VHF radio test

 

Set Number

As you may wish to test several radios under the same MMSI, each radio can be given its own individual set number for recognition. Default number is 1. Press OK to confirm or press ↑ or ↓ to change to another number. Then, press OK and go to the test you wish to perform.

Receive DSC

In the Receive DSC test mode, the test box will receive and display the radio’s MMSI number and DSC data transmitted, and at the same time measure the frequency and the forwarded and reflected power.

 

Use this setup with the Receive DSC test:

Receive DSC (VHF radio test_image1)

 

The test can also be performed over the dummy load inside the test box.  If so, use the short coax cable supplied with the test box and connect like this:

Receive DSC over dummy load (VHF radio test_image2)

 

To perform the test, select Receive DSC and press OK. Following this, the DSC frequency will appear in the display. Press OK again and activate the transmitter to send a DSC call.

The received MMSI number, DSC data and the measured frequency and power values will be stored in the test box memory and at the same time appear in the LCD display, line by line.   You may toggle between the lines using and ↓ to view all the results.

Example of Printout from the Memory:

VHF # 1   Time/date: 08:16:03 / 21-11-2011
DSC DATA: CH70-156.525 MHz   RX MMSI: 2190123450  Format 120 Cat.: 100
TX MMSI: 2195576240  Telecommand: 100 126 90 00 16 126 126 126
EOS: 117 ECC: 113  Status: OK
Freq.: 156,525.2 kHz  Fwd.: 19.8 Watt  Rev.: 0.2 Watt

If you only want to check DSC data and frequency (no power measurement), connect the telescopic VHF antenna to RF IN and use this setup:

DSC data and frequency (VHF radio test_image3)

If there are DSC transmissions from more than one radio in the area – for instance in ports with many ships – the test box will receive data from the radio first detected.

To make sure that the test box will be receiving data from one particular radio, use the test mode “Receive DSC sele” below.

Receive DSC sele

In the Receive DSC sele mode, the test box will receive data from the radio having its MMSI number currently registered in the test box. So, please check and change number, if required, using the Edit ship’s MMSI menu on page 12.

Use the same setup as above.

Example of Printout from the Memory: 

VHF # 1   Time/date: 08:16:03 / 21-11-2011
DSC DATA: CH70-156.525 MHz RX MMSI: 2190123450  Format 120 Cat.: 100
TX MMSI: 2195576240 Telecommand: 100 126 90 00 16 126 126 126
EOS: 117 ECC: 113  Status: OK
Freq.: 156,525.2 kHz

Send DSC

In the Send DSC mode, the test box will transmit a DSC call for you to check on the DSC receiver accordingly.

It is a requirement that the MMSI number registered in the test box is identical with the MMSI of the radio to be tested. Please check and change number, if required, using the Edit ship’s MMSI menu. See Page 12.

With selective calls, connect the telescopic VHF antenna to RF OUT and use this setup:

Send DSC (VHF radio test_image4)

With distress calls, it is important to use a coax cable for the connection between the test box and the DSC receiver. This will prevent other ship stations to be alerted.

Use this setup with distress calls:

Send DSC_distress calls (VHF radio test_image5)

Select Send DSC and press OK. The DSC frequency will appear in the display. Press OK again and select Dis to send a distress call or Sele to send a selective call.

Following the DSC call, the test box will display Received status. Press OK if the call was successfully received. Press Fail if the call was not well received. The answer will be stored in the test box memory for your test report. 

The selective call transmits the following information:

120,120             Format specifier - individual call.
21,95,57,62,40  Address - 2195576240
100                   Category - Routine
99,99,99,99,90 Self-identification = Testbox “MMSI no”.
100                   First telecommand 
126                   Second telecommand
90 0 6 90 0 6    Frequency or channel
117                   Ack. RQ - End of sequence
76                     Modulus-2 checksum 

The distress call transmits the following information:

112, 112           Format specifier - Distress call
99,99,99,99,90 Testbox “MMSI no”.
107                   Category - Undesignated distress
99,99,99,99,99 Coordinates - 99 99 99 99 99 at test.
88,88                Time - 88 88 at test.
100                   First telecommand
127                   EOS - End of sequence
57                     Modulus-2 checksum

 

Send custom DSC

The Send custom DSC mode enables the test box to send a custom-made DSC call composed in advance on a PC. For the purpose of composing, a free PC software TEST BOX MANAGER can be downloaded from Danphone’s website. See page 48.

Once downloaded, connect your PC to the test box via the USB cable supplied. Follow the instructions of how to compose a new custom-made call and transfer it to the test box accordingly.

To make the test box transmit the custom-made call, select Send custom DSC on the test box. The DSC frequency will appear in the display. Press OK again to send the call. 

Following the DSC call, the test box will display Received status. Press OK if the call was successfully received. Press Fail if the call was not well received. The answer will be stored in the test box memory for your test report.

 

Receive ATIS

ATIS (Automatic Transmitter Identification System) is a signaling protocol used on the inland waterways of Europe that enables the authorities to identify each transmission by a short data burst sent when the PTT key is released.

In the Receive ATIS mode, keying of an ATIS equipped VHF on CH 6 or CH 15 will enable the test box to receive the station’s ID.

Use this setup:

Receive ATIS (VHF radio test_image6)

Select Receive ATIS on the test box and press OK. Select channel and press OK. Then, activate the ATIS transmitter.

 The test box will receive and display the transmitter’s ID and at the same time store it in the test box memory.

 

VHF power test 

The VHF power test mode is used to measure the transmitted and the reflected power from non-DSC VHF radios.

Use this setup with the VHF Power test:

VHF power test (VHF radio test_image7)

 

The test can also be performed over the dummy load inside the test box.  If so, use the short coax cable supplied with the test box and connect like this:

 

VHF power test over dummy load (VHF radio test_image8)

Select VHF power test on the test box and press OK.

Then, activate the transmitter and keep it activated while selecting Meas or Cont

In the Meas (= Measure) mode, the test box will perform and display a single power measurement and store it in the memory.

In the Cont (= continue) mode, the test box will continue taking measurements until pressing the EXIT button stops it. Cont readings are not stored, but the feature can be used e.g. for checking/adjusting the antenna.

Example of Printout from the Memory:

VHF # 1   Time/date: 08:18:16 / 21-11-2011
Power Measure Fwd: 20.3 Watt  Rev: 0.1 Watt  VSWR 1.16

 

VHF Frequency test

In this mode you can decide whether you wish to perform a frequency test only or a simultaneous frequency and power test.

If you wish to measure the frequency only, use this setup:

VHF frequency test (VHF radio test_image9)

On the test box, select Frequency test and the preferred frequency range. Then press OK and activate the transmitter. Select Meas or Cont to start measuring.

In the Meas (= measure) mode the test box will perform and display a single frequency measurement and store it in the memory.

In the Cont (= continue) mode the test box will continue taking measurements until pressing the EXIT button stops it. Cont readings are not stored, but the feature can be used e.g. for checking/adjusting the antenna.

Example of Printout from the Memory:

VHF # 1  Time/date: 15:00:52 / 22-11-2011
Frequency measure: 156,300,128 Hz

If you wish to perform a simultaneous frequency and power test, use this setup:

VHF frequency and power test (VHF radio test_image10)

The test can also be performed over the dummy load inside the test box.  If so, use the short coax cable supplied with the test box and connect like this:

VHF frequency and power test over dummy test (VHF radio test_image11)

On the test box, select Frequency test and the preferred frequency range. Then press OK and activate the transmitter. Select Meas or Cont to start measuring.

In the Meas (= measure) mode the test box will perform and display a single frequency and power measurement and store it in the memory.

The test box displays the result in two lines. Scroll down to read line two.  

In the Cont (= continue) mode the test box will only take frequency measurements and continue until pressing the EXIT button stops it. Cont readings are not stored, but the feature can be used e.g. for checking/adjusting the antenna.

Example of Printout from the Memory:

VHF # 1  Time/date: 18:11:42 / 22-01-2018
Frequency Measure: 156,300,008 Hz  Power Fwd.: 19.4 Watt Rev.: 0.1 Watt  VSWR: 1.16

FM Deviation

The audio reference device for use with this test offers three tone frequencies (500 Hz, 1 kHz and 2 kHz) and two volume levels.

FM deviation (VHF radio test_image12)

The single-tone 1 kHz AF generator previously supplied with the test box can also be used.

The illustration below shows how to set up for measuring the VHF FM Deviation on CH 6:

FM deviation on CH 6 (VHF radio test_image13)

The test procedure is as follows:

1) Select FM Deviation on the test box,
2) Hold the audio reference device / AF generator close to the transmitter’s microphone and activate the tone,
3) Activate the transmitter on CH 6,
4) Press OK on the test box. Maximum deviation and actual deviation are shown on the LCD display,
5) Press OK on the test box, and the maximum deviation value will be stored in the memory,
6) Stop the transmitter.

Example of Printout from the Memory:

VHF # 1   Time/date: 08:22:24 / 21-11-2011
Maximum deviation:  1.1 kHz

AM  / 123.1 MHz

The AM / 123.1 MHz test mode allows you to measure the frequency and to check the modulation of an AM signal transmitted on 123.1 MHz. 

Use the same setup as with measuring the FM deviation above.

Select AM / 123.1 MHz on the test box and press OK. Then, select either Img (= Image) or   Ord (= Ordinary). In both modes there is a choice to measure the Frequency or check the AF modulation.

If you wish to measure the frequency, activate the transmitter WITHOUT modulation and press Frq on the test box. Frequency and signal level are shown on the LCD display and are also stored in the memory.

If you wish to check the AF modulation, activate the transmitter WITH modulation and press AF on the test box. The AF signal can be heard in the test box loudspeaker.

When checking the AF modulation, please note that the test box will limit a strong input signal in order to protect the loudspeaker.

 

Signal level

This mode can be used to check the signal strength level of the received signals at 156.300 MHz and 156.525 MHz transmissions respectively. 

The level figure is used to indicate if the signal strength is sufficient to ensure proper radio communication between the test box and the GMDSS station during the following tests.

Use this setup:

Signal level (VHF radio test_image14)

For an indication of the actual signal strength level, select Signal level on the test box and press OK. Select frequency. Then, press OK and start transmission from the radio. The level figure appears in the test box display. A figure of 70 or higher is advisable.

 

Test sensitivity

In the Test sensitivity mode, the test box outputs a modulated signal on VHF channels 6, 13, 16 and 67 respectively. With an external attenuator (Optional accessory, not supplied with the test box) this test can be used to check the sensitivity of a ship's VHF radio. The modulated signal can be heard and checked in the radio’s speaker as a 1 kHz tone.

Use the setup below. It is very important to use coax cables for the connection of the equipment.

Test sensitivity (VHF radio test_image15)

Select Test Sensitivity and press OK. CH 06 will appear as the default channel in the display. Other channels can be selected by pressing ↑ or ↓.

At the desired frequency, press OK and the test box will keep sending the modulated signal. To stop the transmission, press EXIT.

For reference, the test box RF output level is approx. -45 +/- 2 dBm. In order to match with the sensitivity of a ship’s radio (approx. -115 dBm), the attenuator to be used should be approx -70 dB.

To simply check if the 1 kHz-modulated signal is well received over the air, use this setup:

Test sensitivity_signal well received (VHF radio test_image16)
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