RACORDER - The Marine Black Box

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Marine Radar Recording System

Operations Manual

revised November, 2004


Racorder Model N is designed to work with shipboard raster scan marine radar systems.

Using Racorder Model N and an ordinary VHS video tape cassette, an exact recording of the radar display as set up by the radar operator will be made on the tape in ordinary NTSC television format, which can be replayed on any VHS television playback system.

All controls necessary for operation are easily accessible on the front panel and clearly marked. The operator can easily maintain continuous recording with little training and minimal disruption of his normal duties.

The standard readily available T-120 VHS video cassette will record just over six hours of operations, making it ideal for recording operations a watch at a time. Racorder will only operate at this speed to ensure that the tape will not end before the end of a six-hour watch. T-180 tapes can provide approximately nine hours of recording time.

Optionally, audio can be recorded, such as radio conversations or sounds picked up using a wheelhouse microphone. Audio input connections and adjustments are described later in this manual.

A clock and calendar circuit provides a date-time stamp on the recording, along with provision for additional text useful for including the name of the vessel. This is programmable by the user as described later in this manual.

An automatic dimmer circuit monitors the ambient light level and adjusts the brightness of the front panel lamps so that they are easily seen in daylight and non-glaring in nighttime conditions.

A video output jack allows the use of a video monitor to be used either to monitor tape playback at the Racorder location or as a real time remote radar display. Several monitors can be "daisy chained" if desired.

An audio output jack allows playback audio to be connected into a PA or other audio system if desired. Record audio can also be made available here if desired.

If a video monitor is attached the incoming radar video can be continuously monitored, and tape playback can be monitored for evaluation. Recorded audio will sound from the front panel speaker. The front panel volume control sets the sound level from the speaker, but does not affect audio recording level in any way. The speaker is normally muted except during playback to prevent audio feedback problems. This mute feature can be disabled if desired.

An audio output jack allows playback audio to be connected into a PA or other audio system if desired. Record audio can also be made available here if desired.


We recommend using broadcast quality video tapes, available from Racorder or from most professional audio/visual distributors. Be sure to store the cassettes in their original cases which helps keep them clean. This will serve to greatly increase the life of the mechanism and virtually eliminates the need for cleaning.

There is only one recording speed available. Standard T-120 tapes will run just over six hours in Racorder; T-180 tapes a little over 9 hours.

The T-120 tapes work well in applications utilizing six-hour watches where tapes are changed at watch change. Keeping 12 tapes aboard and cycling through them results in a three day history of vessel operations at any time.

Insert a tape cassette and press the Record button. The Record button will illuminate, giving an indication of what Racorder is doing. If the tape is not stopped, when it reaches the end it will automatically rewind and then stop and wait for operator action. An internal jumper can be set to automatically begin recording again at this point. If your unit does not have this capability, contact your dealer for an upgrade which can be easily installed on location.

If the internal alarm jumper is set and Racorder is in the RECORD mode, when the end of the tape is reached it will start rewinding as described above and an alarm will sound and will continue to sound until stopped by the operator. To stop the alarm press any front panel button. Pressing a button to stop the alarm will not otherwise change the current operating mode. For example if the unit is rewinding with the alarm sounding and you press the Stop button the alarm will stop but the unit will continue to rewind. Pressing the stop button again will then stop the rewind and Racorder will enter the STOP mode. If your unit does not do this or behaves differently, contact your dealer or Racorder for an upgrade which can be easily installed on location.

Racorder will rewind a T-120 tape in about two and a half minutes. For continuous operation it may be worth considering using a separate tape rewinder to eliminate the gap in recording operations, and save a little wear on the mechanism. It is permissible to press the Play button during Fast Forward or Rewind without harming the machine or the tape. If Racorder is in the PLAY mode and either Fast Forward or Rewind is pressed, PLAY will continue but at a much faster speed and you can view the picture on the monitor. In this mode, on units with later versions of control board firmware, the button pressed and the play button will both be illuminated and flickering.


Video from the radar is first processed by a buffer module installed in the radar display unit. Since each radar make and model is different, connection instructions are provided in a separate document specific to the radar in use.

A video cable supplied with Racorder is routed from the module inside the radar display unit to the VIDEO INPUT jack on the rear panel of Racorder. A standard VGA computer monitor extension cable can be used if additional cable length is needed, or a longer cable can be obtained from your dealer or from Racorder.

A video monitor connected to the VIDEO OUTPUT jack on the rear panel is needed during setup and programming. This or another monitor can optionally be installed permanently to view the radar display and tape playback.

There are five audio jacks on the rear panel of Racorder, one output and four inputs. The input jacks, labeled 1 through 4, connect to an internal four input audio mixer with individual level controls. The output jack provides playback audio output suitable for driving a monitor or PA amplifier.

The audio board is accessible by removing the top cover, and is located near the audio jacks on the rear panel. The four trimmer controls on the board correspond to the four input jacks near them.

Input number one has a microphone preamp available which can be optionally inserted by setting the links on JP1 near the center of the board. If the two jumpers are set in the "OUT" positions the number one input goes straight to the mixer and behaves just like the other three inputs. If the two jumpers are set to the "IN" positions the preamp is inserted into the line from the number one input to the mixer, enabling a low impedance dynamic microphone to be used as an audio source. The other three inputs will be unaffected by this setting.

Jumper JP2, located near the upper right corner of the audio board, can be opened during setup to allow input audio to pass through to the front panel speaker for monitoring purposes. It should be closed during normal operation allowing the front panel speaker to be active only during playback of tapes.

Audio input levels should be in the range of 50 - 200 mv. Levels outside this range can be used, but it may become more difficult to get reliable level settings or full recording levels. Input impedance is 100K resistive, and if audio is taken by modifying a radio it is suggested using a series resistor of at least 10K to prevent loading of the radio circuits in case of a malfunction. This resistor can be higher to achieve an input level within the range noted above, or ideally around 100 mv.

Installation kits and specific instructions are available for many popular models of marine VHF radios, with more being added as we gain access to them.

The most current information is available on the website www.racorder.com, or from our Engineering Dept.

Once all audio connections are made, you need to set the input level controls. Remove the top panel and locate the audio board at the right rear of racorder near the audio input jacks. On the audio board note four trimmer controls at the left rear corner of the board, JP2 (mute) jumper near the right rear and the red and green LED's near the front center. These will be used in the setup process.

Also note JP1 (Preamp) and determine that it is set properly. If the Audio Input #1 is connected to a dynamic microphone, jumper the two positions labeled "IN". Otherwise jumper the two positions labeled "OUT".

Temporarily remove jumper JP2 and set the front panel volume control about midrange; this will allow incoming audio to be monitored at the front panel speaker.

Each of the trimmer controls is approximately opposite and in line with the four audio input jacks on the rear panel. With Racorder powered up and audio coming in, adjust the appropriate trimmer while watching the two LED's. Set the trimmer so that the green LED lights most of the time and the red one lights seldom or never. This adjustment is not critical; internal AGC circuits will make the fine adjustments.

Once you are satisfied with the input adjustments replace jumper JP2, record a test tape with audio and check for good playback from the front panel speaker.

The Control Board, located under the top cover in the right front corner, controls the behavior of the Racorder unit. Version 4 and later of this board includes alarm and automatic continuous record functions, controlled by two jumpers at the rear center of this board. If you need these functions and your board does not have the jumpers, or if operation is not as described on page 3, contact your dealer or Racorder engineering department for an upgrade.

Set the ALARM jumper JP1 to closed to sound an alarm at the end of the tape in the RECORD mode, remove it to disable the alarm.

Set the AUTO REC jumper JP2 to closed to continue recording after rewind at the end of the tape in the RECORD mode, remove it to disable this function.


The controls for setting the date, time, text and appearance of the text block are located inside the top cover of Racorder.

You will need a video monitor or television with a video input jack to make these adjustments. Plug the monitor into the video output of Racorder and turn everything on. You should see the radar image and the text on the monitor.

Remove the top cover by removing the ten phillips head screws on the top of Racorder.

Near the left rear as viewed from the front of Racorder is the video circuit board with four white pushbuttons. These are labeled "RESET", "POS", "UP" and "DOWN".

Notice the format of the text line. First is the date in MM/DD/YY format. Next is the time in 24 hour (military) format. Following all that is space for additional text such as name of vessel.

To enter the programming mode, press the "POS" button. A cursor in the shape of an arrow will appear above the first character.

This is the current character position and can be changed by pressing the "UP" or "DOWN" buttons.

Move the cursor to the character you wish to change. While holding the "POS" button down you may change the character at the cursor by pressing the "UP or "DOWN" button.

Continue the above process unitl all characters are set as desired. When finished press the "RESET" button to return the display to normal.

Available characters are number digits 0-9, all capital letters, some punctuation marks and a blank space.

There are two configurations of the video board, one for color radars and one for certain monochrome radars.

The monochrome version has two adjustments, except for some older boards with one control.

The control labeled "VIDEO" sets the overall picture level. On some boards this control is labeled "CONT".

The control labeled "OVERLAY" is used to set the brightness of the text line.

Initially, turn both controls fully CCW, so that all video disappears or is as dim as it will get.

Slowly turn the "VIDEO" control clockwise noting the point where the picture level stops increasing, and leave the setting at that point.

Then increase the "OVERLAY" to no more than the point where the text is plainly visible. Too high a setting of the "OVERLAY" control may cause the Video AGC circuit in Racorder to dim the radar picture.

The color radar version of the video board has numerous controls in addition to the "OVERLAY" control described above, and does not have the "VIDEO" control. The "BRIGHT" and "CONT" take its place.

The "PAN" and "ZOOM" controls can be used to adjust the entire radar picture or a portion of it to fill the output screen.

The other controls are normally left in their center positions or adjusted as necessary to improve picture quality.


It should seldom be necessary to disassemble Racorder in the field, but if it should become necessary, such as to remove a jammed tape, the process is very easy and the following discussion will be helpful. Please read this section carefully before starting, and keep this manual handy until assembly is completed.

Racorder can quickly be broken down into four pieces: Top Cover, Front Panel, Upper Chassis and Lower Assembly. Once this is done, all components of Racorder are easily accessible. Following these instructions in the order given will make the job easy.

Before starting, push the cassette door in a little way and find the cassette door operating lever, a white plastic lever positioned between the door and the front panel on the right side just above the eject button. This is how the internal mechanism opens the door to eject a tape cassette. It is very important to make sure this lever is IN FRONT OF the door during reassembly; otherwise tapes cannot be loaded or unloaded. We'll touch on this subject again later.

After removing the top cover with the ten screws around the top edge, loosen the front panel by removing the three screws along the lower edge of the front panel, then the three screws on each side panel along the front edge. Lift the front panel carefully towards the front and then up, and unplug the two attached cables by carefully pulling them straight up from their connectors. Lay the front panel aside.

You can now see the service display and some of the mechanical works including the cassette door control lever. Be careful not to damage this lever while the front panel is off.

Racorder can still be operated normally in this condition; service buttons along the bottom front edge of the lower circuit board and up the front edge of the vertical circuit board on the right side control all racorder functions. These buttons are labeled by lettering on the circuit boards.

Field service of the tape transport mechanism is pretty much limited to removing jammed tapes, cleaning or inspection. Discussion on further repairs or alignment is beyond the scope of this manual, and must be done in a properly equipped service facility. A complete service and alignment manual is available from the Racorder engineering department.

If it is necessary to gain full access to the tape transport mechanism, the upper chassis assembly can be easily removed.

Make sure all cables are removed from the rear panel. Remove the three screws along the bottom of the rear panel. Turn Racorder around so that the front of the unit is facing you. Unplug the cable on the right side leading from the lower PCB to the control board on the Upper Chassis. Then remove the two screws along the bottom edge of each side panel.

Carefully lift up the front of the Upper Chassis assembly, leaving the rear panel on the bench and slowly rocking it back. As the inner workings are exposed, look for the audio/video I/O cable near the right rear corner of the inside. Continue lifting the Upper Chassis back until you can reach this cable and unplug it from the lower PCB. Then lay the Upper Chassis assembly aside.

At this point the power cord can be reconnected and the lower chassis can be operated normally, allowing the tape mechanism to be inspected for proper operation, cleaned or serviced. If an input/output adapter cable is used (available from the Racorder engineering department) the unit can be connected to a video source and video monitor and tapes can be played and recorded and the mechanism serviced and aligned.

Some of the tape control functions are controlled by light beams which monitor the tape position. Normal or bright ambient light will interfere with the beam sensors making the unit behave strangely during operation while the upper chassis is removed. Shading portions of the tape mechanism from bright light will allow normal operation of the unit.

If a tape is jammed in the mechanism and will not unload by normal operation of the unit, it can be unloaded manually. Look for the main cam gear, which is the large white plastic gear near the right rear of the tape deck. Be sure the input power cord is disconnected and carefully rotate this gear clockwise to manually unload the tape cassette.

Reassembling Racorder is essentially the reverse order of the disassembly process. The following discussion will help with the process.

First install the Upper Chassis Assembly on the Lower Unit. Place the Lower Unit on the bench in front of you with the front of the unit facing towards you. Place the Upper Chassis Assembly on its rear panel behind the Lower Unit, and plug the I/O cable (with the four black wires) into the connector near the left rear of the Lower Unit Main PCB. Then rock the Upper Chassis towards you and onto the Lower Unit, making sure the cable near the right front of the Lower Unit comes out the front. Secure the Upper Chassis to the Lower unit with two black phillips head screws on each side panel.

Route the cable in front of the unit to the right and up the right side of the unit to the Upper Chassis and connect it to P2 on the Control Board located at the right front of the Upper Chassis.

While routing its two cables towards the top, place the Front Panel on the front of the unit while holding the Cassette Door open so that it clears the Cassette Door Operating Lever on the right side of the Tape Deck. When the Front Panel is in place release the Cassette Door and see that the Operating Lever is sandwiched between the Cassette Door and the Front Panel. Then carefully secure the Front panel with three black phillips head screws, first one at the top of each side panel then one at the bottom center of the Front Panel.

IMPORTANT! Recheck that the cassette door operating lever is still properly positioned between the door and the front panel, and that the door easily hinges all the way in to allow cassette loading. If this is not done properly the door will not open and you will not be able to insert or eject tapes! If the lever is not properly positioned, remove the bottom front screw, slightly loosen but do not remove the two top side screws, hinge the front panel up, hold the Cassette Door in and lower the front panel into place again. Recheck the lever position and the door for proper operation and replace the bottom front screw.

Connect the cable with the five pin connector to header P2 on the Audio Board at the right rear on the Upper Chassis. The other cable has a two part connector; connect this to the double header P1 on the Control Board with each part of the connector to its mating part of the header. This connector assembly will only go in one way.

Install six more black phillips head screws; two on each side and two on the lower front edge. Install three pan head phillips screws on the lower edge of the rear panel. Ensure that all screws are properly tightened.

See that all connectors are in place and check Racorder for proper operation. Secure the Top Cover with ten black phillips head screws.


If there are any questions about operation of this system, or in case of need for service or repair, contact your local authorized dealer or our engineering department at (phone) 931 924 3216 or (fax) 931 924 3287.

RACORDER WEBSITE http://www.racorder.com

The RACORDER website is a good source of current information, including updated manuals, installation, service and technical information, service bulletins and other technical support.

You will also find there a general discussion on adding transmit and receive audio outputs to marine radios for connection to Racorder installations, as well as detailed instructions for many makes and models of radios.

General and technical questions can be sent via email to:


Dimensions: 15" W X 11.5" D X 5.3" H
Weight: 12 lbs
Power requirements: 120 VAC 50/60 HZ 25 Watts
Recording format: EIA; NTSC color signal on VHS Tape
Video Input: Video and Sync from radar interface
Audio Input: 100 mv, 100K ohms
Video Output: 1v p-p NTSC 75 ohm
Audio Output: 400 mv, 1K ohm
Tape speed: 11.1 mm/sec
Record/Playback time: 370 min using T-120 tape
Rewind/FF time: 90 sec with T-120 tape

RACORDER is manufactured and marketed in the USA by

Hiway 41 North, PO Box 938
Monteagle, TN 37356
Phone 931 924 3216
Fax 931 924 3287

This page created by Roark Enterprises - last modified December 7, 2004