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短波通讯链路不是非常可靠, 并不能保证你整个旅行途中都能传送位置信息
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在没有大的电磁灾害情况下通过合理选择频段短波通信的可靠性还是比较高的，对于位置信息的传送这种数据量应该没有什么问题，要想真正做好这个当然需要很多技术来保证，比如gln的短波数据业务（包括定位信息）在一个区域至少采用三个频段，而且基站采用一种称之为fs的信号来引导各移动站进行传播状况评估，移动站采用频率扫描方式对每个频段的fs信号进行评估，然后自动选择（当然也可以手动）合适的频段或信道来建立数据传送，并且通过fs信号技术可以最大可能的避免信道冲突。
早上写的帖子是手机回复的，没有提供相关的资料，下面的站点可以中转rpr或者pr的aprs格式定位信号，不过他离你好像都很远啊，权且作为参考以后有兴趣试验一下：
注意：只写有rpr方式的站台并不中转常规的短波fsk300信号，写有rpr和fsk300两种方式的站台可以自适应中转新旧不同的格式，根据不同的站点目的，大部分的站点只是作为igate使用而并不支持digipeater。
digipeater and aprs gateway
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前天看了美国政府的一个备忘录，他们现在也有意开始短波的商用计划，转发如下，有感兴趣的可以研究一下：
navy finds a use for old tech
by bob brewin | thursday, june 28, 2007 | 04:04 pm
naval amphibious base, little creek, va. – when the uss harry s. truman carrier strike group deploys this fall it will use communications that have a high-tech twist on one of the oldest forms of radio communications that the navy used in the days of morse code, said officials of headquartered here.
instead of the "dits" and "dahs" transmitted by morse code, the truman, along with the nine other ships in the strike group, will communicate over high frequency (hf) by sending internet protocol-based traffic such as text messages, said paul dixon, allied coalition networks action officer for the naval network warfare command (netwarcom).
the highest levels of the navy have endorsed the use of high frequency ip communications for intra-strike group communications for one simple reason, dixon said: it’s much cheaper than satellite communications systems that the navy embraced in the late 1980s, when the service all but abandoned high frequency as its standard means of communications.
dixon also said its makes no sense to use expensive and often leased satellite communications systems that require a 44,400 mile trip – from a ship to a satellite and then back down to another ship five to ten miles away – when high frequency can easily bridge that gap over free spectrum in the 3 to 30 megahertz frequency band, dixon said.
dixon said that high frequency has roughly the same speed as dial-up modems used in the 1980s compared with satellite bandwidth that is as much as 100 times greater. but it is fast enough to meet the command and control needs of today’s strike groups, which are run by text messages and over chat groups based on internet relay chat standards.
the navy also has provided the truman strike group with the ability to send ip traffic over uhf channels, which provides better throughput than the high-frequency band, about 64 kpbs, or slightly more than the dial-up modems built-into most personal computers.
eric johnson, a professor at new mexico state university whose specialty is high frequency and wireless networking, said the high frequency’s low throughput is due to the noise inherent on that spectrum band, which is apparent to anyone who has listened to a short wave broadcaster such as the bbc, and the narrow channels.
the high-frequency modems the navy uses – which new mexico state university helped develop – punches data through that noise with a stable signal thanks to sophisticated error checking protocols, johnson said.
dixon said that the navy plans to outfit 25 ships with high-frequency ip systems through 2008 under a “fast track” project backed by the chief of naval operations. much of the work involves adding computer servers and firewalls to work with high-frequency radios already on the ships, dixon said.
the high-frequency ip project will also make it easier to communicate with allied navies, which rely heavily on high frequency because they cannot afford satellite communications, dixon said.
the navy’s trip back to high frequency will require going back to offering high-frequency training to the service’s school curriculum, said chuck tabor with the netwarcom spectrum management division. it’s been so long time since the navy has used high frequency “hardly anyone [in the navy] even knows what it is anymore,” tabor said.
