CGC #1127

by CGC on March 21, 2012



                         THE CGC COMMUNICATOR

                              CGC #1127

                      Wednesday,  March 21, 2012


                  Robert F. Gonsett, W6VR,  Editor

    Copyright 2012, Communications General® Corporation (CGC)



  The FCC has made fundamental changes to the Low Power FM and FM 
Translator rules and other changes are being contemplated.

  URLs galore are posted in Tuesday's FCC Daily Digest (second URL 
below); Wednesday's Digest may contain more items yet (third URL 
below -- Wednesday's Digest should become available by noon Pacific 
The Radio World synopsis comes first:



  The USDA Forest Service is beginning to enforce the provisions 
of Appendix G of their land management plan.  This could have a 
significant impact on your operations if your facility is located 
in the Angeles, Cleveland, Los Padres or San Bernardino National 
Forests.  That means many operations on Mt. Wilson and Santiago 
Peak will be impacted, for example.  Potentially affected users 
should read Appendix G carefully.  The text is available here:



  The Appendix G story begins with the following letter received by 
Communications General Corporation, consulting radio engineers, on 
March 6, 2012:

  "Well I just received an inspection notice from the Forest 
Service regarding my [communications facility on Forest Service Land 
here in southern California].  What is significant is the FS states, 
"Anti-perching devices must be present along open horizontal 

  "Appendix G was created as a result of a Stipulation the FS signed 
with the Southwest Center for Biological Diversity back in 1999....  
This stipulation only makes reference to towers in relation to 
electric power [lines].  Eventually, Appendix G was finished and 
now applies to all communications sites on FS property in southern 

  "The issue is to prevent harm to birds.  Clearly, on high voltage 
power lines, this is quite possible, but on communication towers & 
buildings, it is very very unlikely.  In creating Appendix G, the 
FS assumed any bird near an antenna would be harmed....  They also 
assumed if a bird perched on a building rooftop.... it must also be 
in harms way [presumably because of RF signal exposure]....  This 
is junk science.

  "At this point I will simply put up a batch of worthless anti- 
perching strips for show to simply make the problem go away.  My 
concern is the FS may want us to put [these devices] all over our 
towers & antennas, and that becomes a safety hazard to tower 
workers.  See for a sample of bird spike strips 
(these can also cause RF interference)...."

  Editor's comment:  There are several problems with Appendix G.
For example, if metal spike strips are used, there is a huge 
likelihood that loose strips, rubbing wires and/or electrolysis 
will generate significant levels of harmonics and intermodulation 
products that will seriously degrade reception on site receivers 
over time.  Everyone needs to proceed slowly and carefully, as a 
group, least anti-perching devices become an unintentional recipe 
for electromagnetic disaster.

  More when this story continues.

                       LETTERS TO THE EDITOR


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  The CGC Communicator is published for broadcast engineering
  professionals in so. California by Communications General®
  Corporation (CGC), consulting radio engineers, Fallbrook, CA.

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