Agreement signed to end noise interference in air traffic communications by community radios

[webfact]

Transport signs agreement with NBTC to end noise interference in air traffic communications by community radios



BANGKOK: -- The Transport Ministry today entered an agreement with the National Broadcasting and Telecommunications Commission (NBTC) to resolve interference of aeronautical radio system by community radios that could threaten air travel safety.

Signing the memorandum of understanding to end the harmful radio interference by community radio stations using substandard radio equipments and antennae are Transport Minster ACM Prajin Hunting, and NBTC chairman ACM Thares Punnasri.

The agreement followed complaints from pilots and air traffic controllers that their radio communication were interfered by noises from community radio stations that sometimes caused them to have difficulties in hearing instructions for landings.

Under the agreement, NBTC secretary-general Takorn Tanthasith said the NBTC will work closely with the Royal Thai Police and the Nautical Radio of Thailand to check substandard radio antennae of community radios and in near future install a radio monitoring system that will work around the clock.

He said there are about 3,000 community radio stations under the supervision of the NBTC and most of them have substandard transmission antennae and some have higher antennae of over 30 metre, thus interfering with air traffic communication frequencies.

The agreement today will resolve the radio interference on a sustainable basis and ensure air travel safety.

Source: http://englishnews.thaipbs.or.th/transport-signs-agreement-with-nbtc-to-end-noise-interference-in-air-traffic-communications-by-community-radios


-- Thai PBS 2015-07-06

[rheinwiese]

guess ICAO will be listening

[aircut]

He said there are about 3,000 community radio stations under the supervision of the NBTC and most of them have substandard transmission antennae and some have higher antennae of over 30 metre, thus interfering with air traffic communication frequencies.

50 meter antenna with the politically correct content will not be an issue.

i don't remember a case of crashing airplanes due to news reports on 1.44FM anywhere in the world

they are trying to pass their censorship on scientific wave frequencies

[Barin]

The ATC frequency is around 120 MHz while the FM band is 88-108 MHz.

http://www.radioreference.com/apps/db/?aid=2866

The output power of some FM broadcasting stations may be over 100 kW.

There is always a risk of spurious emissions from the poorly aligned FM broadcast transmitters.

The antenna matching circuit must be carefully adjusted and the low-pass filter too.

In certain cases an additional Low Pass Filter (LPF) is required between the antenna and the transmitter's output.

[Muhendis]

If your radio aerial is not carefully matched to the transmitter then you will be transmitting an unacceptable level of spurious harmonics which will interfere with other stations in the vicinity. Mismatch examples can include the wrong size aerial or the wrong/poor quality downlead connection between the transmitter and the aerial. There are plenty of other things that could cause interference by using substandard transmission equipment. Most of the rest of the world has very strict and well policed regulations covering this type of problem. I guess Thailand is a bit slow to catch up.

[Manbing]

This is a ridiculous situation which should have been sorted out years ago.

I recall an incident where an international flight was experiencing difficulties crossing Khon Kaen and was cut off from the Area ATC for 15 minutes, listening to the sultry sounds of Pirate Red Shirt FM (made up name).

Had it crashed there would have been more than a few orange faces around Thailand.

[Pimay1]

If these radio stations are using the cheap Chinese FM transmitters and some of them probably are, spurious emission and harmonics are almost the norm as they are not built to high quality standards. The low pass filters in them are notorious for not meeting industry standards.

[halloween]

This is a ridiculous situation which should have been sorted out years ago.

I recall an incident where an international flight was experiencing difficulties crossing Khon Kaen and was cut off from the Area ATC for 15 minutes, listening to the sultry sounds of Pirate Red Shirt FM (made up name).

Had it crashed there would have been more than a few orange faces around Thailand.

Now you've done it! We will soon have posters pointing out this is a suppression of free speech with political bias against the red shirt majority.

[Muhendis]

If these radio stations are using the cheap Chinese FM transmitters and some of them probably are, spurious emission and harmonics are almost the norm as they are not built to high quality standards. The low pass filters in them are notorious for not meeting industry standards.

I expect they have to be changed every few months. QA is not at the top of the list of priorities in Chinese electronics.

[halloween]

If these radio stations are using the cheap Chinese FM transmitters and some of them probably are, spurious emission and harmonics are almost the norm as they are not built to high quality standards. The low pass filters in them are notorious for not meeting industry standards.

I expect they have to be changed every few months. QA is not at the top of the list of priorities in Chinese electronics.

Is this because of the crap being passed through them? Can't they be backwashed?

[NCC1701A]

when you key the mic on these cheap Chinese radios, (non FCC approved) they create spurious emissions up and down the band. very type of cheap radio transmitter has this problem. police, taxi, gov, business. that is why crap from China is crap and only costs one third what it should. This is a serious problem for Thailand.

and leaking unshielded cables for cable TV signals operate across a very wide section of RF, including both aircraft bands.

ever see any cables just hanging around on poles in Thailand?

[than]

The ATC frequency is around 120 MHz while the FM band is 88-108 MHz.

But ILS and VOR frequency begin at 108 Mhz

If a radio antenna is near an air navigation aid and his frequency is proxy to him he can interfere and jam signal

Word document from ICAO

https://www.google.fr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCQQFjAA&url=http%3A%2F%2Fwww.icao.int%2Fsafety%2Facp%2FACPWGF%2FACP-WG-F-19%2FACP-WGF19-WP06_FM%2520Broadcast%2520Interference%2520into%2520VM4rev.doc&ei=x-aaVYPlHMWqsgGV0JroCw&usg=AFQjCNHrwyw_Dqb9NY2KeqV7Rs6YWNW1gg

[Muhendis]

The ATC frequency is around 120 MHz while the FM band is 88-108 MHz.

But ILS and VOR frequency begin at 108 Mhz

If a radio antenna is near an air navigation aid and his frequency is proxy to him he can interfere and jam signal

Word document from ICAO

https://www.google.fr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCQQFjAA&url=http%3A%2F%2Fwww.icao.int%2Fsafety%2Facp%2FACPWGF%2FACP-WG-F-19%2FACP-WGF19-WP06_FM%2520Broadcast%2520Interference%2520into%2520VM4rev.doc&ei=x-aaVYPlHMWqsgGV0JroCw&usg=AFQjCNHrwyw_Dqb9NY2KeqV7Rs6YWNW1gg

Reading the ICAO document reveals that there should be an unused 4MHz guard band between the highest commercial frequency (108 MHz) and the lowest aeronautical frequency (112MHz). Reading that, the thought occurred to me that this guard band may not be implemented which would make the airport/aviation authority at fault as well as the commercial broadcaster.

[ballpoint]

This is a ridiculous situation which should have been sorted out years ago.

I recall an incident where an international flight was experiencing difficulties crossing Khon Kaen and was cut off from the Area ATC for 15 minutes, listening to the sultry sounds of Pirate Red Shirt FM (made up name).

Had it crashed there would have been more than a few orange faces around Thailand.

Now you've done it! We will soon have posters pointing out this is a suppression of free speech with political bias against the red shirt majority.

Too late. Check out post #3. Quite appropriate really given the OP. Political noise spilling over into other threads.