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FCC Enforcement Actions

R

rfry

A common belief posted on this forum and others is that the FCC Enforcement Bureau only takes action when unlicensed FM stations use "a lot" of power, such as 10 watts or more. But a recent action was taken against an operator for having a measured field strength of ~17 mV/m at a distance of ~227 meters from the transmit site.

That field strength at that distance seemed low for a power of 10 watts or more, so calculations were done to try to get some idea of what the radiated power actually was.

The radiated power needed from a typical transmit antenna height was something in the vicinity of 300 milliwatts (see below).

Radiated Power > Tx Ant Height > Path Distance > Field Strength
300 mW > 10 meters > 227 meters > 16.95 mV/m
(Free space equation was used.)

It doesn't take much radiated power to generate a considerable amount of field strength at close distances.

This information is provided not to "bash" Part 15 FM operators, but to give some reality-based information that should be useful to them.
//
 
> A common belief posted on this forum and others is that the
> FCC Enforcement Bureau only takes action when unlicensed FM
> stations use "a lot" of power, such as 10 watts or more.
> But a recent action was taken against an operator for having
> a measured field strength of ~17 mV/m at a distance of ~227
> meters from the transmit site.
>

Oh, I just took a big dump in my shorts over that one. I'll try to get myself back together and stop shaking.

It's amazing to me that the FCC even pretends it's doing enforcement anymore. Instead, it does an occasional raid on some dinky pirate and calls all the papers.

Ho hum.

How about them busting the really big pirates running 100,000 Watt rigs? Some of the crap that the licensed guys are pulling makes these little pirates look like the small fry that they are.


- Big Dick
 
> > A common belief posted on this forum and others is that
> the
> > FCC Enforcement Bureau only takes action when unlicensed
> FM
> > stations use "a lot" of power, such as 10 watts or more.
> > But a recent action was taken against an operator for
> having
> > a measured field strength of ~17 mV/m at a distance of
> ~227
> > meters from the transmit site.
> >
>
> Oh, I just took a big dump in my shorts over that one. I'll
> try to get myself back together and stop shaking.
>
> It's amazing to me that the FCC even pretends it's doing
> enforcement anymore. Instead, it does an occasional raid on
> some dinky pirate and calls all the papers.
>
> Ho hum.
>
> How about them busting the really big pirates running
> 100,000 Watt rigs? Some of the crap that the licensed guys
> are pulling makes these little pirates look like the small
> fry that they are.
>
>
> - Big Dick
>


OK... I did an analysis and calculation of the above 300mw at 10 meters antenna height and came nowhere near what Rfry states... so I figured what signal strength I would need so I did the following:

Frequency of the Transmitter : 100 MHz (0.1 GHz)
Power Output of the Transmitter : 100.000 Watts (50.000 dBm)
Height of the Transmitter Location : 30.000 meters (98.425 feet)
Height of the Receiver Location : 2.000 meters (6.562 feet)
Distance Between Transmitter & Receiver Locations : 1.609 kilometers (1.000 miles)

Environment Type : Rural Desert - Open
Free Space Path Loss : 76.579 dB
Urban Area Path Loss : 85.332 dB
Grazing Angle : 0.997 degrees
Approximate Received Power Level : -35.332 dBm

Now at -35dBM that equates to: 4mV/ at 1 mile, that is FREE SPACE!!!!

The above person had to be in the desert or ocean to get that 17mv/.5 mile!

I did the above calculation in three different RF calculators and it still does not give me 17mv/.5 mile like he states... So I went to the FCC FM page and used the calculator there to determine what a 1Kw station at 1 mile would give me and that figure comes close to what he states... the pirate in question above was probably running between 50-100 watts and running a high gain antenna at alot higher height than 10 meters!

I don't know but please someone else do the calculation yourself and see that a 300mw signal is not going to be a powerhouse at 1/2 mile... yes you can hear the signal at 2 miles but it does not have the signal strength of a 1-5kw station, perhaps somewhere near 3-7uv/1 mile or less!

Radiopilot
 
> I...came nowhere near what Rfry states... so I figured
> what signal strength I would need so I did the following:

(Calculation cut/paste omitted)

> Now at -35dBM that equates to: 4mV/ at 1 mile, that is
> FREE SPACE!!!!

In the first place, your numbers are based on a different setup than I posted. Beyond that, you aren't reading your results correctly. They said the free space loss was 76.579 dB, and when combined with the urban path losses the total path loss was 85.332 dB. Urban path loss, then, is the difference of those two, or ~8.8 dB. So the free space power at the rx location would be 8.8 dB higher than the nominal -35.3 dBm you quoted, or -26.5 dBm.

Assuming a rx antenna system with unity gain, the field strength arriving at the rx antenna needed to produce -26.5 dBm is 26.6 mV/m (the similarity of these values is coincidental for these conditions). But again, your numbers are for higher radiated power, and a longer path than the data I posted. Even so they show a higher field than in my post, and even 6.6X higher than in your conclusion about it. Comparing the two situations and sets of calculations for a relevant conclusion just isn't possible.

> I don't know but please someone else do the calculation
> yourself and see that a 300mw signal is not going to be a
> powerhouse at 1/2 mile... yes you can hear the signal at 2
> miles but it does not have the signal strength of a 1-5kw
> station, perhaps somewhere near 3-7uv/1 mile or less!

Here is the free-space field strength for 300 mW ERP at a distance of 1/2 mile (calculated using equation 15 on page 27-7 of "Reference Data for Radio Engineers," 1975 edition).

Distance, meters: 804.5
Radiated Power, watts: 0.3
Free Space Field Strength: 4.775481 mV/m

Note: that's millivolts/meter, NOT microvolts/meter.

//
 
I'm sorry to say that either your setup is wrong or the values you use are wrong... I tried this on three different RF calculators assuming unity at the antenna and no gain and still I get different results, If that was the case there would be airplanes/helicopters falling every hour from the skies...

I do know how to read millivolts from microvolts, miiliwatts from microwatts... but there is no way in my 'physics world' that 300mw at 10 meters height at ~1/2 mile (~277 meters) the signal will be ~17millivolts... and in a city/suburban environment to boot!

I suggest you re-think that formula over or make it simple so that you get the right answer...

Radiopilot
 
> > > A common belief posted on this forum and others is that> > the> > > FCC Enforcement Bureau only takes action when unlicensed> > > FM> > > stations use "a lot" of power, such as 10 watts or more.> > > > But a recent action was taken against an operator for> > having> > > a measured field strength of ~17 mV/m at a distance of> > ~227> > > meters from the transmit site.> > > > > > > Oh, I just took a big dump in my shorts over that one.> I'll> > try to get myself back together and stop shaking.> > > > It's amazing to me that the FCC even pretends it's doing> > enforcement anymore. Instead, it does an occasional raid> on> > some dinky pirate and calls all the papers. > > > > Ho hum.> > > > How about them busting the really big pirates running> > 100,000 Watt rigs? Some of the crap that the licensed guys> > > are pulling makes these little pirates look like the small> > > fry that they are. > > > > > > - Big Dick> > > > > OK... I did an analysis and calculation of the above 300mw> at 10 meters antenna height and came nowhere near what Rfry> states... so I figured what signal strength I would need so> I did the following:> > Frequency of the Transmitter : 100 MHz (0.1 GHz) > Power Output of the Transmitter : 100.000 Watts (50.000 dBm)> > Height of the Transmitter Location : 30.000 meters (98.425> feet) > Height of the Receiver Location : 2.000 meters (6.562 feet) > > Distance Between Transmitter & Receiver Locations : 1.609> kilometers (1.000 miles)> > Environment Type : Rural Desert - Open> Free Space Path Loss : 76.579 dB > Urban Area Path Loss : 85.332 dB > Grazing Angle : 0.997 degrees > Approximate Received Power Level : -35.332 dBm > > Now at -35dBM that equates to: 4mV/ at 1 mile, that is FREE> SPACE!!!!> > The above person had to be in the desert or ocean to get> that 17mv/.5 mile!> > I did the above calculation in three different RF> calculators and it still does not give me 17mv/.5 mile like> he states... So I went to the FCC FM page and used the> calculator there to determine what a 1Kw station at 1 mile> would give me and that figure comes close to what he> states... the pirate in question above was probably running> between 50-100 watts and running a high gain antenna at alot> higher height than 10 meters!> > I don't know but please someone else do the calculation> yourself and see that a 300mw signal is not going to be a> powerhouse at 1/2 mile... yes you can hear the signal at 2> miles but it does not have the signal strength of a 1-5kw> station, perhaps somewhere near 3-7uv/1 mile or less!> > Radiopilot> The threads on this subject over the past several months "assume" a high gain, or highly placed antenna. At these small powers (even though they may seem illegal) I can't seem to imagine a 100mW transmitter being hoisted onto a 100 foot tower. The losses from the coax (or whatever is used) would kill most of the power.100mW just won't cut through most of the interference to give most people a distant signal.......all these mathematics are fine, but they need to be put into perspective of what is actually happening out there, not what is assumed is happening.......unless you are killing a local signal (and that is pretty hard to do at these powers), it is highly unlikely that even a station owner would bother looking at any of this...interesting for discussion as it is.<P ID="signature">______________
[email protected], [email protected],[email protected]</P>
 
Carl,

The reason why I used 100 feet as the transmitter antenna height was to indicated even at this height a 300 milliwatt transmitter would never in it's lifetime put out a 17 millivolt signal at 1/2 mile... physics just won't allow that to happen... and anyone can prove it quite easily either with equations, calculators, or even going out and ACTUALLY measuring the signal with a receiver and antenna with no gain and known specifications for the receiver....

I know it's hard for some to digest but the answer is there in plain sight if anyone cared to look it up!

Radiopilot


The threads on this subject
> over the past several months "assume" a high gain, or highly
> placed antenna. At these small powers (even though they may
> seem illegal) I can't seem to imagine a 100mW transmitter
> being hoisted onto a 100 foot tower. The losses from the
> coax (or whatever is used) would kill most of the
> power.100mW just won't cut through most of the interference
> to give most people a distant signal.......all these
> mathematics are fine, but they need to be put into
> perspective of what is actually happening out there, not
> what is assumed is happening.......unless you are killing a
> local signal (and that is pretty hard to do at these
> powers), it is highly unlikely that even a station owner
> would bother looking at any of this...interesting for
> discussion as it is.
>
 
>.. but there is no way in my 'physics world' that 300mw
> at 10 meters height at ~1/2 mile (~277 meters) the signal
> will be ~17millivolts... and in a city/suburban
> environment to boot!
>
> I suggest you re-think that formula over or make it simple
> so that you get the right answer...
____________

The path distance in my first post was 227 meters (0.141 miles). It was NOT 277 meters as you wrote above, and which is 0.172 miles, not 1/2 mile, as you wrote above. Maybe that partly accounts for your different conclusion. And both of us were writing about free-space conditions, ie, without urban loss.

I don't know how you were converting dBm to the field strength arriving at a unity gain antenna that is needed to produce it. I'll be glad to send you the equation, if you need it (email me). If you are using a table, maybe it doesn't really apply to this situation?

"Showing my work" is no problem to me. Physics will give both us the same answer when the correct methods and equations are used.

//
 
> >.. but there is no way in my 'physics world' that 300mw
> > at 10 meters height at ~1/2 mile (~277 meters) the signal
> > will be ~17millivolts... and in a city/suburban
> > environment to boot!
> >
> > I suggest you re-think that formula over or make it simple
>
> > so that you get the right answer...
> ____________
>
> The path distance in my first post was 227 meters (0.141
> miles). It was NOT 277 meters as you wrote above, and which
> is 0.172 miles, not 1/2 mile, as you wrote above. Maybe
> that partly accounts for your different conclusion. And
> both of us were writing about free-space conditions, ie,
> without urban loss.
>
> I don't know how you were converting dBm to the field
> strength arriving at a unity gain antenna that is needed to
> produce it. I'll be glad to send you the equation, if you
> need it (email me). If you are using a table, maybe it
> doesn't really apply to this situation?
>
> "Showing my work" is no problem to me. Physics will give
> both us the same answer when the correct methods and
> equations are used.
>
> //
>


Rfry,

Here is the dBm to Watts and it's microwatts equivalent.

http://www.minicircuits.com/dg03-110.pdf

The reason I used 1/2 mile was to simplify the equation, but using even 1 mile in the equation does NOT give me the results you get whether with a unity antenna or a gain antenna of 3db... there is just no way...

In the above scale look at 17mV (millivolts) and it's equivalent in wattage and it's dBm... this is right at the receiving end and the signal strength in watts is only a little over .01mw (milliwatt).

So a receiver with 4uV (microvolts) sensitivity and would get -95dBm and a received signal power of .001nw (nanowatt).

This must only mean that the transmitting power of Part 15 devices HAS to be over the ~11nw (nanowatt) that you suggest here....

Radiopilot
 
> The reason why I used 100 feet as the transmitter antenna
> height was to indicated even at this height a 300 milliwatt
> transmitter would never in it's lifetime put out a 17
> millivolt signal at 1/2 mile... physics just won't allow
> that to happen... and anyone can prove it quite easily
> either with equations, calculators, or even going out and
> ACTUALLY measuring the signal with a receiver and antenna
> with no gain and known specifications for the receiver....
>
> I know it's hard for some to digest but the answer is there
> in plain sight if anyone cared to look it up!
>
> Radiopilot
__________________

You are a hard guy to convince, but here is another try.

Below is a paste from the FCC's website app giving FM field strength for various input conditions. The program didn't allow an ERP of 300 mW -- it re-set it to 1 watt. So the ~30.9 mV/m answer it produced is off by the square root of that 1/3X power difference. The corrected value then is 0.577 x 30.9 mV/m = 17.8 mV/m.

Note that 17.8 mV/m is a LARGE signal. Commercial FM stations only need 3.16 mV/m for "City Grade" coverage.

And that 17.8 mV/m field at 0.141 miles was the result of a mere 300 mW of ERP. Believe it or not for yourself, but how about letting others read this thread and come to their own conclusions?

--- FCC CLIP FOLLOWS ----

(202)-418-2700 FCC > MB > Audio Division > FM and TV Curves Calculations FCC site map

Results -- FM and TV Propagation Curves Calculations

ERP entered is less than 1 watt -- ERP set to 1 W (0.001 kW)
Entered HAAT is less than 30 meters -- Set to 30 m
Free Space equation used, not curves

Results of Calculation
Field Strength= 30.91237 mV/m

For input data from Pages 1 and 2:
ERP entered = 0.001 kW
HAAT entered = 30.00 feet
Distance entered = 0.141 miles
Find the Field Strength, Given a Distance to the Contour
F(50,50) curves for service contours
FM and NTSC analog TV Channels 2 through 6

//
 
> Here is the dBm to Watts and it's microwatts equivalent.
>
> http://www.minicircuits.com/dg03-110.pdf
>
> In the above scale look at 17mV (millivolts) and it's
> equivalent in wattage and it's dBm... this is right at the
> receiving end and the signal strength in watts is only a
> little over .01mw (milliwatt).
>
> So a receiver with 4uV (microvolts) sensitivity and would
> get -95dBm and a received signal power of .001nw (nanowatt).

No, sorry. That chart does not convert power units into FIELD STRENGTH units (or vice-versa). Units of mV/m and mV are not the same. Any conclusions you have reached by thinking so will be incorrect. (We had this conversation a few months ago -- maybe you forgot.)

> This must only mean that the transmitting power of Part 15
> devices HAS to be over the ~11nw (nanowatt) that you suggest
> here....

Sorry, but ~11.4 nW into a resonant 1/2-wave dipole will produce the maximum legal Part 15 FM field at 3 meters. Physics say so, and I have posted the equation. So does the FCC (of course).

//
 
> > Here is the dBm to Watts and it's microwatts equivalent.
> >
> > http://www.minicircuits.com/dg03-110.pdf
> >
> > In the above scale look at 17mV (millivolts) and it's
> > equivalent in wattage and it's dBm... this is right at the
>
> > receiving end and the signal strength in watts is only a
> > little over .01mw (milliwatt).
> >
> > So a receiver with 4uV (microvolts) sensitivity and would
> > get -95dBm and a received signal power of .001nw
> (nanowatt).
>
> No, sorry. That chart does not convert power units into
> FIELD STRENGTH units (or vice-versa). Units of mV/m and mV
> are not the same. Any conclusions you have reached by
> thinking so will be incorrect. (We had this conversation a
> few months ago -- maybe you forgot.)
>

I musty have failed mathematics in school becuase 1 millivolt is the same whether I am 1 inch or 1 meter away!

> > This must only mean that the transmitting power of Part 15
>
> > devices HAS to be over the ~11nw (nanowatt) that you
> suggest
> > here....
>
> Sorry, but ~11.4 nW into a resonant 1/2-wave dipole will
> produce the maximum legal Part 15 FM field at 3 meters.
> Physics say so, and I have posted the equation. So does the
> FCC (of course).
>
> //
>


That cannot be true if the Belkin Tunecast and other FM certified transmitters are outputting more wattage than your ~11 nanowatt... but someone else with similar sense as I will see that you're assumptions are wrong!

I say there is at least another person on this board with engineering/mathematics knowledge that can take the challenge..

It's easy... take 100mw (milliwatts), no gain antenna, place the antenna at 30 foot height (transmitter and the antenna), and see what field strength at the receive end (tuner/receiver - No gain antenna) you get at 1/2 mile and then 1 mile..... simple.....

There are several RF calculators on the net you can use or look up a simple formula to get your results... I won't post any formulas or calculators since I don't want to bias any results you get.

Radiopilot
 
Not Going to get to deep into this , But you Guys are Overlooking the One simple answer... No matter how you look at OK so you get 300mw
No mater what math you use thats Over 100mw.... PERIOD.. thats not Part 15
the Guy is in Violation clear and simple...
Personally I take it as 100mw ERP
any transmitter over 10mw is NON Part 15.
10mw and a High Gain antenna to develop 100mw ERP thats a true Part 15 Legeal station...
gee wonder why they call me groucho


> >
>
>
> That cannot be true if the Belkin Tunecast and other FM
> certified transmitters are outputting more wattage than your
> ~11 nanowatt... but someone else with similar sense as I
> will see that you're assumptions are wrong!
>
> I say there is at least another person on this board with
> engineering/mathematics knowledge that can take the
> challenge..
>
> It's easy... take 100mw (milliwatts), no gain antenna, place
> the antenna at 30 foot height (transmitter and the antenna),
> and see what field strength at the receive end
> (tuner/receiver - No gain antenna) you get at 1/2 mile and
> then 1 mile..... simple.....
>
> There are several RF calculators on the net you can use or
> look up a simple formula to get your results... I won't post
> any formulas or calculators since I don't want to bias any
> results you get.
>
> Radiopilot
>
 
> I musty have failed mathematics in school becuase 1
> millivolt is the same whether I am 1 inch or 1 meter away!

I hope you are joking. Maybe spend some time Googling to learn why a volt is not the same as a volt/meter of field strength.

> That cannot be true if the Belkin Tunecast and other FM
> certified transmitters are outputting more wattage than your
> ~11 nanowatt... but someone else with similar sense as I
> will see that you're assumptions are wrong!

The FCC doesn't prohibit Part 15 FM txs from generating more than 11 nW. The FCC only defines field strength 3 meters from the radiator. If the Part 15 tx was certified with a matched vertical whip of any length longer than several inches up to 36 inches or so, very likely the tx was adjusted for less than its maximum power during certification procedures. Otherwise radiation would exceed the limit.

> It's easy... take 100mw (milliwatts), no gain antenna, place
> the antenna at 30 foot height (transmitter and the antenna),
> and see what field strength at the receive end
> (tuner/receiver - No gain antenna) you get at 1/2 mile and
> then 1 mile..... simple.....

Just use the FCC's website. It's way easier, and you won't exceed Part 15 Rules to do it.

//
 
100mw is Part 15 AM....

> Not Going to get to deep into this , But you Guys are
> Overlooking the One simple answer... No matter how you look
> at OK so you get 300mw
> No mater what math you use thats Over 100mw.... PERIOD..
> thats not Part 15
> the Guy is in Violation clear and simple...
> Personally I take it as 100mw ERP
> any transmitter over 10mw is NON Part 15.
> 10mw and a High Gain antenna to develop 100mw ERP thats a
> true Part 15 Legeal station...
> gee wonder why they call me groucho
>
>


Groucho,

The 100mw for AM Part 15 transmitters is Kosher... I get this... But what I'm saying here is quite simple... a 100mw (milliwatt) FM transmitter is not ever in it's life going to output a signal strength of 'xx millivolts' to a receiver 1/2 mile away... that's all I'm saying.... Yes it's a silly argument but not one that will be won easily here...

Radiopilot
 
Nope... I think if people here would just do the calc's and see for themselves they will see it differently.... I have!


> You are a hard guy to convince, but here is another try.
>
> Below is a paste from the FCC's website app giving FM field
> strength for various input conditions. The program didn't
> allow an ERP of 300 mW -- it re-set it to 1 watt. So the
> ~30.9 mV/m answer it produced is off by the square root of
> that 1/3X power difference. The corrected value then is
> 0.577 x 30.9 mV/m = 17.8 mV/m.
>
> Note that 17.8 mV/m is a LARGE signal. Commercial FM
> stations only need 3.16 mV/m for "City Grade" coverage.
>


So what you are saying here is that a 1 kilowatt station only puts out 3.16mV/m, than HOW IN THE HECK is .300 milliwatts putting out MORE signal strength than a commercial 1 killowatt station?

If that were the case Commercial FM stations should scrap their $100,000.00 transmitters and employ the use of a 300 milliwatt Ramsey for $200.00 and GET better signal coverage...

Ramsey 300 milliwatt = 17mV/m for $200.00

Commercial FM transmitter = 3.16mV/m for $100,000.00

Hmm, if you were a station owner what would you pick?????


> And that 17.8 mV/m field at 0.141 miles was the result of a
> mere 300 mW of ERP. Believe it or not for yourself, but how
> about letting others read this thread and come to their own
> conclusions?
>


The conclusion would be that you're nuts!


Radiopilot<P ID="edit"><FONT class="small">Edited by radiopilot on 01/29/06 10:34 PM.</FONT></P>
 
Re: 100mw is Part 15 AM....

> > Not Going to get to deep into this , But you Guys are
> > Overlooking the One simple answer... No matter how you
> look
> > at OK so you get 300mw
> > No mater what math you use thats Over 100mw.... PERIOD..
> > thats not Part 15
> > the Guy is in Violation clear and simple...
> > Personally I take it as 100mw ERP
> > any transmitter over 10mw is NON Part 15.
> > 10mw and a High Gain antenna to develop 100mw ERP thats
> a
> > true Part 15 Legeal station...
> > gee wonder why they call me groucho
> >
> >
>
>
> Groucho,
>
> The 100mw for AM Part 15 transmitters is Kosher... I get
> this... But what I'm saying here is quite simple... a 100mw
> (milliwatt) FM transmitter is not ever in it's life going to
> output a signal strength of 'xx millivolts' to a receiver
> 1/2 mile away... that's all I'm saying.... Yes it's a silly
> argument but not one that will be won easily here...
>
> Radiopilot

This is just extremely painful to watch. Apparently no well supported technical argument from an engineer is going to get you people to break through this wall of delusion regarding physics and the real world. Ultimately, you ignore this good advice at your own risk, pure and simple.
 
> So what you are saying here is that a 1 kilowatt station
> only puts out 3.16mV/m, than HOW IN THE HECK is .300
> milliwatts putting out MORE signal strength than a
> commercial 1 killowatt station?
>
> If that were the case Commercial FM stations should scrap
> their $100,000.00 transmitters and employ the use of a 300
> milliwatt Ramsey for $200.00 and GET better signal
> coverage...

No, I said that 3.16 mV/m was required for city grade coverage by commercial FM stations. That doesn't mean they can't have more -- and most have considerably more.

You see, the FCC mandates a MINIMUM field strength for licensed FM broadcast stations, and a MAXIMUM field strength for unlicensed Part 15 FM stations. Big difference.

Here is what the FCC says for field strength at 0.141 miles for 1 kW ERP:

(202)-418-2700 FCC > MB > Audio Division > FM and TV Curves Calculations FCC site map

Results -- FM and TV Propagation Curves Calculations

Free Space equation used, not curves

Results of Calculation
Field Strength= 977.17877 mV/m

For input data from Pages 1 and 2:
ERP entered = 1.000 kW
HAAT entered = 30.00 meters
Distance entered = 0.227 kilometers
Find the Field Strength, Given a Distance to the Contour
F(50,50) curves for service contours
FM and NTSC analog TV Channels 2 through 6

> The conclusion would be that you're nuts!

With all due respect, such statements on your part don't reflect well on your educational background, temperament or credibility.

//
 
> > So what you are saying here is that a 1 kilowatt station
> > only puts out 3.16mV/m, than HOW IN THE HECK is .300
> > milliwatts putting out MORE signal strength than a
> > commercial 1 killowatt station?
> >
> > If that were the case Commercial FM stations should scrap
> > their $100,000.00 transmitters and employ the use of a 300
>
> > milliwatt Ramsey for $200.00 and GET better signal
> > coverage...
>
> No, I said that 3.16 mV/m was required for city grade
> coverage by commercial FM stations. That doesn't mean they
> can't have more -- and most have considerably more.
>


That is minimum Commercial FM signal strength at 3.16mV/m, for what transmitter power? 100watt, 500watt, 1 kilowatt????

We are talking about 300 milliwatts here, 1/3 of 1 watt....


> You see, the FCC mandates a MINIMUM field strength for
> licensed FM broadcast stations, and a MAXIMUM field strength
> for unlicensed Part 15 FM stations. Big difference.
>

No one said any different, but if you say COMMERCIAL FM stations, I asssume that most Commercial FM stations are using 1 kilowatt or more....


> Here is what the FCC says for field strength at 0.141 miles
> for 1 kW ERP:
>
> (202)-418-2700 FCC > MB > Audio Division > FM and TV
> Curves Calculations FCC site map
>
> Results -- FM and TV Propagation Curves Calculations
>
> Free Space equation used, not curves
>
> Results of Calculation
> Field Strength= 977.17877 mV/m
>
> For input data from Pages 1 and 2:
> ERP entered = 1.000 kW
> HAAT entered = 30.00 meters
> Distance entered = 0.227 kilometers
> Find the Field Strength, Given a Distance to the Contour
> F(50,50) curves for service contours
> FM and NTSC analog TV Channels 2 through 6
>

Look we went through this before and YOU indicated that these tables on the FCC website CANNOT be used for figuring PART 15 field strength or of any value to obtain anything useful for Part 15, the field data and info were for COMMERCIAL FM Broadcasters only... remember that post?

> > The conclusion would be that you're nuts!
>
> With all due respect, such statements on your part don't
> reflect well on your educational background, temperament or
> credibility.
>
> //
>

My education, emotional, and temperament are just fine....

Radiopilot
 
> That is minimum Commercial FM signal strength at 3.16mV/m,
> for what transmitter power? 100watt, 500watt, 1
> kilowatt????

That is the minimum value needed for city grade coverage no matter what is the licensed ERP.

> > Here is what the FCC says for field strength at 0.141
> > miles for 1 kW ERP: <snip>

> Look we went through this before and YOU indicated that
> these tables on the FCC website CANNOT be used for figuring
> PART 15 field strength or of any value to obtain anything
> useful for Part 15, the field data and info were for
> COMMERCIAL FM Broadcasters only... remember that post?

Yes I do, but the data I posted from the FCC site was not for a Part 15 station, it was for 1 kW ERP. In any case, extrapolations to Part 15 FM power levels are valid when the correct procedures are used.

//
 
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