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Send and receive email (plus weatherfax data) using your existing or new HF radio system. See the full range of SCS HF modems on our webpage here.                 

Which Pactor Modem to buy?

Which Radio Modem to Buy
There are 2 models of Pactor Radio Modems from which to choose; The SCS PTC-IIusb ore PTC-IIex. From a Sailmail or Winlink viewpoint, the primary differences between these two are:
  1. The PTC-IIusb connects directly to a computer's USB port and gives you computer-controlled frequency selection.
  2. The PTC-IIex does not provide for computer-controlled frequency selection; however, computer-controlled frequency selection can be provided to some SSB radios by connecting specially constructed cables between the SSB and the computer (you need to be quite computer savvy to get this solution opoerational).

Both modems incorporate the same digital signal processing circuitry and have the same ability to send and receive emails etc. Both of our modems include the pactor 3 upgrade in the price (most other dealers try to add this cost as an option post sale) and also include blue tooth functionality (usually an optional added cost with other dealers)

Frequency Control via Computer - How Important is it?
 Currently there are seventeen shore-side Sailmail Coast Stations worldwide to which you can connect. Each of these stations scans from five to twelve frequencies, making a maximum total of around 115+ frequencies to be monitored. So just how important is the ability to control the radio with your computer? The short answer is it's really important - Here's why:
  • The transmitting frequency and station call sign must be associated with each other in order for radio-based e-mail to work. AirMail must send a connect request to a Sailmail network coast station using both the correct station call and frequency. Radio memory is organized serially, beginning at location 00 and counting up, so the programmed list of frequencies becomes one long onerous series of frequencies. 
  • The Pactor II/III Radio Modem/SSB system makes an excellent weather FAX (WEFAX) receiving system using the GetFAX/ViewFAX applets that run under Sailmail/AirMail. GetFAX supports 59 additional frequencies for 14 WEFAX stations worldwide, This, added to the 88 Sailmail frequencies, makes a total of about 123 Sailmail & WEFAX frequencies to keep current and access.

  • For safety while underway, it is important to keep the ships systems as simple to use as practical while maintaining necessary functionality. Pushing one single computer key (up/down arrow), to select a station and a frequency is both easier and more error-free than finding the radio channel guide, looking up the correct radio channel, and turning channel selector knobs to the appropriate channel number. If the desired station can't be heard on the selected frequency, then the whole lookup process must be repeated again, and again, until a station is heard. Yes, the manual look-up system can be used, but it's a "pain", and with any kind of sea running it's totally impractical.

The Solution
Computer control of the radio is easily achieved with  PTC-IIusb  model - using the Airmail program is a simple two-step process; plug in a cable, configure the Airmail program... you're done.

If the SCS PTC-IIex is chosen, computer control of the radio can be done directly through a computer serial port and a serial cable if you have an Icom M802, or a specially made cable if you have an Icom M700Pro or M710. Most boats these days, however, have a laptop computer on board, and most laptop computers sold today have multiple USB ports and no serial port. The PTC-IIex radio control solution requires that your computer have two serial ports available; one to connect to the SCS PTC-IIex, and one to connect to the radio. It's possible to add one or two serial ports by purchasing a USB to serial adaptor but many of these have varying data transmission protocols (depending upon brand) and may not work properly in conjunction with your pactor modem package. If a second serial port is available, a custom cable can be fabricated to control the Icom M-700Pro, M710, & M710RT.  An Icom M-802 can be controlled with a standard off-the-shelf serial cable available from most computer stores.

 

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