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To: <rfi@contesting.com>
Date: Sun, 15 Mar 1998 08:38:50 -0800
From: Cortland Richmond <ka5s@saber.net>
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To: tduffy <tduffy@sygnet.com>
CC: rfi@contesting.com, K1ZM@aol.com
Subject: Re: [RFI] K1ZM needs help
References: <350BF0FD.8F0F9625@sygnet.com>
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The size of the towers is irrelevant here; if the amateur operation is on ten
meters, it's likely 27 MHz R/C will have
problems. In fact, 27 MHz R/C has become rare due to problems from CB, and I
am surprised it is being used as an argument
here.
However... the Radio Control service is NOT protected from interference. Look
in the FCC site at
http://www.fcc.gov/wtb/prs/radcntrl.html.
I quote part of that page here:
"R/C Rule 7 lists 50 channels in the 72-73 MHz VHF range that may only be used
to operate model aircraft devices and 30
channels
in the 75.4-76.0 MHz VHF range that may only be used to operate model surface
craft devices. You must stop such transmissions,
however, if they interfere with authorized radio operations in those VHF ranges
or with broadcast TV reception on channels 4
or 5.
R/C Rule 7 also lists HF channels at 26.995, 27.045, 27.095, 27.145, 27.195,
and 27.244 MHz that may be used to operate other
kinds of devices. **R/C channels are not afforded any protection from
interference due to the operation of fixed and mobile
stations in other services assigned to the same or adjacent frequencies.** "
(Emphasis added)
Radio Control hobbyists and organizations have often complained about the (to
them) excessive amounts of liability insurance
local governments insist they carry. This is one reason why.
1) How valid are the allegations and fears posed?
Probably valid. However, the size of your towers doesn't have much to do with
it. 20 feet or 100 feet, same problem. And
they CAN'T forbid you from operating. As a non-protected Service, they have to
take a back seat to all the others, including
Amateur. Even CB!
2) Will ALL amateur bands likely affect the 27Mhz controller?
Probably not. However, if the aircraft fly into an area of high RF field
strength, and the non-radio circuits start
rectifying, the operating frequency probably won't matter. VHF might be worse.
(If the hobbiest planes have a wideband front-end receiver of poor selective
design, an amateur KW signal operating on 28Mhz
MIGHT possibly be a problem. Would a harmonic from 14Mhz also be an issue?)
Maybe. But your harmonic is at least 40 dB down, right?
3) Does anyone out there have any experience with these hobbiest aircraft?
My son was active in R/C cars for a while, and I was always asked not to
transmit on my VHF or UHF gear -- even handy-talkies
-- in the area of an R/C event, but after showing the operators that wasn't a
problem they didn't worry. All they could do
was ask; politeneness -- and the fact that my son was participating and would
be kicked out -- lead me to accede to their
requests.
4)Can anything be done to remedy interference/interaction issues that MAY ARISE?
Probably not. While you may be operating perfectly legally, the R/C users are
too, and though the Rules say they have to put
up with your signals -- I won't call it interference because you are NOT on
their frequencies -- the R/C operators, being
mostly ignorant of electronics, and forbidden to modify the sets anyway, are
pretty much at the mercy of R/C equipment
manufacturers. They probably do not know that they must accept interference
that does occur. As you can imagine, tempers
might get pretty hot.
I suspect any remedies in this area will be handled (because of potential
liability issues) by attorneys.
Finally, I suggest you get the ARRL Volunteer Counsel in on this. If an R/C
organization has been operating for a while, it
may have considerable experience, not to say influence, with the zoning board,
and its word may carry enough weight there to
overcome even the laws of Physics and the FCC. It works in Congress, after all.
Good luck!
Cortland, KA5S
tduffy wrote:
>
> ------------------------------------------------------------------------
>
> Subject: BOUNCE rfi@contesting.com: taboo header: /^cc:\s*.+/i
To: <rfi@contesting.com>
> Date: Sun, 15 Mar 1998 04:16:54 -0500 (EST)
> From: owner-rfi@contesting.com
> To: owner-rfi@contesting.com
>
> >From k3lr Sun Mar 15 04:16:52 1998
> Received: from imo14.mx.aol.com (imo14.mx.aol.com [198.81.17.36])
> by dayton.akorn.net (8.8.5/8.8.5) with ESMTP id EAA23015
> for <rfi@contesting.com>; Sun, 15 Mar 1998 04:16:52 -0500 (EST)
> Received: from K1ZM@aol.com
> by imo14.mx.aol.com (IMOv13.ems) id QUFBa26753;
> Sun, 15 Mar 1998 04:16:39 -0500 (EST)
> From: K1ZM <K1ZM@aol.com>
> Message-ID: <fcc09cd3.350b9c7b@aol.com>
To: <rfi@contesting.com>
> Date: Sun, 15 Mar 1998 04:16:39 EST
> To: rfi@contesting.com
> Cc: ehare@arrl.org, K2EK@aol.com
> Mime-Version: 1.0
> Subject: Radio Controlled Hobby Planes
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>
> Hi Folks
>
> I am posting this message to the RFI reflector seeking help/advice in an area
> where I have limited experience. Input is necessary to help buttress an
> amateur tower permit application that is pending here in our town - and is
> most urgently needed.
>
> The subject is radar controlled hobbiest airplanes.
>
> >From testimony to date, we have been told that these hobbiest aircraft are
> controlled by a low power transmitter controller operating at about 1 watt of
> output power on 27 Mhz.
>
> The controlling 27 Mhz (1) watt signal essentially guides the hobby plane's
> maneuvers - while in flight - allowing it to be safely flown and landed.
>
> The questions being raised are whether the establishment of an amateur radio
> station with 100 foot towers and full legal power operating on the parcel next
> door will cause destructive interference STRONG enough to "override" the
> aircraft controller 1 w signal thus causing the aircraft to crash in flight.
>
> Questions:
>
> 1) How valid are the allegations and fears posed?
> 2) Will ALL amateur bands likely affect the 27Mhz controller?
> (If the hobbiest planes have a wideband front-end receiver of poor selective
> design, an amateur KW signal operating on 28Mhz MIGHT possibly be a problem.
> Would a harmonic from 14Mhz also be an issue?)
> 3) Does anyone out there have any experience with these hobbiest aircraft?
> 4)Can anything be done to remedy interference/interaction issues that MAY
> ARISE?
> 5) Has anyone out there run into this one before?
> 6) If interference IS unavoidable, how far must the controller/planes be
> removed from the amateur site for SAFE operation?
>
> Any guidance/information/assistance would be most welcome at this point.
>
> Testimony must be given in defense of the amateur position in this matter -
> and it will be quite important with respect to a pending application for two
> 100 foot amateur towers.
>
> Thanks in advance to all for reading this message and for the help. It is
> greatly appreciated.
>
> 73 Jeff
>
> K1ZM@aol.com
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