Point to point microwave question(s)

[Radiogeek97]

Gentlemen

we have a very small voted system (2 recievers and a spectratac comparitor) Our main transmitter/reciever is a 90's vintage quantar and our back-up transmitter and secondary reciever is a 70's vintage micor. Our sites are linked by a combination of in-house and verizon RTNA loops. The problems other than the age of the infrastructure is that the phone lines cause us greif to the point where it is now a serious officer saftey concern. Verizon has had years to figure out how to fix this mess and has had no luck, so our system admin has made inquiories to the local moto shops about linking the sites via short range microwave.
I am not too familiar with current microwave backbone infrastructure and i was looking for reccomendations and cautions. Also if for some miracle we go over to p-25 some day are there products out there that will be compatable with an "astro system" that will work for our basic needs now? One more thing I have heard that Moto has some sort of system called "canopy" what is that and will it work effectively for a basic spectratac and Possible future voted astro system

thanks

[515]

Probably the first thing to look at would be to make sure you have good paths for microwave between the sites, before considering microwave links an option.

You might take a look at the RAD AirMUX 200 and IP MUX-1E, if your hops aren't too long. This setup has a lower cost than a big Harris or Alcatel microwave setup. They claim up to 50 miles is possible, but then you'd probably be looking at 10-15 foot diameter microwave antennas to get any decent reliability for something that long. Given a good path, you should be able to get 10 miles or so with much more moderately sized antennas.

The IP MUX-1E can have an E&M interface to pass full-duplex analog audio over the link with minimal latency around 8ms. It also allows ethernet to be sent over the link.

http://www.rad.com/Article/0,6583,36623,00.html
http://www.rad.com/Article/0,6583,36509 ... ay,00.html

For P25, the Quantar Astro Modems (which may no longer be available) can be used over the E&M interface of the IP MUX-1E. If the Astro Modem's aren't available, there are other options, like the RAD ASM-10/8, or the Telenetics 326X series.

As far as I know, Canopy is only an ethernet bridge, so unless your repeaters, receivers, and consoles have IP interfaces on them, you won't be able to do much with it.

[N4DES]

Probably the first thing to look at would be to make sure you have good paths for microwave between the sites, before considering microwave links an option.

That would be correct. This is no doubt the first step. ComSearch is IMO the leader in the industry that does path survey's and frequency coordinations. Being we don't know the distances and terrain we can't really comment on specifics, but the frequencies of choice could be 4.9, 6, or 10 GHz. and all depend on other local usage. 6 GHz is just about all taken around here and licensing a new path is almost impossible.

[Wowbagger]

Yes, you need a clear path, but remember, that can change.

I was at an APCO-25 site (working with Motorola service engineers on how to better met their testing needs), and they had a REALLY NICE microwave setup - pressurized feedline, nice big horn, the works. It was intended to be the backhaul from the site to dispatch.

It was unused.

It was unused because after the site was live, had been live for some time, and was using the link, the municipality decided that the best place to locate a new water tower on on that nice high spot where the site was located. The workers building the water tower were a little uneasy about having that dish pointed RIGHT AT THEM as they built the water tower, but they kept right on working.

The first anybody know of it was when the link went down, and they found a brand spanking new water tower RIGHT IN THE WAY.

[Radiogeek97]

fellas

The distances are very short, from H.Q to the main quantar is about 2 miles line of sight, and from H. to the backup micor is at most 1/4 mile. The paths should not be a problem unless somebody down the road puts up a high rise. The area is a large city with congested rf of all kinds from various public saftey and commercial RF. The moto guy was out doing a site survey with his gps ect. I just wanted some pointers and cautions should he try to quote us something that may not be what we need as far as current and future plans.

[N4DES]

With the additional information, good bet that a low density 4.9 shots would do the trick for ya.
Other option would be 10 GHz where the equipment is a lot smaller, but that freq. is affected by heavy rain so it may not be a good option for the 2 mile shot.

[Batwings21]

If you have a voting system and if you may go p-25 you do not want to use any Ethernet based systems or share your link with data. The JPS SNV compartitor will allow adjustable path delays, but if you have a Ethernet network the latency can change, causing improper voting and missing or double words and syllables.

[Radiogeek97]

bat

would the devices above from rad.com be what you are refering to as Not being compatable with a future astro p25 system? Also we dont have a jps comparitor its an old spectratac and there are NO plans i'm sure to replalce it. If the Rad.com links are not what we should be looking at can you reccomend somthing?

thanks

[George]

Ladies and germs,

I would go back to Verizon and tell them to get their Sh!T together. This ain't rocket science and your cost of ongoing operation is going to be better than replacing their facilities with microwave.

I have considerable experience with the Airmux 200 after having installed over 200 links to transport T1 circuits The Airmux 200 does not have the capability to transport individual voice grade channels. What it can do is transport ethernet or up to four T1/E1 circuits. depending upon the configuration of the IDU.

How you get a DS0 voice grade circuit from this type of unit is to take a T1 to a channel bank and break it out to an E&M trunk. A channel bank can be a CAC ADIT 600, Newbridge 3624, 3630 and any number of other pieces to do this job. Adtran comes to mind also.

Keep in mind also the Airmux has a 28 millisecond latency to it and while the transport time may not be a problem, if you have a local receiver and a circuit coming in via radio, accounting for the conversion time, you may have a problem with the voter. It may sound strange if the audio arrives at different times. A really bad idea would be to connect two of these back to back to extend a link over two hops.

The Canopy equipment has the same problem.

The reason for this is Airmux and Canopy both are not full duplex radios. They get their speed by operating in a half duplex mode and buffering the output. That's why there is delay...it has to make it through the buffer to the output.

Again, read the telephone company the Riot Act and FIX IT! Also, use the following magic words:

[size=200]"PUC Complaint"[/size]

Combine those words with the words

[size=200]Public Safety Organization[/size]

Also keep opening tickets if the phone company keeps closing them. Repeat problems drive local managers nuts and grinds their trouble indicies into the dirt. They hate that because their compensation and bonuses are driven by those numbers.

Any wire that falls to your internal maintenance needs to be rerun or repaired...come on now...it's not that hard.

zzzzzzzzzzzzzzzzzzzzzzGeorgezzzzzzzzzzzzzzzzzzzzzturn up my Diet Mountain Deew drip....Nurse.....Nurse!

[Batwings21]

We have used MDS LEDR 900mhz pt to pt licensed radios,with MDS mux's and they are fairly reliable, with a fixed latency. In that system we do use a JPS comparator, but I'm not sure if we have a path delay enabled. The RAD units you are asking about I have not dealt with, but I have dealt with the RAD TDMoip mux's and they do not have a consistent enough path delay to use in a voting system. And I don't know that either of those options will provide the kind of link an astro system would require. I am not an expert at this, but those are some questions you would want answers to with any proposed system, or even making vendors guarantee a consistent path delay on all links that way its not your responsibility if something doesn't match up.

[nmfire10]

Again, read the telephone company the Riot Act and FIX IT! Also, use the following magic words:

"PUC Complaint"

Combine those words with the words

Public Safety Organization

Also keep opening tickets if the phone company keeps closing them. Repeat problems drive local managers nuts and grinds their trouble indicies into the dirt. They hate that because their compensation and bonuses are driven by those numbers.

Yes, do this. These are the things that cause them to lose money and thats the only thing that motivates any phone company to do anything properly. FYI, PUC stands for PUBLIC UTILITY CONTROL.

[chartofmaryland]

If you like driving with no doors, or windshield and with an engine on fire, then go with MDS. They have no tech support, products that fail from the factory and are the equal to a drunk on a skateboard. Not a product for Public Safety applications.

CoM

[Jim202]

You need to be a pain in their lower rear on a multiple daily basis. Follow the other
suggestions on here, but the real secret is to use some buzz words that a phone
company doesn't like to hear. Being a public safety agency you have the ability
to require the phone company to have a short wire on the time they have to
respond to a complaint. In some cases, this response time is as short as only
2 hours. Be sure to ask for the "trouble ticket number" assigned to the problem.

Anyway, what you do is put in the first trouble call. Don't forget to obtain the
operator number of the person taking the call. Request that a supervisor call
you to respond to the trouble report. Find out what the time duration is for
your type of service on this call. Then when that time limit passes, this is
where the fun starts. Put in another trouble call, only this time use the words
"subsequent trouble report" and ask that you be put in contact with a supervisor
before you hang up.

Don't let the trouble ticket taker hang up on you. Stay on the phone until you
get one of the supervisors to talk with you. Explain the problem and that you
are "escalating" the trouble report. Have the supervisor explain to you why no
resolution has been made on the trouble.

If you have a 2 hour, 4 hour, 6 hour, 8 hour or what ever time duration on the
resolution, make another call at the end of this time frame. Go through the same
steps and tell the call taker that your placing a "subsequent trouble report" and
would like to talk with the supervisor. After a couple of these calls and nothing
seems to be moving forward, find the corporate office for your region and place
a call to the president's office. You won't get him, but you should end up with
the secretary there. Be nice and explain your problems and how long this has
been going on. You might even provide the ticket numbers you have been given
on each trouble call. It shouldn't take very long before the heads start rolling.

I have found this to be very effective over the years. The main secret is to be
polite, keep up being persistent and keep your facts straight. Write down the
names of everyone you talk to and phone numbers on how to get back to them.
Keep a running log of what the problem is, the ticket number, the date, time and
who you talked with, what they said would be done and when it would be done by.
Follow up, follow up, follow up. Keep your log going on each and every trouble.

The bottom line is that all the supervisors have their job review keyed to the
trouble tickets and how fast they are cleared. The "subsequent trouble reports"
just throw a monkey wrench into this process. They don't want a long list of
troubles hanging on for any long time frames. They don't want the next up
supervisor asking why this problem isn't resolved.

Jim

Gentlemen

we have a very small voted system (2 recievers and a spectratac comparitor) Our main transmitter/reciever is a 90's vintage quantar and our back-up transmitter and secondary reciever is a 70's vintage micor. Our sites are linked by a combination of in-house and verizon RTNA loops. The problems other than the age of the infrastructure is that the phone lines cause us greif to the point where it is now a serious officer saftey concern. Verizon has had years to figure out how to fix this mess and has had no luck, so our system admin has made inquiories to the local moto shops about linking the sites via short range microwave.
I am not too familiar with current microwave backbone infrastructure and i was looking for reccomendations and cautions. Also if for some miracle we go over to p-25 some day are there products out there that will be compatable with an "astro system" that will work for our basic needs now? One more thing I have heard that Moto has some sort of system called "canopy" what is that and will it work effectively for a basic spectratac and Possible future voted astro system

thanks

[Astro Spectra]

Actually you might want to be careful with the MDS product as it does not have fixed latency. Have a read of this application note:

http://www.simulcastsolutions.com/PDF/L ... ulcast.pdf

Note the comments "in the event of a loss of synchronization caused by a weak signal
or momentary loss of power the MDS LEDR 900S radio exhibits changes in link delay" this change might be OK for analog voting but it plays merry hell with simulcast.

Anything IP is likely to be an issue - it's easier to beat up the phone company...

[ka8ypy]

If I may from the Verizon perspective, when you first open the trouble ticket you need to ask for an immediate escalation and to speak to a supervisor at that time. If after the given time frame has elapsed, escalate to the next level (manager) and ask to speak to them. If still not resolution after the given time frame, call back and escalate to the next level (Director) and ask to speak to them. Also if you have a service manager, get them involved as well as their manager. I worked in special services for 10+ years at Verizon (the last 7 as a team leader) in a major call center for the Potomac Region, any questions on what they are telling you, feel free to PM me and I can let you know to call BS or not.

You need to be a pain in their lower rear on a multiple daily basis. Follow the other
suggestions on here, but the real secret is to use some buzz words that a phone
company doesn't like to hear. Being a public safety agency you have the ability
to require the phone company to have a short wire on the time they have to
respond to a complaint. In some cases, this response time is as short as only
2 hours. Be sure to ask for the "trouble ticket number" assigned to the problem.

Anyway, what you do is put in the first trouble call. Don't forget to obtain the
operator number of the person taking the call. Request that a supervisor call
you to respond to the trouble report. Find out what the time duration is for
your type of service on this call. Then when that time limit passes, this is
where the fun starts. Put in another trouble call, only this time use the words
"subsequent trouble report" and ask that you be put in contact with a supervisor
before you hang up.

Don't let the trouble ticket taker hang up on you. Stay on the phone until you
get one of the supervisors to talk with you. Explain the problem and that you
are "escalating" the trouble report. Have the supervisor explain to you why no
resolution has been made on the trouble.

If you have a 2 hour, 4 hour, 6 hour, 8 hour or what ever time duration on the
resolution, make another call at the end of this time frame. Go through the same
steps and tell the call taker that your placing a "subsequent trouble report" and
would like to talk with the supervisor. After a couple of these calls and nothing
seems to be moving forward, find the corporate office for your region and place
a call to the president's office. You won't get him, but you should end up with
the secretary there. Be nice and explain your problems and how long this has
been going on. You might even provide the ticket numbers you have been given
on each trouble call. It shouldn't take very long before the heads start rolling.

I have found this to be very effective over the years. The main secret is to be
polite, keep up being persistent and keep your facts straight. Write down the
names of everyone you talk to and phone numbers on how to get back to them.
Keep a running log of what the problem is, the ticket number, the date, time and
who you talked with, what they said would be done and when it would be done by.
Follow up, follow up, follow up. Keep your log going on each and every trouble.

The bottom line is that all the supervisors have their job review keyed to the
trouble tickets and how fast they are cleared. The "subsequent trouble reports"
just throw a monkey wrench into this process. They don't want a long list of
troubles hanging on for any long time frames. They don't want the next up
supervisor asking why this problem isn't resolved.

Jim

Gentlemen

we have a very small voted system (2 recievers and a spectratac comparitor) Our main transmitter/reciever is a 90's vintage quantar and our back-up transmitter and secondary reciever is a 70's vintage micor. Our sites are linked by a combination of in-house and verizon RTNA loops. The problems other than the age of the infrastructure is that the phone lines cause us greif to the point where it is now a serious officer saftey concern. Verizon has had years to figure out how to fix this mess and has had no luck, so our system admin has made inquiories to the local moto shops about linking the sites via short range microwave.
I am not too familiar with current microwave backbone infrastructure and i was looking for reccomendations and cautions. Also if for some miracle we go over to p-25 some day are there products out there that will be compatable with an "astro system" that will work for our basic needs now? One more thing I have heard that Moto has some sort of system called "canopy" what is that and will it work effectively for a basic spectratac and Possible future voted astro system

thanks