Help specing a repeater?

[zspitzer]

I've inherited a system of about 30 CP200's and 6 CP200d's at work, and am hoping to add a repeater to the system as we often have trouble hearing each other from opposite ends of the space (basement location with a lot of rebar in the walls). I'm putting together a cost estimate for the upgrade, and was hoping to have some assumptions confirmed, and few questions answered. And please tell me if there's a better solution than this!

For background, my CP200's are the 4 channel models, the first two we use constantly (two different departments), the second two are only used occasionally. The CP200d's are 16 channel models and are used by some of my supervisors (which works out, I could give them the talk-around frequency for if repeater goes down). We're currently in the 460mhz range.

To hopefully solve the reception issue, I want to get a repeater for the two channels we constantly use. As I need to keep the analog-only CP200's for at least a few more years, I'd be setting up at what I believe Motorola calls the "Single Site Conventional" system, where each channel is two frequencies and the radios TX on one to the repeater, and RX from the repeater on another. I've used (though didn't build) this type of system at a prior job with a fleet of HT750 and HT1250's.

Looking at repeaters on the Motorola site, it seems like the SLR5000 has a channel capacity of 64 and judging from the picture of the front panel, that it would be able to simultaneously act as a repeater for two analog channels in conventional mode. Is that correct? And that channels 1 and 2 could be used simultaneously? This is my biggest question/concern.

It seems like the SLR5000 does not come with an antenna or cabling, if that's correct what antenna would be recommended? I expect to place the repeater within about 10' of where I'd place its antenna.

Clearly I'd need to reprogram my existing radios. Would I need to buy three different CPS programs (CP200, CP200d, SLR5000), or just one? And how much (roughly) is a copy of CPS? I want to include that in my estimate and can't seem to find a price without bothering Motorola (which seems premature at this point).

Longer-term, I'm hoping to upgrade some of the CP200's to SL300's for the customer-facing employees. It seems like the SL300's could be programmed to work in conventional mode and join the system before I've retired the last CP200?


Hopefully I've written all of that clearly. I welcome any advice that could be offered!

 

[N1GTL]

You are only getting 2 time slots on an SLR5700 if you are using digital, not analog. In analog, you get one repeater pair. Your weakest link is the 4 channel CP200's, analog only. You need two repeaters, 2 sets frequencies. You need a duplexer for each repeater, antennas, cabling, licensing, etc. CP200 software is different. CP200d and the SLR5700 is the TRBO software.

You really need a shop or consultant to oversee this. There are tons of things involved to do it right. Grounding, lightening arrestors, antenna mounting, roof penetration. If two repeaters, you'll need vertical spacing to minimize de-sense. etc, etc, etc

 

[RFI-EMI-GUY]

The SLR5000 will only repeat one duplex channel (Repeater programmed 460.xxxx TX 465.xxxx RX). In analog mode, that is one talk path. In the MotoTrbo mode, the repeater will repeat two simultaneous talk paths.

Options:

1. Upgrade all subscribers now to MotoTrbo and buy one repeater, that way both departments use a different time slot and get same range improvements. But you will have no redundancy on the repeater if it goes down.

2. Buy two repeaters, one for each department and operate in analog mode for time being. Then later convert all to MotoTrbo and use second repeater as a coverage enhancement and link via IPSC. Depending on its location, your second repeater may provide redundancy. Or keep second repeater co located with first and use additional capacity for other departments.

Don't go cheap on the duplexer, especially if you plan a second repeater or are in a high RF environment. The cheap flat pack duplexers are simply band reject filters. They protect the repeater from itself and nothing else. You want bandpass-reject.

Use either copper "hard line" or double shielded COAX. Copper, no aluminum. Don't skimp. Even 10 feet of crappy coax will wreck things. Dont forget surge protectors on antennas, power, LAN cables. Ground and Bond per R56. Lightning is big killer or radio gear. Also put the repeaters on two hour UPS or better. If something happens and power is affected at least your radios will work while you make an evacuation plan.

 

[mmckenna]

Yeah, I agree.
Unless you are currently licensed to use a repeater, this will require the involvement of a frequency coordinator and a modification of your FCC license.
Then the system needs to be properly designed, built and aligned. This isn't something that you can do by purchasing parts on line. The knowledge and test gear required to do it right (and legally) is beyond what most hobbyists have access to.

I'd really, strongly, suggest you talk to a consultant, or at least talk to your radio shop. They have the knowledge and tools to design a proper system for you and make sure it works correctly.

If you are using multiple channels now, then you'll likely need either an individual repeater for each channel, or a trunked radio system.
If this is a relatively small space, then changing technologies might be a better approach.

The frequency coordination and FCC licensing is going to require the services of a professional, and that's going to cost some money. Do NOT start buying equipment first, you may not be able to get enough frequency pairs coordinated for a UHF system in your area. This is where the services of the professionals can save you a lot of money and headaches.

 

[zspitzer]

Thanks everyone. I had been trying to price out a system for an estimate before talking to my local shop, but seems like this is actually complex enough I should get a quote directly from them. I've reached out to them to start the conversation.

 

[MTS2000des]

Repeaters (duplex operation) isn't a plug and play adventure like setting up a wireless access point.

Aside from the licensing/coordination issues mentioned above, to transmit into the same antenna requires:

Good quality filtering (duplexers, circulators, etc) tuned and set by a qualified person with access to expensive test equipment and the knowledge to do it right.

Good quality feedline, Polyphaser, proper R56 grounding, etc.

Good quality antenna installed at a proper location to give the desired coverage.

Transmitting into the same antenna a radio is receiving in simultaneously (which is how repeaters function) requires precise tuning of the filtering system for good performance. Sometimes even more hardware like pre-selectors and pre-amps may be needed if there are other sources of interference or variables in play.

A site survey with a spectrum analyzer is step one, that is, once a licensed/coordinated frequency pair is assigned to determine what you're working with.

 

[mmckenna]

Thanks everyone. I had been trying to price out a system for an estimate before talking to my local shop, but seems like this is actually complex enough I should get a quote directly from them. I've reached out to them to start the conversation.

I understand wanting to have an idea of what it will cost, but there are so many variables involved that it would be difficult to do remotely. Quoting a repeater price is easy. It gets a bit harder quoting feed line, antenna and duplexer costs when we don't know the size or application. It really is wise to bring in a pro to do this. You can hire a consultant, but they'll cost you a lot of money on their own. A reputable shop can do that work for you.

However, do walk into it with the idea that it's going to be a specific brand or technology. The dealers can smell that a mile away and will go at it like vultures. You need to get quotes from multiple vendors and compare them.

It's not going to be cheap, I'll tell you that much.

 

[n5ims]

A couple of questions for you and comments.

Does your company own the building? Rent it as the only occupant? Are you just one tenant in a multi-tenant building?

These are important since if you own the building outright you can pretty much do what you want (there may still be restrictions with zoning, etc. or even height restrictions in some areas like near an airport or the like). If you're the only occupant, you may not have many landlord issues but should still get their OK prior to mounting the antennas on the roof. Chances are those will be allowed, but if you move, they may need to remain with the building. Knowing the rules upfront will be good. If you just one of the tenants, you will most definitely need to get the landlord involved since you may need to also rent space on and near the roof for your antennas, repeaters, etc. and getting cables ran from the repeaters to your office spaces if necessary.

Having this information up front will be very important, especially in a multi-tenant building. That roof rent can get expensive pretty quick and any cables routed from the repeater site down to your basement location may need to be of an approved type to meet code or building rules. Often these cables will be routed in a return air space and will need to be rated for fire and smoke to meet code. These specs will be important in your conversations with your consultant.

There may also be some "easier" and less expensive ways to accomplish allowing one side of your basement space to have reliable communication with the other side. Thinking an antenna on both sides of the space with a cable linking them (perhaps through a bi-directional amplifier) may do the trick pretty well. This wouldn't require any additional frequencies or action by the FCC and would be much less than a repeater solution. Assuming you have the entire basement, you may not have any landlord issues beyond what you'd normally have running other cables like for linking WiFi hotspots. Since the cable would probably be ran in the ceiling, you may still need the fire/smoke rated cable to link both antennas. A good consultant should be able to handle this as well, but since the cost is less, they may not offer it as an initial solution, but if you ask about it first they can let you know if it's a good solution to your problem. If not, then you might move to the more expensive repeater solution.

Remember that you're looking for a cost effective solution to your problem (signal issues with your handheld radios) so you should let the consultant provide that solution. If you go in up front saying you want a repeater to help expand the range of your handheld radios, that's what they'll work on, ignoring any effective, but less expensive solutions.

 

[N1GTL]

Don't go cheap on the duplexer, especially if you plan a second repeater or are in a high RF environment. The cheap flat pack duplexers are simply band reject filters. They protect the repeater from itself and nothing else. You want bandpass-reject.

THIS!!! For the price of one of these garbage "duplexers" and usually thrown in, a pre-selecter, you can get a true duplexer with separate pass and reject tuning. When tuned right, you should see 1.5db loss or better. That basically means that if you're putting 100 watts out at the repeater, you're getting 75+ watts out of the duplexer.

No one can guarantee a price based on what you're describing, sight unseen, but you're, at minimum $10K, probably much higher based on the equipment mentioned here.