Been in the cell business for 21 years now and never had a ³Ham issue with
noise on either side². Not saying you won¹t get a GC stuck on stupid
sometime though.
73 Dave n4zkf
e-mail: n4zkf@n4zkf.com
web: http://www.n4zkf.com
CC-Cluster node: 145.07 Mhz. or telnet://ccc.n4zkf.com:7373 23
Packet BBS: 145.05 Mhz.-14.098 Mhz. or telnet://bbs.n4zkf.com:6300
BPQ Node: 145.05 Mhz.-14.098 Mhz. (n4zkf-5)
SEDAN Node: 145.770 Mhz. (n4zkf-7)
N4ZKF/R 147.375 Mhz. Tone 103.5
On 2/12/17, 11:42 AM, "TowerTalk on behalf of Steve Maki"
<towertalk-bounces@contesting.com on behalf of lists@oakcom.org> wrote:
>Cell sites are generally pretty quiet. The whole site pretty much runs
>on batteries. Tower top equipment is always connected via fiber data
>lines and -48VDC power lines. RF amp outputs always go thru steep
>bandpass filters.
>
>The battery banks in cell sites ARE charged by switching supplies, but I
>often have a spectrum analyzer running while I'm working in the
>shelters, and have occasionally hooked up a simple dipole to it to see
>what the levels are like in there, and I haven't seen much noise
>pollution at all.
>
>That said, there has been some recent equipment with design flaws. One
>such case involved the surge arrestor units that are placed at the tower
>top that serve as the interconnection point between the -48V trunklines
>and the branch cables that go out to the radios. These units have alarm
>wiring that run back down to the base equipment. The units have a
>multitude of indicator LEDs, and the LEDs and/or associated circuit
>boards were generating wideband noise that was being picked up in the
>700 MHZ band by antennas that were only a few feet away.
>
>It was causing noise floors in the -80 dBm range, instead of the -100
>dBm that the carriers need for LTE. The manufacturer provided retrofit
>boards to cure the problem.
>
>-Steve K8LX
>
>
>On 2/11/2017 14:47 PM, Barry Merrill wrote:
>
>> I have a major cell building with antennas on the 125 foot pylons
>> that are located 420 feet to the Northwest, and as the antenna
>> swings thru that azimuth there is switching noise that adds 5-10db
>> for about 25 degrees either side.
>>
>> Barry W5GN
>
>_______________________________________________
>
>
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|