WBUR / WXRV interference

[Scott Fybush]

Keep in mind that WXRV shares its transmitter site with WCCM 1490, 1.49 MHz 
away from 92.5. Mike just had an article in the most recent issue of Radio 
World Engineering Extra talking about the interference that can occur at 
shared AM/FM sites, using his experience with this particular problem as an 
example.

The article doesn't appear to be available online, but it suggests that the 
problem was RF from 1490 getting into the composite cable that connected 
WXRV's studio-transmitter link receiver to their exciter. It was creating a 
pair of sidebands at 91.01 and 93.99 MHz, and that lower sideband was what 
was killing WBUR.

s

At 10:43 PM 10/20/2005 -0400, Rob wrote:
>Awhile back I had written to the chief engineer at WBUR to let him know the
>difficulty I was having picking up WBUR in the Lawrence/Haverhill area.
>
>I assumed it was because of WXRV.
>
>However, since the dial spacing between XRV and BUR is a full 1.6 mhz....I
>wasn't sure that stations this far apart could interfere with each other.
>
>Also, when I drive on 495 thru Methuen, Haverhill and such, WBUR was
>unlistenable.
>
>After a long wait (I had forgotten about it!), I recieved this response 
>(below) from
>Michael LeClair of WBUR.
>
>I'm still puzzled what the interference could've been.
>
>Anyone have any idea...or maybe shed some more light on what issue was at
>play here?
>
>Thanks
>
>Rob
>
>
>----- Original Message ----- From: "MICHAEL LeCLAIR"
>Sent: Thursday, September 22, 2005 11:26 AM
>Subject: Re: Reception Question....
>
>
>>
>>Hello-
>>
>>This is a follow up answer in regard to your message from
>>last February.  You had brought to our attention the
>>interference to WBUR that was being caused by WXRV in
>>Haverhill.
>>
>>I am pleased to let you know that we have solved this
>>problem completely as of last week.  In my driving tests in
>>the area I hear no sign of interference any longer.
>>
>>I apologize for the amount of time needed to take care of
>>this problem, but it involved more than one broadcast owner
>>and took a bunch of us engineers to figure it out.
>>
>>Please let me know if you experience similar interference
>>in the future as we would like to keep track of this
>>problem in case it recurs.
>>
>>thanks
>>
>>Michael LeClair
>>Chief Engineer
>>WBUR Group
>>
>>
>>On 9 Feb 2005 at 12:55, Rob wrote:
>>
>>Subject:        Reception Question....
>>Date sent:      Wed, 9 Feb 2005 12:55:17 -0500
>>
>>>Hello There....I'm hoping you can answer a question I have about
>>>reception
>>>issue with WBUR.
>>>
>>>I live in the Merrimack Valley, and when I am driving North on I-495
>>>through Lawrence. Methuen and Haverhill,
>>>the reception for WBUR get's pretty spotty.  Since I-495 encircles
>>>Boston...and is almost equi-distant to Boston, I am not getting further
>>>away
>>>from the signal...but it starts to come in spotty enough that I cannot
>>>listen.
>>>
>>>On occaision my home
>>>radios have trouble getting a steady signal from WBUR.
>>>
>>>Someone mentioned to me that it might be due to the station in Haverhill
>>>at
>>>92.5.  Seems unlikeley to me...as it is a whole 1.6 Mhz away.
>>>
>>>Are you aware of the spotty recpetion in this area?
>>>
>>>Any idea why reception is unreliable up here?
>>>
>>>(I mean, I'm not in the boondocks of NH, just about 25-30 miles North of
>>>Boston.)
>>>
>>>Thanks for your help!.