Bi-directional amplifiers

[N_Jay]

Quote me title and section about a PROHIBITION on putting a BDA on a system, . . . ..

Not this again!!

Try Section II here:
http://files.ctia.org/pdf/CTIA_Repeater_White_Paper_Final_050106.pdf

Again, I am using Jack's pages but you can go look at the FCC site if you wish.

http://www.rfsolutions.com/part90.htm
http://www.rfsolutions.com/part22.htm
http://www.rfsolutions.com/part101.htm

Note it is always the LICENSEE not the CONSUMER/OWNER/USER who is given permission.

you are not transmitting with another transmitter, you are merely boosting (usually no more than -70 to -90 db) an already transmitted signal inside a building (AKA TV antenna boosters).

Wrong! You are re-transmitting as soon as your output end is hooked to a radiator and not a terminating device.

From the info links you provided I see no restriction for in building boosters(BDA) other than they meet type acceptance and non-interfenece to the original carrier.

You are either not reading well, or with a biased eye.
It is quite clear. Look up the meaning of LICENSEE.

BTW if the FCC found these BDA's to be so troubling, why havn't they gone after the manufacturers.

Its been requested. The issue is the equipment can be used LEGALLY or ILLEGALLY.
You intended use (without EXPLICIT PERMISSION of the LICENSEE) is illegal.

As far as others paying for extensions of existing services, all the tunnels in NYC are now provided with service by a private, non-phone company provider(they taggged it on with standard AM/FM broadcast antenna's), also same goes for the subways and MTA. Ma-Bell didn't pay a penny for it. GCT was done if not mistaken by the MTA themselves.

Yes, all with PERMISSION of the LICENSEE!
P.S. The latest is the subway stations, which a contract was bid for a vendor to install the system at no-cost to the MTA. So if they are going to get revenue from the carriers, don't you think the carriers were involved?

ALL the buildings I have done provide no service outside of their respective buildings, so in essence you are not transmitting a signal outside to cause any harm.

Good to hear. (guess they have magic windows).
Unless the building (quoting FCC rules here)(Tunnels and mines only) "provides attenuation to the radiated signal due to the presence of naturally surrounding earth and/or water." you are CLEARLY outside the permissible uses.

Now to 911 taxes, it's probably a lot easier to asses a tax on a building for emergency services, than most other taxes. It's not a tax district (unless you state has specific prohibitions to it) all our Fire services are paid for by a Fire tax, all Police services are paid by a Police tax, even the Library has a tax. I don't know who thought that one up, and believe me I hate taxes, but it is nice to know exactly how much is spent by the respective agency.

Those ARE tax districts. (I don't know what state you are in, but in IL we have Fire Districts, Law Enforcement Districts, Park Districts, Library Districts, School Districts, Water Districts, and probably a few others).
By The Way (BTW) those districts will provide cash flow, but not one time costs. Hence the invention of "Impact Fees".

As far as you unsettled feeling for my installation of BDA, you havn't seen the worst of it. There are company's on the Internet that talk to you for about 5 min and send you a PACKAGE which you then install yourself.

Glad to hear you are one of those "Responsible" law breakers. Yes, I am all to familiar with MANY of the "Irresponsible" ones. (Some beyond responsible, to the point of intentionally malicious)

The best I heard was a house wife installing one in her home because she couldn't get service.

Way too common. (even by some supposedly "in the know"!)

I spend most of my time correcting those type of installs. I also verify that no service is provided outside the building by switching the service on/off a taking readings.

Good to hear.
Sort of like making sure the kid down the street with the unlicensed car had good brakes! (Get it?)

How do you address cell loading and location data distortion?

Most installs provide service in buildings that the cell providers will not, and or refuse to do anything about.

Robin Hood, hu??:roll:

Unless the FCC does something to change that attitude of the cell providers, I see this as necessary, and when done correctly, there is no reason for concern.

If the carrier does not provide service, change carriers! (It is not the FCC's job to tell a career how to do business)
I really don't care how YOU see it. It is CLEARLY ILLEGAL.
If you want to continue, fine, but don't try to say it is not ILLEGAL.
Yes, there is lots of reason for concern. Start with $10,000 per violation per day!

 

[N4DES]

Quote me title and section about a PROHIBITION on putting a BDA on a system, you are not transmitting with another transmitter, you are merely boosting (usually no more than -70 to -90 db) an already transmitted signal inside a building (AKA TV antenna boosters). From the info links you provided I see no restriction for in building boosters(BDA) other than they meet type acceptance and non-interfenece to the original carrier. BTW if the FCC found these BDA's to be so troubling, why havn't they gone after the manufacturers.

Part 90:

http://edocket.access.gpo.gov/cfr_2007/octqtr/47cfr90.219.htm

Part 22:

http://edocket.access.gpo.gov/cfr_2007/octqtr/47cfr22.383.htm

The key word in both of these are "licensees" If you are not the Licensee you are not allowed to deploy such an item. You also can't compare TV amps with wireless BDA's because they are wired and closed, much like cable TV systems that have leakage standards so they don't interfere with the wireless users.

Here is a recent FCC action:

http://www.fcc.gov/eb/Orders/2008/DA-08-1093A1.html

The second LOI stated
that, contrary to Digital Antenna's assertions, cellular and PCS
boosters and repeaters are transmitters and may only be used by
licensed cellular/PCS providers or by end user customers with the
express authorization of the licensed provider.

 

[N_Jay]

Part 90:

http://edocket.access.gpo.gov/cfr_2007/octqtr/47cfr90.219.htm

Part 22:

http://edocket.access.gpo.gov/cfr_2007/octqtr/47cfr22.383.htm

The key word in both of these are "licensees" If you are not the Licensee you are not allowed to deploy such an item. You also can't compare TV amps with wireless BDA's because they are wired and closed, much like cable TV systems that have leakage standards so they don't interfere with the wireless users.

Here is a recent FCC action:

http://www.fcc.gov/eb/Orders/2008/DA-08-1093A1.html

Thanks Mark!

 

[ofd8001]

"Dear Mr. Fire Chief:
Start by insisting that your radio vendor program a simplex fireground frequency into your radios. And then do radio tests in the buildings you are worried about. Switch back and forth between the simplex freq and the repeater channel you were using before. You are going to be pleasently suprised at how much clearer the simplex freq is, compared to trying to use the repeater freq."

We will have simplex frequencies for that use and any other condition where the "system" isn't functioning properly. We in the fire service exist because every now and then, things don't function as planned.

However, as I'm sure you know, simplex frequencies do not enter the "system" and are thus not repeated or even heard by the dispatcher. I'm looking out for my police friends beside just us fire folks who may be the only person in the building and are engaging in fisticuffs with someone and wouldn't mind a few more offiicers coming to participate. Same holds true for EMS if they have a combative patient.

We have, as many other jurisdictions, a Land Development Code, similar to a building code. We can, by way of the legislative process, amend that code do require supplemental radio equipment, and that is my inclination. Unfortunately, in Kentucky, we cannot hold up someone's Certificate of Occupancy for failing to comply with the Land Development Code. If they comply with the building code, then they must receive their CO.

911 surcharges, according to Kentucky state law, cannot be used for radio equipment. Different states have different laws on 911 surcharges and the use thereof.

Thanks to all who have responded. I'm sorry that a hornet's nest got stirred up by a simple question.

 

[N_Jay]

"Dear Mr. Fire Chief:
Start by insisting that your radio vendor program a simplex fireground frequency into your radios. . . .

Simplex is NOT the answer.

 

[zerg901]

Check out www.bfdradio.net - click on "BDA Info" on the left side - Boston FD initially required "inhouse repeaters" on their primary fireground channel (483.1875R) in large buildings - now they want BDAs.

$30K to $50K isnt a bad price if you can get 20 years out of the system. I dont think there are any real alternatives - either portable radios work everywhere inside a building, or they dont. Simplex, portable extenders, remote receiver sites - none of them seem to be as good as the BDAs.

Too bad that all cellphones and all public safety aren't all in the same band - then 1 BDA system would / might serve every major bld. (yeah I know about NEXTEL and rebanding).

I like the idea of the city and the bld owner splitting the BDA costs. But it is just so much more fun to pay lawyers millions to argue over it.

Peter Sz

 

[W7LES]

Using simplex for fire comms from in-building operations works A-OK. Quite often, the simplex channel in question is talk-around on the dispatch repeater output frequency, so that the users can hear when dispatch needs to call them.

But - you say that you need to have simplex operations recorded? Try this one out, that surprised me when I heard about recently ...

>>> Go simplex talk-around on the dispatch repeater input, PL/DPL and all. <<<

- everyone hears it real well, brass can monitor it from anywhere;

- it gets recorded in dispatch as normal, no problem;

- the in-building operations all hear each other great, to and from the street.

Drawback: it ties up the dispatch repeater. But, in real life, is this a real handicap? Don't most agencies that use repeater output talk-around simplex, still try to limit traffic on the repeater channel anyway, to try to keep the channel clear for the operations?

Just my $ 000.02 worth.

Larry W7LES

 

[MASTRTECH]

Here's my 2 cents worth. I'm not a fireman but, If a building is on fire, do they cut the electrical power? if so, now the BDA doesn't work anyway..

 

[N_Jay]

Here's my 2 cents worth. I'm not a fireman but, If a building is on fire, do they cut the electrical power? if so, now the BDA doesn't work anyway..

Properly designed systems have backup power.

That is whet systems NEED to be PROPERLY DESIGNED!

 

[MASTRTECH]

Once again, Will the back-up power be available if the building is on fire......

 

[wlmr]

Once again, Will the back-up power be available if the building is on fire......

Proper design takes into consideration that the Fire Dept. may cut power to the building and provides a way for the system to run on self-contained batteries for a reasonable duration.

(I'm assuming reasonable duration would be long enough for either the fire to be exterminated and power restored -or- long enough to give the evacuate warning and go defensive outside the building where the amplifier shouldn't be needed.)

 

[N_Jay]

Once again, Will the back-up power be available if the building is on fire......

Much like 30 minuet and 1 hour rated fire doors, it can be DESIGNED to meet the need.

A casual observer may not recognise what planning went into the design (and may think; 'Geeze, why did we pay that guy so much, I could have done this)

 

[wlmr]

Much like 30 minuet and 1 hour rated fire doors, it can be DESIGNED to meet the need.

A casual observer may not recognise what planning went into the design (and may think; 'Geeze, why did we pay that guy so much, I could have done this)

Never have been able to minuet for 30 minutes!

I agree that the cost of the design can amaze people who think all that you need to do is go into a catalog and price out a box, some coax, and a couple antennas. Hire an expert, don't go thinking that hiring the kid who knows how to wire up the speakers in your car is the way to go.

 

[RKG]

Well . . . I guess you got a point there.

Here's the deal. I'm a fire chief in a community with a new radio system. I'm trying to get a law/code/regulation introduced that says "If you build a large new building made out of stuff that plays havoc with radio signals, then you gotta do something about it." The first question out of people's mouths will be "OK - how much is this going to cost?"

I ain't got no idea, but I think an answer to that question probably ought to be in my head. I don't think I'll get too far with the protective undergarment response: "Depends".

If I could say "Any where from $500 to $4,000" or "About 1/2 of a percent of construction cost", I might be a little more persuasive.

So if anyone can give me an idea of a range, I'd be appreciative.

Chief:

The subject of BDAs is both technically complex and a bit controversial.

Having advised a couple of local fire chiefs here on the same question you have posed, let me give you the quick overview.

BDAs come in two flavors. There is the $500 box that you mount "somewhere" with two antenna ports. Sometimes these work. Sometimes they work but cause all sorts of unintended problems. Sometimes they do nothing.

On the other side of the page is a true engineered BDA. For my money, the company to work with is Tx/Rx Systems. You hire a good local radio shop to take some site data, from which Tx/Rx will design you a basic system, which your radio shop then installs. Most of these installs are in the $10,000-$20,000 range.

What a BDA is is a box that is capable of repeating, on one antenna, signals that it hears on the same frequency on the other antenna, and usually it can do this in either direction. For example, assume the Fire Panel is located in the basement of a supermarket, and your jakes' portables can neither hit the repeater from the basement nor even hear the transmitter while in the basement. You have the supermarket install an engineered BDA, with one antenna (called the "donor antenna") on the roof and one or more antennas (called "client antennas") in the basement. Now, your guy keys his portable in the basement, transmitting on your input freq. The client antenna receives this and passes it to the box, and the box re-transmits your guy's audio from the donor antenna, and also on the input freq; at this point, the nearest receiver(s) of your radio system here the donor antenna on the input freq and (a) repeat that from your high site and (b) pass it along the wireline to Fire Alarm. When Fire Alarm answers, the process is essentially reversed: the donor antenna hears Fire Alarm (on the output freq) on the donor antenna and passes the audio down to the client antennas, also on the output freq, when then transmit to your guys' portables in the basement.

Now you are probably aware that in designing a conventional repeater system, the reason we have two frequencies (the input and the output) is because in most cases you can't have a device that receives and transmits on the same freq at the same time. The key (or, I should say, one of the keys) in designing a BDA is to design it so that there is enough RF separation between the donor and client antennas that neither can ever hear the other. If they do hear one another, they remained keyed up, transmit a cascade noise, and effectively take your channel off the air until disabled.

However, there is another key design issue the failure to account for which has caused all sorts of havoc in this area (where the untrained deployment of cheap $500 BDAs has caused all sorts of havoc on public safety channels): the system must be designed so that no client antenna will hear an input freq from your guys when they are out on the street, working something (such as an MVA) that has nothing to do with the building in which the BDA in installed. If not designed properly, here is what happens. Your jake pushes his button out on the street. His signal reaches one or more of your receivers (or would, but for the BDA). At the same time, his signal reaches a client antenna on the nearby BDA, and this causes the donor antenna on the roof of the building to also transmit -- on the input freq. The result is that the donor transmission and the jake transmission collide and all is garbled, just the same as if two jakes transmitted at the same time.

Some years ago, some folks on Boston Fire went a little wild inducing building owners to install cheap BDAs, and it all but took Boston off the air (at least on the fireground channels). Most of these are now gone; remember, you have leverage because the BDA is operating on your licensed freqs and this is illegal absent your permission. If you PM me, I'll give you the name of the officer presently in charge of this function for BFD, who can give you more details.

Sorry for the long post.