[amsat-bb] Maritime Mobile Lessons Learned
k5oe at aol.com
Tue Apr 19 12:49:47 PDT 2011
For hams that want to try working Maritime Mobile, the very first stop should be N5AFV’s very informative how-to guide(s):
This was my second attempt at this and I can add a few lessons learned to the subject that may help future cruisers.
1. When a satellite has multiple frequencies available, and your radio has all of them pre-programmed, be careful of relying on the alpha identifiers. For example, on my FT-51R, 145.920 and 145.880 are both identified as “AO-51.” I guess I don’t have to explain why this is a lesson learned.
2. Allen mentioned his attempt to stay away from the ship’s antennae. I learned from experience on this trip that the intermod was far worse on the bow than the stern, and non-existent from the stateroom balconies. If you can get the captain to steer the vessel so that you can see the entire pass from your stateroom, it is easy to hear the bird(s) and you don’t have to brave gale-force winds at night.
3. Transcribe your QSOs right after the pass onto a log. I seemed to have gone back to bed one morning and completely forgot to log one pass. I only became aware of this when I got three QSL requests for the same pass! I used an mp3 player and still had it, so the only loss was the embarrassment of declining a QSL and then realizing I was wrong.
4. I only recorded my own voice (not a perfect system, but simple and easy). Still, out of 235 contacts, I still have about a dozen calls I am not sure of in my log (95% accuracy, or almost 2 sigma for you statisticians out there). I actually had a few more garbled in the audio but was able to pick them out of the K8YSE online recordings, but since his QTH is far north of where I was, the recordings did not cover my entire pass (or all of the passes). A better setup, for those inclined to do more work, would be to also record the speaker output from the radio.
And, as a general recommendation to stations wishing to work a MM op, please always use phonetics (no intent to incite another riot) as it is sometimes very difficult to hear onboard, with extremely high wind noise, intermittent IM, fading, etc.
The official stats by satellite were:
AO-51, 11 passes and 148 contacts
AO-27, 5 passes and 65 contacts
SO-50, 3 passes and 22 contacts
ARISSat-1, not heard.
Equipment used was an FT-51R with an Arrow from the stateroom balcony and a Pryme AL-800 when on the deck (most of the passes, as the ship was predominantly heading at 135 and 310 degrees and not conducive to "seeing" a whole pass). Ancillary equipment was a portable GPS and an mp3 recorder.
Thanks again to Allen, the AO-51 crew, and to all the patient ops who gave me their calls two and three times :-)
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