HD Radio Boston Area

Aaron Read readaaron@friedbagels.com
Fri Oct 13 16:20:15 EDT 2006

John Mullaney wrote:
> -----Original Message-----
> A great example is the Pru - try listening to each Pru station's IBOC signal
> and you'll notice that not all them "come in" as good.  Which shouldn't be
> the case...they all use the same damn antenna!  So why's that difference
> there?
> Actually they are not all on the same antenna. WBCN, WZLX, and Kiss108 are
> all using separate single bay antennas. These antennas are on the corner
> tower and have been in place as back up antennas since the original master
> went up. WMJX I don't believe is using their single bay for HD but I think
> along with the other Greater Media PRU stations is using the second Master
> antenna mounted below the original. This would be WMJX, WBOS, WROR and WTKK.

Yeesh.  I should've known you nitpickers would come out of the woodwork! 

Yes, yes, yes, I know not EVERY station on the Pru shares the same 
antenna.  I meant you should try listening to the stations that ARE on 
the same master antenna (yes, GM's WMJX, WROR, WBOS and WTKK's IBOC 
signals are all combined and then injected into GM's analog master 
antenna - see here:

Especially out on the fringes, you'll notice that some come in better 
than others.  Well, admittedly the last time I heard this effect was 
nearly a year ago, it's likely they've tweaked it since then and maybe 
the difference isn't so pronounced.   I don't have a car so I don't have 
an IBOC car radio.  I've been pushing Zipcar to install 'em, though.  :-)

Anyways, as I just mentioned to Garrett, the presence of adjacent 
channel interference can make a substantial difference in IBOC reception 
since it's "all or nothing" digital.  See this article, for example:

So that certainly could account for the variations in reception of 
similar signals from the same location.  WXRV could, for example, affect 
WBOS's signal when you're up in the Haverhill/Andover area.  But that 
wouldn't affect WTKK's signal (just as an example).


Aaron Read
Boston, MA 02246

Fried Bagels - Broadcast Radio & Web
Engineering & Operations Consultant

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