Severe Inconsistency with TRBO Capacity Plus

[sjaltavilla]

Hello all!

Allow me to cut right to the chase - I am one of two techs that oversee a MOTOTRBO Capacity Plus Single-Site trunking system at a decent-size ski resort in Southern VT (approx. 3875' elevation). We recently transitioned from a 4-channel VHF analog system to our new UHF trunk last November. The new system has given us great capabilities such as GPS locations for all of our ski patrollers, and the ability for users to call each other privately. The digital audio is fantastic, and much clearer than our decaying analog channels.

However, since this system was installed last year, we have faced issue after issue. First it was power issues (self-inflicted - one of our generators was not switching over properly. This has since been rectified), and then it was coverage issues across the mountain. We have one summit, and therefore, our repeater antenna is located approximately 20 feet above the summit, mounted on a tower. For some reason, we face tremendous coverage drops all over the hill. Sometimes we can't talk, sometimes we can't hear, and sometimes our portables show out of range. Sometimes we lose coverage all together and then all of the sudden, nobody on the property can communicate unless they switch to one of the talkaround channels I have programmed. What is extremely frustrating is that transmitting in the same exact spot on two different days will yield two different results. Meanwhile, in my car, I am able to consistently transit and receive 30-40 miles away from the mountain, where the peak isn't even visible. This was not possible in analog.

Me and my partner have tried literally everything. Omnidirectional antennas (with a wider beamwidth angle), diploe antennas, etc. Hell, we even moved the repeater location all around the mountain. Every time we fix one coverage gap, we create another. We ordered equipment to do a fill-in receiver site at the base area, but I am afraid that is simply going to make things worse. I have spent countless hours troubleshooting - driving up and down the mountain in a beat up Silverado recording RSSI values that seemingly are generated at random (i.e. - received beacon from control station reads -60 dBm , yet the radio bonks when I key up).

I'm ready to switch all of our equipment back to analog at this point because at least the old MTR2000s were bulletproof. I know this isn't the best place to solicit advice, but I'm curious to see if anyone may have some insight on what else I can try before I lose my mind. Below are some statistics of our network:

Repeaters: 3 Motorola SLR5700's (UHF - 55W output)
Antenna: Commscope DB633-C (360 degree omnidirectional with 35 degree beamwidth angle)
Subscribers: approx. 250 units- mix of XPR7550e and XPR3500e. All brand new as of last year.

Any ideas?

 

[ecps92]

Why did you not just stay VHF and convert the VHF to TRBO ?

Hello all!

Allow me to cut right to the chase - I am one of two techs that oversee a MOTOTRBO Capacity Plus Single-Site trunking system at a decent-size ski resort in Southern VT (approx. 3875' elevation). We recently transitioned from a 4-channel VHF analog system to our new UHF trunk last November. The new system has given us great capabilities such as GPS locations for all of our ski patrollers, and the ability for users to call each other privately. The digital audio is fantastic, and much clearer than our decaying analog channels.

However, since this system was installed last year, we have faced issue after issue. First it was power issues (self-inflicted - one of our generators was not switching over properly. This has since been rectified), and then it was coverage issues across the mountain. We have one summit, and therefore, our repeater antenna is located approximately 20 feet above the summit, mounted on a tower. For some reason, we face tremendous coverage drops all over the hill. Sometimes we can't talk, sometimes we can't hear, and sometimes our portables show out of range. Sometimes we lose coverage all together and then all of the sudden, nobody on the property can communicate unless they switch to one of the talkaround channels I have programmed. What is extremely frustrating is that transmitting in the same exact spot on two different days will yield two different results. Meanwhile, in my car, I am able to consistently transit and receive 30-40 miles away from the mountain, where the peak isn't even visible. This was not possible in analog.

Me and my partner have tried literally everything. Omnidirectional antennas (with a wider beamwidth angle), diploe antennas, etc. Hell, we even moved the repeater location all around the mountain. Every time we fix one coverage gap, we create another. We ordered equipment to do a fill-in receiver site at the base area, but I am afraid that is simply going to make things worse. I have spent countless hours troubleshooting - driving up and down the mountain in a beat up Silverado recording RSSI values that seemingly are generated at random (i.e. - received beacon from control station reads -60 dBm , yet the radio bonks when I key up).

I'm ready to switch all of our equipment back to analog at this point because at least the old MTR2000s were bulletproof. I know this isn't the best place to solicit advice, but I'm curious to see if anyone may have some insight on what else I can try before I lose my mind. Below are some statistics of our network:

Repeaters: 3 Motorola SLR5700's (UHF - 55W output)
Antenna: Commscope DB633-C (360 degree omnidirectional with 35 degree beamwidth angle)
Subscribers: approx. 250 units- mix of XPR7550e and XPR3500e. All brand new as of last year.

Any ideas?

 

[sjaltavilla]

Why did you not just stay VHF and convert the VHF to TRBO ?

I wasn't involved in the purchasing of the new equipment. Story goes that Bearcom sold us on UHF because it was "cheaper". We're kicking ourselves now because our local ambulance dispatch is still on VHF and now our interoperability is reliant on a janky crosspatch over IP. We should've done VHF TRBO but oh well.

 

[mmckenna]

What kind of testing have you done?

Random/intermittent issues could be a number of things:
Antenna damage
Coax issues
Noise issues

I'd sweep the coax/antenna system. Have someone physically shake the tower to see if it's a bad connector/connection.
I'd use a spectrum analyzer to look for local noise sources.
I'd check all the connections, transmit combiner, etc.

If Bearcom sold it to you, are you covered under any sort of support contract, warranty, etc?

 

[sjaltavilla]

Antenna damage
Coax issues

Definitely not these two. That's exactly what I thought the problem was at first.

I'd check all the connections, transmit combiner, etc.

We swapped out for a new cable, replaced connectors and the whole nine yards. Didn't find anything wrong, but figured we would do it anyways.

I'd use a spectrum analyzer to look for local noise sources.

I did this back in June and everything looked pretty clean to me. It might be worth another shot to see if anything has changed.

If Bearcom sold it to you, are you covered under any sort of support contract, warranty, etc?

We are covered under warranty. Trying to get them to come out to our site is like pulling teeth. They are going to be here in late October to assist us with installing our remote receiver site. We've already informed them of the issues we've been having so hopefully they've got more knowledge than I do so we can actually isolate where the problem is.

 

[mmckenna]

We are covered under warranty. Trying to get them to come out to our site is like pulling teeth. They are going to be here in late October to assist us with installing our remote receiver site. We've already informed them of the issues we've been having so hopefully they've got more knowledge than I do so we can actually isolate where the problem is.

OK, sounds like you tried all the basics.

Sometimes getting the shop to come back after the sale can be a challenge. Hopefully they'll find some time to respond a bit sooner.

 

[Firebuff880]

So you have some good answers already.. But one question I have is what were the specs on the MTR2000 repeaters. Did you change out 100Watt out for 55 Watt. What was the talk in on the old analog subscribers.

You said you were doing GPS are you looking at the RSSI talk in and doing any mapping of coverage. Do you have anything doing stats for the system.

I am not a dealer, but I am an Application Developer and have 800Mhz system at a couple of Colorado areas. Be happy to discuss this with you or if you happen to be at the NSAA show in NJ this week, stop by the Motorola booth and talk with the reps there. Unfortunately I could not go. But I will PM you my contact data and If you want I would be happy to talk this over with you.

PS: We are doing a digital voting site for one run because while the repeaters, SLR-8000s, can talk in the portables can not talk out.

 

[mmckenna]

My experience doesn't lie in Trbo trunked systems, so there may be some DMR specific things that would cause this. Hopefully one of the more experienced members with some real world DMR trunking system experience will see this and drop some knowledge for you.

 

[wa8pyr]

We have one summit, and therefore, our repeater antenna is located approximately 20 feet above the summit, mounted on a tower. For some reason, we face tremendous coverage drops all over the hill. Sometimes we can't talk, sometimes we can't hear, and sometimes our portables show out of range. Sometimes we lose coverage all together and then all of the sudden, nobody on the property can communicate unless they switch to one of the talkaround channels I have programmed. What is extremely frustrating is that transmitting in the same exact spot on two different days will yield two different results. Meanwhile, in my car, I am able to consistently transit and receive 30-40 miles away from the mountain, where the peak isn't even visible. This was not possible in analog.

Because the repeater site is atop the mountain and your coverage area includes the slopes of the mountain, it's possible that the affected location(s) may be in under the antenna coverage pattern, resulting in spotty coverage.

The fact that you can hit the system consistently 30-40 miles away, yet experience coverage issues close to and on the mountain makes this a pretty good possibility.

You may have to look at investing in repeater antennas with downtilt; this will shift the antenna pattern down, giving you better coverage on the mountain where you need it.

 

[mikewazowski]

Because the repeater site is atop the mountain and your coverage area includes the slopes of the mountain, it's possible that the affected location(s) may be in under the antenna coverage pattern, resulting in spotty coverage.

This.

One of our local ski hills runs a 2 site Linked Capacity Plus system. One site is at the top of the hill on a 20 foot tower and the other site is at the bottom of the mountain.

 

[jeepsandradios]

I think a 5db gain antenna on a mountain top is issue #1. Years ago we did a UHF repeater for a ski resort and used a UHF yagi pointed down the mountain from the ski lifts. It was on a 45 degree angle from the ground. Not sure that would work in your situation but high gain doesn't work well for local coverage.

 

[mmckenna]

I agree that the antenna may be a big part of the issue, but it shouldn't result in intermittent coverage at the same locations. There's still something weird going on.

 

[R8000]

1. You do not need gain antennas at all to cover into the valley directly below the repeater. In fact, you are making it worse. Much worse by using gain antennas. A small 0 db gain antenna system is all you need.
2. Do you have GPS updates going to a data only repeater? With three repeaters, you have a ton of capacity. If GPS data is important, you may want to make your third repeater data only and hand off GPS updates there. How is your GPS data being handled? In other words, where does the GPS location data go? Console? PC with software?
3. 55 Watts is plenty of power for what you want to do.
4. UHF should be fine. It will penetrate into the buildings better than VHF will. You will also benefit from not having quite as much skip as you had on VHF. You may see some, but it won't be as bad.
5. Bearcom should send someone sooner than that. It has been a year since it was installed, and you moved the system so they won't be too anxious to offer a warranty repair. To be fair, that idea is out the door. But, it sounds like you have had issues since day one and that's a good arguing point with your sales person at Bearcom. They should make it right.
6. There are tools available to assist with troubleshooting. Genwatch offers some software tools that can tell you some very cool things about your system as well as decode status and error messages into plain English for troubleshooting. Genwatch isn't cheap, but it is a damn good tool to have.
7. Do you use a combiner or three separate antennas and duplexers? If you are not using a combiner, you may be causing interference to yourself. (Genwatch would note this in logs). RF jumpers in good shape and high quality? If duplexers, I hope they aren't flat pack (cheap small black ones).
A general rule of thumb I go by is if it's two repeaters, two seperate antenna systems are fine. Three or more, you need a combiner.
8. If you are at the repeater site, does all trunking operation work as expected? Bonks? If so, you may have a programming problem. It's easy to hose up Cap+ codeplugs. When setup right, Cap+ is awesome.

There's more that could be checked but it becomes a long post.

If you don't know these answers, this would be good things to have the Bearcom techs look into. If they don't resolve it, call another Motorola shop to step in for a second opinion. The Cap+ system is awesome if it's setup right. So, don't abandon it quite yet. You have all the parts to have a great system.

 

[KM4OKT]

Have you tried it just simplex analog or digital from the problem places back to the summit?

 

[N1GTL]

Are all three repeaters sharing one antenna using a combiner? Perhaps that is not tuned correctly.

Using RDAC, I would look at the noise floor on each repeater. It's possible that as the repeaters rotate, one of the frequencies is receiving distant interference given the height. When that repeater is in use, you'll get the dreaded bonk. Then, when the rest channel changes to one with no major noise floor, the system will work great. You'll be chasing your tail. I know this because I ran across this issue and I had to drop the threshold down to -96 or something like that and it resolved the issue. This was an IPSC system but the RF theory is the same.

 

[sjaltavilla]

Wow - thanks for all of the input overnight. Allow me to respond to as many questions as I can.

what were the specs on the MTR2000 repeaters. Did you change out 100Watt out for 55 Watt.

The old VHF setup consisted of four repeated channels. Our main site was located halfway up the mountain and housed four MTR2000's putting out 100 watts a piece. Each repeater had it's own antenna and duplexer. Our secondary (receive only site) was at our satellite base area (about 2 miles down the road from the main base lodge/ski village. We had many issues talking out from that side of the hill before we installed that equipment. Over at that site, we only had two MTR's since we only needed the ski patrol and lift maintenance channels over on that side. The old network ran like a charm - almost no dead spots anywhere.

Because the repeater site is atop the mountain and your coverage area includes the slopes of the mountain, it's possible that the affected location(s) may be in under the antenna coverage pattern, resulting in spotty coverage.

The fact that you can hit the system consistently 30-40 miles away, yet experience coverage issues close to and on the mountain makes this a pretty good possibility.

This is one of the main conclusions we have come to. We are considering moving everything to mid-mountain in an attempt to balance the coverage area.

You may have to look at investing in repeater antennas with downtilt; this will shift the antenna pattern down, giving you better coverage on the mountain where you need it.

Any good recommendations on antennas? Do you think physically tilting the antenna 30 or so degrees downhill will help?

Do you have GPS updates going to a data only repeater? With three repeaters, you have a ton of capacity. If GPS data is important, you may want to make your third repeater data only and hand off GPS updates there. How is your GPS data being handled? In other words, where does the GPS location data go? Console? PC with software?

GPS updates are not set to a data revert channel. I considered doing this, but I was afraid that dedicating one repeater to be data-only would reduce our talking capacity dramatically. Our GPS updates are being handled by a PC with software - we use Elcomplus SmartPTT. Note that only about 40% of our subscriber radios are GPS capable.

55 Watts is plenty of power for what you want to do.

Considering I can hit the repeater from 40 miles out, I would hope so.

There are tools available to assist with troubleshooting. Genwatch offers some software tools that can tell you some very cool things about your system as well as decode status and error messages into plain English for troubleshooting. Genwatch isn't cheap, but it is a damn good tool to have

Thanks for the recommendation - we currently don't have any monitoring software (I know, I know) but it is certainly a much-needed investment.

Do you use a combiner or three separate antennas and duplexers?

We have a brand-new combiner unit, so we only use one antenna.

If you are at the repeater site, does all trunking operation work as expected? Bonks?

Trunking operation works flawlessly when we are well within the coverage area. No bonks until you make it halfway down the mountain.

It's easy to hose up Cap+ codeplugs.

Tell me about it. The one that was sent to us originally was terrible. I ended up reworking the entire thing and had to manually touch each unit on property since Bearcom didn't set us up with Radio Management originally. What a time to be alive lol.

Have you tried it just simplex analog or digital from the problem places back to the summit?

Funny enough - we have an analog simplex channel that we use in case of system failure. We can pretty much cover the entire main face of the mountain on 4 watt simplex. Yet the 55 watt repeater has problems. Go figure.

Using RDAC, I would look at the noise floor on each repeater. It's possible that as the repeaters rotate, one of the frequencies is receiving distant interference given the height. When that repeater is in use, you'll get the dreaded bonk. Then, when the rest channel changes to one with no major noise floor, the system will work great.

This is a really good thought. I might have to take a closer look at this. Since we are at the top of the mountain, we have had interference from the west of us (NY)...

 

[nhfdcadet]

You would have been better off putting the equipment off-site and had a directional antenna facing your mountain (assuming your trails are only on one side of the mountain and not both)

 

[sjaltavilla]

You would have been better off putting the equipment off-site and had a directional antenna facing your mountain (assuming your trails are only on one side of the mountain and not both)

We joked about putting all of our equipment atop one of the other mountains that sits about 5 miles due east of us. Wouldn't be a bad idea until the site needs maintenance.

 

[com501]

At this point, not enough information. Have someone review the programming on your radios, first. There are common issues that can be overlooked when setting up a system. Get a tech out to go over the system, ASAP. Snow is coming. This should have been done in the Spring, to give you all Summer to troubleshoot. I am not sanguine about the level of expertise from your vendor, caveat emptor. If you are running data like GPS, you SHOULD have a dedicated channel for this. Another reason to look at codeplug programming. How often the the GPS signal? What do the system loading tables show?

Agreed, high mountain, low gain antennas with down tilt are your friend here. Who did the coverage survey when the system was proposed? Did they actually do one?

 

[KC3ECJ]

I think a 5db gain antenna on a mountain top is issue #1. Years ago we did a UHF repeater for a ski resort and used a UHF yagi pointed down the mountain from the ski lifts. It was on a 45 degree angle from the ground. Not sure that would work in your situation but high gain doesn't work well for local coverage.

Yeah. Where I live there's many mountains and hills. So with the one vehicle and dual band radio I specifically used separate quarter wave antennas, one for 2m VHF, and the other 70cm UHF with a diplexer. So I'm using antennas that can "see" up and down mountains.