Repeater questions

[ts442k9]

Our local fire department has three repeaters. They're all Motorola Quantars. They are in 3 different locations to cover our service area. They're currently programmed so that the repeater output is all the same with matching DPL's. They all have the same input freqs BUT have different DPL's based on the area we are in.
I asked our county radio shop and he said that it's fine how it is.
I, however, disagree.
We have highspeed fiber internet running to all the locations where the repeaters are held.
My question is, how do I link these together? What hardware/software is needed. I did call our local dealer as well but they don't want to touch it because of how old our repeaters are.

TIA

 

[tweiss3]

Most of those parts you would need are end of life and no longer available. It's not just as simple as linking them when they are in overlapping coverage and on the same frequency, you are looking into simulcast, which is possible, but becomes increasingly complicated and expensive.

 

[ts442k9]

Most of those parts you would need are end of life and no longer available. It's not just as simple as linking them when they are in overlapping coverage and on the same frequency, you are looking into simulcast, which is possible, but becomes increasingly complicated and expensive.

Would it be better just to leave 1 repeater and put in vehicle repeaters? The only reason there are 3 is so we have handheld coverage everywhere.

 

[tweiss3]

You should ask another local dealer for a second opinion, but if it's working, and you have complete coverage, probably leave it alone.

 

[K4EET]

Would it be better just to leave 1 repeater and put in vehicle repeaters? The only reason there are 3 is so we have handheld coverage everywhere.

I agree with @tweiss3 since the equipment is so old. If it ain’t broke, don’t fix it. You might invite new problems. As for a single site repeater and using vehicular repeaters, you would want to start by comparing coverage maps of the two configurations. Your system that you have now might be better than a single site system even with vehicular repeaters.

 

[a1emt]

Sounds like the system is ripe for an update. As some have mentioned, the Quantar is no longer supported so an upgrade to simulcast and/or voting receivers will likely have to be a whole new system from the ground up. A good investment, in my opinion, especially if you have 3 sites that provide good portable radio coverage.

However, I would strongly advise you to stay away from designing your system's portable radio coverage solely around relying on vehicular repeaters. Way too many moving parts and points of failure. Invest in the infrastructure, especially since you have the fixed antenna sites already. Vehicle repeaters should only be used for specific, unusual circumstances such as hard to cover buildings, etc.

Good luck!

 

[nokones]

If the one site provides good coverage for the entire service area, you could install voting receivers at each site and place the comparator at the repeater site and use just the one Input DPL code for all three receivers.

If there is no plan in updating the equipment, then keep the other two repeaters as spares.

 

[N5XPM]

Approaching this from a project benefit / cost perspective might help.
It sounds like the coverage is sufficient. If more capacity and less “interference” is the goal, then coordinating and licensing two new repeater frequency pairs makes sense and retuning two repeaters makes sense. Simulcast voice is expensive to establish and generally doesn’t sound great.
I worked with some fire departments that had two repeaters like these and we went to two separate frequency pairs as radio traffic increased.
The dispatcher and user radios will need reprogramming as well as two repeaters. While retuning repeaters and duplexers, it would make sense to check antennas and feed line as well.
Anrennas are not as exciting as a new radio but often neglected and essential to good results.
Most narrowband radios have lots of channel capacity and modern voice pagers do as well.
The final question is the budget.
How many radios and different types of radios will need reprogramming?

 

[cavmedic]

I asked our county radio shop and he said that it's fine how it is.
I, however, disagree.

How is it that you disagree? What experience do you have with setting up and maintaining simulcast?
The fiber at the sites, is it fiber that is direct connection from site to site or is it " fiber to the home internet" type of fiber?

 

[N4DES]

Our local fire department has three repeaters. They're all Motorola Quantars. They are in 3 different locations to cover our service area. They're currently programmed so that the repeater output is all the same with matching DPL's. They all have the same input freqs BUT have different DPL's based on the area we are in.
I asked our county radio shop and he said that it's fine how it is.
I, however, disagree.
We have highspeed fiber internet running to all the locations where the repeaters are held.
My question is, how do I link these together? What hardware/software is needed. I did call our local dealer as well but they don't want to touch it because of how old our repeaters are.

TIA

From a redundancy perspective, it is also fine as it is. Adding simulcast is expensive and requires a lot of TLC, especially when the backhaul is provided by a 3rd party, and you will need someone with the expertise to run a simulcast coverage map to identify the overlap areas and calculate the launch times.

As others have mentioned, the Quantar is no longer supported so things you will need, like a Simulcast Distribution Amplifier and a voter, will be from the used market.

 

[jeepsandradios]

Our SAR systems are based exactly as what you describe. Same input and output frequency with different PL/DPL on input. There is no issue with this and is done alot of places. As said the equipment is old but is useful. Part of our SAR system has been upgraded but in phases.

First step was we voted the RX audio from the 3 sites to a single tx site. That helped portables but casued a few dead spots. In the end we went simulcast but it requires GPS units as well as other equipment to vote and key equipment over IP. There is the old way of 4 wire cuircuits to analog comparators and transmit controllers. We used Digi Tacs originally but when IP was available switched to that.

Unless you have alot of funds to spend and lots of technical support I'd leave it alone. Go after a grant for 3 new IP base radios and IP comparator if thats the final plan.

 

[nokones]

It is best to think of the operation from the end user perspective. In a public safety environment the system design needs to be simple and effective, and in all cases never cut corners and go cheap. Providing public safety is never cheap in the first place.

If the single site provides the desired broadcast coverage to the mobiles and in-building portables, simulcast would not be of any benefit to the agency using the system. It will just make the equipment provider richer and require more maintenance and over work probably a short staff of technicians. And most technicians do not know how to maintain a simulcast system.

The best solution is install remote voting receivers so the repeater can broadcast the best possible audio from the portables. A voting receiver system would take the guess work away from the end user in selecting the proper channel for the area they are in.

If a second site is required on the same operating channel pair, you still can use the same input DPL code by implementing a vote and steer system with instant vote release. In all cases, the voting comparator should never be in the vote and hold mode.

 

[MTS2000des]

What always surprises me is how "professional radio" end users come to a hobbyist forum for professional advice on a life safety/IDLH system. It's like a Delta Airlines pilot going on an aviation buff forum asking "does anyone here know how to fly a Boeing 737-max 8?"

 

[wa8pyr]

Who the Hell are you ?
Are you tasked by the system owners to be meddling in their business ?
What do the taxpayers who are going to end up paying for it think ?

If it ain't broke, don't fix it !

FYI - Quantar parts are plenty. I know of a system owner that has a
storage room full of spare parts - boxes never opened - since the system has
been humming along fine 24x7 for almost 30 years.

Stay in your lane.

Ever stop to think that he may have been tasked with finding out if there's a different (better) way to do things? There's nothing wrong with asking, and based on my 40+ years of experience, the response he got from the radio shop was likely because they just don't want to put any time into it.

There's no such thing as "enough" knowledge.