Recently I have noticed that in the evenings, it's not uncommon to hear loud intermittent zapping noises on the police scanner, covering some officers transmissions, sometimes completely. I didn't think much of it until I realized that no matter where I was in the county, I still hear it, as do the dispatchers and other officers using the system. This means that it is not interference received by my scanner directly, but re-broadcast by the county repeater system after receiving it on the system inputs.
Once I realized that it wasn't some sort of interference that my scanner was picking up. I decided to do some digging. The first thing I thought of was the fact that it has a cycle rate of four seconds (on for two, off for two). What would cause that kind of pattern of interference? Well, some towers have beacons on top that strobe, some blink, some are just steady. The Melbourne tower has two LED beacon lights atop it's mast, and they flash at the same cycle rate as the interference. What's more, this beacon seems to pulsate very quickly when lit, as if the LEDs themselves are simply driven off the mains voltage through a resistor.
Next I parked near the tower after sunset and listened to the scanner, waiting for an officer with a weak radio or one who is almost out of range to key up. I didn't have to wait very long at all, maybe five minutes. I watched the lights on the tower as I listened to the traffic coming across the scanner and confirmed that it is in fact the beacon causing the interference as they are both perfectly in sync with one-another. Below is a link to a recording I made of the interference causing trouble for several of the police departments in Brevard county on September 18th. The original is an hour long, and was recorded (using voice activation) over a 4 hour period at night.
I have been in contact with Communications International about this issue. At first the gentleman I spoke with didn't want to believe me, though after a couple days of testing, and listening to me talk about how I came to the conclusion that it was the beacon, he knew I was right. I told him I have recordings of the interference making it hard for the police to communicate, and offered to deliver them on CD. About five minutes after I got to the radio shop to deliver them, someone from the county walked in and he said he had been talking to the same gentleman as I have. We talked, and he struck me as an intelligent person. He told me that he would make sure the tower owner gets it fixed.
Melbourne Tower Beacon Interference by Dark Overload on SoundCloud - Create, record and share your sounds for free
This recording is the same recording that I delivered to them on CD on September 19th. The interference usually happens after 5PM when the beacon is activated. This time may be variable or override-able, or they are working on or have fixed it, because I have not heard it yet tonight. I did hear a couple departments talking about "re-banding" of the fleet's radios yesterday evening though, so they may have all been programmed to inhibit transmission on the Melbourne tower's set of inputs. They may have also setup an alternate input site for testing. I am just glad that I figured out what it was, and someone is working on it. Our first responders' abilities to communicate priority information quickly and unhampered by noise is vital.
Once I realized that it wasn't some sort of interference that my scanner was picking up. I decided to do some digging. The first thing I thought of was the fact that it has a cycle rate of four seconds (on for two, off for two). What would cause that kind of pattern of interference? Well, some towers have beacons on top that strobe, some blink, some are just steady. The Melbourne tower has two LED beacon lights atop it's mast, and they flash at the same cycle rate as the interference. What's more, this beacon seems to pulsate very quickly when lit, as if the LEDs themselves are simply driven off the mains voltage through a resistor.
Next I parked near the tower after sunset and listened to the scanner, waiting for an officer with a weak radio or one who is almost out of range to key up. I didn't have to wait very long at all, maybe five minutes. I watched the lights on the tower as I listened to the traffic coming across the scanner and confirmed that it is in fact the beacon causing the interference as they are both perfectly in sync with one-another. Below is a link to a recording I made of the interference causing trouble for several of the police departments in Brevard county on September 18th. The original is an hour long, and was recorded (using voice activation) over a 4 hour period at night.
I have been in contact with Communications International about this issue. At first the gentleman I spoke with didn't want to believe me, though after a couple days of testing, and listening to me talk about how I came to the conclusion that it was the beacon, he knew I was right. I told him I have recordings of the interference making it hard for the police to communicate, and offered to deliver them on CD. About five minutes after I got to the radio shop to deliver them, someone from the county walked in and he said he had been talking to the same gentleman as I have. We talked, and he struck me as an intelligent person. He told me that he would make sure the tower owner gets it fixed.
Melbourne Tower Beacon Interference by Dark Overload on SoundCloud - Create, record and share your sounds for free
This recording is the same recording that I delivered to them on CD on September 19th. The interference usually happens after 5PM when the beacon is activated. This time may be variable or override-able, or they are working on or have fixed it, because I have not heard it yet tonight. I did hear a couple departments talking about "re-banding" of the fleet's radios yesterday evening though, so they may have all been programmed to inhibit transmission on the Melbourne tower's set of inputs. They may have also setup an alternate input site for testing. I am just glad that I figured out what it was, and someone is working on it. Our first responders' abilities to communicate priority information quickly and unhampered by noise is vital.
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