Many growers who use HID lights have had problems with Hon&Guan smart controllers that show the wrong temperature and humidity readings. This can be frustrating, because accurate readings are important for making sure plants grow in the right environment and make more money. A smart controller and the Hon&Guan Inline Duct Fan that it connects with are both affected by these false reading.
What Does Radio Frequency Interference (RFI) Mean?
RFI is the transmission or conduction of radio frequency energy that causes noise to be made by an electronic or electrical device. This noise usually interferes with the operation of another device near it. Radio astronomy can also cause a satellite to not work properly. Radio frequency interference can make electronic and electrical devices not work as well as they should, so it is important to keep it to a minimum when possible.
Radio frequency interference comes from many types of electronic and electrical devices, such as switching power relays, industrial controls, medical instruments, electronic printers, personal computers, game consoles, and other devices that use electricity. This is one of two ways an electronic or electrical device can make radio frequency interference: by emitting radio frequency interference or by making it happen. In the case of the first, the interference comes from the device itself. In the case of the second, the interference is released into an AC power line through the power cord of a component or device. In the case of satellite communications, radio frequency interference can happen naturally and also be done on purpose, Different types of space weather, like solar storms, can cause natural radio frequency interference. Man-made interference, on the other hand, is called intentional radio frequency interference.
Proper shielding in the case of a device helps to keep radio frequency interference from being radiated. It can help to keep the level of radio frequency interference that is transmitted through the power lines to a satisfactory and acceptable level. Highly directional antennas and strong filtering at the ends of radio waves can help solve interference in satellite communications. Changing the source of broadband interference can help cut down on the amount of noise that is coming from the source.
Safety agencies and many government bodies have set rules about how much radio frequency interference and noise can be released. As for radio frequency communication, they also have rules and norms in place.
RFI detection and mitigation methods in microwave radiometry include the following ones:
- Power peaks with more than a certain amount of variance are "blanked out" by time-domain techniques. However, the detected power is an average of the instantaneous power, so RFI peaks that last less than the integration time may not be detected.
- Frequency-domain techniques don't use sub bands with more power than a certain amount of the expected variance. Similar to the time-domain techniques, the detected power is an average over a certain range. This means that RFI power peaks that are smaller than the resolution range are "blurred" and may go unnoticed.
- If there are still some signal samples, sub bands, or bins of time and frequency that can be used, the signal power is estimated from the rest of them, which are properly scaled.
Based on the fact that the RFI-free radiometric signal should be a zero-mean random Gaussian variable, statistical methods are used to figure out how to do this.If the normality test isn't passed, the whole sequence is thrown out and you can start over again. It's called the Kurtosis method in the field of remote sensing because it's the ratio of the fourth moment and the square of the second moment. There is time- and frequency-domain versions of this test, too.
In these two cases, all data are lost when RFI is detected.
Explanation & Prevention of RFI
Finally, wavelet techniques can also be used to figure out the RFI signal without having any idea of what it is and then cancel it. In this case, there is no loss of signal, but there may still be a small amount of RFI. Because of the ratio of sampling frequency to signal bandwidth, interference-to-noise ratio (INR), wavelet family, and level of decomposition, it does well or not so well.
Interference isn't hard to find, but it's hard to avoid, especially in cities where the wireless revolution is well under way. By definition, interference comes from a source outside of a signal path and makes the signal look bad. A radio frequency, or RF, can be thought of as being in the part of the electromagnetic spectrum above audio (about 20 kHz) but below infrared (about 700 nm). Electromagnetic interference (EMI) is a more general term that means the same thing but doesn't have any frequency restrictions.
These types of interfaces use single-conductor shielded cable and two-contact connectors. The sad thing is that most commercial equipment hasn't been tested for RF interference, whether it comes through the air or is connected to its inputs, outputs, or other outside world ports, like its power cord. Even if the equipment is well-designed, it will break down if it is exposed to a lot of RF interference.
Two ways to control RFI:
There are two main ways to control RFI. Filters or arc snubbers can be used at the source to stop it from connecting in the first place. Equipment can be moved or cables can be rerouted, and shielding or ferrite chokes can be added to the cables. It does this when possible after the RF is connected but before it reaches a sensitive part of the equipment. There are a lot of things you can do to avoid or fix most RFI problems.
Find and treat the source of the problem. This mostly applies to sources that were not meant to be power line-related. A portable AM radio that is tuned to a quiet frequency can be used as a "sniffer," for example, to find an offending fluorescent light or dimmer, Then, the offender can be changed, repaired, or a power-line RF filter can be put in.
Keep wires as short as possible, and pay attention to where they go. A long cable not only improves power line common-impedance coupling (for unbalanced cables), but it also makes the cable a better antenna because it has more surface area. When you run cables near metal racks or concrete floors, they won't have as much of an effect on antennas. Keep extra cable length out of the way.
Keep the probe's cord away from your ballast and its other cords so it doesn't get in the way. This can be done by organizing the cables in your Hon&Guan 600D Mylar Grow Tent and routing them through different ducts. The cord can also be wrapped around the sensor head and made into a cone with aluminum foil tape. These conduits will protect the probe from the electromagnetic field that comes from the ballast cords and make sure that the readings are correct.
No, don't plug your grow light and an Hon&Guan Inline Duct Fan in at the same time. This will also cause radio-frequency interference because it affects electricity both up and down the line. In this case, if they use the same outlets or power strip, the sensor probe will be able to pick up on RFI if they do.
They should have shields made of a heavy gauge. Coupling between cables with copper braided shields and those with foil and drain wire shields is much higher. This means that noise from power lines is more likely to travel through the cables. The more shields you have, the less good they are unless they are connected at both ends.
Maintain strong connections. Connectors that aren't moved for a long time can have high contact resistance or become metal oxide detectors for RF. Humor and other interference that changes when the connector is wiggled means that there isn't a good connection. Use good commercial contact fluid and/or gold-plated connectors to make things work.
Do not add too many grounds. It will most likely make the circulating ground noise worse, not better. Most of the time, using thick ground wires to try to short out RFI isn't going to work. When you use RF, the impedance of a wire is related to its length, but almost not at all to its gauge. Of course, you should never cut off a safety ground or lightning protection ground to solve a problem. It is both illegal and dangerous to do this.
Add RFI filters to the signal path. If the RF interference is more than about 20 MHz, ferrite clamshells, which can be put on the outside of a cable, can help. There are usually better places for them to be on the cable. They usually work best when they are near the end that you are going to get the signal from. When it comes to the shape of C, it should be a ceramic disc that has short leads. For very bad AM radio interference, C can be increased to about 1,000 pF at the most.
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