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155.25 freqy interference

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  • dataman60435
    I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook PD)here in my area not the PL or IF shift...I wish they would change freqys...I have
    Message 1 of 8 , Dec 30, 2009
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      I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook PD)here in my area not the PL or IF shift...I wish they would change freqys...I have been told it has something to do with the Comcast Cable??....
    • Rich Carlson
      If you get interference and it goes away or weaken when you remove the scanner antenna, then it is likely from outside sources. It seems to be a common
      Message 2 of 8 , Dec 30, 2009
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        If you get interference and it goes away or weaken when you remove the
        scanner antenna, then it is likely from outside sources. It seems to
        be a common situation for frequencies at the 1/4 th MHz. (151.250,
        155.250 etc.) to originate from cable TV installations, often a poorly
        grounded amp or connection.

        My agency also uses 155.250 and when I hear noise on it I try to
        locate the specific area and call Comcast, they usually get it fixed
        pretty quickly.

        If you are getting it in your home, then try to find where the drop
        come into the house for cable TV and disconnect it, then see if the
        interference goes away, if so then the issue is likely inside.

        On Wed, Dec 30, 2009 at 2:45 PM, dataman60435 <dataman60435@...> wrote:
        > I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook PD)here in my area not the PL or IF shift...I wish they would change freqys...I have been told it has something to do with the Comcast Cable??....
        >

        --
        Rich Carlson, N9JIG
      • Brian
        I would like to clarify something about this post. My OLD 396 and the new 396XT both have that terrible whine going all the time. In the car, out of the car,
        Message 3 of 8 , Dec 30, 2009
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          I would like to clarify something about this post. My OLD 396 and the new 396XT both have that terrible whine going all the time. In the car, out of the car, middle of a parking lot....everywhere. It is not an indoor Comcast issue or a matter of taking the antenna off. It is an overpowering signal that obviously does not affect the police radios but wreaks havoc on the scanner itself. I posted something about this a LONG time ago in another forum and no one commented or replied because it wasn't their issue. There definitely is some interferring source whether it is internal to the 396 and XT or in the Bolingbrook area. Lockport, Woodridge, Romeoville, Crest Hill, Joliet, Plainfield, and Naperville with 155.250 all render that same bizarre constant whiley tone. It becomes slightly better but still intolerable when Bolingbrook units communicate. This isn't an indoor/inside the car issue. I gave up on Bolingbrook listening a long time agio due to it. It
          doesn't happen on the Pro 106, Uniden 250, Pro 92, or Uniden 330. Something about that 396 and XT model brings it out. If anyone disputes that, take your 396 and/or XT to Bolingbrook and see for yourself.

          By the way, Happy New Year Rich! Be safe out there and thanks for everything you have contributed to the scanner/radio community.




          ________________________________
          From: Rich Carlson <rich.n9jig@...>
          To: BCD396XT@yahoogroups.com
          Sent: Wed, December 30, 2009 3:41:23 PM
          Subject: Re: [BCD396XT] 155.25 freqy interference

           
          If you get interference and it goes away or weaken when you remove the
          scanner antenna, then it is likely from outside sources. It seems to
          be a common situation for frequencies at the 1/4 th MHz. (151.250,
          155.250 etc.) to originate from cable TV installations, often a poorly
          grounded amp or connection.

          My agency also uses 155.250 and when I hear noise on it I try to
          locate the specific area and call Comcast, they usually get it fixed
          pretty quickly.

          If you are getting it in your home, then try to find where the drop
          come into the house for cable TV and disconnect it, then see if the
          interference goes away, if so then the issue is likely inside.

          On Wed, Dec 30, 2009 at 2:45 PM, dataman60435 <dataman60435@ yahoo.com> wrote:
          > I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook PD)here in my area not the PL or IF shift...I wish they would change freqys...I have been told it has something to do with the Comcast Cable??....
          >

          --
          Rich Carlson, N9JIG






          [Non-text portions of this message have been removed]
        • SRehm24416@aol.com
          I echo your statement word for word. Just remove all the cities you mentioned and replace them with Kirkwood, MO PD. I will add that at times the only way I
          Message 4 of 8 , Dec 30, 2009
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            I echo your statement word for word. Just remove all the cities you mentioned and replace them with Kirkwood, MO PD. I will add that at times the only way I can get what I consider a good signal on this freq is if I am in or very near the city of Kirkwood. Sometimes, but not always it can be enjoyable listening to them.

            I also wish everyone a happy and safe new year.





            -----Original Message-----
            From: Brian <chicagostretch2002@...>
            To: BCD396XT@yahoogroups.com
            Sent: Wed, Dec 30, 2009 4:02 pm
            Subject: Re: [BCD396XT] 155.25 freqy interference


            I would like to clarify something about this post. My OLD 396 and the new 396XT
            oth have that terrible whine going all the time. In the car, out of the car,
            iddle of a parking lot....everywhere. It is not an indoor Comcast issue or a
            atter of taking the antenna off. It is an overpowering signal that obviously
            oes not affect the police radios but wreaks havoc on the scanner itself. I
            osted something about this a LONG time ago in another forum and no one
            ommented or replied because it wasn't their issue. There definitely is some
            nterferring source whether it is internal to the 396 and XT or in the
            olingbrook area. Lockport, Woodridge, Romeoville, Crest Hill, Joliet,
            lainfield, and Naperville with 155.250 all render that same bizarre constant
            hiley tone. It becomes slightly better but still intolerable when Bolingbrook
            nits communicate. This isn't an indoor/inside the car issue. I gave up on
            olingbrook listening a long time agio due to it. It
            doesn't happen on the Pro 106, Uniden 250, Pro 92, or Uniden 330. Something
            bout that 396 and XT model brings it out. If anyone disputes that, take your
            96 and/or XT to Bolingbrook and see for yourself.
            By the way, Happy New Year Rich! Be safe out there and thanks for everything you
            ave contributed to the scanner/radio community.


            _______________________________
            rom: Rich Carlson <rich.n9jig@...>
            o: BCD396XT@yahoogroups.com
            ent: Wed, December 30, 2009 3:41:23 PM
            ubject: Re: [BCD396XT] 155.25 freqy interference

            f you get interference and it goes away or weaken when you remove the
            canner antenna, then it is likely from outside sources. It seems to
            e a common situation for frequencies at the 1/4 th MHz. (151.250,
            55.250 etc.) to originate from cable TV installations, often a poorly
            rounded amp or connection.
            My agency also uses 155.250 and when I hear noise on it I try to
            ocate the specific area and call Comcast, they usually get it fixed
            retty quickly.
            If you are getting it in your home, then try to find where the drop
            ome into the house for cable TV and disconnect it, then see if the
            nterference goes away, if so then the issue is likely inside.
            On Wed, Dec 30, 2009 at 2:45 PM, dataman60435 <dataman60435@ yahoo.com> wrote:
            I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook
            D)here in my area not the PL or IF shift...I wish they would change freqys...I
            ave been told it has something to do with the Comcast Cable??....

            --
            ich Carlson, N9JIG



            [Non-text portions of this message have been removed]

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            [Non-text portions of this message have been removed]
          • shelleysh1@att.net
            Rich, I haven t heard it in the 1/4 th MHz, but I have major interference here in St. Louis, mobile, at the intersection of I-64 and I-270. The problem here
            Message 5 of 8 , Dec 31, 2009
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              Rich, I haven't heard it in the 1/4 th MHz, but I have major interference here in St. Louis, mobile, at the intersection of I-64 and I-270. The problem here is, I'm almost sure, due to the fact that that our MO Dept. of Transportation has an active facility as well as two large hospitals all residing on either side of the interchange - one of the hospitals being a level one trauma center. When going through the interchange one of the frequencies for the Muni covering this area will always lock up in a "high whine" (typical birdie type signal). But the frequencies involved are 158.790 173.8 PL, 154.650 156.7 PL and 154.115 no PL. Once a mile or so past the interchange, then the muni returns to normal. Since I regularly monitor them I know that this doesn't happen on their equipment, in fact I'm hearing them right now, on all their frequencies. So why would I experience this interference (on both of my 396XTs) and they wouldn't? I've also tried using the radios with the handheld antenna instead of the Larson installed on the car - same results.

              Shelley


              --- In BCD396XT@yahoogroups.com, Rich Carlson <rich.n9jig@...> wrote:
              >
              > If you get interference and it goes away or weaken when you remove the
              > scanner antenna, then it is likely from outside sources. It seems to
              > be a common situation for frequencies at the 1/4 th MHz. (151.250,
              > 155.250 etc.) to originate from cable TV installations, often a poorly
              > grounded amp or connection.
              >
              > My agency also uses 155.250 and when I hear noise on it I try to
              > locate the specific area and call Comcast, they usually get it fixed
              > pretty quickly.
              >
              > If you are getting it in your home, then try to find where the drop
              > come into the house for cable TV and disconnect it, then see if the
              > interference goes away, if so then the issue is likely inside.
              >
              > On Wed, Dec 30, 2009 at 2:45 PM, dataman60435 <dataman60435@...> wrote:
              > > I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook PD)here in my area not the PL or IF shift...I wish they would change freqys...I have been told it has something to do with the Comcast Cable??....
              > >
              >
              > --
              > Rich Carlson, N9JIG
              >
            • Rich Carlson
              The 1/4th mHz. interference is common with cable TV, there are numerous other sources of interference all over the place. Mixing two signals together to result
              Message 6 of 8 , Dec 31, 2009
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                The 1/4th mHz. interference is common with cable TV, there are
                numerous other sources of interference all over the place. Mixing two
                signals together to result in interference on a third frequency is
                called Intermod, it is possible that two or more cable TV leaks or
                other types of noise on different freqs could result in intermod on
                other frequencies.

                Another issue is image rejection. While newer scanners are much better
                at image rejection than older models, they usually are not better than
                the actual radios used on the systems. The radios are built for a
                specific band segment while the scanners have to cover a wide variety
                of freqs, therefore system radios usually are much tighter with
                respect to image rejection.

                On Thu, Dec 31, 2009 at 8:43 AM, shelleysh1@... <shelleysh1@...> wrote:
                > Rich, I haven't heard it in the 1/4 th MHz, but I have major interference here in St. Louis, mobile, at the intersection of I-64 and I-270. The problem here is, I'm almost sure, due to the fact that that our MO Dept. of Transportation has an active facility as well as two large hospitals all residing on either side of the interchange - one of the hospitals being a level one trauma center. When going through the interchange one of the frequencies for the Muni covering this area will always lock up in a "high whine" (typical birdie type signal). But the frequencies involved are 158.790 173.8 PL, 154.650 156.7 PL and 154.115 no PL. Once a mile or so past the interchange, then the muni returns to normal. Since I regularly monitor them I know that this doesn't happen on their equipment, in fact I'm hearing them right now, on all their frequencies. So why would I experience this interference (on both of my 396XTs) and they wouldn't? I've also tried using the radios with the handheld antenna instead of the Larson installed on the car - same results.
                >
                > Shelley
                >
                >
                > --- In BCD396XT@yahoogroups.com, Rich Carlson <rich.n9jig@...> wrote:
                >>
                >> If you get interference and it goes away or weaken when you remove the
                >> scanner antenna, then it is likely from outside sources. It seems to
                >> be a common situation for frequencies at the 1/4 th MHz. (151.250,
                >> 155.250 etc.) to originate from cable TV installations, often a poorly
                >> grounded amp or connection.
                >>
                >> My agency also uses 155.250 and when I hear noise on it I try to
                >> locate the specific area and call Comcast, they usually get it fixed
                >> pretty quickly.
                >>
                >> If you are getting it in your home, then try to find where the drop
                >> come into the house for cable TV and disconnect it, then see if the
                >> interference goes away, if so then the issue is likely inside.
                >>
                >> On Wed, Dec 30, 2009 at 2:45 PM, dataman60435 <dataman60435@...> wrote:
                >> > I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook PD)here in my area not the PL or IF shift...I wish they would change freqys...I have been told it has something to do with the Comcast Cable??....
                >> >
                >>
                >> --
                --
                Rich Carlson, N9JIG
              • Bill Lauchlan
                I think I would try two facilities on the XT to see if it improves the situation . One being to switch in Front end Attenuation (assuming you can tolerate the
                Message 7 of 8 , Dec 31, 2009
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                  I think I would try two facilities on the XT to see if it improves the situation . One being to switch in Front end Attenuation (assuming you can tolerate the drop in Fundamental signal level) and other being to switch XT to alternative IF. These two tests could give some further clue to nature of interference problem.

                  Regards BL
                  ----- Original Message -----
                  From: Rich Carlson
                  To: BCD396XT@yahoogroups.com
                  Sent: Thursday, December 31, 2009 10:06 AM
                  Subject: Re: [BCD396XT] Re: 155.25 freqy interference



                  The 1/4th mHz. interference is common with cable TV, there are
                  numerous other sources of interference all over the place. Mixing two
                  signals together to result in interference on a third frequency is
                  called Intermod, it is possible that two or more cable TV leaks or
                  other types of noise on different freqs could result in intermod on
                  other frequencies.

                  Another issue is image rejection. While newer scanners are much better
                  at image rejection than older models, they usually are not better than
                  the actual radios used on the systems. The radios are built for a
                  specific band segment while the scanners have to cover a wide variety
                  of freqs, therefore system radios usually are much tighter with
                  respect to image rejection.

                  On Thu, Dec 31, 2009 at 8:43 AM, shelleysh1@... <shelleysh1@...> wrote:
                  > Rich, I haven't heard it in the 1/4 th MHz, but I have major interference here in St. Louis, mobile, at the intersection of I-64 and I-270. The problem here is, I'm almost sure, due to the fact that that our MO Dept. of Transportation has an active facility as well as two large hospitals all residing on either side of the interchange - one of the hospitals being a level one trauma center. When going through the interchange one of the frequencies for the Muni covering this area will always lock up in a "high whine" (typical birdie type signal). But the frequencies involved are 158.790 173.8 PL, 154.650 156.7 PL and 154.115 no PL. Once a mile or so past the interchange, then the muni returns to normal. Since I regularly monitor them I know that this doesn't happen on their equipment, in fact I'm hearing them right now, on all their frequencies. So why would I experience this interference (on both of my 396XTs) and they wouldn't? I've also tried using the radios with the handheld antenna instead of the Larson installed on the car - same results.
                  >
                  > Shelley
                  >
                  >
                  > --- In BCD396XT@yahoogroups.com, Rich Carlson <rich.n9jig@...> wrote:
                  >>
                  >> If you get interference and it goes away or weaken when you remove the
                  >> scanner antenna, then it is likely from outside sources. It seems to
                  >> be a common situation for frequencies at the 1/4 th MHz. (151.250,
                  >> 155.250 etc.) to originate from cable TV installations, often a poorly
                  >> grounded amp or connection.
                  >>
                  >> My agency also uses 155.250 and when I hear noise on it I try to
                  >> locate the specific area and call Comcast, they usually get it fixed
                  >> pretty quickly.
                  >>
                  >> If you are getting it in your home, then try to find where the drop
                  >> come into the house for cable TV and disconnect it, then see if the
                  >> interference goes away, if so then the issue is likely inside.
                  >>
                  >> On Wed, Dec 30, 2009 at 2:45 PM, dataman60435 <dataman60435@...> wrote:
                  >> > I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook PD)here in my area not the PL or IF shift...I wish they would change freqys...I have been told it has something to do with the Comcast Cable??....
                  >> >
                  >>
                  >> --
                  --
                  Rich Carlson, N9JIG




                  [Non-text portions of this message have been removed]
                • shelleysh1@att.net
                  Thanks Rich. Brain fade here! I suppose, since I haven t experienced any intermod on either my previous 396Ts or current 396XTs, I didn t even think about it -
                  Message 8 of 8 , Jan 1, 2010
                  • 0 Attachment
                    Thanks Rich. Brain fade here! I suppose, since I haven't experienced any intermod on either my previous 396Ts or current 396XTs, I didn't even think about it - DUH on my part! I've gotten very spoiled by our radios. *grin*

                    Shell

                    --- In BCD396XT@yahoogroups.com, Rich Carlson <rich.n9jig@...> wrote:
                    >
                    > The 1/4th mHz. interference is common with cable TV, there are
                    > numerous other sources of interference all over the place. Mixing two
                    > signals together to result in interference on a third frequency is
                    > called Intermod, it is possible that two or more cable TV leaks or
                    > other types of noise on different freqs could result in intermod on
                    > other frequencies.
                    >
                    > Another issue is image rejection. While newer scanners are much better
                    > at image rejection than older models, they usually are not better than
                    > the actual radios used on the systems. The radios are built for a
                    > specific band segment while the scanners have to cover a wide variety
                    > of freqs, therefore system radios usually are much tighter with
                    > respect to image rejection.
                    >
                    > On Thu, Dec 31, 2009 at 8:43 AM, shelleysh1@... <shelleysh1@...> wrote:
                    > > Rich, I haven't heard it in the 1/4 th MHz, but I have major interference here in St. Louis, mobile, at the intersection of I-64 and I-270. The problem here is, I'm almost sure, due to the fact that that our MO Dept. of Transportation has an active facility as well as two large hospitals all residing on either side of the interchange - one of the hospitals being a level one trauma center. When going through the interchange one of the frequencies for the Muni covering this area will always lock up in a "high whine" (typical birdie type signal). But the frequencies involved are 158.790 173.8 PL, 154.650 156.7 PL and 154.115 no PL. Once a mile or so past the interchange, then the muni returns to normal. Since I regularly monitor them I know that this doesn't happen on their equipment, in fact I'm hearing them right now, on all their frequencies. So why would I experience this interference (on both of my 396XTs) and they wouldn't? I've also tried using the radios with the handheld antenna instead of the Larson installed on the car - same results.
                    > >
                    > > Shelley
                    > >
                    > >
                    > > --- In BCD396XT@yahoogroups.com, Rich Carlson <rich.n9jig@> wrote:
                    > >>
                    > >> If you get interference and it goes away or weaken when you remove the
                    > >> scanner antenna, then it is likely from outside sources. It seems to
                    > >> be a common situation for frequencies at the 1/4 th MHz. (151.250,
                    > >> 155.250 etc.) to originate from cable TV installations, often a poorly
                    > >> grounded amp or connection.
                    > >>
                    > >> My agency also uses 155.250 and when I hear noise on it I try to
                    > >> locate the specific area and call Comcast, they usually get it fixed
                    > >> pretty quickly.
                    > >>
                    > >> If you are getting it in your home, then try to find where the drop
                    > >> come into the house for cable TV and disconnect it, then see if the
                    > >> interference goes away, if so then the issue is likely inside.
                    > >>
                    > >> On Wed, Dec 30, 2009 at 2:45 PM, dataman60435 <dataman60435@> wrote:
                    > >> > I agree, nothing stops the hetrodyne whine in with the 155.25 (Bolingbrook PD)here in my area not the PL or IF shift...I wish they would change freqys...I have been told it has something to do with the Comcast Cable??....
                    > >> >
                    > >>
                    > >> --
                    > --
                    > Rich Carlson, N9JIG
                    >
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