system upgrade for Hospital

[johnny1225]

We are a Motorola Dealer here in Toronto Canada, We have a Hospital that has a MSR2000 Repeater in the main Hospital and coverage is very well inside the Hospital. There is another building that is apart of the hospital that is about 2000 feet away and also has a MSR2000 Repeater into that building, and coverage is very well there.There is also a child day care that is also aprt of the hopital about 1500 feet away from the hospital and about 500 feet away from the 2nd building with no repeater there at all. The hospital wants to get rid of the old MSR2000 Repeaters and get new once, but my question to someone that could help tie this system together, meaning the hospital can talk to the building 2000 feet away on all floors and to the child day care centre, bacially all three building would be tied together. Hospital is about 5 stories, 2nd building about 10 stories and child day care about 3 stories, my questions would be as follows...

1) What would be the best repeaters for this job, we were thinking MTR2000 UHF Repeater (RKR1225)

2) Should we stay UHF or LTR or trunking

3) What would be the best option for antenna's that would be benifical along with cabling recommendations.

Basically we are tieing 3 building together about 2000 feet away from each other.

I would like to get some remendations or speak to someone even by telephone about this system we are coming up with.

thanks in advance for a quick reply.....

john

[thebigphish]

how many frequencies do you have access to? avg. system load? users? fixed points? i'm thinking unless you have a serious problem with loading or excessive users, you MIGHT not need LTR. [snip]

[nmfire10]

... i'm from a town of 50k that doesn't need our townwide LTR system.

Hey, that is a state-of-the-art homeland security top-notch super-save-the-world ala Marcus system! You definately need it... because he said so.

[Dan562]

Hello John,

I tried to envision your 3 building hospital repeater system not quite a half mile away from each other. Having all three building at different levels also complicates signal levels and distribution throughout the individual structures. Hospital in general have many dead spot due to construction, type of material (metal) and dedicated special exam areas especially dealing with X-ray equipment.

I've designed Radio Paging and Two-Way systems for many commerical complexes with excellent results although I must admit I was able to walk the facilities, exam blueprint drawings on the building structures before making any proposals. Since you have not provided a simple building layout for each location and height it would almost impossible to second guess what can be done.

I don't think you need to switch bands of operation ... UHF works very well for signal penetration from a centrally located (100 Watt) repeater. The normal signal problem is found using Handheld Portable radios which leads up to installing a Voting Comparator and Satellite Receivers within the external buildings.

You should also consider proposing and installing Andrews 50 Ohm Radiax RF cable vertical centrally located through each building with antenna -3 dB Power Dividers and no higher gain that +6 dB vertical antennas on each roof top. Where the Radiax terminates in the basements or lower levels use 1/4 wave antennas / magnetic mounts attached HVAC duct work. Radiax RF cable is otherwise known as leaky line allowing signal output and input.

Between the roof top antennas and Radiax RF cable, I would suggest using 50 Ohm Heliax RF cable to keep the feedline losses to a minimum. If you're trying to cover under ground tunnel throughout the complex, you would need Radiax cables in those area too.

Saying all of this, heaven knows what your customer needs for wide area coverage outside the hospital complex and that has to be considered in system coverage. With the combined system losses, I can predict what it would be .... not enough information given.

MTR2000 is sold as T5544 Base Station / Repeater and the individual T5731 Second Receiver. You would want to order one Base Sation Repeater with C269 S-TAC & X182 UHF Duplexers and two Second Receivers with the C269 Spectra-TAC Option plus a T1786B Spectra-TAC Comparator with (3) C178 Signal Quality Modules, (1) C175 Tone Keying Module, (1) C235 Tone Priority Module (Console Priority) and (1) C366ADSP Roofing Filter for the Co-located site (this prevents Down Voting and it's one of Motorola's best kept secrets).

Regards,

Dan

[Alan]

and (1) C366ADSP Roofing Filter

Can you explain this option a bit further. I have not heard of this terminology before.

Thanks

[Dan562]

Hello Alan,

Apparently you've never encountered the C366ADSP Option Voice Frequency module before seeing it listed in my reply. In essence this "VF" module is used when Co-locating a T1786B Spectra-TAC comparator with a Analog Base Station Repeater. When selling and designing a multiple receiver Voting system (2 or more Satellite receivers) the Base Station is set up in a 4-Wire Line configuration. The first pair of WL carry the XMTR TRC and Voice, and the second pair of WL are wired to the comparator's VF module in the 1st chassis slot and then into the 1st Signal Quality Module (SQM) mounted in the 2nd chassis slot, the 2nd SQM mounted in the 3rd chassis slot, the 3rd SQM mounted in the 4th chassis slot, etc.

The C366ADSP is a Specialty Product & is not normally listed in the /\/\ Standard Price Pages with the except of possibly this year 2004. Never the less, it is an orderable option that should be included while ordering the Spectra-TAC comparators saving a lot of headaches for the field service technicians and the end users in the long term. Practically everyone in /\/\ Area Systems Engineering teams know the advantage of using this module option while designing new Analog S-TAC systems.

What is the purpose of this module? The VF module serves only one purpose and this is a "Low Pass Audio Filter". The VF module has unity gain and rolls off any noise above 2 kHz preventing the first SQM to appear as having too much noise mixed with the recovered audio from the co-located receiver or VF filter emulates a standard Telco conditioned RT2002, RT3002 or T1 phone lines.

If the S-TAC comparator does not include the VF module, when the S-TAC comparator starts voting, it will detect too much audio noise on the 1st SQM, locking it out of the Voting process and creating what is known as "Down Voting" to a weaker signal site and more noise on the signal. We all understand that the WL Output of the Base Station Repeater is designed for a 600 Ohm impedance and the Analog audio comparators are designed for the same 600 Ohm impedance Input.

Unfortunately regular or even shielded twisted pair do not perform the impedance matching in real world conditions therefore setting up the conditions of additional noise bandwidth, up to 6 kHz to be super imposed on that pair of wires. By adding the required module, it eliminated these conditions. If you should happen to have this "Down Voting" condition out in the field, you can order the separate VF Module QRN8498B which includes the 2 chassis mounting rails and Spark Gaps from the /\/\ factory and install into your T1786B Spectra-TAC comparator to eliminate the unwanted problems.

Dan

[d119]

According to my Motorola Online account, that's a $407.00 option. I have SpectraTAC voting installed on two UHF repeaters, and I've never needed that option... Nor had I heard of it before tonight

Lucky me I guess. Nice to know it's around though, albeit a bit pricy... Probably something you could build yourself on a blank MICOR protoyping card.

[johnny1225]

Thanks for the info Dan. I was wondering about the Comparator. It will be in the same room as the MTR2000 Repeater? Where do the Recievers go in the other buildings, do you usually go up high on the roof type deal or
in the centre of the building. What would your recommendations be. The Hospital is 8 stories and the building that i was talking about that is 2000 ft away is 10 stories, and the child day care is also 8 stories. What would your recommendations be for set up, and is all of this equipment hard to program with all the different features that this setup has??

thanks again Dan for you very helpful reply...

thanks

john

[d119]

If I can just chime in again... Sorry, Dan.

There is no programming involved in the SpectraTAC comparator. Just audio level settings. My typical experience & installations put the comparator in the same rack as the transmitter/repeater. They also use the existing receiver of the repeater as a voting channel (usually on SQM1 in my setups).

If you are using SpectraTAC receivers, they are crystal-controlled units based off of a MICOR receiver board. I would suspect you're more likely going to be using MTR2000 receivers instead, as they are the current product. It's as simple as programming everything in RSS, connecting it all together, and then doing the dirty work - audio levels.

Dan can give you the skinny on that.

[nmfire10]

We have three 9-12 floor buildings attached, another massive building several blocks in size and 6 floors high across the street, and another building beyond that several blocks away from the main. The basement between the attached buildings have no less than 3' thick concrete blast walls seperating the buildings. The actual buildings are all concrete and steel, full of a million miles of wire and electronics found in big hospitals.

A UHF repeater on the roof covers quite nicely on it's own. We have a remote receiver in the basement of the main complex and the first floor of the far away building. Between the rooftop, the basement, and the off-site building, we have probably 90% portable talkback. Problem areas are around the sub-garage and MRI areas for obvious reasons. More receivers are on the to-do list.

So, if talk-back is your problem, remote receivers and one well placed transmitter should do the trick. If it is talk out, that could be a bigger problem. You might need to steer transmitters with the voter or something.

[Dan562]

Hello John,

As I recall the hospital wanted to get rid of the 2 UHF MSR2000 and upgrade the 2-way radio repeater system. This is why I suggest a single UHF MTR2000 Base Station Repeater, 2 - MTR2000 Satellite Receivers, a T1786B Spectra-TAC comparator with the specified options, 1/2" Radiax cable centrally located & installed vertical down through each building for better signal penetration even into sub basements assuming this is for a hospital Public Safety system, lower gain outside antennas with 1/2" Heliax cable and use "N" Type connectors throughout the system.

Possibly Matt has a point about using a single repeater in his application but I notice that he's adding Satellite Receivers to over come poor signal talk-in problems at that hospital complex. Matt didn't state if his 2-way system is currently using a Voting comparator or not ..... possibly I over looked those lines in Matt's reply.

John I just don't want to see you get stung by under designing a new 2-way radio system for the customer. Customers are so picky when it comes to budgets and what they want. If you read between the lines when the customer is stating what they want for an upgraded system, they'll tell you they want the world with a fence wrapped around it .... but on a Diet Pepsi budget and a few potato chips thrown in. Here, have a couple of tin cans with waxed string between them .... pull the string tight when communicating! It's wireless .... we only use the best string, wax and tin cans.

In essence you could present three proposals, Good, Better and Best, and let the customer make the final decision. This way the customer can't throw the blame on your company or dealership. I'd almost bet the hospital would choose the least costly proposal unless their management over seeing this project are forward thinking people.

As far as MTR2000 RSS, it's pretty simple programming on the Base Station Repeater and the individual MTR Satellite Receivers. As d119 has previously stated the T1786B Spectra-TAC comparator levels are all adjusted by potentiometers so all you'll need is a TIMMS or a 600 Ohm dB meter. The Status Tone being sent out of the receivers is set at -13 dBm on Standard RT2002 telephone lines to keep the local Telco happy :^) I'll think about where to place the 2 Satellite Receivers in the external buildings and antennas, and get back to you regarding this issue.

Dan

[nmfire10]

Yea, it's voting. How else would it pick a reciever??

[N4DES]

I agree that the voting configuration would work perfectly in this application. You would want to find out is if there is "hospital owned copper" between the buildings. This would streamline the interconnection process and you wouldn't have to include your local phone company.

One other thing is "antenna downtilt" for the rooftop antennas. Being your coverage area is limited to a 2000' radius I would highly reccomend buying antennas with 3 degree of downtilt to put the highest gain point below the horizon for both talk-out and talk-back.

[Dan562]

Hello Matt,

As I stated I didn't notice in your wording about using a comparator but in lieu of that, I've seen many other official and non-official SP system configurations used out in the field. I'm not saying they were correct for the application but they were there and interfaced.

Mark, antenna downtilt is a very good idea and point to make available to John regarding the hospital's upgrade providing the end user doesn't need the additional off site coverage for their radio system. The second good point was made about internal copper pairs within the hospital's complex.

There's one other item I kept forgetting to mention about using Andrews Radiax cable. Since this is a hospital complex, generally speaking hospitals have their own RF Paging systems. Many times the customer was sold not only the outside vertical antenna but also a 3 dB RF Power Divider and Radiax installed down into the building for better internal coverage for the Pagers. Depending on which frequency bands 150 or 450 MHz are used, you could include in the proposal incorporating the 2-way system into that same Radiax cable with a TX RX Product Crossband Coupler or Combiner. Yes they add some system losses but the advantages outweigh the disadvantages on most systems.

Dan

[johnny1225]

Dan, i was wondering alot of people including you are talk about superflex 1/2 " heliax cabling. I was wondering who is the manufacture of this type of cabling and if you had anymore infor were to put the mtr2000 recievers you said that you might have time to see where they would fit best...

i would also like to say how i appreciate all the help you gave me on this project and it will be closing this wednesday, so if you could a quick reply would be much appreciated......

thanks again Dan....


john

[Dan562]

Hello John,

For Healiax, Radiax (radiating cable) and required "N" type connectors, here Andrew's website: http://www.andrew.com/

You may have another supplier in Canada that's a dealer for the Andrews Products and can supply pricing to your company for your proposal. This cable is not inexpensive to purchase and naturally double the price to the customer.

Since the hospital already has 2 MSR2000 UHF repeaters, I believe there should be existing antennas on those 2 structures and they are probably mounted on the mechanical penthouse walls very near the top of the building. You can reuse these antennas as is, no retuning required. Hopefully these mechanical penthouses are located in the center of the buildings. If the are not just use the outside antennas because installing Radiax internally near outside walls defeat the purpose of this type cable.

I would centrally located the Base Station Repeater on the 8 floor hospital building so the transmitted signal would radiate into the 10 floor building and the 3-5 floor child day care center equally as strong. The 2 Satellite receivers would be programmed for the repeater's receive frequency. The Child Day Care Center receiver could be mounted in that mechanical penthouse with either 1/2" Heliax or Super Flex 50 Ohm cable and either a +3 dB or +6 dB Antenna, possibly selling the customer a RFS (Cellwave)
PD201 +5 dBd, Sinclair SRL-335-2 +6 dBd or SRL-335 +3 dBd.

In the hospital's main mechanical penthouse the MTR2000 UHF Base Station Repeater would also have the T1786B Spectra-TAC Voting Comparator (Co-located with the Repeater), the repeater's receiver would connect the 1st comparator Signal Quality Module (SQM) input, and then you can choose which external building you want next for the 2nd SQM and 3rd SQM inputs. The output of the comparator will wire to the XMTR wireline input and the Console will wire to the input of the T1786B Spectra-TAC comparator.

It's apparent that the hospital's administration aren't providing you enough time to provide am up graded system proposal as they are still only thinking about using two repeater rather than one with vothing receivers.

Good Luck on your proposal.

Dan

[nmfire10]

The remote recievers we use simply have an Antenex stealth shot glass antenna with an NMO mounted on the top of the rack cabinet. They are INSIDE the buildings. We have NO problems with a signal getting out of the middle of the building. In all of these buildings, no where is there a reason to use Radiax anywhere... and these are BIG buildings.

[Dan562]

Hello Matt,

I scrolled back into the posts and found your comments about the your own satellite receiver system path loss problems.

"Problem areas are around the sub-garage and MRI areas for obvious reasons. More receivers are on the to-do list."

This is justification for Radiax cable incorporated into a system design besides the voting receiver to enhance the system coverage. As I have stated before in this post, most hospitals have Radiax installed into their building structures because of poor signal penetration from a RF Radio Paging (XMTR) system and the Pagers (RF Receiver Sensitivity). I don't care if the Paging system is on 30 to 50 MHz, 132 to 174 MHz, 450 to 520 MHz or 900 MHz. Each frequency band presents it's own signal path loss problems within building structures.

May I suggest a very good product manufactured by SCALA Electronic Corp in Medford, Oregon, The PD Series Antenna Power Dividers can be ordered as 50 Ohm PD2-55 50%-50% 50% to the roof antenna amd 50% to the inside of the building utilizing Radiax cable. The next two provide options as far as steering the RF signal either way PD2-72 75%-25%, 75%
to the roof antenna and 25% to Radiax cable or 25% to the roof antenna and 75% to the Radiax cable and the same applies to this version PD2-91 90%-10%.

Depending on your RF signal application using the combination of an outside antenna, internal Radiax cable, and the SCALA 50 Ohm power dividers provide more system vesatility. On short lenghts 400 Feet or less, you must terminate the Radiax with a 50 Ohm resistive loads. On longer installs it doesn't matter as the signal attentuation reflects little VSWR back to the transmitter.

Radiax should not be confused with Heliax cable as they both provide different RF advantages for the system signal. Refer to Andrew Products for each signal system application.

I'm not against new technology or ideas just as long as the product can provide what the customer needs in their system applications.

Dan

[nmfire10]

The MRI and Sub-Garage are very small areas and are on the outskits of the basements. I guess you're just going to have trust me, knowing how this place is layed out, that radiax is not the solution for these areas.

I know the paging system does have Radiax in various places although I am not sure to what extent,

[N4DES]

I'm sure using antennas with downtilt, either 3 or 6 degrees, will outperform a radiax system. Were only talking 2000 feet here, it's not like it's miles away.

Talk-back limitations (if there are any) can be solved with SAT receivers at critical locations.

[Dan562]

Hello Matt,

I trust you on your signal penetration problem ... I was just offering up experience on similiar commerical installation solutions in hospitals, horse
racetrack facilities, DoD manufacture buildings (especially in their guarded research areas) and automobile manufacturing plants. Each facility provides it's own challenge to the technical personnel involved with providing an inexpensive but effective solution. It should be very obvious that I do not know your facility nor John's customer ... the hospital in Toronto, Canada.

We're all here trying to provide options, alternative ideas and solutions to help resolve the infrastructure system problems. I personally think that John should have notified his customer within a few days, that his company was "thinking outside of the box" for a better solution on the two-way system and it might take up to 2 or 3 weeks to provide a professional quote and documentation. I haven't seen a proposal yet that has be provided overnight, it always take time so hopefully nothing is forgotten. And it can take weeks or up to months for the customer's approval no matter how good the system proposal might be.

KS4VT antenna solution would work great if John didn't need to worry about signal penetration directly below the antenna in the hospital. There's one little minor detail that KS4VT has touched upon and it's referred as "the umbrella effect" for RF radiation directly underneath the antenna. I've studied antenna patterns and built antennas in my spare time mostly for VHF and UHF and found that not always is the highest forward gain antenna going to solve every signal penetration problem. In fact the signal will shoot out over rather than down into the areas where it's most needed. There's no one stop solution on antenna systems.

This is why I like the use of RF Pwer Dividers, Heliax to the roof top antenna and Radiax centrally located installed vertically down through mechanical closets within the building structure itself. One thing you want to remember is "keep the Radiax away from HVAC duct work" at all cost because the duct work appears as a antenna reflector.

I hope John is reading all of our advice and not basing his knowledge on any one of our solutions, "we're providing alternative solutions for John and his customer.

Dan