It would be good if IBOC fizzles out sooner than later. In my correspondance
with WTMJ, I did tell them that I can phone them and actually play one of my
radios............demonstrating that actual level of interference.
We as SWLs are more aware of this type of interference because the receivers
we use are sensitive enough to hear that interference in the first place.
WTMJ's sideband noise is at the 30uV level here in Waukegan Illinois, and
many of the "household" radios that you find in homes aren't going to detect
that low of a level. Exceptions are some of the better auto radios.
It is a shame about that interference but, maybe it won't be forever.
Pete
"Doug Smith W9WI" wrote in message
...
Pete KE9OA wrote:
I agree on the point of myself having any appreciable effect. I did
receive an e-mail response from Mr. Miller of the FCC this morning. He
wants me to send him some spectrographs of the stations in question. I am
going to see if I can take one of the 8560 spectrum analyzers home for a
day or two. This way, I can use the marker function and show the delta
between the carrier and the adjacent channel sideband power. The VSA
would be even better, because it could measure ACCP (adjacent channel
coupled power).
I did get a response from one of the managers from WTMJ 620 this
afternoon. Nothing from WBBM yet, but I won't hold my breath on this one.
WTMJ is certainly a smaller group, and I don't think they have the
financial interest in Ibiquity some of the larger groups have.
I *have* heard reports of IBOC signals splattering out considerably
further than the theory suggests they should. (for example, of "FM" IBOC
stations trashing 2nd and 3rd adjacents - which shouldn't happen) I can
certainly see where problems in the transmission system can cause that,
and since this is a new mode I'd bet a lot of engineers aren't yet
familiar with what can go wrong.
I doubt you'll get any action from a spectrum analyzer plot that shows all
its energy within 15KHz of carrier. However, I wouldn't be surprised to
see some outside that range, and I can see the FCC acting on that.
I do believe that if many people expressed their concern there would be a
very small chance that it would have some effect. Unfortunately, money
makes the world go around and if the radio stations think IBOC can
increase their revenue they will go for it.
I think they're grasping at straws, hoping IBOC can stave off competition
from satellite. (much as AM station operators hoped analog AM stereo
could stave off competition from FM)
I just hope it fails quickly enough to not kill off the service entirely.
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com
Ham stuff for sale:
http://www.w9wi.com/articles/4sale.htm