Can a UHF channel temporarily "blackout"?

Status
Not open for further replies.

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
I am having an issue I have never seen before.

For around 10 years, with even the most basic of antennas, I have been able to receive 453.350MHZ on my BCT15 and BR300T.

Though ever since yesterday around 1PM when cable TV crews working on lines down the street seemed to cause a 12 min cable TV outage.

Even though 453.350MHZ is only 5 miles away it normally could be picked up with a coat hanger antenna if you wanted.

Though various antennas, the RH77CA, BCT15's original whip, BR330T with homemade OFCD, Uniden BC147XLTs with default whip, and others cannot pick up the frequency at all anymore.

There is a data channel at 453.3375 also.

Can the cable co have caused some sort of cable leakage but if so wouldn't many other frequencies in that range be ruined?

I did get reception for around 20 seconds at 4:44PM but then it vanished again.
 
Last edited:

popnokick

Member
Joined
Mar 21, 2004
Messages
1,904
Location
Northeast PA
453.350 is a NEW license for Blair County Central dispatch and is P25 digital. Your analog BCT15 and BR300T scanners will NOT receive this new radio system, listed as follows:
453.35000 RM 350 NAC BC Cent PD Central Police Dispatch (New) P25 Law Dispatch
You'll need to get a new, P25 digital-capable scanner.
 
Last edited:

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
The FCC Callsign DB listing for 453.350 in Cambria County shows WYC552 as once belonging to Cambria County Transit Authority. The current Status of that license is now shown as "CANCELED 03/29/2013". While it's not impossible that there may be some CATV leakage desensing your receiver, it is highly unlikely. More likely scenario: The license was canceled on the date shown, and they just now got around to taking it off the air. Why not contact the Transit Authority and find out?
That was canceled due to them consolidating their various licenses in to one. Their current license is WFE619.

Another person in the area claims the frequency was working fine yesterday.
 

ecps92

Member
Joined
Jul 8, 2002
Messages
10,570
Location
Taxachusetts
http://eaglecomtronics.com/Cable_Television_Channel_-_Frequency_Chart.pdf
453 Mhz is not generally a Freq impacted by Any Cable TV Channel

I'd look at it being something else.
I am having an issue I have never seen before.

For around 10 years, with even the most basic of antennas, I have been able to receive 453.350MHZ on my BCT15 and BR300T.

Though ever since yesterday around 1PM when cable TV crews working on lines down the street seemed to cause a 12 min cable TV outage.

Even though 453.350MHZ is only 5 miles away it normally could be picked up with a coat hanger antenna if you wanted.

Though various antennas, the RH77CA, BCT15's original whip, BR330T with homemade OFCD, Uniden BC147XLTs with default whip, and others cannot pick up the frequency at all anymore.

There is a data channel at 453.3375 also.

Can the cable co have caused some sort of cable leakage but if so wouldn't many other frequencies in that range be ruined?

I did get reception for around 20 seconds at 4:44PM but then it vanished again.
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
Yes

http://eaglecomtronics.com/Cable_Television_Channel_-_Frequency_Chart.pdf
453 Mhz is not generally a Freq impacted by Any Cable TV Channel

I'd look at it being something else.
That's what I thought also.

I checked all around my house to see if anything at all could be causing interference but I did not add anything new to my place at all except a Fire TV Stick and just to be safe I even unplugged that.

I just know right around 12:45PM yesterday it went from great signal to randomly a few seconds of really staticy audio before it "disappeared".

I can still receive 453.3375 from the same tower and it's sister freq on another tower from 453.475 just not 453.350.
 

popnokick

Member
Joined
Mar 21, 2004
Messages
1,904
Location
Northeast PA
Re-read my first reply. I corrected the info regarding the canceled Cambria Transit freq. Welcome to the era of digital scanning.
 

ecps92

Member
Joined
Jul 8, 2002
Messages
10,570
Location
Taxachusetts
Did they change modes?
Did they change PL/DPL?
Did you accidentally lock them out
...so many things to check, if you are hearing other stations, it's likely not within your house...
That's what I thought also.

I checked all around my house to see if anything at all could be causing interference but I did not add anything new to my place at all except a Fire TV Stick and just to be safe I even unplugged that.

I just know right around 12:45PM yesterday it went from great signal to randomly a few seconds of really staticy audio before it "disappeared".

I can still receive 453.3375 from the same tower and it's sister freq on another tower from 453.475 just not 453.350.
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
Ok

453.350 is a NEW license for Blair County Central dispatch and is P25 digital. Your analog BCT15 and BR300T scanners will NOT receive this new radio system, listed as follows:
453.35000 RM 350 NAC BC Cent PD Central Police Dispatch (New) P25 Law Dispatch
You'll need to get a new, P25 digital-capable scanner.
I see that now but I am not trying to receive a P25 system.

453.350 has always been analog in Cambria County.
 

ScannerSK

Member
Joined
Mar 6, 2005
Messages
1,136
Location
Gilcrest, CO
I am having an issue I have never seen before.

For around 10 years, with even the most basic of antennas, I have been able to receive 453.350MHZ on my BCT15 and BR300T.

Though ever since yesterday around 1PM when cable TV crews working on lines down the street seemed to cause a 12 min cable TV outage.

Even though 453.350MHZ is only 5 miles away it normally could be picked up with a coat hanger antenna if you wanted.

Though various antennas, the RH77CA, BCT15's original whip, BR330T with homemade OFCD, Uniden BC147XLTs with default whip, and others cannot pick up the frequency at all anymore.

There is a data channel at 453.3375 also.

Can the cable co have caused some sort of cable leakage but if so wouldn't many other frequencies in that range be ruined?
Yes, it is very possible for this to happen. The signals in the cable lines are amplified so many times over that even a small leak can create major interference.

I would try driving away from your immediate area and see if the signals you are attempting to receive are able to be received. This should help to either verify or rule out local interference. It could also be a problem with the radio station itself.

Here is a chart of cable channel frequencies. In the old days, if there was a leak in the cable grid a person could tune into the audio carriers and listen to cable TV stations. Nowadays, I'm not sure if cable uses analog any further; most likely cable is using digital transmissions which would just sound like a lot of static.
North American cable television frequencies

You might try tuning above and below the frequencies you are attempting to monitor to see if there is wide-band noise. This would be noise on basically every frequency and may be most noticeable in AM mode if your scanners have that option.

Shawn
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
Yes

Did they change modes?
Did they change PL/DPL?
Did you accidentally lock them out
...so many things to check, if you are hearing other stations, it's likely not within your house...
I tried without the PL of 173.8.

I checked locked out, but 4 separate scanners aren't receiving it.
 

Ubbe

Member
Joined
Sep 8, 2006
Messages
3,437
Location
Stockholm, Sweden
I can still receive 453.3375 from the same tower and it's sister freq on another tower from 453.475 just not 453.350.
That can't be right, having only 12,5KHz separation from transmitters in the same tower.
That will cause severe degradation of reception from both frequencies. They should have planned
neighboring channels to not cover the same area. The physics of radiowaves make the two
frequencies interfere with each other, independent of how good receiver you have.

/Ubbe
 

ScannerSK

Member
Joined
Mar 6, 2005
Messages
1,136
Location
Gilcrest, CO
I tried without the PL of 173.8.

I checked locked out, but 4 separate scanners aren't receiving it.
Try monitoring the frequencies away from your house maybe even as far as a mile or two away from your house to see if that helps. If there is local interference it will usually also show up on the signal strength indicator on your scanner if you have one.

Shawn
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
Exactly

That can't be right, having only 12,5KHz separation from transmitters in the same tower.
That will cause severe degradation of reception from both frequencies. They should have planned
neighboring channels to not cover the same area. The physics of radiowaves make the two
frequencies interfere with each other, independent of how good receiver you have.

/Ubbe
This is what I thought of for years now.

I actually told their radio service once they shouldn't have put them so much but they said "The FCC now says channels are 12.5KHz apart" or something like that.

For years 453.350 will have background noise of 453.3375's buzzing for their GPS units while people talk on 453.350.

For some reason the BCT15 was able to ignore the majority of this background buzz but not the BR330T.
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
Oddly it's coming back into reception.

It's rather staticy and hard to understand but it's coming back.
 

jonwienke

Member
Joined
Jul 18, 2014
Messages
9,321
Location
PA
It's most likely due to the system being changed over to P25, or some other nearby transmission desensing your receiver.
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
It's most likely due to the system being changed over to P25, or some other nearby transmission desensing your receiver.
Most likely.

The P25 is the next county over while 453.350 is still analog here.

Though I will have to wait and see what happens.
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
I could be wrong but from the sounds of what I am receiving now it sounds like possibly the data channel at 453.3375 is really over powering the voice channel right now.

Before if you tuned to 453.350 without PL tone you got a few blips of the data channel.

Right now, I am getting a rather consistent flow of the data channel on 453.350.

I know a few months ago even the radio users themselves said in some areas they get a rather annoying buzz on the radios that cause them to turn their radios down and can't easily make out what people are transmitting,
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
Oh an update.

Even though another person in the area said they could hear the channel just fine, I just heard a faint staticy voice saying "Testing 1-2-3 Testing 1-2-3".

So maybe they are noticing a repeater issue after all.

EDIT: It looks like it was for a fact something with the tower. "Radio Maintenance" just signed on and said stated the radio should be back to normal now.

The person on Facebook who told me they received them fine must have been closer to the antenna or something as there definitely was an issue.
 
Last edited:

slicerwizard

Member
Joined
Sep 19, 2002
Messages
5,531
Location
Toronto, Ontario
That can't be right, having only 12,5KHz separation from transmitters in the same tower.
That will cause severe degradation of reception from both frequencies. They should have planned
neighboring channels to not cover the same area. The physics of radiowaves make the two
frequencies interfere with each other, independent of how good receiver you have.

/Ubbe
What? Some trunked systems here have used 12.5 kHz separation for the last couple of decades. My old 246T receives them just fine. Some newer systems use only 6.25 kHz. Cheap SDR dongles have no problems with them. Really doesn't jive with your claim.
 

RedPenguin

Member
Premium Subscriber
Joined
Feb 28, 2007
Messages
1,007
Not Sure

What? Some trunked systems here have used 12.5 kHz separation for the last couple of decades. My old 246T receives them just fine. Some newer systems use only 6.25 kHz. Cheap SDR dongles have no problems with them. Really doesn't jive with your claim.
This is what I thought also.

Though with this system it seems they are getting interference into each other.

453.350 on most scanners even when set properly to NFM will constantly get a faint buzz in the background as users talk.

My BCT15 is the only scanner to date that I found that filters the two successfully.
 
Status
Not open for further replies.
Top