Subject: [NEXTEL-1] Nextel's Excesses

From: [email-masked]
Date: Tue, 16 Dec 2003 23:19:00 -0500

-------- Original Message --------
From: [email-masked]
Subject: Re: Nextel's Excesses

In a message dated 12/16/2003 12:39:22 PM Eastern Standard Time, 
[email-masked] writes:
Returning only momentarily to the "legal" answer, I add, if Nextel was truly
held to the parameters of its authority granted under its licenses, then the
whole rebanding thing would be mooted.  After all, the interference is
caused in most cases by out-of-band emissions which are, necessarily,
unauthorized transmissions.  And you see the fine job of enforcement the FCC
has done with these cases.

Robert
And, Mr. Schwaninger and I respectfully disagree in the analysis of that 
particular issue.

Alan T.

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---

From: [email-masked]
Date: Wed, 17 Dec 2003 19:02:28 -0500

------- Original Message --------
From: Paul J Zawada <[email-masked]>
Subject: Re: Nextel's Excesses

On Tuesday, December 16, 2003, at 03:25 PM, [email-masked] wrote:
Calculating ERP (effective radiated power) doesn't require the
> knowledge of system losses. But you're right, it is a calculated
> answer and the fudge factor will be due to antenna pattern.

The strict FCC definition of ERP in 47CFR2.1(c) is "The product of the 
power supplied to the antenna and its gain relative to a half-wave 
dipole in a given direction. "   To know the power to the antenna you 
must measure it or calculate the loss from the transmitter though the 
combiner, lighting protection, connectors, coax, all the way to the 
antenna, and that assumes the transmitter is operating at its rated 
output power.

> To measure ERP you'll need a reference antenna, a calibrated field
> strength meter(usually a spectrum analyzer), a calculator(for me
> anyway) and a known distance from the transmit antenna.
>
> It takes a certain amount of effective radiated power to generate a
> given voltage at a certain distance from the radiating point.
>
> Given the measured voltage and applying this to a standard formula
> will provide you with a pretty fair aproximation of ERP.

"Pretty good approximation" may not be a high enough standard for 
regulatory enforcement.

I agree you can make a pretty good guess at the power applied to 
antenna from measuring field strength and knowing the antenna's gain.   
However I would argue that making such a measurement at accurate 
distance and angles in a real world installation would be difficult at 
best and a good attorney could probably put such a measurement in 
doubt.   (and to many folks it's pretty apparent that Nextel is an army 
of good regulatory lawyers masquerading as an SMR...)    If you are 
talking about an antenna that is mounted on a tower in an empty field, 
where one can neatly measure distance, swing a transit, and measure 
field strength without worrying about reflections, fine.  However 
trying to do the same in a dense urban environment where one is likely 
to receive an interference complaint is a whole other ball of wax, at 
least IMHO....

--zawada

 

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