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BR-200_User_Manualdoc - K5PRTcom

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BR-200_User_Manualdoc - K5PRTcombr,USER,User,user

STANDING WAVE ANALYZER Model BR-200

    The BR-200 Standing Wave Analyzer is a precision apparatus which measures Standing Wave Ratio (SWR), impedance, and which may be used for determination of the resonant frequency (and other properties) of an antenna system.

     The BR-200 directly measures antenna properties without the need for a separate transmitter, SWR meter, impedance bridge, or other equipment. The compact, single-unit design makes it easy to evaluate HF and VHF antenna system performance by yourself, and its intuitive displays make antenna adjustments quick and accurate.

     What’s more, the BR-200 may be utilized as a general-purpose, low-level, wideband RF signal source, ideal for all-around experimentation with receivers, amplifiers, etc.

     We recommend that you read this manual thoroughly, so as to understand the capabilities of the BR-200 to the fullest.

MAIN FEATURES

    ;;Wide-band RF oscillator permitting measurements from 1.8 to 170 MHz. ;;Built-in frequency counter, for direct frequency readout.

    ;;High-sensitivity, high-precision meter, manufactured by Yokogawa, for high

     measurement accuracy.

    ;;Easy operation check-out using standard 50; dummy load.

    ;;Low current drain, long battery life (typically 14 hours using alkaline cells).

     Blinking decimal point on frequency counter indicates “Low Battery” condition.

    ;;Small size and light weight (approx. 800 g./1.8 lb including batteries). ;;Output Connector: “M” Type (“PL-259”).

SPECIFICATIONS

OSCILLATION/MEASUREMENT CIRCUITRY

    ;;RF oscillation frequency range: 1.8 170 MHz (switched oscillator circuits).

    ;;.

    ;;Impedance measurement range: 12.5 300 ; (SWR Time Base Range: 1:1 - ).

FREQUENCY COUNTER

    ;;Sampling Rate: 32 mS (Fast) or 0.32 mS (Slow).

    ;;Display Method: six 7-segment LEDs.

    ;;Display Time: 64 mS (Fast), 640 mS (Slow).

    ;;Frequency Resolution: 1 kHz (Fast), 100 Hz (Slow).

    ;;Precision: ?5 ppm (?1 count).

GENERAL

    ;;Power Requirements: DC 8 12 V, negative ground.

    ;;Current Consumption: Approx. 160 mA maximum (DC 9V, six “AA” Alkaline

     cells).

    ;;Size: 80 x 170 x 60 mm (3.1” x 6.7” x 2.4”) WHD (not including connectors)

    ;;Weight: Approx. 800 g (1.8 lb.) w/batteries installed.

About Power Supplies and Batteries

    The BR-200 may be powered from six internal “AA” type Alkaline cells, or from a well-

    regulated external power supply capable of delivering 200 mA continuously at 8 12

    Volts DC. Note that many power supplies used in radio stations put out 13.8 Volts, and this is too high for use with the BR-200; a 9-Volt power supply, however, is ideal.

    When using an external power supply, it is absolutely necessary to observe the proper polarity on the DC cable. The Red DC cable wire connects to the Positive (+) power supply terminal, and the Black DC cable wire connects to the Negative (-) power supply terminal. Serious damage may be caused if improper polarity is used, and the Warranty policy does not cover such damage. Be sure to confirm plug polarity when using accessory cords other than the one supplied.

    Before connecting the DC cable to the BR-200, we recommend that you confirm that the output voltage from your power supply is within the 8 12 V DC rating. Adjust the

    voltage within this range, if necessary, and we recommend that you mark the DC cable with a label as a reminder not to connect it to a 13.8-Volt supply. Use of voltages outside the specified range may cause damage and/or inaccurate readings.

    When using an external DC power supply, the internal batteries are automatically disconnected, so as not to cause them to discharge.

Installation of Batteries

Six “AA” type (SUM-3) batteries are required to power the BR-200.

    To install the batteries, remove the screw affixing the battery cover on the back of the BR-200, and remove the battery cover. Be sure to align the batteries correctly within the battery case, so as to ensure proper polarity. Replace the battery cover, and replace the screw to secure the battery cover in place.

    We recommend the use of Alkaline cells for longest battery life. Approximately 14 hours of operation may be expected from a set of alkaline cells. Approximately 20-30 minutes prior to battery depletion, the decimal point of the counter will begin to blink, indicating it is time to replace the batteries.

     Note: If you are not going to use the BR-200 for a long time, we recommend that

     you remove the batteries, so as to avoid the possibility of leakage that

     could damage the internal circuitry.

About Standing Wave Ratio (SWR)

    The radio frequency (RF) power applied to a transmission line advances toward the antenna. If the characteristic impedance of the feeder and the antenna are identical, there will be no power reflected to the source (for re-reflection back to the antenna) in the form

    of “Standing Waves,” and only Ohmic resistance losses will occur, with no losses due to SWR. However, if the antenna feedpoint impedance is different than the impedance of the feeder, the SWR will rise and there will be losses of a varying magnitude, depending on the Ohmic losses in the cable and the magnitude of the SWR.

    By connecting a transmission line of the same characteristic impedance as that of the transmitter’s output stage (typically 50 Ohms), the only adjustments required to ensure minimal losses will be performed at the antenna feedpoint, or in the antenna’s fundamental design, to secure the desired 50-Ohm load impedance.

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COMPONENT DESCRIPTIONS

1. POWER/GATE TIME

This is the main On/Off switch for the BR-200. Switching it out of the “OFF” position

    supplies power to the Analyzer’s circuitry in either the “FAST” or “SLOW” sampling rate modes. The “FAST” mode provides faster measurements at lower (1 kHz) resolution, while the “SLOW” position provides slower measurements at higher (100 Hz) resolution.

2. Frequency Display

    The display consists of six 7-segment LEDs. When the battery level is nearing depletion, the decimal point in the frequency display will blink.

3. OVER

    This LED lights up when the frequency exceeds the available field size for the display.

4. Band Selector Switch

    This switch selects the general frequency range for SWR measurement. Six frequency bands are provided, covering the range 1.8 to 170 MHz.

5. FREQ

    This control allows you to dial up the exact frequency on which measurements are to be performed.

6. Measurement Function Switch (right side)

    This switch allows selection of the measurement function: Impedance Measurement or SWR Measurement.

7. ANT (Antenna) (right side)

This “M” type (“SO-239”) jack allows connection of the connector affixed to the device

    to be measured.

8. METER

    The upper scale is used for impedance measurement, while the lower scale is used for SWR measurement.

9. EXT. DC INPUT (top panel)

This is the input terminal used for application of external DC voltage (8 12 V).

10. Battery Compartment (rear)

This is the compartment into which “AA” type batteries may be installed.

BEFORE YOU BEGIN. . .

    Check to be sure there is no damage to the meter, and that it appears to move freely with gentle movement of the meter.

    Connect the supplied miniature Dummy Load. Set the POWER switch to FAST, and set the Measurement Function Switch to SWR. Verify that the SWR indication is “1:1.” Now set the Measurement Function Switch to Impedance, and verify that the reading is “50

    Ohms.” Repeat these tests on each frequency band, checking at several frequencies in each band by rotating the FREQ adjustment dial.

    Note: The supplied miniature Dummy Load is designed only for use with the BR-200, as

     it has a power rating of only 0.5 Watt.

IMPEDANCE MEASUREMENT AT ANTENNA FEEDPOINT

1. Connect the BR-200’s ANT jack to the antenna feedpoint, using the shortest possible

     length of coaxial cable. Remember that the coaxial cable between the feedpoint and

     the BR-200 will act as a “transformer,” providing inaccurate impedance figures if the

     length of the coaxial cable is a significant portion of a wavelength.

2. Set the Measurement Function Switch to the “Impedance Measurement” position.

    3. Set the Band Selector switch to the band covering the frequency at which you desire to

     perform the impedance measurement.

    4. Rotate the FREQ dial so as to select the exact frequency on which the impedance

     measurement is to be made. The frequency selected will appear on the display.

    5. At this point, the impedance of the antenna, at the selected frequency, will appear on

     the display. Presuming that the antenna is being used in a 50-Ohm environment, the

     target impedance will be 50 Ohms.

RESONANT FREQUENCY MEASUREMENT

1. Connect the antenna system’s coaxial cable to the ANT connector, as in the previous

     section.

2. Set the Measurement Function Switch to the “SWR Measurement” position.

    3. Set the Band Selector switch to the band covering the frequency at which you desire to

     perform the impedance measurement.

    4. Rotate the FREQ dial while watching the SWR meter and the display. The frequency

     at which the SWR is nearest to “1:1” is the resonant frequency of the system.

SWR MEASUREMENT

1. Connect the antenna system’s coaxial cable to the ANT connector, as in the previous

     section, and set the Measurement Function Switch to the “SWR Measurement”

     position.

    2. Set the Band Selector switch to the band covering the frequency at which you desire to

     perform the impedance measurement.

    3. Rotate the FREQ dial to the target measurement frequency, as indicated on the display.

4. The meter will now indicate the SWR at the selected frequency.

    Note: In some cases, the impedance may include high levels of capacitive or inductive

     reactance, causing the impedance to indicate “50 Ohms” but the SWR not to

     indicate “1:1.” In such cases, it generally is best to adjust the frequency to the point

     where the SWR is lowest, and use that as the frequency for initial antenna

     adjustments.

ANTENNA ADJUSTMENTS

1. Connect the antenna system’s coaxial cable to the ANT connector, as in the previous

     sections, and set the Measurement Function Switch to the “SWR Measurement”

     position.

    2. Set the Band Selector switch to the band covering the frequency at which you desire to

     perform the impedance measurement.

    3. Set the FREQ dial to the target frequency, and observe the SWR. If the SWR is not

     1:1, rotate the FREQ dial to find the frequency at which the SWR does become 1:1 (if

     any). If the 1:1 frequency point is at a higher frequency than desired, the driven

     element must be lengthened; if the 1:1 frequency point is at a lower frequency than

     desired, the driven element must be shortened. If the SWR never reaches 1:1, then you

     will need to make other adjustments to the impedance matching circuitry at the antenna

     feedpoint.

ANTENNA SYSTEM FINAL CHECKOUT

    If you have used a very short coaxial cable in the above sections, you should find that the adjustments will be sufficiently accurate not to require further adjustment when the main coaxial cable is connected to the antenna.

    At VHF frequencies, however, even a short piece of coaxial cable may cause confusing readings, so it is always recommended that the impedance and SWR readings be verified, using the main station coaxial cable, before all connections are sealed against weather (by tape, etc.).

    If a significant difference is found in performance with different lengths of coaxial cable, try a different piece of cable, just to eliminate the possibility that there is a problem in your proposed cable (bad connector, internal short or open connection, etc.). If the problem persists, re-connect the main cable once more, and try some minor adjustments to antenna length and/or matching circuitry. When the desired 1:1 SWR is obtained at the “station end” of the coax, it is a good idea to check again using the short coax originally used; it is highly likely that it also will indicate a 1:1 SWR; this will confirm that “transformer action” in the original test cable was providing misleading results, and you may wish to reduce the cable length for future antenna projects.

    --------------------------------------------------------------------------------------------

Testing Whip or “Rubber Duck” Antenna for Hand-Held Transceiver

Too long

     SWR will become 1:1 when length is approximately /4.

Too short

    The body of the BR-200 emulates the body of the hand-held. Better antenna adjustment accuracy will result if you connect (temporarily) a /4 counterpoise wire to the shield

    side of the coaxial connector at the ANT jack, and position the wire so it extends horizontally (at a 90º angle relative to the antenna under test).

Use Reference Chart

LPF, HPF, BPF or Antenna Tuner Adjustment

Connect a suitable dummy load here (not supplied).

Connect a dummy load to the “Antenna” side of the filter or tuner under test.

    The frequency range, etc. of the device under test can now be measured by setting the Frequency Band switch appropriately, and sweeping the FREQ dial across the intended operating frequency range while observing the SWR or impedance.

Antennas (including Multiband Antennas)

“V” type Doublet

50 Ohm Coaxial Cable, Arbitrary Length

GP

    When measuring at antenna feedpoint, use “Impedance Measurement” mode for best results.

    When measuring at “station end” of coaxial cable, use “SWR Measurement” mode for best results. When adjusting multiband antenna, begin with the highest frequency band first, obtain the lowest SWR, then progressive move to the lower frequency bands.

Gamma and Omega Matches

Use “Impedance Measurement” mode for best results, and use shortest possible coaxial

    cable for attachment.

Important Cautions

• This device uses a precision meter with some delicate parts; do not drop this device nor

     subject it otherwise too severe shock.

    • Never apply an external RF signal (from a transmitter, etc.) to this device. The internal

     components may be severely damaged, and may even catch fire.

• If using this device near a functioning transmitter, the RF energy may be detected by the

     BR-200, causing erroneous or variable readings.

• This device is not waterproof. Do not use it in the rain or near other sources of water.

    • This device has been carefully adjusted at the factory. Do not open it and make adjustments to internal components.

    Specifications and performance are subject to change, in the interest of performance improvement, without notice.

Kuranishi, Ltd.

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