playing. > > > > cheers, > > s. > > > > > "Paul Plack" wrote: > > > > > > Using an isolator between a 100-watt transmitter and a perfectly > > matched antenna still only gets you 90 watts out. A typical isolator > > loses 0.5 dB on the forward path. > > > > > > 73, > > > Paul, AE4KR > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > >
[Repeater-Builder] Re: Isolator retuning question
> Bob Dengler <[EMAIL PROTECTED]> wrote: > > It takes more than a spectrum analyzer to properly > > tune a circulator or isolator. > > Yes, need a tracking gen. to go with the spectrum > analyzer. Personally I use a TX, wattmeter & 2nd > isolator (already tuned to freq. of course, to > keep the TX looking like 50 ohms while tuning the > isolator under test). > The tracking generator is used as a review tool. Some circu/isolators drift quite a bit with applied power. Best to tune it up near the expected temp and operating power as you get it into the ball part. Service monitor cold (low signal) tuning only gets you in the area. Multiple loads, watt meters and a service monitor are the big players. Tune it once at lower power, then tune it again at full power. There will be a difference. skipp Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Isolator retuning question
In addition to the below, tuning changes pretty fast with heat rise (applied rf) and proximity to other metals. skipp > Eric Lemmon <[EMAIL PROTECTED]> wrote: > Tom, > > If you have been following this thread for a while, you probably have > picked up on the fact that the typical isolator cannot be tuned more > than 1 or 2 MHz away from the original factory tuning. It takes more > than a spectrum analyzer to properly tune a circulator or isolator. > Moreover, the typical isolator/circulator must be remanufactured in > order to work properly on a frequency that is more than 2 or 3 MHz away > from the original frequency. > > Although the best action is to return the isolator to the factory for > rework, some firms, such as EMR and Telewave, have the expertise and > wherewithal to remanufacture isolators made by others. Judging from the > postings on this subject, I think that some readers may believe that an > isolator may be retuned to the 2m band from the 160 MHz band simply by > tweaking a few variable capacitors. Not true! Several internal > components may need to be replaced, reground, or remachined in order to > fit the precise parameters needed by a new operating frequency. > > 73, Eric Lemmon WB6FLY > > Thomas Oliver wrote: > > > After losing a PA I am wanting to put an isolator in line before > > installing the new amp and was needing some information about an > > isolator I have, it is a Microwave Associates model # J-2101multi > > stage isolator origionaly on 460 Mhz. Does anyone know if it can be > > retuned down to 442 Mhz? or any othe specifications of this beast? I > > have tried to remove the outer cover and it seems to be held with > > something other than the 4 cover screws. tom n8ies > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: isolator / circulator needed
Think you sold them all to me a year or two back Doug. Or some guy with a similar Ebay ID sold them to me... been that long... Email me direct if you need one, I'll pass it back to you for cost (If I can remember what I paid for them), just let me know. I've got UHF and (mostly) VHF circuilators rated at 300 watts. I'll sell them out to serious project hams. Email me off the list if you need something. skipp025 at yahoo.com www.radiowrench.com/sonic > doug <[EMAIL PROTECTED]> wrote: > > i need one of those monster 300+ watt capable > circulators from (i think) rockwell. > > these are fairly broad-banded (last one i saw > was 140-155) and requires NO TUNING. > > i can't seem to find the one i had and i have > a 350w MSF station i just put on 2m that i > really need this for. i'm not so concerned > with intermod as much as i am saving the PA > should anything go amiss not that the MSF > will key anyway with problems! > HELP! > > > > doug Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Isolator retuning question
The case is probably being held together by the magnets :) I had one shipped from the US to me in Canada, and customs pried mine open and broke the magnets, so be careful. Mine was tuned with small metal shims epoxied around the outside of the magents. It was a royal pain to tune as you have to see what happens to the power in all three directions. I ended up having to throw it in the useless pile, and purchased a new one for my band split. Dave Cameron VE7LTD --- In Repeater-Builder@yahoogroups.com, "Thomas Oliver" <[EMAIL PROTECTED]> wrote: > > After losing a PA I am wanting to put an isolator in line before installing the new amp and was needing some information about an isolator I have, it is a Microwave Associates model # J-2101multi stage isolator origionaly on 460 Mhz. Does anyone know if it can be retuned down to 442 Mhz? or any othe specifications of this beast? I have tried to remove the outer cover and it seems to be held with something other than the 4 cover screws. > > tom n8ies Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
