Overcoming the Radio Broadcast Jamming Facilities Bought and Installed by the Chinese Authorities at Huge Expense


The French president and his accompanying trade delegation visited Beijing on the 9th of October and the 10th of October. One of the deals made at the time was by the Thales Company, which sold China antenna facilities used to jam foreign radio broadcasts, cutting them off from the people of China. This action further limits the rights of Chinese people to freely access information from outside China.

The Thales Company refused to divulge details of the transaction, but if we use the international market price of around 10,000 US dollars per kilowatt to make an estimation, we will find these 19,500-kilowatt facilities cost at least 100 million US dollars. Adding in the cost of electrical power generation, land, technicians and guards, the Chinese authorities must have spent a total in the billions of yuan (1 USD is a little more than 8 yuan) on these facilities. Sadly, the facilities bring no benefit to the people who actually paid for them.

To use taxpayers' money to deprive them of their right to information is characteristic of what China's ruling group has always done, going against their directive "to represent the interests of the people."

In the past, the Chinese Communist Party (CCP) regime consistently adopted the hard-line policy of jamming foreign radio stations such as BBC, VOA, RFA, CBS, etc. VOA, situated in the Philippines and very familiar to Chinese people, is the CCP's biggest headache. In recent years, other radio stations such as Voice of China, Falun Dafa Radio Station and Voice of Tibet in Norway have also appeared on CCP' s blacklist.

In the early days, they jammed the foreign radio stations by broadcasting noise or the programs of their Central Radio Station of the People on the same frequencies. Later they added Chinese drum music to the jamming signals. In recent months they even broadcast Waltz music to jam the foreign broadcasts.

It was reported that the CCP regime has installed a high-power antenna in Kashi, Xinjiang Province, and also installed similar facilities in more than 10 other areas including Hainan, Nanjing, Urumqi and Kunming. These facilities include 500-kilowatt transmitters (type TSW2500) and ALLISS huge 360-degree-rotational tower antennas to transmit short wave frequencies. They use "sky wave" jamming technology to eliminate the foreign media's possible influence on Chinese people.

Why would they install these facilities along the border and use 360-degree-rotational broadcast towers to transmit "sky waves"?

First let's look at a case scenario - for instance if ground waves are used as a jamming source. Here we take Thales TSW2500 (500 kilowatts) transmitter for an example. Suppose a ¼ wavelength vertical antenna is used and the sensitivity of the radio is 50 μV.

The following is a table of the data for ground waves:

Frequency Wavelength Sensitivity Ground Wave Distance

3MHz 100m 50 μV 580 km
6MHz 50m 50 μV 400km
15MHz 20m 50 μV 220km
30MHz 10m 50 μV 157km

From this table it can be seen that the above-mentioned nineteen sets of facilities are insufficient to cover the entire Chinese mainland if ground waves are used. During the Cold War, the former Soviet Union used ground waves as a jamming source, and they had to build 2,500 jamming stations.

Therefore Jiang Zemin's clique and the party decided to transmit "sky wave" jamming signals into the ionosphere to block foreign radio stations, because they are more effective and flexible than ground wave jamming signals. Using more powerful transmitters has made the jamming effect even better.

However, everything has both advantages and disadvantages. Jiang's group overdid things in this matter too. Why? It is because their 500-kilowatt sky wave jamming systems can do nothing to deal with the cheap, flexible small-power ground wave radio stations and the visible range radio stations, which can be built anywhere.

Take the example of the Nanjing jamming station. The average antenna gain in short wave range is 5 decibels. It is able to jam the radio broadcasts at short wave lengths of 31m and 49m from Beijing effectively. However, such a jamming station has its own disadvantages as follows:

1. The sky wave it transmits needs to be reflected by the F layer of the ionosphere and, therefore, its actual jamming effect is limited by the state of the ionosphere.
2. It can jam a few radio stations, but is unable to jam a lot of small-powered ground wave radio stations or visible range radio stations that can be set up everywhere and broadcast at various frequencies.
3. For high frequency signals (especially from 16-19m), the ionosphere has a time window, i.e. its reflective effect is weak during day.
4. For short distances a visible range transmitter with power as small as 5 watts can beat a high-powered jamming station thousands of miles away.

Any dictator is afraid of having his crimes and lies exposed to the public. Jiang's group often cited international broadcast laws to attack Falun Gong practitioners and other righteous people's activities to broadcast the truth by tapping into cable TV signals. Media such as TV and radio broadcasts should belong to the people, and should certainly not be used as a dictators' private property. In democratic countries, the media observe the law and play their proper roles in society. In China, however, the dictator controls all the media, using them to support his private agenda, while the cost of it all is paid by the people. Instead of reflecting the needs and sufferings of the people, the media in China are actually tools of the rulers used to cover up their crimes and to cheat the people.

Under such a circumstance, Falun Gong practitioners and other righteous people in China continuously broadcast the truth about Falun Gong by tapping into cable TV signals to expose the lies and the crimes of the dictatorial regime. These kinds of actions defend freedom of speech and freedom of access to information for the people. History will remember their brave deeds.

Recently http://www.gbxtd.org (a Chinese language website) introduced a type of dual-function transmitter, which uses both medium and short waves. In addition, they introduced other techniques such as:

1. Power cord techniques to extend the equivalent length of antenna and to improve security.
2. Refitting of household audio facilities into medium and short wave transmitters.
3. 500-100 watt powered amplifiers.
4. Relay broadcasts across borders between countries.

We should particularly mention medium wave. Medium wave has its unique characteristics. First of all, there is no difficulty in obtaining the instruments. Many types of MOS diode used for power switches can be perfectly suited to high-powered medium wave transmitting circuits. Secondly, unlike the circuits that need high frequency techniques, the medium wave circuit is not very hard for inexperienced people. Thirdly, after adopting the power cord technique to extend the equivalent antenna length and improve its security, there will be no difficulty in making an antenna and increasing its effective isotropic radiated power (EIRP).

If we have a transmitter of 5 watts, the gain of the equivalent ¼ wavelength vertical antenna (150m, 75m, 50m) of which is 0 decibels, and supposing the sensitivity of a radio receiver is 1mV, there is the following data available:

Frequency Wavelength Sensitivity Range at Sea Range on Land

500KHz 600m 1mV 13km 2.6km
1000KHz 300m 1mV 11.5km 1.1km
1500KHz 200m 1mV 10.6km 720m

This kind of radio transmitter is very convenient in the countryside and residential areas in the city. It is absolutely impossible to jam all these small sized transmitting sets with the Thales TSW2500 short wave system they imported at huge expense.

You are welcome to print and circulate all articles published on Clearharmony and their content, but please quote the source.