Cable return path has outside signals at 22mhz

Cable return path has outside signals at 22mhz
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Subject Author Date
Cable return path has outside signals at 22mhz Dana 08-02-2007
Posted by Dana on August 2, 2007, 8:51 pm
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Hi all
In our return plant that we are starting to implement, we are seeing signals
in and around 22mhz. Does anyone know of a way of isolating the ingress
point they must be coming in at. Seems they are some form of radio
navigation signal, as it sounds like a beacon when you use a communication
analyzer to look at the signals.

Thanks



Posted by Eric on August 2, 2007, 11:23 pm
> Hi all
> In our return plant that we are starting to implement, we are seeing signals
> in and around 22mhz. Does anyone know of a way of isolating the ingress
> point they must be coming in at. Seems they are some form of radio
> navigation signal, as it sounds like a beacon when you use a communication
> analyzer to look at the signals.
>
> Thanks

Could be a lot of things. I remember hearing a lot of Spanish
language stuff around there several years ago. Best thing is to move
to a clear part of the spectrum (above 30MHz seems to be good in most
plants), and use the carrier to train the line crews on finding
ingress.


Posted by Dana on August 3, 2007, 1:49 am

>> Hi all
>> In our return plant that we are starting to implement, we are seeing
>> signals
>> in and around 22mhz. Does anyone know of a way of isolating the ingress
>> point they must be coming in at. Seems they are some form of radio
>> navigation signal, as it sounds like a beacon when you use a
>> communication
>> analyzer to look at the signals.
>>
>> Thanks
>
> Could be a lot of things. I remember hearing a lot of Spanish
> language stuff around there several years ago. Best thing is to move
> to a clear part of the spectrum (above 30MHz seems to be good in most
> plants), and use the carrier to train the line crews on finding
> ingress.

Thanks for the reply.
As it is, our outside plant guys are the ones who bought me in, I am the
inside plant /cellular tech. I showed them how to use the spec a, and then
they showed me this signal around 22mhz. Seems our mad scientist on our
staff found a deal on return amps, and decided that we should go into the
cable modem side with our rural cable system. So the outside plant guys
placed the return amps in the housings, and then our mad scientist wondered
why the Motorola surfboard cable modem did not work with the c9 CMTS he also
bought.
I asked if we placed any high pass filters in the return, and the answer was
no. I also asked if all the amps and housings were checked for proper
terminations of the connectors and contacts to ensure no Common path
distortion, etc, and again the answer was no. All they did was place the
amps in and expected it to work.
What is interesting is that at our headend, these 22mhz signals are not
present on the return path. We observed them at our CO which is across the
street from our rural airport. We do have a large FAA presence here, as we
are like a regional hub for this part of rural Alaska, whcih is why I
thought it may be some kind of radio navigation signal, as they are kind of
close to that freq.

Thanks again
>



Posted by Ed Nielsen on August 3, 2007, 12:57 pm
Dana,

Go to http://cabletv.org/mailman/listinfo/cabletv-list and join that list.
There are many CATV engineers and technicians there who may be able to help
you.

--

CIAO!

Ed N.


>
>>> Hi all
>>> In our return plant that we are starting to implement, we are seeing
>>> signals
>>> in and around 22mhz. Does anyone know of a way of isolating the ingress
>>> point they must be coming in at. Seems they are some form of radio
>>> navigation signal, as it sounds like a beacon when you use a
>>> communication
>>> analyzer to look at the signals.
>>>
>>> Thanks
>>
>> Could be a lot of things. I remember hearing a lot of Spanish
>> language stuff around there several years ago. Best thing is to move
>> to a clear part of the spectrum (above 30MHz seems to be good in most
>> plants), and use the carrier to train the line crews on finding
>> ingress.
>
> Thanks for the reply.
> As it is, our outside plant guys are the ones who bought me in, I am the
> inside plant /cellular tech. I showed them how to use the spec a, and then
> they showed me this signal around 22mhz. Seems our mad scientist on our
> staff found a deal on return amps, and decided that we should go into the
> cable modem side with our rural cable system. So the outside plant guys
> placed the return amps in the housings, and then our mad scientist
> wondered why the Motorola surfboard cable modem did not work with the c9
> CMTS he also bought.
> I asked if we placed any high pass filters in the return, and the answer
> was no. I also asked if all the amps and housings were checked for proper
> terminations of the connectors and contacts to ensure no Common path
> distortion, etc, and again the answer was no. All they did was place the
> amps in and expected it to work.
> What is interesting is that at our headend, these 22mhz signals are not
> present on the return path. We observed them at our CO which is across the
> street from our rural airport. We do have a large FAA presence here, as we
> are like a regional hub for this part of rural Alaska, whcih is why I
> thought it may be some kind of radio navigation signal, as they are kind
> of close to that freq.
>
> Thanks again
>>
>
>


Posted by Dana on August 4, 2007, 12:35 pm

> Dana,
>
> Go to http://cabletv.org/mailman/listinfo/cabletv-list and join that list.
> There are many CATV engineers and technicians there who may be able to
> help you.
>
> --
>
> CIAO!
>
> Ed N.

Thanks for the link.


>
>
>>
>>>> Hi all
>>>> In our return plant that we are starting to implement, we are seeing
>>>> signals
>>>> in and around 22mhz. Does anyone know of a way of isolating the ingress
>>>> point they must be coming in at. Seems they are some form of radio
>>>> navigation signal, as it sounds like a beacon when you use a
>>>> communication
>>>> analyzer to look at the signals.
>>>>
>>>> Thanks
>>>
>>> Could be a lot of things. I remember hearing a lot of Spanish
>>> language stuff around there several years ago. Best thing is to move
>>> to a clear part of the spectrum (above 30MHz seems to be good in most
>>> plants), and use the carrier to train the line crews on finding
>>> ingress.
>>
>> Thanks for the reply.
>> As it is, our outside plant guys are the ones who bought me in, I am the
>> inside plant /cellular tech. I showed them how to use the spec a, and
>> then they showed me this signal around 22mhz. Seems our mad scientist on
>> our staff found a deal on return amps, and decided that we should go into
>> the cable modem side with our rural cable system. So the outside plant
>> guys placed the return amps in the housings, and then our mad scientist
>> wondered why the Motorola surfboard cable modem did not work with the c9
>> CMTS he also bought.
>> I asked if we placed any high pass filters in the return, and the answer
>> was no. I also asked if all the amps and housings were checked for proper
>> terminations of the connectors and contacts to ensure no Common path
>> distortion, etc, and again the answer was no. All they did was place the
>> amps in and expected it to work.
>> What is interesting is that at our headend, these 22mhz signals are not
>> present on the return path. We observed them at our CO which is across
>> the street from our rural airport. We do have a large FAA presence here,
>> as we are like a regional hub for this part of rural Alaska, whcih is why
>> I thought it may be some kind of radio navigation signal, as they are
>> kind of close to that freq.
>>
>> Thanks again
>>>
>>
>>
>



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