I was dismayed by some of the comments made by Don Melcher regarding the use and economics of using HF single-sideband for digital message communication ("One way to measure the cost of offshore e-mail," Issue No. 91). Readers who are not familiar with the reality of the use of the various communication services may be sadly misled by the letter in question. I hope the following commentary will be of value to those contemplating use of a digital communication service from a vessel.
The reality of using HF SSB service, such as that provided by my company, PinOak Digital, differs significantly from what Mr. Melcher has portrayed. Rather than present a hard-to-follow, paragraph-by-paragraph commentary on Mr. Melcher’s letter, I offer the following facts for consideration by your readers.
A valid comparison of the likely cost of transmitting a digital-format message cannot be made using the per-minute rate of any communication service unless there is a guaranteed data throughput rate. Such comparisons would be valid based on real-life data sent and costs actually charged. Just quoting the maximum data rate for a service cannot give you an actual indication of the charges for "time." PinOak’s charges are for multiples of 1,000 correct characters delivered (95 cents per 1,000 bytes or 12 per 1,000 bits). Each type of service must impose unique communication overhead requirements on the message transmitted.
In addition, the apparently low cost of satellite communication may be significantly increased by billing techniques designed for voice communication, where charges are based on the time the circuit is used rather than the actual number of bytes handled. Satellites do a good job, but at a higher cost than PinOak in most instances.
Satellite systems rely on an artificial infrastructure consisting of the launch costs, the satellite costs, and Earth station costs. This can be billions of dollars today and is subject to depreciation as are most physical assets. These costs must be amortized by user charges. High frequency uses the ionosphere provided by nature for its global communications. Its cost is $0, and it does not depreciate. Until recently, it was very difficult to use HF for digital communications. With the advent of low-cost and powerful microprocessors and new types of protocols (software), the noise and interference on HF circuits can be conquered in the case of digital traffic. Propagation is well understood, and our simple computer program can make the selection of frequencies easy. Also, code gain allows useful links to occur that cannot be heard by the ear but can be detected by the microprocessor. Thus, this new field has been recognized by many, including the FCC. We have PODLink systems at work globally now and are doing basic messaging service and transmissions for such organizations as the Massachusetts Maritime Academy (T/S Patriot State) and the U.S. Naval Academy (Y/P American Promise).
Mr. Melcher’s letter incorrectly states the cost for sending a 3,000-character message via PinOak to three children at $8.55. Actually, that message could be sent to 10 children via PinOak for $2.85. Multiple computer graphics such as from digital cameras are regularly sent all over the world from our system10 graphics for the price of one. Also, the letter is incorrect regarding forwarding mail. PinOak forwards all mail for members (including attachments), without limitation, to any e-mail address in the world. We have a per-time cost to set up or take down this service of $15.00. There is no per-message charge. Our members tell us that they use these services easily and with satisfaction.
Mr. Melcher’s comments on the functioning and description of our e-mail system are inaccurate. All of our nodes scan virtually all of our 22 FCC-assigned frequencies under our PODSCAN technology, and connection is made particularly easy with another technology called PODGO. We have consistently expanded our capacity to keep ahead of demand and are now in our fifth year on the air. We were the first FCC license for such a service in the U.S. and believe that we are leaders in this field.
The bottom line is that in long-distance communication where there is no infrastructure of telephone poles, microwave links, and the like, there are only two ways to send messageshigh frequencies and satellites. New developments are occurring in both of these fields, and the broad field of communications generally is growing at a spectacular rate as costs decrease and Internet use increases. Clearly, for digital messages, use of HF SSB offers numerous advantages to the voyaging sailor, not the least of which is that the same radio installation that carries routine digital traffic can also be used for voice communication, including emergency traffic.
No one system in communications is probably going to be best for all purposes, and it will be commonplace in the future to have several different communications systems on board that will complement each other, just as we have VHF, HF, and so on now. We are just entering the age of communications, and development will continue to make connectivity available for people all over the world. It is truly an exciting time that we live in.