Author Archives: Stan Honey

Grib files, Saildocs, Weather data

The following link will take you to the Saildocs site.

Saildocs

Saildocs provides custom grib weather-data files per request from data downloaded from NOAA/NCEP and other sources.

Additionally, Saildocs provides document-retrieval for the delivery of text-based Internet documents either on request or by subscription.

Saildocs is supported by the Sailmail Association and can be used by anyone who agrees to the terms and conditions (below).

Troubleshooting Slow Receive Speeds

Slow receiving speeds is usually a symptom of interference- electrical noise from some on-board equipment creating interference with your radio receiver. Common culprits are shore-power battery-chargers (yours or a marina neighbors, or running from a genset), also some AC inverters (especially small ones often used to power computers), also some 12v fridge units (e.g. Adler Barber, Frigiboat), some 12v florescent lighting, some instrument systems, etc. This is a general radio problem, not particular to Sailmail or email.

Clues that this is a problem include continuous or periodic tones or squealing or chirping over a wide range of frequencies, or simply a higher-than-normal level of static or “hiss”. The radio’s signal-strength indicator may also show a higher signal level than expected for a quiet channel- the M710 should no signal-strength bars when listening to a quiet channel above 8 megs, and perhaps 1 or possibly 2 bars on lower frequencies.

Isolating receiver noise requires a bit of rigorous testing, don’t try to shortcut this. When underway or in a quiet anchorage (and away from marinas and power lines), turn off everything except the radio (everything!). Then find a weak-but-clear radio station (e.g. WWV on 5 or 10 megs, or a shortwave broadcast station). Then listen carefully while you turn on each circuit one at a time. If the station disappears under static, or you hear suddenly hear beeps or squeals, then you found a source of interference- turn off that circuit and continue, there may be more source of interference.

Depending on what you find, it may be possible to filter the offending equipment but the short-term fix is to make sure that circuit is turned off when using the radio. The biggest problems are often in marinas, where noisy battery chargers can wipe out radio reception for a whole dock or the entire marina. Short of pulling the main breaker, there is no easy solution. Fortunately most marinas also offer some sort of wireless internet connection.  There is information here on how to connect to Sailmail directly via internet.

Also check the antenna and ground connections carefully, a corroded connection can cause problems for both sending and receiving. It is a good idea to disassemble, clean and reconnect the antenna and ground connections at least once a year, especially in the tropics.

And of course pay attention to Airmail’s propagation window, make sure your lat-lon is up to date and select times and frequencies which are well within the “green” zone.

Good luck and good sailing,
Jim & Sue

Troubleshooting Slow Transmit Speeds

If your sending speeds are consistently slow then there is something wrong on the transmit-side of your equipment– an incorrect setting, a problem with the radio itself, or perhaps a problem with the tuner or antenna. Check your equipment carefully, or find a qualified radio technician to help (and have him read this also). In order to send at optimum speed your needs to be transmitting full power (or some reasonable fraction) and the antenna must be working efficiently.

Start with the radio power-settings and make sure that your radio is set to hi-power mode, power-level “3” for an Icom-M710. (Note that these comments are general but include some specific details for the Icom M710, other radios will vary). One of the myths is that low-power works just as well, this is only true when the station is relatively close- and definitely NOT the case from the middle of the South Pacific.

Next check the tuner connections- make sure that the ground and antenna connections are clean and tight. It is a good practice to remove, clean, and reconnect these connections every year or so, and make sure they are protected from the weather. Also make sure that the wire from tuner to antenna is as short as possible and spaced away from other wiring and metal by at least 2-3″, do not strap this wire into a harness bundle or to the lower backstay for example.

Next check the tuner function: Most marine radio’s have a “TUNE” indicator which indicates when the tuner is active, and when it has properly tuned. For an M710 and M802 radios the “TUNE” indicator on the display will flash for a few seconds when first transmitting as the radio completes its auto-tune cycle, then “TUNE” will remain ON steady. If “TUNE” flashes and goes off then the tune-cycle failed, and the radio will be transmitting very inefficiently and only with a few watts. This is either a tuner problem, or a problem with the control-cable, or a corroded antenna or ground connection.

Next check the transmit power-output. Most radios have a power-output indicator, the M710 has a “bar-graph” of 8 segments. For a M710 the power-out indicator should indicate 7 bars on steadily when calling the station, with the 8th bar (above the “SQL” label) flickering). (You can initiate FSK-transmission with Airmail’s “Set-PTC Aplitude” control, under the Control menu on Terminal window).

If you have a battery monitor which shows DC amps used from the battery, then another good way to check transmit-power is to check the INCREASE in DC amps while transmitting (with battery-charger OFF). For an M710 or M802 this should be 8-14 amps, 100W radios will be a bit lower. For example, if the battery-monitor shows 5 amps when listening, then it should show about 15 amps (a 10-amp increase) when the radio is transmitting.

If the transmit power is low, then this likely indicates that the “FSK” and “PSK” amplitude settings in Airmail are not correct for your radio. (These settings control the modem’s audio “volume” control for the signal sent to the radio, and this in turn controls the transmit-power. The FSK setting is used for calling, PSK once connected. PSK should always be about 30% higher than FSK).
Open Airmail’s Tools/Options menu, connection tab, and check these settings in the lower-right. (You can also access these settings when Terminal-window is open, via Control/Set PTC amplitude menu). Older Icom M710’s are usually 140/170 for FSK/PSK, newer M710’s and M802’s are usually 250/330, systems which Marc Robinson set up usually have special cables and are set to 600/1000, Furuno radios are usually 1500/2000.

If increasing the FSK/PSK levels does not increase transmit power then the radio may be set to low-power mode (see above), or there may be a failure in the radio’s power-output transistors. You can verify the transmit function independently of the modem by finding an unused voice-frequency (e.g. 12,359.0) and whistling into the mic while watching the power-out indicator and/or battery-monitor. You should be able to reach full-power output no problem.

If problems persist then Sailmail members should write to sysop@sailmail.com with as many details as possible.

Good sailing,
Sue & Jim

Troubleshooting USB problems

Most new computers do not include RS-232 serial ports, and a USB/serial adapters is the most common way to connect serial devices such as a Pactor modem or a GPS. Most USB/serial adapters are reliable but unfortunately there are enough bad ones out there to cause a lot of problems. Our current favorites are any of the adapters that use the “FTDI” chipset, for example the Sabrent  CB-FTDI or search Amazon for “FTDI RS232”. Many others also work fine, just be sure that drivers are included for whatever version of Windows you are using.

If you are having problems with a serial device connected with a USB/serial adapter, here are some troubleshooting tips.

First, try to enlist the help of whoever you purchased the adapter from. If it was a Comp-USA store or a low-budget local vendor, then you may find this approach unrewarding. File that away for next time, and keep reading…

The first step in troubleshooting any system is to simplify it as much as possible. If you have multiple devices connected, then remove all but one and focus on that. If you are connecting through a USB-hub (multiple USB ports connected to a single USB-connector on the computer) then remove that, and plug your USB/serial adaptor directly into the computer. Be methodical, take notes, and simplify the configuration to the minimum and get that working before adding other devices.

Next, open Airmail’s Options window (Tools menu) and click the connection tab. Select each com-port in turn and note the description. Find your device and make sure that it is selected. The most common problem is having the wrong COM-port number. Also make sure that the baud-rate is set correctly, some USB adaptors do not like 115200 baud but all should be happy with 57600. (PTC-IIusb modems always use 115200 baud, and Airmail’s “Getfax” fax companion will be happier at 115200 if the modem-firmware is current).

If the device is not visible in Airmail’s options window com-port list, then open Windows Device manager: Right-click on “my computer” and select properties, or open Windows control-panel and select “System”. Click the “Hardware” tab and then the “Device Manager” button. Look for yellow question-marks, this would indicate a device whose driver did not load properly. If you find one of these then you need to identify the device, get the appropriate drivers and then right-click on the device and “update drivers”. Next find “Ports”, expand that (click the little “+”) and look for your USB/serial adaptor. If found, note the com-port number. That same com-port number should appear in Airmail’s Option window (remember to re-open the options window after changing devices), if not they it did not install properly.

If still no luck then make sure you have the correct– and latest– drivers for your USB/serial adaptor. Go to the manufacturer’s website, click on “support” or “dowloads” and find the drivers page. Download the driver-files for your device, save then in a “drivers” folder and then go back to device-manager (above) and try updating the drivers.

If still no luck then you may just have a turkey, see the comments above about Keyspan single-port adaptors or Edgeport multiport boxes. Or find a dealer who can supply an adaptor that they will stand behind, and will help you with if things don’t go according to plan.

Also worth noting: Some adapters assign com-port numbers according to the device serial number, so that a given adapter will always be “COM4” for example. Alternately, some devices assign COM-port numbers according to which USB-socket the adapter is plugged into. In this case moving an adapter from one USB socket to another will cause things to stop working. So a good rule of thumb is to always use the same USB socket for each adapter.

Good luck and good sailing!
Jim Corenman

Relaying group messages Part I. How to send lots of cc’s.

A “relay” feature is available for Sailmail members, to make sending group messages easier. Traditionally, messages were sent to family and friends using “CC” addresses, allowing one message to be sent to multiple recipients. However, with the increased concern over “spam” (junk email), many internet services are blocking messages with large numbers of CC’s. Additionally, many folks do not want their email addresses to appear on long CC-lists for privacy reasons. BCC’s or “blind copies”, where the CC-addresses are hidden, are another possibility but those are often used by spammers and are increasingly being blocked by spam-filters. The only kind of message that reliably gets through spam-filters and does not cause privacy concerns is an individually-addressed email to each address, which was not previously practical via a radio link.

As a service for Sailmail members we’ve written some new software and created a special address (as part of the Saildocs weather server) for handling group mailing. Send one copy of your message to relay@saildocs.com. At the beginning of the message (before the normal text) include a list of email addresses, formatted with one address per line. Follow this with a blank line, then the message text as normal.

The relay-processor will check the format, and then step through the list of email addresses and create a new message addressed to each recipient, with only the message text (not the email list). The from-address and subject line will be the same as your original message and any bounce-messages will be returned to you (so check addresses carefully!).

Here is a sample message:

=====================
To: relay@saildocs.com
Subject: Update from the “Leaky Duck”

wxy9999@sailmail.com
somebody@hotmail.com
another@hotmail.com

This is an update of our adventures aboard “Leaky Duck”.
Please send us mail at this address (but keep it short).
=====================

This will send three copies of our test message, the first to wxy9999@sailmail.com, the second to somebody@hotmail.com and the third to another@hotmail.com.

You can set this up as a group in Airmail as follows:
Open the Airmail address book (Toolbar button or Window-menu, address-book), click “New” and enter a name for the group. In the “To” box enter “relay@saildocs.com” (without the quotes). Then in the “Message Text” box, enter your list of email addresses one per line (use the right-click mouse button to copy and paste from elsewhere, such as the CC-box of an existing CC-style group list). Add an extra blank line at the end, then click OK. You can revise this the same as any address, by selecting the group name and using the “Properties” button. (If you want to create multiple entries of this sort, use “relay1@saildocs.com” for the first, “relay2@saildocs.com” for the second, up to relay9).

Then to create a new group message, click the “new message” button (or File/New menu), select the appropriate group name from the address-book, and click OK. Fill in the subject, then hit Tab to go to the end of the email-list and start your message. Always make sure there is a blank line at the end of the list of addresses, but no blank lines in the list of addresses.

The list of email address can either be simple addresses (example: somebody@hotmail.com) or can include a “friendly name” using the following format– include quotes around the “friendly-name” and enclose the email-address in <>’s per the following example:
“Arthur Dent” <somebody@hotmail.com>

Also note that from Airmail ver 3.1.933 onwards, you can enter your own “friendly name” in the Tools/Options window, settings tab. The “From name” is sent using quotes in the above format, along with your usual email address. With most email programs, the “friendly” from-name is what folks will see, so they will know who the message is from. Use plain-text only for the From-name, no special or accented characters.

There is also an “insert” feature available for folks who want to get fancy (and are comfortable messing about with computers), see click here or send a blank email to relayinfo2@saildocs.com.

IMPORTANT NOTE: For security reasons, this feature is only available to Sailmail members for messages sent through the Sailmail server, either by radio or internet using direct-access “telnet” connections or Sailmail’s POP3/SMTP server. The Sailmail terms and conditions apply to the use of this service.

Enjoy!
Jim & Sue Corenman
Stan & Sally Honey
sysop@sailmail.com

USB drivers for the SCS Pactor modems

Any USB device requires drivers to operate. In some cases (keyboards, mice) these are included with Windows, but in most cases they are provided by the device manufacturer (SCS, in the case of the USB-connected Pactor modems).

This note applies to the SCS USB-connected modems: the PTC-IIusb, DR-7800 Dragon, and the PTC-IIIusb, and “PTC-IIusb” here will refer to any of these modems. Serial-connected modems (PTC-II, PTC-IIe or IIex, PTC-IIpro) may be connected with a USB/serial adaptor, those also require drivers and much of this note will apply– except that the driver-files must come from the manufacturer of the USB/serial adaptor, and not with Airmail nor from SCS.

For the SCS PTC-IIusb and other USB modems, the drivers are provided on a CD-Rom that was provided with the modem, or can be downloaded from the SCS website, and are also installed with Airmail. Once installed properly, the drivers will create a virtual “COM port” to access the modem.

There are some potential wrinkles: Drivers on a CD that came with a modem that was purchased years ago will not be compatible with newer versions of Windows. Similarly, an older version of Airmail may not have installed the newer drivers needed for Win-7, and in particular Win-7 64-bit version. Also, if the modem was plugged in before the drivers were made available then Windows may have “given up” trying to install it, even after the drivers are available.

This note will outline how to check for USB driver issues and how to fix them. You need to be logged into the computer as an “administrator”, usually the primary (first) login if there is more than one. For Win-7 you can check (and change) your user-status in Control Panel, “User Accounts” (select “small-icon” view in the upper-right part of the Control Panel window).

If the drivers are installed correctly then Airmail’s “Setup Wizard” (Tools menu) will automatically find the PTC-IIusb modem, and show the correct COM-port on the “HF-Modem” page.
If it doesn’t, then cancel that window and proceed with some checks:

Device Manager:

First, open Windows “Device Manager”. Start by opening Windows Control Panel, select small-icon view (upper-right) if needed, then find “Device Manager” and click on that. This opens the Device Manager window, which shows all connected hardware devices.

Start by looking for yellow “?” or “!” icons (symbols), those are “unknown devices” and indicate that something is not working– perhaps the modem, maybe something else. A modem with no drivers may be listed as “USB serial port” with a yellow icon, that is the same thing as “unknown device”. Leave the Device-Manager window open and disconnect the modem’s USB cable from the computer. Does the yellow icon disappear? If so then the “unknown device” is your modem, continue below.

If there are no yellow icons, then find “Ports” and expand that by clicking the little arrow. The “SCS PTC-IIusb” should be listed there, along with the assigned COM-number. Note that COM-port number, then compare to Airmail’s settings (Tools menu, Options window, connection tab) and correct that setting if needed. The baud rate for a PTC-IIusb modem is always 115200.

If you do find an “unknown device” (yellow icon) and you have confirmed that it is the modem (by disconnecting and reconnecting the USB cable), then we need to sort out drivers as follows.

Installing Drivers:

The Airmail install program also installs the SCS drivers, but older Airmail versions will not have the correct drivers for newer versions of Windows. Specifically, Airmail ver 3.4.062 has drivers for all Windows versions including Win-7/x64 (64-bit), while Airmail ver 3.4.034 is only good through Win-7/x86 (not 64-bit).

So if you have an older version of Airmail, then download the latest Airmail version (3.4.062) and install that, making sure that the “Install PTC-IIusb drivers” box is checked on the last page. Do this with the modem unplugged from the computer. Then power on the modem and plug in the USB cable, Windows should automatically find the drivers and install them. Restart Airmail and run Airmail’s setup wizard.

If you have deleted driver software (below), then you can always re-run the Airmail installer program. If you don’t change any settings, then the installer will not change your Airmail setup. When you get to the last page, check the box that says “Install PTC-IIusb drivers” and click “Finish”. Do this with the modem unplugged, then reconnect the modem and power it on.

If Windows can’t find drivers, or Airmail still can’t find the modem, then be sure the modem is connected and powered on, go back to Windows Device Manager and find the unknown device, right-click on that icon (i.e. click with the right mouse-button, not the left), and select “Update Driver Software”. Select “Search Automatically”, and wait while it searches for drivers. If Windows reports success then proceed as above with Airmail’s setup wizard.

Downloading drivers:

If still no luck then download the drivers from the SCS website. Go to www.scs-ptc.com and click on “Download” at the top, then scroll down that page and click on the link for USB drivers:
“USB driver for SCS PTC-IIusb …”. On the next page click on the driver file which will be “SCS USB Driver 2.08.02 WHQL Certified.zip” or similar, and save that file to a “downloads” folder.

Now open your “downloads” folder (whatever it is called), and open the file that you just downloaded. It will be a compressed “zip” folder, containing another folder called “SCS USB Driver 2.08.02 WHQL Certified” or similar. Copy that folder to a “Drivers” folder on the local hard drive (C-Drive) where it can be easily found– create a new “Drivers” folder if it is not already there. So under “Local Disk” you have a “Drivers” folder, and under that the “SCS USB Driver…” folder.

Installing drivers manually:

Once drivers are downloaded and saved in a “Drivers” folder, go back to Device Manager and find the “unknown device” again, and again right-click and select “Update Driver Software”. This time select “Browse my computer”. Click the “Browse” button and select the “SCS USB Driver…” folder that you downloaded and and copied to the “Drivers” folder. Click “Next” and wait while Windows installs the drivers.

Windows may come back and report success, in which case you should be done– go back to Airmail’s setup wizard, above, and see if Airmail finds the modem. If Windows says that the drivers could not be installed then unplug the USB cable, wait a few seconds, and reconnect. Check Device Manager– the modem should be listed as “SCS PTC-IIusb” under “Ports”. Continue as above.

Deleting old drivers:

If still no luck, and you have either downloaded the drivers from the SCS website, or you have the current Airmail install program, then the next step is to delete any current PTC-IIusb drivers and start over. Go back to Windows Device Manager, find the PTC-IIusb or “unknown device” icon, right-click on that and select “Uninstall”, and check the box that says “Delete driver software” (if visible). Click OK, Windows will uninstall the device and delete the current drivers.

It should re-appear as an unknown device, if not then select “Scan for hardware changes” (Action menu) or disconnect and reconnect the USB cable. It should now be an “unknown device” (yellow icon). If you don’t see it then check under “Ports” for a “SCS PTC-IIusb modem”, it might be re-installed but with older drivers– repeat the “Uninstall” (and delete driver-software) as many times as needed until it appears as an “unknown device” or (“USB Serial port” with a yellow icon). Then proceed with “Installing drivers”, above.

If there is still no luck then something is likely broken. Try a different USB connector on the computer, try your modem on a different computer, or try a different modem on your computer– the USB interface may be faulty.

(revised 2012-05-05)

COM-port assignments for Airmail

Pactor modems are connected to the computer via a “communications port”, either a built-in 9-pin serial port (unusual these days), a USB/serial adaptor, or a direct USB connection e.g. from a PTC-IIusb. COM-port numbers are assigned by Windows as new devices are connected. COM1 will often be a reserved number, even if no COM-ports are previously connected.

Airmail must be set to use the same COM-port number that the Pactor modem is connected to. In the case of a PTC-IIusb, Airmail may have found it automatically, otherwise it needs to be selected from a list of available ports. In any case, if you see an error message from Airmail that initialization failed, or that a particular COM-port does not exist, then the correct COM-port is not selected, or the device was not properly installed and the drivers are not available.

The quickest way to get Airmail’s COM-port set correctly is to use Airmail’s Setup Wizard. With the modem connected and powered on, open the Setup Wizard from Airmail’s Tools menu. Click “Next” until you get to the “HF modem” page (answering questions if this is the first time). If you have a PTC-IIusb then is should have been found automatically– check the COM-port number, and description below the baud-rate box. If you have a serial-connected modem, then click the “Search” button and Airmail will try to find and identify the modem. Click “Next” to finish, or “Cancel” to quit without updating settings.

Another way to check Com-port assignments is with Windows Device Manager. With the modem and adaptor plugged in, open Windows control panel, select small or large Icon view, and click on “Device manager” (for Win-XP, from Control panel select “System”, “Hardware” tab, and then the “Device Manager” button).
In device manager find “ports”, expand that (click the little arrow or “+”), and check for your USB device– it should be listed, with a COM-port number. Take that back to Airmail’s Options window or the Setup Wizard.

If the modem or USB/serial adaptor is not found, then the drivers did not get installed correctly. Look for a yellow “?” or “!” icon, that represents an “unknown device”. Unplug the modem or adaptor from the computer’s USB connector and watch Device manager– it should refresh, and if the yellow icon represents your modem or adaptor then the icon will disappear, and re-appear when plugged back in. That confirms the identify of the device.

USB devices need driver files which have been updated to include your version of Windows. Teh current version of Airmail includes drivers for the PTC-IIusb for all current Windows versions, but the CD’s that are supplied with many USB/Serial adaptors are years old and out of date. Go to the manufacturer’s website, find the “Support” pages and look for driver files, and follow the instructions there.

If you need more help, send a note to support@sailmail.com and include the type of modem (e.g. PTC-IIusb, etc), what version Windows, and how the modem is connected (e.g. for a PTC-IIex or PTC-IIpro, what make/model USB adaptor), and what you found in Windows Device Manager.

Cheers, Jim
2011-10-31

Using AirMail with both SailMail and Winlink

The same copy of Airmail can can be used to access both the SailMail system and the ham radio stations.

The SailMail Association is a non-profit association of yacht owners that operates and maintains a network of private coast stations in the Maritime Mobile Radio Service. Sailmail provides low-cost email service to its membership, which is limited to recreational vessels. Users must be registered, details and registration information are available from http://www.sailmail.com/. The advantage for hams is that Sailmail has no restrictions on third-party traffic or business-related messages. The stations are also in different places which might provide easier access from some locations.

In order to activate the Sailmail mode for Airmail you need to copy a system definition file (System.Sailmail.ini) to the airmail folder. This is normally done by the same download that brought you this note. (Alternately, send a blank message to: stations@saildocs.com).
When you restart Airmail it reads the definition file and makes the appropriate changes to airmail.ini to add a system called “Sailmail” in addition to “Ham”.

Connecting to Sailmail:
=======================
In order to handle other stations such as Sailmail, a new level of control was created called “System”. Logically speaking, each system includes a set of stations, and each station includes a set of frequencies. Airmail (as downloaded from the Airmail site) comes configured for the “Ham” system alone.

When a second system is defined then a new pull-down box appears to the left of the “Station” box in the Terminal Window, for “System” – HAM, SAILMAIL, etc. When you choose a system it will remember the previous station and frequency and set the appropriate mode if required.

So first select the appropriate system, then the station and (if the remote frequency interface is connected) then choose a frequency. To connect click the green “Connect” button (or use the F5 key), exactly as before.

Posting outgoing messages
=========================
Sending messages to a ham station is done in the same way as before, by posting to the station’s callsign (or multiple callsigns). A message can also be posted “WL2K” for any Winlink-2000 station, or to “Ham” to send it to any connected ham station. There should be a default entry in your Auto-post list (Tools/Options, Routing Tab) that says “Default=Sailmail” or “Default=WL2K” or whatever, if it is not there then add it. This will cause any message to be automatically posted to that system, unless specified otherwise in the Address Book or Message Header “Via” box. You can always change the posting with the File/Change Posting menu (or by right-clicking the message in the message index).

Messages to Sailmail are addressed to the gateway name “EMAIL” rather than “NEXUS”, but Airmail will take care of this automatically. Messages for Sailmail should be posted to the system name “SAILMAIL” rather than the station callsign. Messages posted to “Sailmail” will be sent to any Sailmail station which is connected to. So an address book entry for a message which should always go via Sailmail would specify “Sailmail” in the Via box.

Be sure to add a “support@sailmail.com” entry to your address book as above, that is how you send a note to the Sailmail support folks in case of any difficulties or questions. And for membership questions, send a note to: admin@sailmail.com

Maxsea Grib Compatibility

This note is for Maxsea users, regarding grib-display problems with certain versions of Maxsea.

Background: Grib (GRIdded-Binary) files are packed-binary data files which contain weather-forecast data. The grib format is an international standard which is supported by a variety of systems and software. Data in a grib file is stored as a “grid” or array of numbers in a packed-binary format. The grib format allows data to be organized either by increasing latitude with a positive latitude-increment (delta-lat parameter), or by decreasing latitude with a negative delta-lat. NOAA’s GFS model, Saildocs and Raytech use the positive convention; Maxsea and OCENS/GlobalMarineNet use the negative convention. Any grib viewer must support both conventions, and most do.

However there is a problem with certain versions of Maxsea which fail to correctly display positive-convention grib-files for southern latitudes. The data image gets inverted north-to-south (not east-west). The effected releases include Maxsea version-10 PRIOR to 10.3.5 (which was the final Ver-10 release). Version 10.3.5 is OK, and Ver-9 and -11 also appear to be OK. Others are untested, if you have an earlier/later version please check it (see below) and send me a note if you see the problem.

To temporarily accommodate users of Maxsea versions with this problem, Saildocs can also supply negative-convention grib files. In the grib-request message change the delta-lat parameter to a negative number, =
for example:
send grib:30S,40S,168E,180E|-2,2|24,48,72
In this example the “-2” specifies a negative-convention file which will avoid the Maxsea problem. (Complete details on the request-format is available be sending a blank email to: gribinfo@saildocs.com).

The simplest way to check whether your Maxsea program has this display problem is to request two small grib-files from Saildocs for the southern hemisphere, one normal file and one negative-convention. Use =
Airmail’s grib-request window and then modify the request message, or simply send the following two lines to: query@saildocs.com

send grib:30S,40S,168E,180E|2,2|24,48,72
send grib:30S,40S,168E,180E|-2,2|24,48,72

This will request two files, identical except for positive/negative data convention. The grib-viewer must display them identically. When you get these files, open each with Maxsea and check the weather over North Island, New Zealand. If the two files display differently then your Maxsea version is not correctly displaying the positive-convention grib file. A short-term fix is to edit each grib-request before sending to specify a negative latitude increment following the example above. Feel free to contact me with any questions at support@saildocs.com.

The longer-term fix is to update your Maxsea version. Furuno now handles distribution and support for Maxsea. They have acknowledged the problem and have made ver 10.3.5 update discs available without charge for users of prior ver-10 releases which are effected. This update only applies to ver-10 users prior to 10.3.5 and won’t work without a version-10 dongle. Contact Furuno for a copy of the 10.3.5 CD.

Jim Corenman
support@saildocs.com