08-22-2012, 11:31 PM
| | Re: AT&T shuts down 800 MHz GSM service in Oakland because ofinterference with the police radio system.
On Aug 22, 3:29*pm, AaronL <5678sd...@fakeemail.com> wrote:
> On Tue, 21 Aug 2012 23:47:21 -0500, "NotMe" <m...@privacy.net> wrote:
> >"sms88" <scharf.ste...@geemail.com> wrote in message
> >> On 8/21/2012 4:12 PM, NotMe wrote:
> >>> "sms88" <scharf.ste...@geemail.com> wrote in message
> >>>> <http://news.cnet.com/8301-1035_3-57497517-94/at-t-cuts-frequency-on-c...>
> >>> It's a well known and documented problem not only for 800 Mhz system.
> >>> Often
> >>> the problem is not caused by the cell tower but can and has been traced
> >>> to
> >>> the design of the public service radios themselves.
> >> Hmm, the FCC investigated this and found the source of interference.
> >> Whether AT&T was doing something wrong, or the public service radio has
> >> priority when there is interference, is not clear.
> >CTIA did an extensive study on the problem in the '90s, *I'll see if Ican
> >find my copy of the report.
> >In any case it's rare where Public Safety has had to bear the burden of the
> Some years ago several neighbors complained to the FCC that a ham was
> causing interference to their TV sets. An investigation found that the
> ham's gear was clean but that the TV sets had insufficient adjacent
> channel interference capability to suppress the ham's strong signal.
> Though the ham was not at fault he was given quiet hours (ordered not
> to transmit) during peak TV viewing time.
Not sure what band that ham was transmitting on. In high school a ham
moved into the neighborhood whose CW could be heard on the TV. I
bought a high pass filter made by Zenith and put it in series with the
antenna input -- no more problem.
> Perhaps this is a similar situation. I doubt the cell tower is
> transmitting on the wrong frequency (public service). More likely the
> public service gear can't handle the strong adjacent frequency signal.
> It's probably easier to shut off a cell tower than to replace all the
> current public service radios. From a public safety standpoint that
> makes sense. However time will likely solve the problem as the PS
> units are eventually upgraded or changed out.
All we read about is problems with public safety radios, not solutions.