Is anyone here familiar with the JPS SNV12 voter? I'm trying to design how this system can do what we need it to do but the manual is leaving some unanswered questions.
Lets say I have two groups, each with transmitters and receivers configured properly. I need to use function tone driven transmitter steering from the console to steer where the dispatcher talks. But the manual also says that if you enable function tone driven steering, it disables the regular RX/TX group repeat steering. If it disables the RX group functionality, how does it handle repeat instead?
JPS SNV12 transmitter steering
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JPS SNV12 transmitter steering
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
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Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
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eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
Re: JPS SNV12 transmitter steering
See if this helps:
The JPS firmware is designed to address two different scenarios:
The common one, where the dispatcher wants to switch all Tx traffic from one transmitter (the main) to a second one (the standby). This is pretty straightforward, though we continue to do it via an external relay. For single console applications, the easiest way to control the relay is via a console auxiliary output. For multiple paralleled consoles, we worked out a somewhat more complex solutions, using TRAs to control sets of relays at each CEB point, which I'll withhold the description of because (a) it is complex and (b) I doubt anyone is interested.
The less common scenario is "receiver-steered transmission," where the receiver used for repeating subscriber traffic varies based on which receiver voted on the subscriber's input. This is a solution that lot's of folks have attempted for applications where a single "main" transmitter won't cover the entire service area. In the main, receiver steered transmission doesn't work very well, not because of any limitation in the hardware, but because of the vagaries of signal propigation.
I suspect what you want to do is the common scenario. If you want to do this via FTs sent by the console to the JPS Voter, hook your main Tx up to SVN-1, and your standby Tx to SVN-2 and use a console AuxOut to pull TB2-8 to ground. Herewith my notes:
========Begin notes=======
As presently set up, Main/Standby is presently handled by wiring Tx+ and Tx- from the comparator Tx line to P1Com and P2Com of the associated relay, the Main transmitter Tx line to P1NC and P2 NC of the relay and the Standby transmitter Tx line to P1NO and P2NO of the relay. In short, Main/Standby switch is done entirely dehors the comparator. There is no electrical reason why this approach cannot be continued with the JPS Voter substituted for the SpectraTac.In the alternative, we can wire the console Tx lines to the JPS Voter CIM module (either TB13-1 and –2 or P2-10 and –3) and the Main and Standby transmitters to pins –4 and –5 of SVMs #1 and #2, respectively (TB1- and TB2-). Normally, the JPS Voter will route transmit audio (repeated and console) to the transmitter attached to SVM #1; if pin TBx–8 of any other transmitter-connected SVM is grounded, transmit audio will be routed to that transmitter so long as the grounded condition endures.Either method will work, and I see little basis for preference. The advantage of leaving things as they are is that one can leave things as they are. Benjamin Hillman of JPS has suggested (correctly) that one advantage of allowing the JPS Voter to handle Main/Standby transmitter steering is that Tx levels can be independently adjusted for each of the transmitters. (Email dated 5/15/08.) This might be important in other applications, but since backhaul to both of our transmitters is by fiber optic circuits that have demonstrated nil line losses, no differential level setting has been or should be necessary.
=========End notes=======
However, as noted, I'd continue to do Main/Stby switching the old fashioned way (completely outside of the voter).
I think the JPS Voter manual is superb, but because the product is so sophisticated (far more so than in required in the usual public safety voted system), the manual can be a tad dense at times. If you hae issues, send an email to Benjy Hillman at JPS. He is quite knowledgeable and quite responsive.
While we're at it, if you're thinking about upgrading some aging SpectraTacs with new JPS Voters (as a lot of people are doing), be aware of one limitation that the JPS folks have yet to overcome:
========Begin notes ========
I detect, however, one significant difference between the JPS Voter and the SpectraTac with respect to status display: the JPS Voter does not appear to have an indication func-tionally equivalent to the output function of SpectraTac SQM Pin 19. That is to say, while externally pulling SpectraTac SQM Pin 19 to ground disables the receiver equally with disabling the receiver via the switch on the front of the SQM, using the front switch of the SVM does not pull the equivalent pin on the backplane to ground, as it does with the SpectraTac. (In fact, the only function of the SQM front panel switch is to pull Pin 19 to ground.) What this means is that the JPS voter has no means of displaying to a console that a technician has locally disabled a receiver (and then, perhaps, forgotten to re-enable that receiver at the conclusion of his work), and the JPS Voter has no means of displaying to one console that a receiver has been remotely disabled by another console (or remote).
========End notes==========
Depending on your set up, this could be important to you or not.
The JPS firmware is designed to address two different scenarios:
The common one, where the dispatcher wants to switch all Tx traffic from one transmitter (the main) to a second one (the standby). This is pretty straightforward, though we continue to do it via an external relay. For single console applications, the easiest way to control the relay is via a console auxiliary output. For multiple paralleled consoles, we worked out a somewhat more complex solutions, using TRAs to control sets of relays at each CEB point, which I'll withhold the description of because (a) it is complex and (b) I doubt anyone is interested.
The less common scenario is "receiver-steered transmission," where the receiver used for repeating subscriber traffic varies based on which receiver voted on the subscriber's input. This is a solution that lot's of folks have attempted for applications where a single "main" transmitter won't cover the entire service area. In the main, receiver steered transmission doesn't work very well, not because of any limitation in the hardware, but because of the vagaries of signal propigation.
I suspect what you want to do is the common scenario. If you want to do this via FTs sent by the console to the JPS Voter, hook your main Tx up to SVN-1, and your standby Tx to SVN-2 and use a console AuxOut to pull TB2-8 to ground. Herewith my notes:
========Begin notes=======
As presently set up, Main/Standby is presently handled by wiring Tx+ and Tx- from the comparator Tx line to P1Com and P2Com of the associated relay, the Main transmitter Tx line to P1NC and P2 NC of the relay and the Standby transmitter Tx line to P1NO and P2NO of the relay. In short, Main/Standby switch is done entirely dehors the comparator. There is no electrical reason why this approach cannot be continued with the JPS Voter substituted for the SpectraTac.In the alternative, we can wire the console Tx lines to the JPS Voter CIM module (either TB13-1 and –2 or P2-10 and –3) and the Main and Standby transmitters to pins –4 and –5 of SVMs #1 and #2, respectively (TB1- and TB2-). Normally, the JPS Voter will route transmit audio (repeated and console) to the transmitter attached to SVM #1; if pin TBx–8 of any other transmitter-connected SVM is grounded, transmit audio will be routed to that transmitter so long as the grounded condition endures.Either method will work, and I see little basis for preference. The advantage of leaving things as they are is that one can leave things as they are. Benjamin Hillman of JPS has suggested (correctly) that one advantage of allowing the JPS Voter to handle Main/Standby transmitter steering is that Tx levels can be independently adjusted for each of the transmitters. (Email dated 5/15/08.) This might be important in other applications, but since backhaul to both of our transmitters is by fiber optic circuits that have demonstrated nil line losses, no differential level setting has been or should be necessary.
=========End notes=======
However, as noted, I'd continue to do Main/Stby switching the old fashioned way (completely outside of the voter).
I think the JPS Voter manual is superb, but because the product is so sophisticated (far more so than in required in the usual public safety voted system), the manual can be a tad dense at times. If you hae issues, send an email to Benjy Hillman at JPS. He is quite knowledgeable and quite responsive.
While we're at it, if you're thinking about upgrading some aging SpectraTacs with new JPS Voters (as a lot of people are doing), be aware of one limitation that the JPS folks have yet to overcome:
========Begin notes ========
I detect, however, one significant difference between the JPS Voter and the SpectraTac with respect to status display: the JPS Voter does not appear to have an indication func-tionally equivalent to the output function of SpectraTac SQM Pin 19. That is to say, while externally pulling SpectraTac SQM Pin 19 to ground disables the receiver equally with disabling the receiver via the switch on the front of the SQM, using the front switch of the SVM does not pull the equivalent pin on the backplane to ground, as it does with the SpectraTac. (In fact, the only function of the SQM front panel switch is to pull Pin 19 to ground.) What this means is that the JPS voter has no means of displaying to a console that a technician has locally disabled a receiver (and then, perhaps, forgotten to re-enable that receiver at the conclusion of his work), and the JPS Voter has no means of displaying to one console that a receiver has been remotely disabled by another console (or remote).
========End notes==========
Depending on your set up, this could be important to you or not.
Re: JPS SNV12 transmitter steering
Oh I only wish this was that easy! Prepare to scratch your head! We have FOUR transmitters. A UHF repeater and low band simplex base on the north end. A UHF repeater and low band simplex base on the south end. Yep. That's right! I'm trying to use this thing to control a cross-band system as well!
What I want to do is this:
Group One has both south transmitters and all the south receivers. Those sites will steer to BOTH those transmitters. Group two has both north transmitters and all the north receivers. I need both transmitters to activate for each group. South sites in group one key up both group one transmitters. North sites in group two key up both transmitters in group two.
I need function tone keying from the console to pick which group the console will transmit from. For example, F1 will key up group one transmitters and F2 will key up group two transmitters. This will let the dispatcher pick north or south and it will work perfect with the paging tones.
Problem is the manual seems to state that if I use function tone driven steering, it will kill the receiver driven steering for repeated transmissions. I can't figure out how it picks which transmitter to use in the absence of that while using function tone driven console steering.
I was going to use aux outputs to ground the TXSEL terminals for overriding the automatic steering.
What I want to do is this:
Group One has both south transmitters and all the south receivers. Those sites will steer to BOTH those transmitters. Group two has both north transmitters and all the north receivers. I need both transmitters to activate for each group. South sites in group one key up both group one transmitters. North sites in group two key up both transmitters in group two.
I need function tone keying from the console to pick which group the console will transmit from. For example, F1 will key up group one transmitters and F2 will key up group two transmitters. This will let the dispatcher pick north or south and it will work perfect with the paging tones.
Problem is the manual seems to state that if I use function tone driven steering, it will kill the receiver driven steering for repeated transmissions. I can't figure out how it picks which transmitter to use in the absence of that while using function tone driven console steering.
I was going to use aux outputs to ground the TXSEL terminals for overriding the automatic steering.
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
Re: JPS SNV12 transmitter steering
Let me ponder this.
I gather what you are doing is what we used to call A-to-B; B-to-A, and in the old days this was done via PL tones (for the subscribers) and AuxOuts and relays for the dispatcher.
I'll have to make some diagrams to see if there is a way to automate it via the JSP Voter.
I gather what you are doing is what we used to call A-to-B; B-to-A, and in the old days this was done via PL tones (for the subscribers) and AuxOuts and relays for the dispatcher.
I'll have to make some diagrams to see if there is a way to automate it via the JSP Voter.
Re: JPS SNV12 transmitter steering
I talked to Benny today! That guy is great. He said this was definitely the strangest application he's come across yet, rivaling the things the guys in Iraq have tried to do. This is a true honor!
First he confirmed that when function tone driven console transmit steering is enabled, all RX group functionality is disabled. So my initial plan won't work. Enter PLAN B!
The voter will be setup for receiver group voting as described. Function tones from the console talk to a separate Tone Panel. In this case, a Telex DSP223 (kick ass tone panel which we just happen to have sitting around doing nothing!) This tone panel can be programmed to do any number of convoluted things based on function tones. Now any other normal person would connect a tone panel to a radio. To hell with that. I'm going to connect it to the SNV-12 and rock it's world.
The PTT output of the tone panel will be routed to the common pin of the tone panel's relay 1 and to the SNV12 console PTT.
The normally closed side of the tone panel's relay one will be connected to the TxSEL terminals on the two north transmitters. So when you key up, it will send ground to the SNV12 console PTT and steer to the the two north transmitters. Releasing the PTT drops the grounded TxSel releasing the voter to go back doing its thing. Perfect.
The normally open side of the tone panel's relay 1 will be connected to the TxSEL terminals on the two south transmitters. F2 from the console will energize Relay 1. PTT will be sent to the SNV12 console PTT and steer to the two south transmitters. Releasing the PTT drops the grounded TxSEL releasing the voter to go back to doing its thing. Perfect.
An axillary output from the console will apply a ground directly to the common pin on relay one (with a diode to isolate it from PTT). This will allow the dispatcher to manually override the receiver group voting and force all repeated transmissions to one site or the other. This button will be entitled AUTO/MANUAL, referring to the site steering. Perfect. I might need to jump the simplex base's COR into the TX inhibit terminal so it doesn't try to repeat onto itself while that site is manually steered. No big deal.
So in the end, I get my group voting and i get my function tone driven console steering and I get my manual override. Everything in the manual agrees and Benny says it will work.
First he confirmed that when function tone driven console transmit steering is enabled, all RX group functionality is disabled. So my initial plan won't work. Enter PLAN B!
The voter will be setup for receiver group voting as described. Function tones from the console talk to a separate Tone Panel. In this case, a Telex DSP223 (kick ass tone panel which we just happen to have sitting around doing nothing!) This tone panel can be programmed to do any number of convoluted things based on function tones. Now any other normal person would connect a tone panel to a radio. To hell with that. I'm going to connect it to the SNV-12 and rock it's world.
The PTT output of the tone panel will be routed to the common pin of the tone panel's relay 1 and to the SNV12 console PTT.
The normally closed side of the tone panel's relay one will be connected to the TxSEL terminals on the two north transmitters. So when you key up, it will send ground to the SNV12 console PTT and steer to the the two north transmitters. Releasing the PTT drops the grounded TxSel releasing the voter to go back doing its thing. Perfect.
The normally open side of the tone panel's relay 1 will be connected to the TxSEL terminals on the two south transmitters. F2 from the console will energize Relay 1. PTT will be sent to the SNV12 console PTT and steer to the two south transmitters. Releasing the PTT drops the grounded TxSEL releasing the voter to go back to doing its thing. Perfect.
An axillary output from the console will apply a ground directly to the common pin on relay one (with a diode to isolate it from PTT). This will allow the dispatcher to manually override the receiver group voting and force all repeated transmissions to one site or the other. This button will be entitled AUTO/MANUAL, referring to the site steering. Perfect. I might need to jump the simplex base's COR into the TX inhibit terminal so it doesn't try to repeat onto itself while that site is manually steered. No big deal.
So in the end, I get my group voting and i get my function tone driven console steering and I get my manual override. Everything in the manual agrees and Benny says it will work.
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
Re: JPS SNV12 transmitter steering
Transmitter steering *NEVER* quite works the way it's supposed to, so don't be upset when it doesn't work as you've designed it. And dispatchers like simplicity, the less buttons the better. Expect to use that AUTO/MANUAL button quite a bit. I say this based on experience.
Your best route is to convert the system to simulcast. Plain and simple. This is why Motorola doesn't do transmitter steering systems much anymore - Simulcast is a near-perfect art, and the way you really should go.
Motorola isn't the only offering out there for simulcast systems.
I recently installed a 4-site VHF simulcast system for a customer out here using Dalman Technican Services (http://www.dalmants.co.uk) COSMOS-5 hardware. All that's required for a system is a 4-wire telephone circuit that can handle 0-3500Hz of audio, a master oscillator at each site, and you've got a simulcast system WITH receiver voting. That's right - their simulcast controller can be configured to do receiver voting without any additional hardware.
We interfaced the system to MTR-2000 base stations, but I think the interface to a Quantar would be even easier to do.
You really should look at going this way vs. transmitter steering because you are not going to be satisfied with the results, and we know what a stickler for performance you are, Marc.
As long as you have a tech who's willing to read the documentation and phase the system properly, it works wonderfully.
And it's not terribly expensive either. You could probably buy the simulcast host and 2 sites for the price you're paying for that Raytheon voter.
Your best route is to convert the system to simulcast. Plain and simple. This is why Motorola doesn't do transmitter steering systems much anymore - Simulcast is a near-perfect art, and the way you really should go.
Motorola isn't the only offering out there for simulcast systems.
I recently installed a 4-site VHF simulcast system for a customer out here using Dalman Technican Services (http://www.dalmants.co.uk) COSMOS-5 hardware. All that's required for a system is a 4-wire telephone circuit that can handle 0-3500Hz of audio, a master oscillator at each site, and you've got a simulcast system WITH receiver voting. That's right - their simulcast controller can be configured to do receiver voting without any additional hardware.
We interfaced the system to MTR-2000 base stations, but I think the interface to a Quantar would be even easier to do.
You really should look at going this way vs. transmitter steering because you are not going to be satisfied with the results, and we know what a stickler for performance you are, Marc.
As long as you have a tech who's willing to read the documentation and phase the system properly, it works wonderfully.
And it's not terribly expensive either. You could probably buy the simulcast host and 2 sites for the price you're paying for that Raytheon voter.
Re: JPS SNV12 transmitter steering
Simulcast is in the long range plan. We just don't have the money for that right now unfortunately. I'm hoping the small size of this and our geography will allow this receiver group transmitter steering to work well in the meantime. It is nearly impossible for a radio on the south end of town be voted on north site. The 500ft mountain in the middle isolates mobiles and portables on each side quite nicely but the bases reach over and around enough that people on both sides can hear it the repeaters. I've long suggested investing our money in high explosives to lower the mountain, thereby reducing the radio budget at the same time. But nobody seems to go for that. I think it would be fun!
This setup is actually much simpler and easier for the dispatchers than the current console configuration. I spend time on both sides of this system (FD LT and part time dispatcher) which helps in laying this stuff out.
This setup is actually much simpler and easier for the dispatchers than the current console configuration. I spend time on both sides of this system (FD LT and part time dispatcher) which helps in laying this stuff out.
Last edited by nmfire10 on Mon Dec 08, 2008 8:57 pm, edited 1 time in total.
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
Re: JPS SNV12 transmitter steering
Matt: Glad you found Benjy helpful. He is one of JPS's real assets.
Your DSP223 sounds a bit like the solution I deferred mentioning, which involves given true parallel status and control to multiple consoles over such features as Rpt/Dis and Main/Stby. You can't simply parallel AuxOuts going to a devices ground-to-activate pin, as you will have created a logical OR gate (i.e., any console can activate the feature but consent of all required to deactivate it). We used garden-variety Tone Remote Adapters (Zetron M250s). They listen on the Tx line and but do not speak over it. Rather, they detect FTs and based on which FT is received, either pull in or drop out a relay.
I concur with d119 re: receiver steering of transmitters. However, simulcast can be no better unless the system is truly well designed; it is important that the area of transmitter overlap by as small as possible. A major agency in Boston not too long ago went way overboard with simulcast and nearly shut its entire system down.
Your DSP223 sounds a bit like the solution I deferred mentioning, which involves given true parallel status and control to multiple consoles over such features as Rpt/Dis and Main/Stby. You can't simply parallel AuxOuts going to a devices ground-to-activate pin, as you will have created a logical OR gate (i.e., any console can activate the feature but consent of all required to deactivate it). We used garden-variety Tone Remote Adapters (Zetron M250s). They listen on the Tx line and but do not speak over it. Rather, they detect FTs and based on which FT is received, either pull in or drop out a relay.
I concur with d119 re: receiver steering of transmitters. However, simulcast can be no better unless the system is truly well designed; it is important that the area of transmitter overlap by as small as possible. A major agency in Boston not too long ago went way overboard with simulcast and nearly shut its entire system down.
Re: JPS SNV12 transmitter steering
The dispatch console is an Orbacom TDM series so there is only one central electronics bank (to borrow an /\/\ term) talking to this thing. All the dispatcher positions are touch screens connected to the CEB so they are all integrated and interconnected. There are no other stand-alone consoles trying to talk to it so that won't be a problem.
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
-
chpalmer
- Posts: 105
- Joined: Mon Jun 17, 2002 9:01 pm
- What radios do you own?: Astro Specta, MT1500, HT1550LS
Re: JPS SNV12 transmitter steering
Keep in mind that simulcasting lowband is never recommended. If you try it... Good Luck! Too much overlap. UHF on the other hand works great.
The SNV12 can make a great crossband voter.
But with major system changes in your future I have to ask why you wouldnt be designing the lowband out of your system? Could another site in the middle somewhere provide the extra coverage your looking for?
Simulcast can be fairly easy to roll out. You obviously need a GPS controlled oscillator at each of the transmitter sites and a method to transport your audio. After that if you provide the PL tone from the hub site and rebroadcast it through the transmitter sites, a simple audio delay panel will be about the simplest way to simulcast a single channel.
The transport method must be dedicated and perfectly stable for this so rf links would be recommended.
The SNV12 can make a great crossband voter.
But with major system changes in your future I have to ask why you wouldnt be designing the lowband out of your system? Could another site in the middle somewhere provide the extra coverage your looking for?
Simulcast can be fairly easy to roll out. You obviously need a GPS controlled oscillator at each of the transmitter sites and a method to transport your audio. After that if you provide the PL tone from the hub site and rebroadcast it through the transmitter sites, a simple audio delay panel will be about the simplest way to simulcast a single channel.
The transport method must be dedicated and perfectly stable for this so rf links would be recommended.
-
chpalmer
- Posts: 105
- Joined: Mon Jun 17, 2002 9:01 pm
- What radios do you own?: Astro Specta, MT1500, HT1550LS
Re: JPS SNV12 transmitter steering
More thoughts.
Your transmitters both coming on at the same time at one site or another?
They can be paralleled using the same key tones with each of the receivers still having their individual return paths to the voter.
The jps sn12 when used with rx groups locks into the first group to receive cor at the voter. This means that if a site has any delay such as from a telco system while the second site is where the voter resides, the second site will vote and lock the first one out. Using this form of transmitter steering makes use of the vote lock feature by default. Just keep this in mind.
If your transport media is stable and identical this should not be an issue.
Your transmitters both coming on at the same time at one site or another?
They can be paralleled using the same key tones with each of the receivers still having their individual return paths to the voter.
The jps sn12 when used with rx groups locks into the first group to receive cor at the voter. This means that if a site has any delay such as from a telco system while the second site is where the voter resides, the second site will vote and lock the first one out. Using this form of transmitter steering makes use of the vote lock feature by default. Just keep this in mind.
If your transport media is stable and identical this should not be an issue.
Re: JPS SNV12 transmitter steering
RTPA circuits, transport time is the same. Can you even effectively run a simulcast system with that? Microwave links are not possible and T1 would be awfully expensive.
Low band is going to be phased out eventually but we are in "transition". And it might be a long transition unfortunately. If it were up to me, I would have cut it loose two years ago. The plan is only to simulcast the UHF system which is all Master III stations.
Low band is going to be phased out eventually but we are in "transition". And it might be a long transition unfortunately. If it were up to me, I would have cut it loose two years ago. The plan is only to simulcast the UHF system which is all Master III stations.
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
-
chpalmer
- Posts: 105
- Joined: Mon Jun 17, 2002 9:01 pm
- What radios do you own?: Astro Specta, MT1500, HT1550LS
Re: JPS SNV12 transmitter steering
Im not familiar with Mastr lll stations. Are they crystal controlled?
If it is then the clock would not be needed but the channel elements would have to be super stable.
An amateur system I help with uses micors on two meters. The elements are from 800mHz stations and are extremely stable. Allen avionics delay cards. The pl is generated at the hub site via a uhf link system. The system sounds better than many commercial systems Ive heard. The problem is that when first setup, the crystals have to age a while before they stay within 10-20 Hz which is fine. Most commercial gear will filter out a 20Hz beat. After many years in service the transmitters stay put without us having to travel to the sites to adjust. This amount of frequency error is just fine. The
The important element is the audio path to the site. The captured audio in the field must be within .2dB at the receiver. The transmitters and transmitted audio must be identical. The audio delay must be exact. figure at 5.4microseconds per statute mile.
What I would do is look at the present sites with prorogation software and look at the interference contour. See if you can make your present sites work for you. An engineer can help here.
Really though Id consider replacing the stations with something that can be frequency controlled via an external clock. We are using MTR2000's quite successfully.
My point of all this is that simulcast might not be as far out of your budget as you think. One channel with a dedicated path should be quite simple to make work.
If it is then the clock would not be needed but the channel elements would have to be super stable.
An amateur system I help with uses micors on two meters. The elements are from 800mHz stations and are extremely stable. Allen avionics delay cards. The pl is generated at the hub site via a uhf link system. The system sounds better than many commercial systems Ive heard. The problem is that when first setup, the crystals have to age a while before they stay within 10-20 Hz which is fine. Most commercial gear will filter out a 20Hz beat. After many years in service the transmitters stay put without us having to travel to the sites to adjust. This amount of frequency error is just fine. The
The important element is the audio path to the site. The captured audio in the field must be within .2dB at the receiver. The transmitters and transmitted audio must be identical. The audio delay must be exact. figure at 5.4microseconds per statute mile.
What I would do is look at the present sites with prorogation software and look at the interference contour. See if you can make your present sites work for you. An engineer can help here.
Really though Id consider replacing the stations with something that can be frequency controlled via an external clock. We are using MTR2000's quite successfully.
My point of all this is that simulcast might not be as far out of your budget as you think. One channel with a dedicated path should be quite simple to make work.
-
chpalmer
- Posts: 105
- Joined: Mon Jun 17, 2002 9:01 pm
- What radios do you own?: Astro Specta, MT1500, HT1550LS
Re: JPS SNV12 transmitter steering
Could always use the lowband as your audio path to your simulcast transmitters... 
Re: JPS SNV12 transmitter steering
I would rather use the Low Band as a bird bath and the antennas as a perch. 
The Master III equipment is the latest and greatest from MA COM. I would compare it to a Quantar. It is capable of simulcast which is why we went with it. So down the road we can do it.
http://www.macom-wireless.com/products/ ... ations.asp
The Master III equipment is the latest and greatest from MA COM. I would compare it to a Quantar. It is capable of simulcast which is why we went with it. So down the road we can do it.
http://www.macom-wireless.com/products/ ... ations.asp
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
-
chpalmer
- Posts: 105
- Joined: Mon Jun 17, 2002 9:01 pm
- What radios do you own?: Astro Specta, MT1500, HT1550LS
Re: JPS SNV12 transmitter steering
I once saw a G.E. station on a hilltop that said mastr lll on it. I had G.E. on my mind.
[rant on]
Those I wouldn't recommend to my worst competition due to the trouble we have had with them here and the lack of support. I was thinking we had the mastr 4 but I think they skipped that number to mastr 5. We have several sites with these due to the fact that they were on the state contract. Dont want to sound too bad here but its hard not to. They have been nothing but trouble. YMMV. [/rant off]
But yes, they have the ability for external reference. Make sure that the power supply to them is clean, filtered, protected, ect ect. (trust me)
But your half way there. Is your transport method to the sites anolog?
[rant on]
Those I wouldn't recommend to my worst competition due to the trouble we have had with them here and the lack of support. I was thinking we had the mastr 4 but I think they skipped that number to mastr 5. We have several sites with these due to the fact that they were on the state contract. Dont want to sound too bad here but its hard not to. They have been nothing but trouble. YMMV. [/rant off]
But yes, they have the ability for external reference. Make sure that the power supply to them is clean, filtered, protected, ect ect. (trust me)
But your half way there. Is your transport method to the sites anolog?
Re: JPS SNV12 transmitter steering
Yes. Plain old voice RTPA phone pairs going all over town. Voter is at dispatch which is the central mothership of the system.
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
-
chpalmer
- Posts: 105
- Joined: Mon Jun 17, 2002 9:01 pm
- What radios do you own?: Astro Specta, MT1500, HT1550LS
Re: JPS SNV12 transmitter steering
People have done simulcast over that but I wouldnt suggest it...
RF links would do the trick though... Lowband rf link would be different...
Then keep using the phone lines for the receivers.
RF links would do the trick though... Lowband rf link would be different...
Then keep using the phone lines for the receivers.
Re: JPS SNV12 transmitter steering
That's the biggest hurdle with simulcast. Microwave links are next to impossible due to terrain. (goes back to the dynamite suggestion...)
Which leaves T1 links which is a lot of money for a debatable gain. If this system as I envision it works the way I want it to, I think it would be more than sufficient for our operations. Its not like we are FDNY here. Implementing simulcast would be cool but I'm not sure it would be a worthwhile expenditure and if this works, it could be just what we need.
Which leaves T1 links which is a lot of money for a debatable gain. If this system as I envision it works the way I want it to, I think it would be more than sufficient for our operations. Its not like we are FDNY here. Implementing simulcast would be cool but I'm not sure it would be a worthwhile expenditure and if this works, it could be just what we need.
"I'll eat you like a plate of bacon and eggs in the morning. "
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
- Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
Re: JPS SNV12 transmitter steering
*sigh* Please have a look at the Dalman COSMOS-5 system at http://www.dalmants.co.uk/
This will interface with your MASTR III stations, the only additional hardware you will require is an external oscillator. I recommend the SpectraCom 8197B coupled with the 1118 CTCSS (PL) generator. One required per site including dispatch.
The MASTR III will accept an external reference and can be interfaced with the Dalman COSMOS site controller quite easily. It will use your standard RTPA/RTNA circuits to handle the simulcast, and as a result, will be as reliable as your phone company circuits are.
The benefit is that it will save you money in transport costs as it overlays it's own signaling over the voice traffic (but notches the signaling out so that you don't hear it).
This product is a perfect fit for you - No, I don't sell it or get a commission off of it, I've just installed it and aligned it and it WORKS. Not to mention as I said earlier, it'll handle all of your voting for you (RSSI based, not Signal to Noise based) in the box without additional hardware.
The system I put in using it was designed around MTR 2000 base stations, but I am familiar enough with the MASTR III to know that interfacing it wouldn't be difficult.
FWIW, a MASTR III shouldn't be compared to a Quantar... Too much of a difference there to make that comparison.
This will interface with your MASTR III stations, the only additional hardware you will require is an external oscillator. I recommend the SpectraCom 8197B coupled with the 1118 CTCSS (PL) generator. One required per site including dispatch.
The MASTR III will accept an external reference and can be interfaced with the Dalman COSMOS site controller quite easily. It will use your standard RTPA/RTNA circuits to handle the simulcast, and as a result, will be as reliable as your phone company circuits are.
The benefit is that it will save you money in transport costs as it overlays it's own signaling over the voice traffic (but notches the signaling out so that you don't hear it).
This product is a perfect fit for you - No, I don't sell it or get a commission off of it, I've just installed it and aligned it and it WORKS. Not to mention as I said earlier, it'll handle all of your voting for you (RSSI based, not Signal to Noise based) in the box without additional hardware.
The system I put in using it was designed around MTR 2000 base stations, but I am familiar enough with the MASTR III to know that interfacing it wouldn't be difficult.
FWIW, a MASTR III shouldn't be compared to a Quantar... Too much of a difference there to make that comparison.