The CGC Communicator Newsletter Web Posting

REPLY TO THE ELLIOTT KLEIN LETTER IN CGC #800

I'm writing to offer a bit of color to the Elliot Klein story regarding FM HD Radio Transmitter Spectral Regrowth in Denver (CGC #800).

I have some fairly intimate knowledge of this particular situation and I believe it is important to note that there are at least three factors which may impact a reader's impression that the licensee of the Denver station or the transmitter manufacturer were somehow dispassionate in pursuing a resolution to dealing with Mr. Klein's client or their complaint .

First, the station licensed to Denver (Full Class C) has been observed to be in full compliance with the FCC occupied bandwidth and spectral mask limitations for operating in the hybrid FM HD Radio broadcasting mode since the day it went on the air.

Second, the area where the observed interference to the reception of the distant station signal occurred was over 17 km beyond the FCC 60 dBu F(50,50) "protected" contour and about 90 km from the transmitter site of this 2nd adjacent channel Class C1 facility.

Third, the subject area of reception problems is less than 10 km from the Denver transmitter site and is well within the Denver station's 100 dBu F(50,10) "interference" contour.

Finally, I'd like to describe the eventual closure to the situation.  When faced with the results of several signal measurement protocols which demonstrated that the Denver station was operating completely legally, the distant signal station requested and received the permission of the Denver station to install an all expenses paid Shively 2606-3A filter on their IBOC transmitter.

(Name withheld upon request)

[Should the FCC emissions mask be tightened up for IBOC? The mask was designed for transient analog artifacts and not intended to be filled with continuous digital noise.   -Ed.]

Posted by Steve Blodgett
Earthsignals.com