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SeaTel Antenna Controllers

SeaTel has a variety of antenna controllers that ship with their antennas. The older 9797 antennas use the DAC-92 which is a 2U controller. The newer 9797s ship with a DAC-03 (also 2U in size) which has newer firmware for better manageability. The Ku-band antennas either have a DAC-97 (mostly for the older 4996 units), or a 2200 or 2202 controller. The newer 2200 series is smaller (1U) and can control the 4006, 4996, and 6006 antennas. The 2202 in particular has an Ethernet interface with a web browser built in, along with a wider tuner card (1 MHz). A 2202 can be used in place of a 2200 anywhere. The firmware versions of the 2202 stops at 5.20, while the 2202 supports revisions of 6.0 as of 2010.

DAC 2202

The 2202 has a built-in web server. The default IP address, the username is seatel, and password is 1234.


We have seen the DAC 2202 unit, even with the most recent firmware as of mid 2007, spontaneously(question) get the AZ trim value set to 10000 more than what it should be. This makes for very strange antenna positions above 890 degrees! When this happens, the trim value needs to be adjusted by highlighting the empty character block just left of the first 0, then tapping the frequency down with the arrow key until it gets back to the correct value.

When the DAC-2200 is power cycled, and the antenna pedestal is not, the DAC will report abnormally low AGC (<1000) and Threshold (<1000) values. If the DAC is then reset using the front panel reset button, the correct values are restored.
Technicians operating the system need to be aware of this peculiarity, and develop the habit of always resetting both the antenna (PCU) and DAC at the same time.
This condition was also experienced on the DAC 2202 units, and the issue was resolved with a software update. However, this is a DAC-2200, and is not capable of accepting any additional software updates, including the one with the fix for this issue. Seatel has no plans for any further improvements or updates to the DAC-2200. Only the DAC-2202 will receive future updates.


Ku-band tracking

When tracking antennas on Ku-band, the best signals to track seem to be wide 3rd party DVB carrier instead of the HiSeasNet shore-to-ship carrier. While this puts tracking at the mercy of the 3rd party carrier's uptime, it seems to lock on much better to the correct antenna and is still something that can be tracked using the DAC-2200 and DAC-2202 wide tuner card. As a result, please use the following tracking frequencies for Ku-band operation on SatMex5 :
Beam 1: 1090 MHz, 1130 MHz. These are DVB carriers, so set FEC="AUTO" (may need to be set first, then loop through the settings again to set the frequency), Tone="OFF", VOLT doesnt matter, NID="0000", and BAUD="20000".
Beam 2: 1360 MHz, 1295 MHz, 1211 MHz, or 1378 MHz. These are SCPC carriers, so set FEC="SCPC" then set the IF correctly (0 KHz).

DAC-97 and DAC-03

C-band tracking

On the Intelsat 701 (POR) satelite, there is an additional carrier at 80.505 MHz available for tracking (as of 9/2009). This is not a HiSeasNet carrier, so its stability and power level are entirely unknown and not guaranteed. If there is trouble tracking the HiSeasNet carrier on POR, this carrier may work better...with the risk of it disappearing at any moment. Some ships have reported better AGC/threshold ratios and better tracking using this carrier. Reliability of this carrier is still in question.


DAC Remote Panel (aka "DacRemP")

This is Windows software that will allow an antenna controller to be remotely displayed and controlled on a Windows computer over a serial link. There is also a version called "DacRemIP" that will allow control over a network connection through a terminal server or directly to a newer, network-attached antenna controller. This is officially unsupported software from SeaTel that was NOT designed for the end user, but rather their engineering department and their installers. However, it seems fairly stable (but does change a little bit from version to version). It provides not only remote panel display, but also some tests (some dangerous to the casual user), tools, and lots of debugging plots and logging capabilities that make it most helpful for getting troubleshooting information back to shore. The software and some slides from the SeaTel training program (about the only documentation there is) can be found in the HiSeasNet fileshare repository.

We have noticed that DacRemP sometimes winds up changing the IF of the DAC. Not sure why (perhaps related to a bug in version 18, maybe related to no error checking on the DAC commands), but it seems to be implicated in mysterious IF changes. Naturally, when the IF changes, then tracking gets difficult as the wrong frequency is being used for AGC. Here's an FAQ related to it.


DacRemP version 0.18 has a bug where the AGC is not recorded. The replacement .exe file (also available in the file share repository) should be copied over the DacRemP binary from 0.18. Be careful to have the ADMC data display window open when making changes and not start a log from the file menu. It is always best to check the log files to make sure you are getting the data you expect before you leave them for long periods of time. There seem to be lots of little ways to get DacRemP to not do what you want.

Error Codes

These are listed in the SeaTel manuals, but might be looked at more if they are listed here. The error code on the right side of the display is a system error that breaks down to these entries. A number that isnt here indicates multiple errors (ie. a 20 indicates a 16 and a 4 error).




Satellite Out Of Range


Reserved for future use


Reserved for future use


Conscan Error


Pedestal Error


ACU-PCU Communication Failure


Wrong Synchro Converter Type


Gyro Read Error

Errors on the left side of the error display screen are "bit errors" or "comm errors" that indicate a minor problem communicating between the dome and the antenna controller. For a little hiccup, the number is increased once. For larger problems, the number increases more rapidly. Those errors count up from 0 to 255 then wrap back to 0. Since bit errors do occur from time to time, having a non-zero number is normal and the occasional increase is also normal. The wrapping nature of the count makes it difficult to compare one number to the next unless the value is continually watched to see when it wraps around again. As such, the error count is really only significant when they increase steadily (1 count every few seconds or faster). If bit errors are increasing quickly (about 10/sec), but all appears normal, it may be related to some sort of activity on the serial control port. Try unplugging any cables to a computer talking to the DAC's M&C port (possibly to DacRemP) and pluging it back in. Sometimes stray commands trigger this bizarre behavior.

Connecting modems to antenna controllers

The newer DAC firmware versions allow for a cable to be connected between the modem's alarm port (DB-15) and the DAC so that the DAC will (a) be automatically put into search mode when it stops searching but does not have a lock on the satellite and (b) stop the modem from transmitting when the antenna enters a blackout zone . This should help prevent locking onto the wrong satellite. Comtech and Teledyne both supply DB-15 "Alarm" ports to handle these features, but the significance of the pins are different between the two modems.

Connecting to Comtech modems

No one has tested this in our configuration yet, but anyone who is interested is welcome to try it. The attached cable schematic shows how to connect to the DAC terminal strip, but we often do not use one. The pinouts directly to the gyro port should be listed in the terminal strip schematic in the DAC-03 manual. If you get this working before we get it tested, let us know! If all goes well, we can purchase these cables for the fleet.

-Nov, 2010:   We have been using the cable for a few years on the Knorr.  More recently, it's been added to the Oceanus and the Atlantis.  Over all, it seems to be a good thing.  There is a writeup here,with a diagram for a cable direct from the DAC to the Modem.  There are some pictures herehere, and here.  Note that there may be some typos.  You need to have some electronics skill to do this.  While it seems to work well, it's probably still in the beta stage.  Robbie Laird, WHOI/SSSG

Connecting to Teledyne Q-Flex modems

The Teledyne modem provides the same features as the Comtech modems when it comes to both:

  1. Tx mute of the modem carrier while the antenna is in a black zone
  2. Automatic search for the satellite when the antenna controller has a high AGC but the modem is unlocked (a condition usually indicating the antenna is locked on the wrong satellite).

To enable these features with the Teledyne modem, one needs to be careful to identify which Terminal Mounting Strip (TMS) hardware is in use. Different antenna controllers provide different DC voltages and different TMS revisions provide different layouts. Ultimately, the goal is to have both:

  1. A correct amount of voltage out of the controller to the TMS external AGC pin. This pin then connects to the Teledyne's normally closed Rx traffic pin (indicating when the modem is locked or not locked).
  2. The Teledyne transmit inhibit pin connected to the SW2 pin of the TMS (muting the modem when the antenna controller is in a blackout zone).

Additionally, the following pinout notes should need to be followed for complete use of the function correctly:


As a baseline, all antenna controllers and terminal mounting strips need to have the following configuration. This description assumes the old Comtech-supplied modem cable is being modified to handle the Teledyne alarms port that has slightly different pinouts than the Comtech modem. The antenna controller pins are likely in the correct spots if this cable is in use.

  • TMS "GND" terminal has a black wire connecting to Teledyne alarms port pin 2 (ground)
  • TMS "GND" terminal may have a green wire that would need to be connected to Teledyne alarms port pin 15 (ground)
  • TMS "SW2" terminal has a red wire connecting to Teledyne alarms port pin 7 (Tx Inhibit aka mute)
  • TMS "EXT AGC" terminal has a white wire connecting to Teledyne alarms port pin 10 (Search-when-modem-not-locked feature)
  • Set the DAC System Type parameter to include the features and use the attached cable. To set this, one needs to activate the binary 2 bit in the value that is the system type. With this features disabled (the antenna controller is not using the cable to the modem), the value should set to 0005, 0013, or 0069. To enable the feature, add 2 to the current System Type value so that it is either 0007, 0015, or 0071. Simply adding 2 to a system type other 0005, 0013, or 0069 will not provide the expected behavior!

Additional adjustments for any DAC with a dual-circuit-board TMS:

There is a yellow wire on the antenna controller side of the cable. One end of that yellow wire is crimped together with the white pin connected to the TMS terminal "EXT AGC", and the other end of the yellow wire should connect to the TMS terminal "+24V".

Additional adjustments for any DAC with a single-circuit-board TMS:  

Jumper JP4 on the TMS must be closed (pins jumpered together)

Jumper JP5 should have the bottom two pins jumpered together so that +24V is indicated.

Measure with a voltmeter between TMS terminals GND and 12/24 (the two next to each other on the same grey header) to confirm there are at least 12V present. No wires need to be connected to the grey headers. The single yellow pin does not need to be connected to the TMS at all.


The MXP system does not have a TMS, but uses a 10-pin header labeled "J12 (Aux)". Erich Gruebel on Endeavor has rigged up an appropriate cable that works between an MXP unit (on the 4012 and 6012 antennas) and the Teledyne Q-flex modem. He made a great write-up on how this works.

Antenna hardware


In addition to the RF safety information at the beginning on the antenna manuals, SeaTel publishes an RF safety document regarding power levels and distances from the antenna that may be deemed safe by FCC standards.

Dome equipment


The 4006 and 6006 antennas are L-band in their IFL cables (the ones that run between the dome and the below decks gear. For this, an RG8/U type coaxial cable such as a Belden 8214 or LMR-400 from Times Microwave is recommended. Both of these cables are the same size and use the same "N" type connectors. Both these cables have very good RF shielding, which is a necessity. At L-Band they both are low loss (approx 5dB/100ft), and have low resistance to DC current. While Belden and Times Microwave are mentioned by name, there are many different cable suppliers that make cables with the same exact specifications. These cables should be fairly easy to come by (if there isnt already some scrap on a ship) and run in the ballpark of $0.30-$0.50 a foot with connectors being about $5 each.

Startup sequence for above decks gear

Please see What should my antenna do on power up? for a description of the startup sequence that the antenna goes through when power is applied.

Radome attenuation

Seatel has been consistent stating that the loss on the XX97 series radomes are approx. 1-3 dB, depending on weather conditions, (more attenuation when the radomes are wet). In clear skies conditions, it may be reasonable to plan on 1 - 1.5 dB of attenuation.

Spare Parts

The belt part numbers have changed since the initial publishing of the manuals. The ones we know about include:

  • Elevation belt: old p/n 1423907-14537, now p/n 123907-14537
  • Timing belt: old p/n 116903-11537, now p/n 116903-17537.

A few notes about specific parts:

  • Servo amps with part number 116000-1 are for the 9797 and 4996 series antennas only. The xx06 series have the motor driver board inside the PCU.


SeaTel Antenna Air Conditioners

The SeaTel 9797 and 4996 antennas ship with air conditioner units from Marine Air Systems More information is at Marine Air Systems Air Conditioners. The L-band based systems (6006 and 4006) do not have air conditioners as they are designed to have less heat-generating equipment up in the antenna radomes.

Routine dome check

If accessibility to the dome while at sea is a problem, it is probably not a bad idea to do a visual check up in the dome at every port stop to make sure things are as they should be before the start of a cruise. Heck, even if there are no accessibility problems, it isnt a bad idea to do a visual gear check every port stop. Such a check might involve the following points:

  • Check the dome for any missing weights or debris on the floor that may have fallen from the antenna frame.
  • Check for damaged or loose cables or connectors.
  • Check the bubble level on the level cage to see that it is mostly centered
  • Check the air conditioner set point (85deg), errors, and filter.
  • Look for leaks, cracks, problems with the radome panels and caulked joints. Check from inside and out.
  • Pressure wash outside of dome if appropriate.
  • Touch 3 motors to see if one is excessively hot.
  • Verify doors are sealed when leaving.
  • Power off checks (start by turning power off):
    • Check the balance (at level 45deg elevation, it should hold its place or gradually drop without acceleration).
    • Verify dish will sweep full elevation range of motion (-15 to +115 degrees) physically.
    • Verify dish will sweep full elevation pointing (0-90 degrees) when commanded by DAC.
    • Verify dish will do a full azimuth sweep physically at the lowest physical elevation.
    • Verify dish will do a full azimuth sweep at the lowest pointed elevation when commanded by the DAC.
    • Verify dish frame lines up with and will safely bump against all rubber stops should it reach the end of its range of motion.
    • Power the antenna back up and watch the startup sequence
  • Verify that any DAC errors generated by the power outage of the dome clear successfully and stay that way.