Question about satellite radios

[INDY72]

I have noticed that a lot of agencies are moving thier operations to satellite radio nets. I was wondering how these are effected by weather conditions, especially since satellite television signals are disrupted by storms. Is there a differnce in the types of signals being sent via transponders???

 

[N_Jay]

I have noticed that a lot of agencies are moving thier operations to satellite radio nets. . . ??

Can you name one?

 

[INDY72]

Sure,... Mississippi Department of Wildlife, Fisheries, and Parks.... Mississippi Emergency Management Agency,... and New Mexico DPS State Troopers.

 

[JediMaster]

I haven't heard about this but I can say that if it's anything like XM Satellite radio then it will be fine. I have both satellite TV and XM satellite radio. And I will lose my TV signal in a severe storm but I have yet to lose my XM signal. Therefore I don't think it will ever lose it's signal or be a problem with agencies going to it. I actually think it will help because then communication in the middle of a park can be easier since normal radio towers are prohibited from national/state parks.

 

[N_Jay]

Sure,... Mississippi Department of Wildlife, Fisheries, and Parks.... Mississippi Emergency Management Agency,... and New Mexico DPS State Troopers.

Any links would be helpfull

 

[INDY72]

http://www.radioreference.com/modules.php?name=Forums&file=viewtopic&t=11130

Thats the easiest to get too,.. the references to MEMA, and MDWF&P I will have to dig through the forums a bit...

 

[INDY72]

matthewtomek
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Joined: Dec 19, 2002
Posts: 65
Location: Memphis, TN

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Posted: 02-01-2004 05:23 AM Post subject: Report post

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I have also learned since I orginally posted this that they purchased a SAT system, radios and all. Just about all the trucks either already have the radios installed or on the way to be installed. That's going to be a lot of talking on the dispatch channel. I'm assuming that each district will have their own talkgroup as well.

I have had some experience with Sat radios. We have one at our EOC in Cleveland that we talk to MEMA on. MEMA has several sat radios with their own talkgroup and there is a statwide talkgroup for all the EOC's to talk to each other. The only drtawback is that when you key the radio up, it takes a couple of seconds to gain access to the system. I feel that this is the future and will eventually replace 800 trunking once the pricing of it comes down.
....................................................................................................

 

[Jay911]

Banff Fire and EMS, and Lake Louise Fire, in western Alberta, Canada, are running a satellite radio system. I'm on the other end of it, and it's interfaced into our Centracom console somehow. They use VHF portables on their end to transmit to their vehicles which have satellite repeaters in them. The range is just insane, as you'd expect with satellite - they've been everywhere from Calgary to Banff, halfway down into B.C. and everywhere in between, and basically I can't recall an area where I haven't been able to make contact. The one pain is the delay in transmitting. We have to hold down the transmit button for ~5 seconds before the satellite opens up. Also, it seems the satellite repeaters out in Banff are always on, and not coded to PL or anything, so we often hear pager intermod and other noise.

 

[N_Jay]

Banff Fire and EMS, and Lake Louise Fire, in western Alberta, Canada, are running a satellite radio system. I'm on the other end of it, and it's interfaced into our Centracom console somehow. They use VHF portables on their end to transmit to their vehicles which have satellite repeaters in them. The range is just insane, as you'd expect with satellite - they've been everywhere from Calgary to Banff, halfway down into B.C. and everywhere in between, and basically I can't recall an area where I haven't been able to make contact. The one pain is the delay in transmitting. We have to hold down the transmit button for ~5 seconds before the satellite opens up. Also, it seems the satellite repeaters out in Banff are always on, and not coded to PL or anything, so we often hear pager intermod and other noise.

???? Are we mixing "Satellite Receivers" with "Satellite Communications"???

I guess my original question was with the tone that "A LOT of agencies" (my emphasis) were going to Satellite systems.

Satellite systems have great advanteges covering large expanses where relitivily little traffic is required, and where the creation of significant infrastructure is a challenge. (Oceans and the polar regions are good examples).

Satellite communications is typically a very poor solution where terestrial services are available.

Just to make the point, even the "Satellite Radio Systems" (XM, Sirus) are looking at installing terestrial systems in denser areas.

There is no way a satellite communications system is going to be cost effective, or even have the neccessary capacity in urban, sub-urband, or even in most (populated) rural areas in the US.

 

[Jay911]

???? Are we mixing "Satellite Receivers" with "Satellite Communications"???

Sorry, I guess I am confused.

I thought the original topic related to communications systems that used a satellite as the main signal carrier.

I was providing an example of one that I know of.

My bad. I'll go back to lurking.

 

[matthewtomek]

This is an article from Mississippi's Clarion Ledger today talking about the new Sat communications in Mississippi:

http://www.clarionledger.com/apps/pbcs.dll/article?AID=/20040622/NEWS01/40622003[/url]

 

[N_Jay]

???? Are we mixing "Satellite Receivers" with "Satellite Communications"???

Sorry, I guess I am confused.

I thought the original topic related to communications systems that used a satellite as the main signal carrier.

I was providing an example of one that I know of.

My bad. I'll go back to lurking.

My bad, I thought the reference to the no PL noise was typical of a "satellite receiver" problem.

You should have about 1/2 second delay in th esatellite path, but key up should be quick, unless there is a delay to prevent false key ups.
I wonder whey they did not use PL to protect the portable to Sat repeater link?
My guess is it was designed by someone with more knowlege about satellite comm than LMR.

 

[N_Jay]

This is an article from Mississippi's Clarion Ledger today talking about the new Sat communications in Mississippi:

http://www.clarionledger.com/apps/pbcs.dll/article?AID=/20040622/NEWS01/40622003[/url]

Interesting.
$6000 a unit.
I wonder what the airtime costs?

 

[INDY72]

Hey matthew, mind if I submit the Clarion Ledger story for you as a NEWS submission?

 

[matthewtomek]

I've already done it, just hasn't been posted yet.

 

[JohnWayne]

My "other job" is researching hurricanes and severe weather for a prominent university, and joint ventures with the National Severe Storms Lab, the National Hurricane Center, and the National Science Foundation. One of our projects, called Wind Engineering Mobile Instrument Tower Experiment (WEMITE) involves putting trailers with weather instrumentation in the path of landfalling hurricanes, as well as using mobile Doppler radar vehicles (SMART RADAR) to study the wind structures, especially boundary layer conditions. One of the goals of our program is to provide real-time weather data for landfalling hurricanes to various agencies and the public.

Anyways, to the point. I have just ordered a two-way satellite system made by EMS Satcom called the CYCLONE (http://emssatcom.com/pdf/CycloneBrochure.pdf). It's a pretty slick unit. It automatically tracks the satellite, which means that we don't have to manually aim it when setting it up in hurricane conditions. In the initial stages of this program, we are going to outfit one of our instrument trailers with the satellite terminal which will be connected to the data acquisition system. Our office will be directly connected to the datalogger via satellite and will be able to have real-time data which we will disseminate to the appropriate agencies.

I know y'all are curious about the costs. I am happy to report that we spent about $14,000 of your tax dollars on the satellite unit itself. We are paying $4.00 per megabit for the data transferred, and we can talk on the phone for $1.75 per minute. There is no monthly fee.

The real test is going to be how well it performs in the rain bands in a hurricane with rain rates up to 30 inches per hour. A great side effect of this project will be that I get to do new research on satellite rain attenuation models in heavy rain conditions.

It should be an interesting and exciting project. Other organizations have tried do the same using cellular-based networks with limited success. I am hoping that we can the sort of "first to market" and secure more grant money in order to expand the project.

I'll try and answer questions about the project if anyone has them.

Jeff

 

[INDY72]

Well yesterday's demo of the MDWF&P sat net was quite impressive, the Conservation Officer talked loud and clear, from Jackson, with not only another unit in the Tupelo area, but also with the Kentucky EMA with there being inclement weather at the other sites. So that pretty much answers my question for me,... will have to ask a few of the ones I know how they do when we get a real hurricane later this season. Another good thing about the system is it elliminated the need for 289 cellular phones, which saves MDWF&P another big chunk of cash.

 

[WayneH]

Going to satellite for communications is only really intelligent if you are looking for a form of communication similar to cell phones where you want constant coverage yet can deal with delays and a cost for use.

For a Fish & Wildlife service it probably works out well given their area of required communication and rarely being in enclosed spaces. And I suppose they don't have a lot of dense forest where they surely would have trouble with getting out through a thick ceiling.

Outside of that you won't see it as the future for public safety. I would never put my life on the line with a satellite radio system. The costs, regardless of technology, will never be cheap and you will always be relying on someone else to maintain the network you use.

They make it sound like they launched their own sat system when in reality they just purchased a pricey cell phone with PTT that has city-like coverage in rural areas.

-Wayne

 

[INDY72]

Plus the system gives them interop with MEMA and other states EMA's

 

[WayneH]

I can hear it now at a meeting with the product vendor and the politicals who make the decisions on a communications system...

Vendor clearly states negatives compared to any common communications system yet words them so they're frosted to sound sweet, he then uses the word interoperability and they are instantly sold immediately forgetting the previous, which they could have later questioned with an experienced advisor. :lol:

-Wayne