Davicom’s DVLD-1 Lightning Detector is a sensor that allows detection and range estimation of incoming lightning storms. It operates by receiving and statistically processing the electromagnetic signals generated by lightning bolts. The receiver operates in a narrow 33kHz band around 500kHz (0.5MHz)
Operation & Sources of Interference
The unit’s maximum detection range is about 40 km. At these distances, the electromagnetic fields generated by lightning are often difficult to detect because they are so weak. These low-level signals can therefore be masked or overwhelmed by nearby strong interfering signals. Typical sources of interference can be such things as electric motors, electrical switching apparatus, high-voltage transmission lines and non-incandescent lighting devices (among others). There have also been cases reported of interference from electric vehicles such as models from Tesla.
Location for Installation
The DVLD should be installed outdoors on a short pole that is as far away as possible from:
- Electrical transmission and distribution lines
- AM broadcast antennas
- Electric motors, such as HVAC units, elevator lift motors and the like
- Spaces where electric vehicles are likely to park or pass through
Ideally, it should not be installed directly on an antenna tower or structure that is likely to be hit by lightning as it could be damaged by a direct lightning strike.
Note that Davicom’s DVLC-1 Lightning Counter (a different product) is designed to be installed directly on a tower or pole that can be hit by lightning. The DVLC is built to count current pulses that are induced when a metallic structure is hit by lightning.
Grounding
Another factor that can greatly influence the DVLD’s operation & sensitivity is grounding of the corresponding Davicom CORTEX Unit. The Davicom CORTEX unit’s back-panel ground screw should be directly connected to an on-site ground with a length of wire that is as short possible. Leaving this terminal disconnected has been known to increase the incidence of disturber detections by the DVLD.
Preliminary Tests
The DVLD-1 and Davicom CORTEX units have built-in noise and interference detection and display features.
Once your DVLD is installed and your Davicom Cortex properly grounded, the noise and interference detectors can give you an indication of the electromagnetic environment in which your unit is operating.
The figure below shows the DVLD Actions window in the Device/DVLD drop down menu.
The Parameters section allows the following parameters to be adjusted:
- Gain (receiver gain)
- Noise floor (squelch)
- Watchdog threshold (lightning detection level)
- Spike rejection (disturber muting)
- Minimum number of detections (counts required before lightning is detected)
The default values are shown in the screen shot. If the DVLD is installed indoors (not usually recommended) the Gain should be set to level 18-Sensor Indoor for higher gain. If outdoor, the Gain should be set to 14. The 4 other parameters shouldn’t need any adjustments.
The bottom Information section displays the Noise (1LD2), Disturber (1LD3) and Lightning (1LD4) Flags.
Once one (or more) of these 3 Flags becomes active, they must be manually reset by pressing the RESET button. This allows interference events to be latched for easier visualisation over longer periods. You can also have the Flags automatically reset by using a Virtual Logic Gate or Virtual Relay in your Davicom Cortex unit. Simply feed the 1LD3 Flag into a VLG and enter that VLG number into the Reset Trigger field on the right side of the screen.
If disturbers are repeatedly detected, then check for proper grounding of the Davicom Cortex and also for nearby sources of interference. A few disturbers occurring a few times a day is normal and will not cause any problems with proper lightning detection.
Faraway lightning can sometimes be detected as Disturbers because it doesn’t produce the exact signal signature expected from nearby lightning. If these Disturbers disappear after a certain time, they are probably caused by distant lightning pulses.
Best Practice Installation
The following photos show and example of a DVLD installation at a broadcast radio site in the state of Wisconsin, USA.
This device has been in operation since 2015 and is still reliably sending lightning data to this day.
Given the nearly infinite variation of locations, site configurations and electrical environments with potentially interfering devices, Davicom cannot guarantee that the DVLD will be able to detect lightning at any location and in every installation. Electrical interference can impede operation of the DVLD.
If you are experiencing lightning detection issues with your DVLD, please contact Davicom Support at dvsupport@davicom.com
