by Collyn Rivers
TV interference
TV interference from LEDs is an issue worldwide. It is mostly caused by LEDs in the same home (or RV) as the TV. This can be checked by turning them off. Another indicator of TV interference from LEDs is good daytime reception until lights are turned on. In the worst cases, TV reception is unwatchable, or not even obtainable.
TV interference from LEDs typically looks like this. It can also prevent a picture appearing.
TV interference from LEDs is electromagnetic ‘noise’ – known as Radio Frequency Interference (RFI). It is an unwanted by-product of some electrical devices. It has been a problem since the beginning of radio and TV. RFI has many sources. These include pollutants on power line insulators, electric fences, garage door openers etc. Most electrical stuff prone to generate RFI has protection to specifically reduce it. Or to shield its radiation. But not all have.
TV interference from LEDs – is from 2010 on
TV interference from LEDs escalated around 2010. Its cause was a global move to a cheaper way of powering low voltage dc LEDs from 110/230 volts. The new way includes switching the current on and off at very high frequency. In so doing, however, it generates high-energy electrical noise (RFI). Good quality LEDS have filters that limit RFI to a few metres. Ultra-cheap ones, however, have inadequate or no filters. As a result, TV interference from poor quality LEDs is a global problem.
Ongoing forum reports of LEDs ‘sucking up TV signals to drive the LEDs’ are fantasy. Nor can this form of RFI affect signal strength. It does however degrade sound and/or picture quality. In extreme cases it precludes reception altogether.
The TV interference from LEDs problem
Not all antenna installers are aware that poor quality LEDs can cause this problem. They may try to fix it by installing a new antenna. Doing this helps if the TV signal strength is too low. It cannot, however, assist if an already strong TV signal contains RFI.
They may also suggest adding an antenna signal booster. This can assist – but may boost RFI as well.
Where the TV signal is already strong, re-aligning the antenna to point away from the source of LED radiation assists.
Self-caused TV interference
To check whether RFI is self-caused, turn off everything electrical except the TV. Then, progressively turn things back on to see if any item causes it. If it does, check a few times. The first may just be a coincidence.
If (in RVs etc) 110-230 volt power is via an inverter, that unit is often the cause. Check by seeing if RFI ceases when the TV is connected to a 230-volt grid supply.
If RFI is only night-time related, cheap LEDs are most likely the cause. One brand sold by a major Australian hardware chain is (allegedly) notorious for this. High-quality LEDs are not cheap, but this is the only simple solution. It can also be done by replacing the tiny associated converter by its transformer-type equivalent. This fixes the issue, but costs more than a few really good LEDS!
It can also be done by adding cheap ferrite cores but needs amateur radio or similar experience.
In essence, apart from a possible antenna issue, there is no realistically affordable way of removing/reducing RFI noise from the signal received. That TV interfering RFI must be eliminated at the source.
TV interference caused by others
Matters become complicated if the cause is not yours. A neighbour causing it may welcome a fix as affects them too. But if that neighbour refuses to act, there’s little one can do (apart from offering to pay all costs yourself).
TV interference from LEDs – mostly from ultra-cheap ones
LEDs most likely to cause problems are ultra-cheap imports.
Also an issue is ‘specials’ sold by hardware stores and on eBay. The only solution is to replace them with good quality units from a reputable local supplier.
Techo talk
The RFI is typically 30 MHz – 300 MHz (and sometimes higher).
Those most commonly offending are the cheap 12 and 24 volt MR16 (also known as GU5.3). These run from 230 volts via a tiny inbuilt or associated switch-mode power supply. Some low price 230 volt GU10, E27 and B22 units are also a problem.
Apart from TV, the so-called RFI may affect 87.5-108.0 MHz FM radio, particularly 174 -230 MHz Digital Audio Broadcasting.
About our books
This article is by RV Books founder Collyn Rivers. Collyn’s books cover all aspects of RV usage – including solar. They are the Caravan & Motorhome Book, the Camper Trailer Book, and Caravan & Motorhome Electrics. Solar That Really Works (is for RVs). Solar Success (is for homes and properties). For information about the author please click on Bio.
