• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

Now THIS is what I call a pirate !!

P

phatdaddy

Guest
I was looking at the FCC enforcement actions and happened upon a love letter sent to a dude for running an unlicensed station with a measured field strength of 5,191,850 uV/m at 321.9 meters !!! Maybe RFry or somebody else with the calculators could work this one backwards and see how many kW this guy was running.
 
phatdaddy said:
...a measured field strength of 5,191,850 uV/m at 321.9 meters.
Click to expand...

It would take an effective radiated power of just under 29,000 watts to generate that field over that free-space path. A typical setup for an FM broadcast station to produce this result uses a 10,000 watt transmitter and a 6-bay antenna system.

Maybe the FCC NOUO data was inaccurate?
//
 
I would hope it's inaccurate, but I doubt it...that would be the mother of data entry mistakes.

Boy, the fun Soupy Sales could have with this one...

Hey boys and girls, Uncle Moron has an idea!!

Let's burn a hole the size of a small town in the ether with an illegal blowtorch!! How 'bout it, kiddies?!!?

Look, up in the sky, a bird? A plane? No, it's this guy's common sense.

Lemme guess...this guy got an F in "Staying Under the Radar 101?"

???
 
R. Fry said:
phatdaddy said:
...a measured field strength of 5,191,850 uV/m at 321.9 meters.
Click to expand...

It would take an effective radiated power of just under 29,000 watts to generate that field over that free-space path. A typical setup for an FM broadcast station to produce this result uses a 10,000 watt transmitter and a 6-bay antenna system.

Maybe the FCC NOUO data was inaccurate?
//
Click to expand...

FM pirates sometimes use directional antennas such as the cubical quad, yagi-uda, and log-periodic when they aren't located in the middle of their desired broadcast areas. Maybe he was using a directional antenna that greatly increased the effective radiated power in the direction from which it was monitored?


-- Black Shire
 
Black_Shire said:
Maybe he was using a directional antenna that greatly increased the effective radiated power in the direction from which it was monitored?
Click to expand...

A 9-element Yagi-Uda (for example) has a linearly-polarized peak gain of about 10 dBd, which is a power gain of 10 X. The antenna input power needed to produce a maximum radiated power of 29,000 watts then will be 29,000 watts/10 = 2,900 watts.
//
 
That's still a boatload of power for a pirate. Even if he had two Yagis co-phased that would only give him 3 dB more power gain thereby reducing his TPO to about 1500W. If he went from two to four Yagis he could drop TPO to 750W, still well above the range of the typical transmitter sold for LPFM or translator service. He would have to go to 8 or even 16 co-phased antennas to get the transmitter power output requirement down into the range of an "affordable" LPFM transmitter. Since this is not very practical, it appears to me that this guy must have gotten his hands on a used full power transmitter somewhere. Guess he figured he'd go down with a big bang when he got busted.
 
phatdaddy said:
He would have to go to 8 or even 16 co-phased antennas to get the transmitter power output requirement down into the range of an "affordable" LPFM transmitter. Since this is not very practical, ...
Click to expand...

How true. Ignoring coax attenuation and matching losses, a "Part 15" FM transmitter rated for 35 milliwatts output power would need an antenna gain of 828,571 times, or 59.2 dBd in order to radiate a peak field of 29,000 watts. And the useful radiation pattern of the antenna would be extremely narrow.

That kind of antenna/array gain is highly impractical in the band 88-108 MHz.
//
 
Hey! I've got a field strength like that! That's because my station has 50,000 watts.
But, I also have this nice piece of paper called an FCC license.
I can sleep well tonight knowing the Feds aren't looking for my butt.
 
The other thing is if a "pirate" were running this sort of power could you imagine he electric bill? Heck, where the hell is this guy parking his transmitter anyway? I think I would cause a neighbor brownout if I ran an appliance with that much power consumption.
 
R. Fry said:
phatdaddy said:
...a measured field strength of 5,191,850 uV/m at 321.9 meters.
Click to expand...

It would take an effective radiated power of just under 29,000 watts to generate that field over that free-space path. A typical setup for an FM broadcast station to produce this result uses a 10,000 watt transmitter and a 6-bay antenna system.

Maybe the FCC NOUO data was inaccurate?
//
Click to expand...

Since when is a wavelength of 321.9 meters considered part of the FM band?

To convert meters to MHz, divide 300 by the number of meters. For example:
300 divided by 42.25 meters = 7.1 MHz


300
------------ = .9319664 MHz or 931.9664 KHz IN THE AM BAND!
321.9 meters
 
SUPERCASTER said:
Since when is a wavelength of 321.9 meters considered part of the FM band?
Click to expand...

That number is not the wavelength of the signal. It is the distance between the transmit antenna and the geographic location where it was measured by the FCC.
//
 
R. Fry said:
SUPERCASTER said:
Since when is a wavelength of 321.9 meters considered part of the FM band?
Click to expand...

That number is not the wavelength of the signal. It is the distance between the transmit antenna and the geographic location where it was measured by the FCC.
//
Click to expand...

Most said the FCC posting seemed wrong and technically the FCC data was unlikely. Perhaps the FCC poster made a typo and included the wavelength instead of the distance. After all, they are both in meters. That's my point.
Since the wavelength in meters might have been accidentally substituted for the distance, also in meters, and the distance omitted entirely, that might explain the somewhat unlikely data.
 
This may be the pirate station in question:

http://www.tcpalm.com/news/2007/aug/30/30fcc-raids-haitian-pirate-radio-station/?printer=1/

Here is a quote from the article:

"The pirate broadcasters apparently put a tower on top of a roof that was hidden in a family neighborhood, Davis said. "From what I've been told, it was a very strong transmitter with a few thousand watts."

I can't imagine what these guys were smoking to embolden them to put out that much power. Oh wait, they were running a Haitian-formated station maybe I can imagine what these guys were smoking.

db
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom