ERP

Ett1033 · Post by **Ett1033** » Fri May 30, 2003 8:05 pm

What is a good way to explain Maximum power output on a FCC license and ERP. So if my base is authorized 110 watts and 90 ERP, what does this mean.

RADIOMAN2002 · Post by **RADIOMAN2002** » Fri May 30, 2003 8:19 pm

Best way to describe it is that you may put out 110w from the base station, but with line loss and antenna gain you may not exeed 90w ERP.

nmfire10 · Post by **nmfire10** » Sat May 31, 2003 4:31 am

Power Output = What comes out the back of the radio

ERP = What comes out of the Antenna. The number can go down with coax loss and up with antenna gain.

In your case, it goes down. I don't know why on earth they would give you a higher output than ERP.

RadioSouth · Post by **RadioSouth** » Sat May 31, 2003 8:16 am

What band is the frequency licensed in ?

EngineerZ · Post by **EngineerZ** » Sat May 31, 2003 8:22 am

nmfire10 wrote: In your case, it goes down. I don't know why on earth they would give you a higher output than ERP.

Simple; they probably have a unity gain antenna (0 dBd) with some coax loss. Contrary to popular belief, gain antennas are not always desirable. e.g. If the area of operation is only up close to the reapeater/base...

--z

nmfire10 · Post by **nmfire10** » Sat May 31, 2003 11:20 am

I understand that. So I guess the FCC is just assuming there will be X amount of line loss so instead of making them both the same, they allow more output to give the umph through the cable. I think?

wa2zdy · Post by **wa2zdy** » Sat May 31, 2003 11:36 am

Or to put it another way, you cannot exceed EITHER number. So if your cable is less lossy than anticpated, you have to turn down the transmitter a bit.

Nand · Post by **Nand** » Sat May 31, 2003 1:24 pm

This subject was covered before. Perhaps you will find the answers here.

http://batboard.batlabs.com/viewtopic.php?t=10246

Nand.

Ett1033 · Post by **Ett1033** » Sat May 31, 2003 5:20 pm

Thanks for the info. The band is VHF. Freq is in the 154.XXX range.

KH · Post by KH » Sun Jun 01, 2003 3:41 am

nmfire10 wrote:I understand that. So I guess the FCC is just assuming there will be X amount of line loss so instead of making them both the same, they allow more output to give the umph through the cable. I think?

You have to calculate and supply output and ERP on your license application(well you supply it to the coordinator in commercial).