[BC] HD Radio near 1 MHz in Boston (WBZ, WILD & WBIX)

[lists]

I've been reading with interest the thread about HD Radio on WBZ 
(1030) and WILD (1090) in Boston, and the possible effects it may 
have on WBIX (1060) also in Boston.  

Since my name has been mentioned in several of these posts, I'm 
concerned that some folks may later think that I actually made some
of the comments that have floated around on this list.  So, for 
the record, here are _my_ thoughts: 

First, I'd like to point out that, while all three of these stations 
are "serving the Boston metro", NONE of them are actually in Boston.  
WBZ is in Hull, WILD is in Medford, and WBIX is in Framingham (days) 
and Ashland (nights).  This is important to note, because it means 
that each of the three stations has the potential to cause a certain 
amount of distress to a third-adjacent signal near their respective 
transmitter sites.  This is not intentional, or due to any animosity, 
it is simply a 'laws of physics" kind of thing, and we all accept it.  

Secondly, I'd like to point out that I am the engineer who actually 
installed and set up the HD equipment at WILD (over the December 
holidays).  I have no axe to grind about HD on FM or AM, as a matter 
of fact I'm installing my share of them as fast as I can.  I don't 
feel that my personal beliefs on the subject are important. . . the 
industry is moving in the direction of HD, I work in the industry, 
and I do what my clients want done.  

Thirdly, HD interference on the AM band at a third-adjacent separation 
is NOT a problem with HD technology.  It's simply an incompatibility 
with some (not the majority) of existing AM receivers in the hands 
of consumers.  

I have driven on the Southeast Expressway in Boston, listening to 
WBIX, and experienced no noise problems at all using quite a few 
different radios.  Specifically, all of the HD radios I have used 
(three different models) seem to have no significant added noise 
underneath WBIX when the radios are switched to "analog mode".  
Also, many older radios also have tight-enough IFs to have the 
selectivity necessary to reject HD carriers from a third-adjacent 
signal unless the signal strength of the third-adjacent undesired 
signal is a couple of orders of magnitude higher than the desired 
signal.  

What this means is that the HD technology is _not_ responsible for 
the noise that is heard on some radios behind third-adjacent 
stations. . . it is the fault of the radio designer(s).  In their 
defense, all of the radios that exhibit the problem were designed 
_before_ HD for AM was approaching reality, and in fact were 
specifically designed for _enhanced_high_frequency_response_ (broad 
IF filters) during the years when broadcasters were pushing 
NRSC down the throats of the receiver manufacturers.  

It is unfortunate that, as we embrace the technologies of the 
future, some of the equipment of the past may have compatibility 
problems.  

Blaming HD radio, or a broadcaster who has upgraded to HD Radio, 
for a compatibility problem with old receivers is VERY much like 
blaming a radio station for noises on someone's telephone a mile 
away.  We ALL know that the phones are the problem, not the 
stations.  

I _AM_ quite interested in trying HD Radio on WBIX, but not as a 
shot across the bow of any other station.  Hey, I've got "the first" 
"Fourier Modulation" AM rig ever built on the floor of my transmitter 
room.  It'll be fun to make it work with HD, and to see if this 
modulation technique will help ameliorate the negative effects of antenna 
bandwidth problems on HD transmission.  

Anything that you may have seen in any other post that contradicts 
what I've written in this post _did_not_come_from_me_.  

Grady