Can a non-standard PL effect the RX sens on a repeater?
We have a repeater with a VERY narrow split and tuned up the duplexers and got the repeater to open sql @ 0.15mV with full quieting around 0.25mV however the range of the repeater sucks.
So I was wondering if a non-standard PL which we use for the input can have an effect on the repeater while in repeater mode?
I am going to have to re-check the tuning on the cans and go from there but as it sits right now the range sucks. Antenna is good, repeater is good, and we will find out about duplexer soon. The only other thing I can think it is, is with the duplexer being tuned for notch and not pass which I think it might be. ( We got the used with no documentation or visable part numbers.)
But before I went looking for maybe a new duplexer I thought I might try and ask this first.
Non-standard PL's and RX sens.
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Non-standard PL's and RX sens.
" ah the fatman made a funny!" - Stewie from the family guy.
I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
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psapengineer
- Posts: 175
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Mis-Matched PL
I don't know if this will be of value but here we go:
Some time back we had a system that generated 151.33Hz for the PL instead of the 151.4 standard PL.
We found that receivers, listening to the system, that used a DSP algorithm to detect PL, had a lot of grief with 151.33 in that it was slow to open and failed to notch out most the PL hum before the speaker.
Good Luck, Bob
Some time back we had a system that generated 151.33Hz for the PL instead of the 151.4 standard PL.
We found that receivers, listening to the system, that used a DSP algorithm to detect PL, had a lot of grief with 151.33 in that it was slow to open and failed to notch out most the PL hum before the speaker.
Good Luck, Bob
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Dan562
- Posts: 533
- Joined: Mon Aug 23, 2004 7:30 pm
- What radios do you own?: Kenwood, Yaesu, ICOM, Motorola
Since you haven't provided the Tx / Rx Frequency separation and band but included as you have stated, "a very narrow frequency split," generally any split lower than 400 kHz on VHF 132~174 MHz and 1 MHz on UHF 380~520 MHz will degrade the performance of the repeater's coverage because of Desense. And you would be required to have special duplexers purchased and built for your frequency split $$$$$$ "if" a commercial manufacture could even provide a less than 400 kHz on VHF or 1 MHz on UHF to satisfying your requirements.
The only alternative I can see, would be to mount a second antenna of the same gain* (+6 dB) on 60~250 foot tower or higher depending on your reqiured signal coverage area. Place the receive antenna on the top of the tower and/or above the transmit antenna with a minimum vertical separation of 20 feet between the bottom of the receive antenna and top of the transmit antenna.
*Antenna Gain can be manipulated as "IF" you're using +6 dB Gain antenna currently mounted on a tower at 40 feet (antenna tip) then add 30 feet of tower sections above and mount a +3 dB Gain at the top of the tower would provide balanced antenna system gain and signal coverage.
It would not hurt to tune a single cavity notch filter for the RF transmit channel and insert the cavity into the receiver feedline to provide better signal isolation. I will also recommend using Andrews RF Heliax feedline 1/2" minimum, preferably 7/8" with silver plated Heliax connectors to insure your losses are at a minimum.
The only alternative I can see, would be to mount a second antenna of the same gain* (+6 dB) on 60~250 foot tower or higher depending on your reqiured signal coverage area. Place the receive antenna on the top of the tower and/or above the transmit antenna with a minimum vertical separation of 20 feet between the bottom of the receive antenna and top of the transmit antenna.
*Antenna Gain can be manipulated as "IF" you're using +6 dB Gain antenna currently mounted on a tower at 40 feet (antenna tip) then add 30 feet of tower sections above and mount a +3 dB Gain at the top of the tower would provide balanced antenna system gain and signal coverage.
It would not hurt to tune a single cavity notch filter for the RF transmit channel and insert the cavity into the receiver feedline to provide better signal isolation. I will also recommend using Andrews RF Heliax feedline 1/2" minimum, preferably 7/8" with silver plated Heliax connectors to insure your losses are at a minimum.
OK well I found out the issue with the repeater on the RX sens side of things was a bad RX front end on the repeaer. I tuned it to have a RX sens at about 0.19mV but when I checked it, it was around 0.70mV.
So I put a new Rx front end in and was only able to tune it down to 0.31mV (mainly due to time).
The split of the repeater is 0.585 MHz between Rx and Tx freq. We have a duplexer which is a pass duplexer and not a notch. We also have a pass filter on the Rx side also.
We are using a 5 dB gain VHF antenna mounted approx one story above the repeater. The repeater is located in the top of a building/doom area.
The repeater is a GE Master 3 repeater with a non-standard input which we are now switching back to a standard PL as we have cleared up the non-authorized usage of the repeater.
The problem I am having is that I can not get even a mile or two away from the repeater and 5 watt handhelds can not keep the repeater open. Mobiles are ok but we are looking for good portable coverage.
I am out of ideals as to what could be the problem. We are using a duplexer, different PL's??? Anybody have any ideals. The repeater is 100 watts and is wideband format. Out of the duplexer I am getting about 77 watts but at the repeater it is 100 watts.
Can someone please offer assistance????
So I put a new Rx front end in and was only able to tune it down to 0.31mV (mainly due to time).
The split of the repeater is 0.585 MHz between Rx and Tx freq. We have a duplexer which is a pass duplexer and not a notch. We also have a pass filter on the Rx side also.
We are using a 5 dB gain VHF antenna mounted approx one story above the repeater. The repeater is located in the top of a building/doom area.
The repeater is a GE Master 3 repeater with a non-standard input which we are now switching back to a standard PL as we have cleared up the non-authorized usage of the repeater.
The problem I am having is that I can not get even a mile or two away from the repeater and 5 watt handhelds can not keep the repeater open. Mobiles are ok but we are looking for good portable coverage.
I am out of ideals as to what could be the problem. We are using a duplexer, different PL's??? Anybody have any ideals. The repeater is 100 watts and is wideband format. Out of the duplexer I am getting about 77 watts but at the repeater it is 100 watts.
Can someone please offer assistance????
" ah the fatman made a funny!" - Stewie from the family guy.
I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
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Dan562
- Posts: 533
- Joined: Mon Aug 23, 2004 7:30 pm
- What radios do you own?: Kenwood, Yaesu, ICOM, Motorola
Here's your assistance .....
I was conversing with a friend today about your Desense RF signal problems with your antenna, repeater and system location. If I recall correctly this repeater's location is in a historic slated county building with a dome built roughly 100 years ago.
The historic fanatics forced everyone's antennas off of the top of the building also forcing the local cellular tower site to relocate somewhere else other than near this structure. Because you're a Paramedic with an amateur radio license, you've been chosen to oversee this repeater system which is now completely inside the building. You have stated that the repeater's antenna is a Cushcraft Ringo Ranger located roughly 15~20
feet above the GE Master III repeater station inside of the wooden dome.
Well, here's the bad news. When that 100 year old structure with the dome was constructed, the workers applied either a bronze, brass or copper sheathing to the dome's outside structure just like in today's roofing construction preventing rain, snow or any other water from penetrating the wooden dome causing leaks and/or rotting conditions.
Therefore mounting any radiating antenna such as your Ringo Ranger or any commercial version antenna will be sitting under a Faraday shield preventing good signal radiation. In other words, all of the signal radiated from the antenna is being sent down into the building and GE repeater no matter what you have tried to do to correct the problem.
Your only solution is to move the entire repeater and antenna from that site to another building or tower providing the signal coverage you need.
I was conversing with a friend today about your Desense RF signal problems with your antenna, repeater and system location. If I recall correctly this repeater's location is in a historic slated county building with a dome built roughly 100 years ago.
The historic fanatics forced everyone's antennas off of the top of the building also forcing the local cellular tower site to relocate somewhere else other than near this structure. Because you're a Paramedic with an amateur radio license, you've been chosen to oversee this repeater system which is now completely inside the building. You have stated that the repeater's antenna is a Cushcraft Ringo Ranger located roughly 15~20
feet above the GE Master III repeater station inside of the wooden dome.
Well, here's the bad news. When that 100 year old structure with the dome was constructed, the workers applied either a bronze, brass or copper sheathing to the dome's outside structure just like in today's roofing construction preventing rain, snow or any other water from penetrating the wooden dome causing leaks and/or rotting conditions.
Therefore mounting any radiating antenna such as your Ringo Ranger or any commercial version antenna will be sitting under a Faraday shield preventing good signal radiation. In other words, all of the signal radiated from the antenna is being sent down into the building and GE repeater no matter what you have tried to do to correct the problem.
Your only solution is to move the entire repeater and antenna from that site to another building or tower providing the signal coverage you need.
Well your correct and not so correct.
Yes we did have some trouble with the cell company and that finally was all resolved with the cell company greeing to pay for the new antenna and a duplexer. (That was a nightmare I never want to deal with again.)
We purchased a brand new 7dB gain antenna, as well as a duplexer. Both were tuned up very very nicely and are at top performance.
I am not a paramedic (do not have time for commitment yet) and I am only an I99. (In WI we jokingly call that paramedic Jr.) I am a radio tech by trade but was getting very very stumped with this as I followed our companies standard set-up and installation guidelines once we were able to get the correct equipment.
MIND YOU: The ringo and the split antenna and the filtering was placed in there by the cell company and at the time the service did not know what to do about the problem and just wanted me to work with it against my better will/judgement.
I never thought about the lead factor in the "seal coating". But is this really going to effect the recieve range greatly???
The rptr is 100 watts and after duplexer loss we transmit at about 80watts going into a 5dB gain antenna. We did purchase a 2 or 3 dB gain antenna (can't remember which) which is smaller that we were going to use on the station building. But if that is the case we can get up into the "pigeon coop" where you can not see any antennas and would be out of the dome.
In addition I also did some digging and found that the freq we are on is only about 30 KHz away from the PW dept. and our location is not that far physically from there antenna so I think we are having some problems there.
Also to since we have ended the un-authorized use issue we have moved to a standard PL and no more of the non-standard PL issues.
Anyways thanks for your help and input. Sometimes it is hard to step back and look at the bigger picture. In closing I hope that you did not refer to me as that stupid dumba$$ ham wannabe radio tech to your friend.
Yes we did have some trouble with the cell company and that finally was all resolved with the cell company greeing to pay for the new antenna and a duplexer. (That was a nightmare I never want to deal with again.)
We purchased a brand new 7dB gain antenna, as well as a duplexer. Both were tuned up very very nicely and are at top performance.
I am not a paramedic (do not have time for commitment yet) and I am only an I99. (In WI we jokingly call that paramedic Jr.) I am a radio tech by trade but was getting very very stumped with this as I followed our companies standard set-up and installation guidelines once we were able to get the correct equipment.
MIND YOU: The ringo and the split antenna and the filtering was placed in there by the cell company and at the time the service did not know what to do about the problem and just wanted me to work with it against my better will/judgement.
I never thought about the lead factor in the "seal coating". But is this really going to effect the recieve range greatly???
The rptr is 100 watts and after duplexer loss we transmit at about 80watts going into a 5dB gain antenna. We did purchase a 2 or 3 dB gain antenna (can't remember which) which is smaller that we were going to use on the station building. But if that is the case we can get up into the "pigeon coop" where you can not see any antennas and would be out of the dome.
In addition I also did some digging and found that the freq we are on is only about 30 KHz away from the PW dept. and our location is not that far physically from there antenna so I think we are having some problems there.
Also to since we have ended the un-authorized use issue we have moved to a standard PL and no more of the non-standard PL issues.
Anyways thanks for your help and input. Sometimes it is hard to step back and look at the bigger picture. In closing I hope that you did not refer to me as that stupid dumba$$ ham wannabe radio tech to your friend.
" ah the fatman made a funny!" - Stewie from the family guy.
I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
-
Dan562
- Posts: 533
- Joined: Mon Aug 23, 2004 7:30 pm
- What radios do you own?: Kenwood, Yaesu, ICOM, Motorola
Hello John,
First of all, it would be unprofessional to refer to another amateur radio operator as a dumba$$ behind their back as people on this forum or in general conversation with other hams. My friend is Jerry N9AVY and he's in the Security and Alarm business but has a great memory on many subjects and one happens to be building construction in late 19th and early 20th centuries.
I described the historic county building with the dome and Jerry pointed out what the construction people did back then by applying either brass, bronze or copper flashing covering the entire dome's outter surface area to prevent water damage to the wooden structure. Hearing that, a light bulb went on in my brain thinking, "I wonder if John thought of this consideration?" It still appears as too much unwanted RF is flying around within the building or structure.
As everyone on this forum, has to read between the lines in many cases because of human nature, we assume the other people knows the situation or problem that has evolved for each individual submitting help and trying to resolve the problems for themselves or their customers.
I use to deal with many /\/\ Area System Engineers, Account Reps, Customers and Independent /\/\ Dealership's personnel. The major problem I found was getting the correct information to SP (modify) and provide Bid & Quotes either for the Quantars or MTR2000 Base Station Products.
It seemed that everyone thought I possessed "E.S.P." to know exactly what they wanted or needed in addition to the standard Base Station Products. Some how I was never assigned a /\/\ crystal ball to see into the future, there was a lot of guess work involved while I developed the new SP options, products and aiding the factory's technical personnel that could barely identify pieces of test equipment. Let alone test the SP functionality with written documentation describing down to the smallest detail how to configure the test equipment and Base Station products for special testing.
It was a sad situation doing this work. I wrote the SP test documents and the published manuals for Grammar School 5th grade students that knew nothing about electronics or even radio communications equipment. I can bet their are many senior technical field personnel wondering why these manuals were written this way.
Now back to your system problem ... I'm not aware of this vinyl embedded lead tar compound material that the historic county boilding has applied to the dome. Does this product have a trade name so I can research it on the internet? Depending on how much of a lead ratio is embedded into the roofing material could degrade the performance of the repeater. By the way, which frequency band is the repeater licensed on, VHF or UHF? I hope the pigeon hole structure is all wood and enough of the +7 dB Gain antenna extends above the roof line. As for the Public Works Fequency being 30 kHz from the GE Master III repeater, "Is the PWs Base Station a repeater too? I will suggest to install a Notch Filter into the Paramedics repeater's receiver antenna line and tune it for the PWs Transmit frequency.
I know exactly how you feel about being dragged into this radio problem as I was a field service tech on radio communications equipment 25 years and an additional 10 years in various engineering positions of my career. It will drive you crazy trying to troubleshoot the problem and sometimes you'll need someone to stop and discuss the problems.
Dan
First of all, it would be unprofessional to refer to another amateur radio operator as a dumba$$ behind their back as people on this forum or in general conversation with other hams. My friend is Jerry N9AVY and he's in the Security and Alarm business but has a great memory on many subjects and one happens to be building construction in late 19th and early 20th centuries.
I described the historic county building with the dome and Jerry pointed out what the construction people did back then by applying either brass, bronze or copper flashing covering the entire dome's outter surface area to prevent water damage to the wooden structure. Hearing that, a light bulb went on in my brain thinking, "I wonder if John thought of this consideration?" It still appears as too much unwanted RF is flying around within the building or structure.
As everyone on this forum, has to read between the lines in many cases because of human nature, we assume the other people knows the situation or problem that has evolved for each individual submitting help and trying to resolve the problems for themselves or their customers.
I use to deal with many /\/\ Area System Engineers, Account Reps, Customers and Independent /\/\ Dealership's personnel. The major problem I found was getting the correct information to SP (modify) and provide Bid & Quotes either for the Quantars or MTR2000 Base Station Products.
It seemed that everyone thought I possessed "E.S.P." to know exactly what they wanted or needed in addition to the standard Base Station Products. Some how I was never assigned a /\/\ crystal ball to see into the future, there was a lot of guess work involved while I developed the new SP options, products and aiding the factory's technical personnel that could barely identify pieces of test equipment. Let alone test the SP functionality with written documentation describing down to the smallest detail how to configure the test equipment and Base Station products for special testing.
It was a sad situation doing this work. I wrote the SP test documents and the published manuals for Grammar School 5th grade students that knew nothing about electronics or even radio communications equipment. I can bet their are many senior technical field personnel wondering why these manuals were written this way.
Now back to your system problem ... I'm not aware of this vinyl embedded lead tar compound material that the historic county boilding has applied to the dome. Does this product have a trade name so I can research it on the internet? Depending on how much of a lead ratio is embedded into the roofing material could degrade the performance of the repeater. By the way, which frequency band is the repeater licensed on, VHF or UHF? I hope the pigeon hole structure is all wood and enough of the +7 dB Gain antenna extends above the roof line. As for the Public Works Fequency being 30 kHz from the GE Master III repeater, "Is the PWs Base Station a repeater too? I will suggest to install a Notch Filter into the Paramedics repeater's receiver antenna line and tune it for the PWs Transmit frequency.
I know exactly how you feel about being dragged into this radio problem as I was a field service tech on radio communications equipment 25 years and an additional 10 years in various engineering positions of my career. It will drive you crazy trying to troubleshoot the problem and sometimes you'll need someone to stop and discuss the problems.
Dan