Batboard

I have just installed a linked capacity plus system. They are using the new SLR5700 repeater as the master and the XPR8400 repeater as the peer. They are using XPR3500 radios. Everything is working fine it is linked through HPMR2003 Routers which motorola recommends. My question is some of the spots in the hospitals where they got coverage before is kinda weak and is giving choppy audio. Does anyone now what could be the case with this. The repeaters RSSI are both at -100dbm does that have anything to do with why i might not dead spots that they had before they went to linked capacity plus???

johnny1225 wrote:I have just installed a linked capacity plus system. They are using the new SLR5700 repeater as the master and the XPR8400 repeater as the peer. They are using XPR3500 radios. Everything is working fine it is linked through HPMR2003 Routers which motorola recommends. My question is some of the spots in the hospitals where they got coverage before is kinda weak and is giving choppy audio. Does anyone now what could be the case with this. The repeaters RSSI are both at -100dbm does that have anything to do with why i might not dead spots that they had before they went to linked capacity plus???

Let me ask this question, because I am not sure of exactly what you have and are trying to do.

Are both of these repeaters operating in the same hospital and on the same frequency?

Are you trying to fill in the coverage by using 2 repeaters?

Your statement about it use to provide some coverage, but now the audio is choppy make me think your trying to produce a simulcast system and going about it wrong.

Before I go any further, you need to clarify the exact details.

Jim

NO these are two different hospitals about 1 mile apart. They are two different frequencies with two different color codes. When i say they got coverage there before i mean they were using capacity plus in both hospitals indepently so they got coverage through out the buildings single site. Now that they are fully linked they talk from one hospital to the next but in each hospital they have certain areas that they got coverage before when they were just single site capacity plus. I would say about 4 areas that did get coverage before but very choppy now in those certain areas.

John

johnny1225 wrote:NO these are two different hospitals about 1 mile apart. They are two different frequencies with two different color codes. When i say they got coverage there before i mean they were using capacity plus in both hospitals indepently so they got coverage through out the buildings single site. Now that they are fully linked they talk from one hospital to the next but in each hospital they have certain areas that they got coverage before when they were just single site capacity plus. I would say about 4 areas that did get coverage before but very choppy now in those certain areas.

John

One possibility is to put antennas inside the hospital. Is there a requirement to provide coverage outside of the hospital for a certain distance away?

What one thought is would be to install leaky coax through the hospital in those areas with poor coverage. You would use couplers to tap off of the main transmission line and then direct the new transmission line into the poor coverage areas. use omni gain antennas and probably omni antennas that can be ceiling mounted. It takes some skill to do an antenna system like this, but that may be your only choice.

I may sound like a broken record, but you really need to supply much more detailed information.
1. Like where is the antenna mounted now and why?
2. What make and model is the current antenna and why was that one selected?
3. What type of transmission line is being used and how long is it?
4. Is there conduit that you can use to run transmission lines between floors?
5. Is the poor coverage areas on the first floor or basement areas?

As you can see from the questions here, this is not just a simple solution. It will take planning and an expenditure to resolve the coverage issues.

Jim

What frequencies are each hospital operating on? Is it possible that now that the repeaters are linked, you are noticing adjacent, or near adjacent channel interference that was not occurring before?

Two hospitals, two repeaters, two different freq pairs, single site LCP, had acceptable coverage, now has several poor coverage areas after linking sites with LCP.

So, what else changed? What stuff got replaced, and what stuff got reused?

Nothing got replaced bill, all filtering cans are the same they are still on the same freq as they where when they were both on single site cap plus indepently the only thing that has changes is that we put in the LCP entitlement keys into the repeaters and turned it to link capacity plus. Thats why i dont understand why the poor coverage issues??

How did you link them? Through the customer enterprise network, or did you put in a short point to point microwave between the buildings?

Coverage is always about two things reality and perception. Unless you have a baseline study proving there was actual great coverage in these areas of interest prior to the upgrade to LCP, it's entirely possible the customer feedback is inaccurate - that coverage there was always marginal. It's also possible that something changed in the customer environment that you have no knowledge or control over. ie: building construction, campus construction, new plumbing or electrical, HVAC on the roof, replacement windows with metalized tint that cuts down RF penetration, new wifi access points that somehow trash your band, wireless security cameras, new equipment in nuclear medicine, etc, etc.

Hospitals always have a hundred projects going on at once. They build hospitals one hallway at a time. Any one of these projects could have achieved a milestone that coincided with your cutting over to LCP, and you would never know it. Case and point: A hospital upgraded their lighting systems from florescent to LED panels. The switching power supplies in the panels trash the UHF band making the below ground tunnel levels radio dark. They are working with their electrical contractor to find a solution. Otherwise, they are considering a DAS. But, for now, they can't use their portables in the basements and tunnels. Neat feature.

Thank you Bill, great information

Thanks Again

John

You say both of these systems worked fine as independent systems but now there are coverage issues? You have roaming/RSSI issues.

My experience would lead me to look at the RSSI baselines of the repeaters and the RSSI settings in the subscriber roam list.

Say you are at location A and you turn your subscriber on. It may have enough of a signal from location B to register on that site. Now, instead of registering at the closer site, it registers at a site with marginal coverage. All you may need to move over a few feet and you may be out of coverage but then 5 more feet, your back within the RSSI threshold and the subscriber will stop looking for a better site.

You mention the repeater RSSI is at -100. That is kind of a high noise floor. Using RDAC, check BOTH repeaters RSSI. In a nice environment, I usually find them to be -124, give or take. The general rule I got from Motorola was get the noise floor of the repeater and add 5. So if your are reading -100, set the RSSI for the repeater to -95.

Now look at the RSSI roam settings in your subscribers. Are they in a noisy area too? I can't recall on the XPR3500 but on the 6550 and 7550, three pushes of the left arrow then three pushes of the right arrow will give you a numerical RSSI value for your RX. Walk around checking the RSSI.

Finally, set a button on the XPR3500 for force a roam. When you go into an area where the coverage is poor, hit the ROAM button, forcing the radio to look at the second site. If it comes in loud and clear, your issue is going to be balancing the RSSI setting and the coverage.

Hope this helps.

Awesome advise thank you very much

It takes a little codeplug trickery, but you can get the radio to show which site it has roamed to by giving unique channel names for each of the sites in the channel pool. I did this for a 6-site setup about 4 years ago...I'd have to look at my notes to give further details.

ok so when i say the repeaters are set to -100 dbm RSSI, i mean the repeaters in the CPS are at -100 dbm RSSI, just got back and set up RDAC to see what the repeaters are reading. They were both reading approx. -125.7 dbms, so does that mean i would set the repeaters to 5 db at -120 dbms?? Also the radios are set at the default of -108 dbm, should i play with this setting as well??

The RSSI setting in the repeater is for interference from other 'same frequency' systems, so it doesn't affect roaming. The RSSI setting in the subscriber roam lists is what you'd be interested in. The default is -108 as you've seen. You need to lower that a lot for your particular usage, as you don't want to be working through the other hospital's repeater. I'd set it for -95 and see if that solves your issues for the most part.

Definitely awesome help. Fits the situation perfectly.

n1gtl wrote:You say both of these systems worked fine as independent systems but now there are coverage issues? You have roaming/RSSI issues.

My experience would lead me to look at the RSSI baselines of the repeaters and the RSSI settings in the subscriber roam list.

Say you are at location A and you turn your subscriber on. It may have enough of a signal from location B to register on that site. Now, instead of registering at the closer site, it registers at a site with marginal coverage. All you may need to move over a few feet and you may be out of coverage but then 5 more feet, your back within the RSSI threshold and the subscriber will stop looking for a better site.

You mention the repeater RSSI is at -100. That is kind of a high noise floor. Using RDAC, check BOTH repeaters RSSI. In a nice environment, I usually find them to be -124, give or take. The general rule I got from Motorola was get the noise floor of the repeater and add 5. So if your are reading -100, set the RSSI for the repeater to -95.

Now look at the RSSI roam settings in your subscribers. Are they in a noisy area too? I can't recall on the XPR3500 but on the 6550 and 7550, three pushes of the left arrow then three pushes of the right arrow will give you a numerical RSSI value for your RX. Walk around checking the RSSI.

Finally, set a button on the XPR3500 for force a roam. When you go into an area where the coverage is poor, hit the ROAM button, forcing the radio to look at the second site. If it comes in loud and clear, your issue is going to be balancing the RSSI setting and the coverage.

Hope this helps.

wavetar wrote:The RSSI setting in the repeater is for interference from other 'same frequency' systems, so it doesn't affect roaming.

In MOST situations I agree with this.... I ran into a unique situation in an LCP set up where the RSSI setting in the repeater was stopping it from working. The RSSI setting on the repeater was -100. When I checked the noise floor using RDAC, it was -96. When a subscriber keyed up locally, they were stronger than the -100 and the repeater worked fine.

However, when a subscriber keyed at one of the other sites, it tried to key the repeater in the high noise environment and that repeater would not key up. The reason was since the repeater RSSI was set to -100 but the noise was higher at -96, the repeater "thought" it was already in use so it would not key up. I dropped the RSSI setting in the repeater to -92 and everything worked perfectly.

I agree that this is not the case here and does not affect the roaming ability but it can drive you crazy trying to troubleshoot. I am just throwing this out here since you don't see many LCP discussions and hopefully it will help someone with a like issue.

-95 is a good suggestion and would be a good starting point for subscribers. An even better way would be to obtain an XPR6550 or XPR7550, put each frequency in it's own channel.... do not set them in the channel pool. Then turn on the RSSI view, put on a good pair of walking shoes and check your coverage and RSSI levels for repeater 1. Then do the same thing for repeater 2. That will give you a good idea of where they should be set. If you have GPS coverage, the Site Survey tool cannot be beat!!!

EDIT: You can also set PER CHANNEL RSSI if you see a big difference in the noise floor between the two channels.

Thanks again guys i am going to try this out next week.

Thanks so much

JOhn

I don't have it in front of me at the moment, under the channel screen near the top on the repeater there is an rssi setting, which set wrong will cause your symptoms if Co channel or interference is present. Dump it down to -40db for testing purposes. That "should" allow. The repeater to bypass fcc compliance feature and always transmit. See if it corrects the issue and then set it for actual field conditions and your fcc license parameters.

Rob

Im sorry when i look at the radio it isnt -108 dbm it is -124 dbm. Would i still try the value of -95 dbms in the radio? Please advise

John

Yes.

ok thank you again for your help guys

John

johnny1225 wrote:Im sorry when i look at the radio it isnt -108 dbm it is -124 dbm. Would i still try the value of -95 dbms in the radio? Please advise

John

Are you looking at the roaming RSSI, or do you have the individual channels set for 'channel free', at -124? If so, you should change that to 'color code free' to eliminate ambient RF noise from causing your radios to not TX, thinking they are seeing a valid transmission when there is really nothing there. The roaming RSSI in the roam list is set to -108 by default, that is where you need to look & change it to -95 for your testing.

wavetar wrote:

johnny1225 wrote:Im sorry when i look at the radio it isnt -108 dbm it is -124 dbm. Would i still try the value of -95 dbms in the radio? Please advise

John

Are you looking at the roaming RSSI, or do you have the individual channels set for 'channel free', at -124? If so, you should change that to 'color code free' to eliminate ambient RF noise from causing your radios to not TX, thinking they are seeing a valid transmission when there is really nothing there. The roaming RSSI in the roam list is set to -108 by default, that is where you need to look & change it to -95 for your testing.

I was wondering if he was looking at the admit criteria too.