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<DIV><FONT face=Arial size=2>The real issue is noise emissions at the field
boundary / property line. Generally (and some clubs have won litigation basis
this), if the sound measured at the boundary is within local ordinance, usually
around 60 - 65 dB-A, or in that range if no ordinance exists. A source for
noise ordinances of major cities is @ <A
href="http://www.nonoise.org/lawlib/cities/cities.htm">http://www.nonoise.org/lawlib/cities/cities.htm</A></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The trick is to take action to prevent complaints
in the first place - proving your position after complaints / litigation can be
done, but is tricky / expensive (continuous records of noise levels @ boundary
obtained by certified personnel / equipment). </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Much easier to avoid conflict up front - any
consistent measuring method / rule is better than none, but be aware that
different frequencies dissipate with distance at different rates (close
measurements tend to accurate high freq that dissipates quickest for
example) if the levels are set to meet boundary limits - your probably
good both practically and legally.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Earl</FONT></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=bob@toprudder.com href="mailto:bob@toprudder.com">Bob Richards</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, June 22, 2006 8:55
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Noise
rules</DIV>
<DIV><BR></DIV>
<DIV>The formula is:</DIV>
<DIV> </DIV>
<DIV>20 * Log ( d1 / d2)</DIV>
<DIV> </DIV>
<DIV>where d1 and d2 are the distances involved, and "log" is log base 10 (not
the natural log).</DIV>
<DIV> </DIV>
<DIV>For 10ft and 25ft, the difference should be close to 8 dB, assuming no
effects from nearby reflecting objects, (like the ground!). :-) Doubling
the distance changes the level by 6dB.</DIV>
<DIV> </DIV>
<DIV>A club I belonged to years ago instituted a noise rule. Some planes would
not pass on the ground, but were quiet in the air. Part of that problem was
due to some propellers being stalled on the ground, particularly planes with
very high pitched props. We had limited success with trying to measure the
in-flight noise, with the pilot flying over the centerline of the runway at
full throttle. We extrapolated the noise limit using the formula above, and
did get correlation with some models. OTOH, there are the models that unload
in the air and the prop tips start developing shock waves, making that classic
giant-scale OOOOOWWWWAAAAAAAHHHHHH sound that some people think is the whole
point of flying giant scale. They are much more of a problem in the air than
what any sound reading on the ground may indicate.</DIV>
<DIV> </DIV>
<DIV>While it is important to the future of model aviation, sound rules are a
real PITA to enforce.</DIV>
<DIV> </DIV>
<DIV>Bob R.<BR><BR><B><I>Joe Lachowski <jlachow@hotmail.com></I></B>
wrote:</DIV>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">>From
what I measured a quite a while ago, I believe the equivalent at 25 ft
<BR>to that at 10ft is about a 7db difference.<BR><BR><BR>>From: "Lance
Van Nostrand" <PATTERNDUDE@COMCAST.NET><BR>>Reply-To: NSRCA Mailing List
<NSRCA-DISCUSSION@LISTS.NSRCA.ORG><BR>>To: "NSRCA Mailing List"
<NSRCA-DISCUSSION@LISTS.NSRCA.ORG><BR>>Subject: Re: [NSRCA-discussion]
Noise rules<BR>>Date: Wed, 21 Jun 2006 22:53:36 -0500<BR>><BR>>I'm
not sure if there may be a perception that measuring at 25 feet is
<BR>>somehow more palatable than at 10 ft. If this is the feeling in your
club <BR>>then go for it. However, I know from experience that all
influences on the <BR>>measured result (wind, hard/grass, fences,
proximity to a covered pit echo <BR>>chamber, cars, etc) are
exponentially amplified with distance. I measured <BR>>the same Extra330
with a large gas engine in every way possible and found <BR>>the results
varied from 101-105 db. This is a huge variation. <BR>>Upwind/downwind in
about 10 mph winds is worth 2-3 db. At 10 ft the <BR>>variation was from
102-103 db. If you have a guy with a plane near the <BR>>limit he may
argue your measurement result. If you say the lmit is the <BR>>highest
value measured then you are really restricting some guys with loud
<BR>>planes to less than the nominal. If you provide leeway, then your
limit is <BR>>effectively raised. It opens a can of
worms.<BR>><BR>>Lance<BR>> ----- Original Message -----<BR>>
From: Glen Watson<BR>> To: 'NSRCA Mailing List'<BR>> Sent: Monday,
June 19, 2006 10:52 PM<BR>> Subject: Re: [NSRCA-discussion] Noise
rules<BR>><BR>><BR>> Links below are to a RC club in the Houston
market who implemented a <BR>>noise standard.. My club has adopted the
same standard. In 2004 we had <BR>>complaints from a nearby neighbor
regarding noise. Since implementing this <BR>>noise standard we've had
zero complaints.<BR>><BR>><BR>><BR>>
http://fortbendrc.com/<BR>><BR>><BR>><BR>>
http://fortbendrc.com/Field/Field%20Noiselevel.htm<BR>><BR>><BR>><BR>>
Regards,<BR>><BR>><BR>><BR>>
~Glen<BR>><BR>><BR>><BR>><BR>><BR>><BR>><BR>><BR>>------------------------------------------------------------------------------<BR>><BR>>
From: nsrca-discussion-bounces@lists.nsrca.org
<BR>>[mailto:nsrca-discussion-bounces@lists.nsrca.org] On Behalf Of John
Ferrell<BR>> Sent: Monday, June 19, 2006 8:09 PM<BR>> To: NSRCA
Mailing List<BR>> Subject: [NSRCA-discussion] Noise
rules<BR>><BR>><BR>><BR>> If someone out there has a set of
noise rules for a general purpose RC <BR>>club? Especially a set that
works.<BR>><BR>><BR>><BR>> I cannot expect the masses to conform
to pattern numbers, but I need <BR>>something to start with. "Reasonable"
does not seem to mean the same thing <BR>>to every
one.<BR>><BR>><BR>><BR>><BR>><BR>> John Ferrell
W8CCW<BR>> "My Competition is not my enemy"<BR>>
http://DixieNC.US<BR>><BR>><BR>><BR>>------------------------------------------------------------------------------<BR>><BR>><BR>>
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