JP4376071B2 - Radiation wave measurement method, radiation wave measurement device, and power line carrier communication device - Google Patents

Description

  The present invention relates to a radiated radio wave measuring method, a radiated radio wave measuring device, and a power line carrier communication device, and more specifically, a radiated radio wave measuring method, a radiated radio wave measuring device, and a radio wave measuring device that measure unnecessary radio waves radiated from a power line during power line carrier communication. The present invention relates to a power line carrier communication device having a radiation wave measurement function.

  In recent years, practical studies of power line communication (PLC) for performing communication using a power line such as a household outlet have been actively conducted.

  The power line carrier communication is characterized in that since an existing power line is used as a network transmission path in each home, a home communication network can be constructed immediately, and the capital investment for a wireless LAN or the like is small.

  On the other hand, power line carrier communication has a problem that leakage power from the power line is large because signals are transmitted and received using a power line with poor balance as a communication medium. For this reason, until now, the usable frequency band has been limited to a low frequency band of 10 kHz to 450 kHz under the regulations of the Radio Law. Therefore, since the transmission speed is as low as about 9.6 kbps, it has not been used much for actual communication.

  However, if the use in the short wave band of 2 to 30 MHz is approved, the transmission speed is as high as several tens of Mbps, and can be utilized as a broadband. For this reason, recently, there are increasing demands from electric power companies, home appliance manufacturers, and the like for the use of shortwave bands due to deregulation in Japan and overseas (for example, see Non-Patent Document 1).

  On the other hand, the short-wave band corresponds to the frequency used for maritime radio, police radio, land radio, amateur radio, etc., weather observation, medical equipment, etc. Interference is a concern. Therefore, when introducing power line carrier communication into the shortwave band, it is essential to accurately grasp the degree of influence on these wireless communications and to reduce them.

  FIG. 6 is a schematic configuration diagram for explaining a conventional power line carrier communication apparatus.

  Referring to FIG. 6, a high-voltage distribution line and a low-voltage distribution line 1 (not shown) are laid on the utility pole 2. The high-voltage distribution line is connected to the primary (high-voltage) side of a power transformer (not shown) that is mounted, and the low-voltage distribution line 1 is connected to the secondary (low-voltage) side of the power transformer. The low voltage distribution line 1 is further connected to the lead-in wire 3 in the utility pole 2. The lead-in wire 3 is drawn into the electric power consumer 5 and is connected to the electric light / power line 7 laid indoors in the watt-hour meter 6. The low-voltage distribution line 1, the lead-in line 3, and the electric light / power line 7 constitute a communication medium of the power line carrier communication device.

  The power line communication modem 4 is usually mounted on a power pole 2 together with a power transformer (not shown), connected to a communication line such as a telephone line or an optical fiber connected to the Internet, and connected to the low voltage distribution line 1. Is done.

  The power line communication modem 9 is connected to the light / power line 7 through the outlet 8 and is connected to a terminal device 10 such as a personal computer used in the power consumer 5.

  In the power line carrier communication apparatus having the above configuration, communication is performed by superimposing a high-frequency signal on a communication medium. The power consumer 5 can easily access the Internet by connecting the power line communication modem 9 to the existing outlet 8.

  As shown in FIG. 6, the power line carrier signal propagates through the lead-in wire 3 wired in the air and is drawn into the power consumer 5 indoors. As described above, when the frequency band of the power line carrier signal reaches a short wave band of 2 MHz or more, the lead-in wire 3 serves as an antenna and leaks strong radio waves. This radiated unnecessary radio wave (hereinafter also referred to as “unnecessary radiated radio wave”) affects existing wireless communication propagating in the air, such as radio wave interference.

  Here, since a wide variety of electric devices are connected to the power line (the lead-in line 3 and the light / power line 7) serving as a communication medium for power line carrier communication, the impedance of the power line that affects communication performance, the noise on the power line, The amount of signal attenuation during transmission varies depending on the wiring state of the lamps and power lines in each home, and also varies depending on the electrical equipment connected to the power lines. Further, since the antenna effect of the power line also varies, the radio wave intensity of unnecessary radiated radio waves generated from the power line also varies greatly from one power line to another.

  Therefore, measurement of unwanted radiated radio waves is not sufficient with field strength measurement using a test site like ordinary radio antennas and radio equipment, and a test signal is transmitted using a power line communication modem placed in the actual facility. Therefore, it is necessary to actually generate unnecessary radiated radio waves and measure them with a field strength meter installed at a predetermined distance from the power line.

As shown in FIG. 6, for measuring unnecessary radiated radio waves, a field strength meter 12 is installed at a predetermined distance from the lead-in wire 3 to detect the field strength of the signal received by the measurement antenna 11 when transmitting the test signal. Can be obtained. Similarly, if the electric field strength meter 14 is installed at a predetermined distance from the lamp / power line 7 and the electric field strength of the signal received by the measurement antenna 13 is detected when the test signal is transmitted, It is possible to know the electric field strength of irregularly radiated radio waves generated indoors.
“Recruitment of opinions on partial amendments to the Radio Law Enforcement Regulations, etc. -Introduction of an experimental system for high-speed power line carrier communication facilities-”, Ministry of Internal Affairs and Communications, August 29, 2003.

  However, the measurement method of the unnecessary radiated radio wave described in FIG. 6 is substantially restricted by the radio wave method and is not feasible. This is because the current radio law does not permit the transmission of high-frequency test radio waves by connecting a power line communication modem to the power line. This is because, as described above, there is a concern that the transmission of test radio waves may adversely affect other wireless communications such as radio wave interference.

  Therefore, at present, there is not even an effective means for measuring unwanted radiated radio waves, which is one factor that slows down the practical use of power line carrier communication.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a radiated radio wave measuring method and a radiated radio wave measuring device for measuring radio waves radiated from a power line without causing interference with other wireless devices, and a power line carrier communication having a radiated radio wave measuring function. Providing a device.

  According to an aspect of the present invention, in a power line carrier communication in which a power line carrier signal is superimposed on a power line from a power line communication modem, a radiation radio wave measuring method for measuring a radio wave radiated from the power line is provided. A test signal having the same frequency as the power line carrier signal is generated from a signal generator arranged at a distance, and a test signal is multiplied by a known gain from an antenna of known gain coupled to the signal generator. A step of outputting a transmission power of a predetermined power level, a step of measuring the reception power when the transmission power is received by a receiver disposed at a place where the power line communication modem is installed, and the transmission power and the reception power. Multiplying the calculated wireless gain by the estimated value of the transmission power output from the power line communication modem, and calculating the wireless gain as a ratio. Comprising a step of calculating a predicted value of the received power at the antenna for value, based on the predicted value of the reception power, and calculating the field strength at the position at a predetermined distance from the power line.

  Preferably, the method further includes the step of setting the predetermined distance and the predetermined power level in accordance with test conditions defined by the Radio Law.

  Preferably, the method further includes the step of sequentially arranging the signal generator and the antenna at a plurality of positions at a predetermined distance from the power line.

  According to another aspect of the present invention, in a power line carrier communication in which a power line carrier signal is superimposed on a power line from a power line communication modem, a radiated radio wave measuring device that measures a radio wave radiated from the power line, the power line communication signal is predetermined from the power line. A signal generator for generating a test signal of the same frequency as the power line carrier signal, an antenna coupled to the signal generator for radiating the test signal with a known gain, and a power line communication modem And a receiver disposed at the installation location. The signal generator transmits the generated test signal as transmission power of a predetermined power level via the antenna. The receiver measures the reception power when the transmission power is received. The radiated radio wave measuring apparatus multiplies the means for calculating the radio gain, which is the ratio between the transmission power and the reception power, and the calculated radio gain multiplied by the planned value of the transmission power output from the power line communication modem. Means for calculating a predicted value of the received power at the antenna with respect to the scheduled value, and means for calculating the electric field strength at a position separated from the power line by a predetermined distance based on the predicted value of the received power.

  Preferably, the radiated radio wave measuring apparatus further includes means for setting a predetermined distance and a predetermined power level in accordance with test conditions specified by the Radio Law.

  Preferably, the signal generator and the antenna are respectively arranged at a plurality of positions separated from the power line by a predetermined distance.

  According to another aspect of the present invention, a power line carrier communication device is installed in a power consumer and propagates by superimposing a power line carrier signal on power, and a power line communication installed in the power line and transmitting / receiving a power line carrier signal A modem, a signal generator arranged at a predetermined distance from the power line and generating a test signal of the same frequency as the power line carrier signal, and an antenna coupled to the signal generator and radiating by multiplying the test signal by a known gain And a receiver disposed at a place where the power line communication modem is installed. The signal generator transmits the generated test signal as transmission power of a predetermined power level via the antenna. The receiver measures the reception power when the transmission power is received. The power line carrier communication device multiplies the means for calculating the radio gain, which is the ratio of the transmission power and the reception power, by the calculated radio gain and the planned value of the transmission power output from the power line communication modem, Means for calculating a predicted value of the received power at the antenna with respect to the scheduled value, and means for calculating the electric field strength at a position separated from the power line by a predetermined distance based on the predicted value of the received power.

  Preferably, the apparatus further includes means for setting the predetermined distance and the predetermined power level in accordance with test conditions defined by the Radio Law.

  Preferably, the signal generator and the antenna are respectively arranged at a plurality of positions separated from the power line by a predetermined distance.

  As described above, according to the present invention, it is possible to easily measure unnecessary radiated radio waves in power line carrier communication without conflicting with laws and regulations.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

  FIG. 1 is an overall configuration diagram of a power line carrier communication device for explaining a method of measuring a radiated radio wave according to an embodiment of the present invention. In this figure, since the site | part which comprises the communication medium of power line carrier communication is the same as that of what was demonstrated in FIG. 6, detailed description is not repeated.

  Referring to FIG. 1, the power line carrier communication apparatus is a measurement generator 11 having a known gain Gs and a signal generator 22 arranged at a predetermined distance d2 from the lead-in wire 3 as means for measuring unwanted radiated radio waves. And a signal generator 23 disposed at a predetermined distance d2 from the lamp / power line 7 and a measurement antenna 13 having a known gain Gs.

  The power line carrier communication device further includes receivers 20 and 21 installed in the power pole 2 and the outlet 8 of the power consumer 5, respectively.

  The signal generators 22 and 23 generate signals in a frequency band in which power line carrier communication is actually performed (for example, 2 to 30 MHz) in measurement of unnecessary radiated radio waves. The measurement antennas 11 and 13 output transmission power Ws obtained by multiplying a signal generated by a corresponding signal generator and a known gain Gs.

  The signal generator 22 is integrated with the measurement antenna 11, and is installed at a place where the electric field strength meter 12 should be originally installed in FIG. 6, that is, at a position separated by a predetermined distance d 2 from the lead-in wire 3. In FIG. 1, the signal generator 22 and the measurement antenna 11 constitute a transmission side. The predetermined distance d2 is set based on test conditions defined in the Radio Law and enforcement regulations.

  Similarly, the signal generator 23 is integrated with the measurement antenna 13 and is installed at a predetermined installation location of the electric field strength meter 14 shown in FIG. 6, that is, at a position away from the lamp / power line 7 by a predetermined distance d2.

  On the other hand, the receiver 20 that constitutes the receiving side is installed in a place where the power line communication modem 4 is to be installed in FIG. 6, that is, in the utility pole 2 that is a coupling portion between the low-voltage distribution line 1 and the lead-in line 3.

  Similarly, the receiver 21 is installed in an outlet 8 which is an installation place of the power line communication modem 9 in FIG. The In terms of an equivalent circuit, the receivers 20 and 21 include a termination impedance corresponding to the output impedance of the corresponding power line communication modem and a coupling capacitor having an appropriate capacity. The power received from the antenna can be measured by being connected to the lead-in wire 3 and the lamp / power line 7 that function as an antenna at high frequencies.

  Next, a method for measuring unnecessary radiated radio waves executed in the configuration shown in FIG. 1 will be described. In summary, the measurement of the radiated radio wave according to the present embodiment radiates from the power line when it is assumed that power line carrier communication is actually performed using the reversibility of the radio gain established between transmission and reception. It is intended to predict the electric field strength of radio waves that can be transmitted.

  Hereinafter, a method for measuring a radiated radio wave will be described by way of an example in which a radio wave radiated from the lead-in wire 3 is measured. In addition, according to this measuring method, it can each measure also about the radiated radio wave from the electric light / power line 7 and the low voltage distribution line 1.

  First, as a measurement preparation stage, the transmission power Ws radiated from the signal generator 22 via the measurement antenna 11 is adjusted. This is an operation to be performed to ensure that the measurement method executed in the subsequent actual equipment does not violate the Radio Law.

  FIG. 2 is a circuit diagram for explaining the adjustment of the transmission power Ws of the signal generator 22 and the measurement antenna 11.

  Referring to FIG. 2, a receiver 25 and a receiving antenna 24 are installed on the signal generator 22 and the measurement antenna 11 on the transmission side, and on the reception side at a predetermined distance d1 from the transmission side.

  In this configuration, the electric field strength Es at the distance d1 is within the allowable range of the test conditions stipulated in the Radio Law in the state where the measurement antenna 11 is connected to the signal generator 22 in order to prevent the influence on the surrounding wireless communication. The transmission power Ws is adjusted so that Specifically, the Radio Law Enforcement Regulations Article 6.1.1 No. 1 stipulates that, as a test condition, the electric field strength at a distance d1 = 3 m from the transmission side is 500 μV / m or less at a frequency of 332 MHz or less. The Accordingly, in the configuration of FIG. 2, the transmission power Ws is adjusted so that the distance d1 between transmission and reception is 3 m and the electric field strength Es is 500 μV / m or less.

  When the transmission power Ws is determined in FIG. 2, next, the signal generator 22 and the measurement antenna 11 are arranged at a position separated from the lead-in line 3 by a predetermined distance d2. This place corresponds to a place where the field strength meter 12 is planned to be installed in order to measure the radiated radio wave in the power line carrier communication system of FIG. The predetermined distance d2 is a value that complies with test conditions determined by future deregulation. Further, when investigating a failure in a specific wireless facility, it is necessary to install the measurement antenna 11 at the position of the wireless facility. Therefore, in this case, the predetermined distance d2 is the shortest distance from the service line 3 to the radio equipment.

  As shown in FIG. 1, the signal generator 22 outputs a test radio wave having a transmission power Ws via the measurement antenna 11 at this installation location.

  On the other hand, in the receiver 20 installed on the utility pole 2, the reception power Wr obtained in response to the transmission power Ws is measured using the lead-in wire 3 as a reception antenna. At this time, the signal generator 22 on the transmission side and the receiver 20 on the reception side are represented by the circuit diagram shown in FIG. As is clear from FIG. 3, when the transmission power Ws of the signal generator 22 is output via the measurement antenna 11 having a known gain Gs, the transmission power Ws is received by the lead-in wire 3 functioning as a reception antenna and is sent to the lead-in wire 3. In the connected receiver 20, the received power Wr is detected.

  When detecting the received power Wr, the installation location and angle of the measurement antenna 11 are adjusted so that the received power Wr is maximized. This is effective in minimizing measurement variations caused by a reduction in received power due to mismatch between the polarization plane of the transmission antenna and the polarization plane of the reception antenna. Furthermore, measurement errors caused by changes in received power due to so-called fading, in which radio waves that directly reach the receiving antenna from the transmitting antenna and radio waves that hit the obstacles such as the earth and buildings and interfere with the receiving antenna interfere with each other. It is also effective for reduction.

Here, in the relationship between the transmission power Ws and the reception power Wr in FIG. 3, the ratio (A ₀ : free space gain) between the reception maximum power Wa given to the load of the receiver 20 and the transmission power Ws is as follows: become.

Here, Wa represents the maximum received power, Ws represents the transmission power, λ represents the wavelength, and d represents the distance between the transmission and reception points.

  Since the above equation is a relationship when two antennas are placed in an ideal free space, it is actually necessary to consider propagation loss due to reflection by the ground, diffraction, refraction by the atmosphere, and the like. Therefore, the received power Wr that can be actually extracted is

It becomes. This coefficient Ap is called a path gain coefficient.

From the above, the radio gain A, which is the ratio of the actual received power Wr to the transmitted power Ws, is given by A = A ₀ · Ap obtained by multiplying the free space gain A ₀ and the path gain coefficient Ap. In the present embodiment, the wireless gain A is not only the antenna gain of the lead-in wire 3 and the free space propagation loss of the radiated electric field, but also the influence of reflection from the surrounding environment and the induction in the near field (2πd / λ <1). Including the influence of electromagnetic field and quasi-electrostatic field, it is a unique value determined by the configuration and arrangement of the lead-in wire and measurement antenna.

  Here, it is known that reversibility is established in the gain and directivity between the characteristics when a certain antenna is used as a transmitting antenna and the characteristics when used as a receiving antenna (for example, Edited by the Institute of Electronics and Communication Engineers, "Antenna Engineering Handbook 1980 Edition", Ohmsha, pages 31-34). This reversibility is established except in the case where a ferromagnetic material having nonlinear permeability or a medium having an asymmetric dielectric constant exists in the space.

In view of this reversibility in the circuit diagram shown in FIG. 3, the free space gain A ₀ and the path gain coefficient Ap obtained when the antenna 11 for measuring the gain Gs is the transmitting antenna and the lead-in line 3 is the receiving antenna, 4, it can be considered that the free space gain A ₀ and the path gain coefficient Ap obtained when the lead-in wire 3 is a transmission antenna and the measurement antenna 11 is a reception antenna are equivalent to each other. From the above, even in the radio gain A obtained by multiplying the path gain factor Ap and the free space gain A _0, it is clear that reversible holds.

  Therefore, in the present embodiment, by using the reversibility of the radio gain A, the transmission / reception relationship in FIG. 3 is switched to output a certain transmission power from the power line communication modem 4 arranged at the position of the receiver 20. Sometimes, the power radiated from the lead-in wire 3 to the measurement antenna 11 is predicted. The prediction method shown below realizes the measurement of the radiated radio wave shown in FIG. 6, which is not permitted in the radio law, in calculation.

  FIG. 4 is a circuit diagram for explaining a method for predicting a radiated radio wave.

  Referring to FIG. 4, it is assumed that the power line communication modem 4 is installed at the place where the receiver 20 is installed in FIG. 3 (corresponding to the utility pole 2) and the transmission power Wt is output on the transmission side.

  On the other hand, on the receiving side, a field strength meter 12 is installed at a place where the signal generator 22 is installed in FIG. 3 (corresponding to a place separated from the lead-in wire 3 by a distance d2), and the gain Gs is measured via the antenna 11 for measurement. Assume that you receive radio waves.

  Since the wireless gain A in the transmission / reception relationship of FIG. 4 is equivalent to the wireless gain A obtained in FIG. 3, from the transmission power Wt and the wireless gain A, the received power Wx in the electric field strength meter 12 is

It becomes. Furthermore, it is a general formula of the received power Wx and the electric field strength Ex.

Can be obtained as the following equation. However, Z ₀ is a specific impedance 120π [Ω].

  Even if the predetermined distance d2 from the lead-in line 3 is the same, the received power Wr varies depending on the arrangement of the lead-in line 3 and the measurement antenna 11, reflection from the surrounding environment, etc. It is desirable to perform calculations and increase reliability. For this purpose, for example, the lead-in wire 3 is appropriately divided in the length direction, and each dividing point is set as a reference location, and at each of a plurality of measurement locations separated by a distance d2 from the corresponding reference location, It is preferable to perform the measurement.

  Referring to FIG. 1 again, by measuring the reception power when the transmission power of the signal generator 22 and the measurement antenna 11 is received by the receiver 21 provided at the installation place of the indoor power line communication modem 9. In the same manner as described above, the radio gain A between the signal generator 22 and the receiver 21 is obtained.

  Further, since this wireless gain A has reversibility between transmission and reception, when the power line communication modem 9 is installed at the setting location of the receiver 21 and power is transmitted, the received power at the setting location of the signal generator 22 is reduced. Can be calculated. Thereby, the electric field strength of the radiated radio wave generated from the lead-in wire 3 can be obtained by the power line communication modem 9 arranged indoors.

  Note that the radiated radio waves generated in the lamp / power line 7 can also be obtained by the above method. Specifically, as shown in FIG. 1, the signal generator 23 and the measurement antenna 13 are installed at a predetermined distance from the lamp / power line 7 inside the electric power consumer 5. If the receiver 20 receives the output test radio wave, it is possible to predict unnecessary radio waves radiated from the light / power line 7 by the test radio wave output from the power line communication modem 4 of FIG. .

  On the other hand, if the indoor receiver 21 receives the test radio wave from the signal generator 23, the radio wave generated on the lamp / power line 7 can be predicted by the test radio wave output from the indoor power line communication modem 9. it can.

  Further, although not shown in the drawing, a signal generator and an antenna are installed at a predetermined distance from the low-voltage distribution line 1, and a test radio wave from the signal generator is received by the receiver 20, whereby the low-voltage distribution is achieved. The electric field strength of unnecessary radiated radio waves generated in the electric wire 1 can be predicted.

  FIG. 5 is a flowchart for explaining the method for measuring an unnecessary radiation wave according to the present embodiment.

  Referring to FIG. 5, first, transmission power Ws output from a signal generator installed at a predetermined distance d2 from the power line is adjusted (step S01). Specifically, the transmission power Ws is determined so that the electric field strength at a predetermined distance d1 is not more than a specified value according to the test conditions specified in the Radio Law. According to the test conditions in the current method, the electric field strength at a predetermined distance d1 = 3 m from the transmission side is required to be 500 μV / m or less during test radio wave transmission.

  Next, the transmission power Ws is radiated from the signal generator through the measurement antenna. At this time, the received power Wr is measured at the receiver 20 arranged at the planned installation location (corresponding to the utility pole 2) of the power line communication modem 4 (step S02).

  Further, the wireless gain A between transmission and reception is calculated based on the transmission power Ws and the measured reception power Wr (step S03).

  At this time, since the radio gain A is reversible between transmission and reception, it is assumed that the power line communication modem 4 is installed at the place where the receiver 20 is disposed, and the signal generator 22 is generated by the output Wa of the power line communication modem 4. The received power Wx received at the installation location (corresponding to a location away from the service line 3 by a predetermined distance d2) is calculated (step S04).

  Finally, the electric field intensity Ex at a predetermined distance d2 is calculated from the obtained received power Wx (step S05).

  As described above, according to the embodiment of the present invention, unnecessary radiated radio waves generated in power line carrier communication can be measured legally and easily without causing radio interference to other radio apparatuses.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall configuration diagram of a power line carrier communication device for illustrating a method for measuring a radiated radio wave according to an embodiment of the present invention. It is a circuit diagram for demonstrating adjustment of transmission power Ws. It is a circuit diagram for demonstrating the principle of the radiation wave measuring method according to embodiment of this invention. It is a circuit diagram for demonstrating the prediction method of a radiation wave. It is a flowchart for demonstrating the measuring method of an unnecessary radiation wave. It is a schematic block diagram for demonstrating the conventional power line carrier communication apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Low voltage distribution line, 2 utility poles, 3 service lines, 4,9 Power line communication modem, 5 Electric power consumer, 6 Electricity meter, 7 Electric light and power line, 8 Outlet, 10 Terminal device, 11, 13 Antenna for measurement, 12, 14 Field strength meter, 20, 21, 25 Receiver, 22, 23 Signal generator, 24 Receiving antenna.

Claims (9)

In a power line carrier communication in which a power line carrier signal is superimposed on a power line and communicated from a power line communication modem, a radio wave measuring method for measuring a radio wave radiated from the power line,
Generating a test signal having the same frequency as the power line carrier signal from a signal generator arranged at a predetermined distance from the power line;
Outputting a transmission power of a predetermined power level obtained by multiplying the test signal by the known gain from an antenna of a known gain coupled to the signal generator;
Measuring the received power when the transmission power is received by a receiver disposed at a place where the power line communication modem is installed;
Calculating a radio gain that is a ratio of the transmission power and the reception power;
Multiplying the calculated radio gain by a planned value of transmission power output from the power line communication modem, calculating a predicted value of received power at the antenna with respect to the planned value of transmission power;
And a step of calculating an electric field strength at a position separated from the power line by the predetermined distance based on the predicted value of the received power.   The radiated radio wave measurement method according to claim 1, further comprising the step of setting the predetermined distance and the predetermined power level in accordance with test conditions defined by the Radio Law.   The radiation wave measuring method according to claim 1, further comprising the step of sequentially arranging the signal generator and the antenna at a plurality of positions spaced from the power line by the predetermined distance. In power line carrier communication in which a power line carrier signal is superimposed on a power line from a power line communication modem for communication, a radiated radio wave measuring device that measures radio waves radiated from the power line,
A signal generator disposed at a predetermined distance from the power line and generating a test signal having the same frequency as the power line carrier signal;
An antenna coupled to the signal generator for radiating the test signal with a known gain;
A receiver disposed at a place where the power line communication modem is installed,
The signal generator transmits the generated test signal as a transmission power of a predetermined power level via the antenna,
The receiver measures the received power when the transmission power is received;
Means for calculating a radio gain that is a ratio of the transmission power and the reception power;
Means for multiplying the calculated wireless gain by a scheduled value of transmission power output from the power line communication modem, and calculating a predicted value of received power at the antenna with respect to the scheduled value of transmission power;
A radiation wave measuring apparatus further comprising: means for calculating an electric field strength at a position separated from the power line by a predetermined distance based on the predicted value of the received power.   The radiated radio wave measuring apparatus according to claim 4, further comprising means for setting the predetermined distance and the predetermined power level in accordance with test conditions specified by the Radio Law.   The radiated radio wave measuring apparatus according to claim 4 or 5, wherein the signal generator and the antenna are respectively arranged at a plurality of positions separated from the power line by the predetermined distance. A power line that is laid in a power consumer and propagates by superimposing a power line carrier signal on the power; and
A power line communication modem installed on the power line and transmitting and receiving the power line carrier signal;
A signal generator disposed at a predetermined distance from the power line and generating a test signal having the same frequency as the power line carrier signal;
An antenna coupled to the signal generator for radiating the test signal with a known gain;
A receiver disposed at a place where the power line communication modem is installed,
The signal generator transmits the generated test signal as a transmission power of a predetermined power level via the antenna,
The receiver measures the received power when the transmission power is received;
Means for calculating a radio gain that is a ratio of the transmission power and the reception power;
Means for multiplying the calculated wireless gain by a scheduled value of transmission power output from the power line communication modem, and calculating a predicted value of received power at the antenna with respect to the scheduled value of transmission power;
A power line carrier communication device further comprising: means for calculating an electric field strength at a position separated from the power line by a predetermined distance based on the predicted value of the received power.   The power line carrier communication apparatus according to claim 7, further comprising means for setting the predetermined distance and the predetermined power level in accordance with test conditions defined by the Radio Law.   9. The power line carrier communication device according to claim 7, wherein the signal generator and the antenna are respectively disposed at a plurality of positions separated from the power line by the predetermined distance.

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