Date: 03 Jan 1993  02:56:23 UTC
From: mrapple@quack.sac.ca.us (Nick Sayer)
Newsgroups: comp.dcom.telecom
Subject: Re: How to Prepare For the Startup of an AM Radio Tower Nearby
Organization: The Duck Pond public unix: +1 408 249 9630, log in as 'guest'.
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X-Telecom-Digest: Volume 13, Issue 3, Message 12 of 12

jrg@bertha.att.com writes:

> Can anyone suggest any measurements, recordings, or other things that
> should be done now, before broadcasting starts, that will help if we
> need to later complain to the FCC about interference, bad phone noise,
> etc.?  If there are any firms that specialize in this type of
> measurment, their names or numbers would be appreciated.

This pushes one of my hot buttons.

In the vast majority of cases the interference is the fault of the
home electronics equipment designers who failed to adequately shield
the equipment from high density RF fields. In all but the tiniest
minority of cases the transmitter in question is operating entirely
normally, legally, and totally within the norms of modern engineering
practice. In many cases it is simply the sight of an antenna that gets
the xenophobes working. It is common practice for a new Amateur Radio
operator in the neighborhood to put up an antenna without connecting
it to a transmitter for a month or two. Invariably a couple RFI
complaints come in from the xenophobic community.

The solution is to make consumer electronics less susceptable to RFI.
The FCC has jurisdiction over susceptability regulation of all home
electronics. They have chosen to abrogate that responsibility in favor
of letting the manufacturers have their own way.

If you suspect that the transmitter is emitting harmonics or other
out-of-band emissions, then you can indeed sick the FCC on them.  It
is incredibly unlikely that a commercial station would put out illegal
amounts of spur simply because spurs cost money A) in fines from the
FCC and grief from the guy at double the frequency and B) it's wasted
energy and therefore wasted money (a 7 kW FM transmitter with a -13 dB
spur is putting out 350 watts on that spur. That's 10% waste. Techies:
Yes, a -13 dB spur is pretty outrageous, and the math is simplified,
but it sort of illustrates the idea).

There is one exception: CB stations with (illegal) amplifiers almost
always throw out spurs because the operators of those stations don't
know how to tune the amp properly. This is NOT the case with Amateur
radio stations (yes, Virginia, there is a bloody huge difference) --
for one thing the amps in the Amateur service aren't illegal (Hams can
use up to 1500 watts PEP, CBers can use about 5 [I forget the actual
number, but it's very tiny]).

So what to do?

1. Don't be a xenophobe. If it's not bothering your home electronics,
don't throw a tantrum!

2. If it IS causing you trouble, it is PROBABLY because your device is
susceptable NOT because the transmitter is doing something wrong. Call
the transmitting agency with this attitude and you'll be a lot more
likely to get help than if you call 'em up and insist that everything
was fine before they came along. Being the cause of RFI and being "at
fault" are two entirely different things.

3. Tell the FCC that the consumer electronics industry is entirely
incapable of regulating susceptability in consumer electronics, as
they have proven quite conclusively.


Nick Sayer <mrapple@quack.sac.ca.us>  N6QQQ @ N0ARY.#NOCAL.CA.USA.NOAM    
+1 408 249 9630, log in as 'guest'    PGP 2.1 public key on request