Pacific Ocean to Gulf of Mexico Ship-to-Ship Satellite Contact

by Andy MacAllister W5ACM and Allen Mattis N5AFV


The first amateur radio satellite contact between a ship in the Pacific Ocean and a ship in the Gulf of Mexico took place on November 4, 2006.  Andy MacAllister, W5ACM, was cruising on a ship in the central Gulf of Mexico in grid square EL54, while Allen Mattis, N5AFV, was located on a ship in the Pacific Ocean approximately 100 miles west of Ensenada, Mexico in grid square DM01.  The two operators made contact on SO-50 at 1645 UTC. 


Both W5ACM and N5AFV have experience operating from cruise ships (MacAllister, 1997 and 2000, Mattis, 2003 and 2005a), and they worked together in advance to plan this contact.  In mid-September Andy and Allen were talking at the weekly Houston AMSAT lunch and discovered that they would be on cruises at the same time.  Andy would be sailing on a western Caribbean cruise out of Galveston at the same time Allen was sailing on a Hawaii cruise out of Los Angeles.  In December 2004, Allen had previously made a ship-to-ship amateur radio satellite contact from grid square EK67 in the western Caribbean with John N8QGC, who was on a ship in grid square FL51 east of Turks and Caicos.   Allen and Andy decided to try to make an amateur radio satellite contact ship-to-ship from the Pacific Ocean to the western Caribbean or Gulf of Mexico. 


The itineraries for the two cruises were compared, and it was decided that the best opportunity for a contact would be when both ships were at sea because there would be no conflict with tours and sightseeing in the ports of call.  In addition, both ships would have to be in the satellite foot print at the same time.  Nova for Windows was configured to run two observers and one satellite during the cruise period.  It was found that the contact would have to take place in the window of November 2-4, 2006.  Because AO-51 was not scheduled to be in V/U mode at that time, only SO-50 was available.  Nova for Windows quickly identified the few satellite passes that met the criteria.  Two passes of SO-50 were selected as the primary passes when the contact would be attempted.


Photo A: Allen N5AFV found the sports deck of the ship to be a good operating position.




The equipment used on the cruise ships for the satellite contacts in the FM V/U mode varied.  Allen used an Icom W32A HT with a telescoping AL800 antenna.  This combination makes an excellent portable satellite station (Mattis, 2005b and 2005c), and contacts have been made on satellite passes with extremely low maximum elevations with this equipment, thanks to the lack of obstructions when operating from ships. Allen has the distinction of being the second station to accomplish the “reverse” VUCC – operation from 100 different grid squares – all via Hamsats.




Andy W5ACM had a collection of radios and antennas for his cruise to the Gulf of Mexico and the western Caribbean. Hindsight is always 20-20, so the theory was that if you have more gear than you need, there will always be a way to make contacts if something goes wrong or is missing. The primary shipboard station consisted of an Alinco DJ-580T HT with a borrowed Arrow antenna from Tony N5RPQ and a set of earbuds. Other gear included a WA5VJB-design, five-element, 70-cm Yagi, telescoping AL800 antenna, Yaesu FT-817 transceiver, Yaesu VR-500 receiver, GPS receiver, and a Palm Treo 600 with tracking software. Rather than traveling alone, Andy had some extra hams on board, including wife Heather WB5RMA, Mike WA5TWT (previous AMSAT Awards Manager), John WA5WOD and Craig WD5BDX.


While Allen N5AFV is known for operations both onboard and on land, Andy and his group could only operate while at sea due to the lack of licenses for the ports of call in Mexico, Grand Cayman and Jamaica. Excellent shore excursions and gentle pressure from non-ham wives were also a factor. The eastern group had two goals. The first was to ensure that everything was ready for the scheduled contact with N5AFV toward the end of the cruise. The second was to experiment with the gear and antennas and have a good time.


Photo B: Eastern Crew – Mike WA5TWT, Craig WD5BDX, John WA5WOD and Andy W5ACM


Can you make ship-board contacts via AO-51 with SSB up on two meters and FM down on 70 cm? Yes, but it’s not easy. The Yaesu FT-817 with the AL800 long whip provided a good uplink signal. For reception, the Yaesu VR-500 receiver was adequate, but the Alinco DJ-580T was somewhat better. The homebrew, five-element WA5VJB-design Yagi was excellent, and due to the small size and ease of use in the constantly-windy environment of the cruise-ship deck. Four contacts were made on two passes with three stations; W7JPI, N5UXT and KO4MA. Working with all of the different radios and antennas was difficult, but thanks to the efforts of Mike, John and Craig, the passes were tracked, the contacts logged, and no gear or hams were lost over the side.


When AO-51 is not in the preferred V/U FM mode, what does it take to make successful contacts via SO-50? For N5AFV, the ICOM W32A with the AL800 antenna and an MFJ-288 headset are quite enough. He’s done it thousands of times. The W5ACM crew discovered that the older Alinco DJ-580T was having problems with the signal level from SO-50. AO-51 is much louder (more output power) and the Alinco needed some help. This was the same HT that had been used nearly 15 years earlier for successful hand-held operations via AO-21 (also known as RS-14, RADIO-M1 and RUDAK-2) by W5ACM using the Diamond RH77B 15”-long antenna, earphones and separate microphone (MacAllister, 1992). After poor results on the first attempt with the Alinco and the AL800, Andy got the borrowed Arrow antenna up on deck for the next pass. Success! Signals were strong, easy to hear, and the antenna doesn’t even show any damage from a few nearby poles and lifeboats that got in the way. There was even a contact with Bob PJ4/K0NR on the island of Bonaire (FK52) while cruising through grid EL-80.


The eastern W5ACM crew was testing gear during the SO-50 pass that was supposed to be too far to the east for Allen N5AFV out in the Pacific on November 4th. In the Gulf of Mexico it was one of those near-overhead passes with lots of Doppler, antenna work, and contacts. After QSOs with N3UNM, XE2AT and KC5TER, the crew was amazed and surprised to hear N5AFV/VP9 booming in. After smiles, congratulations (especially over the air to Allen), the eastern W5ACM crew finished the pass with six more QSOs including contacts with good friends Lou W5DID in Florida and John K6YK in California.


Photo C: Andy W5ACM/C6A makes contact with Allen N5AFV/VP9





Allen N5AFV, was in the satellite footprint before the W5ACM group on the 1645 UTC SO-50 pass on November 4, 2006.  Allen worked a number of stations during the first part of the pass including K6YK, XE2AT, W6GMT, WI7P, N8BBQ and W0TUP, and just as he was about to leave the footprint, he heard W5ACM calling him and quickly made the contact.  Less than a minute later SO-50 was over the horizon - LOS, but the QSO had been successfully completed.   W5ACM and N5AFV also made a contact on the following pass of SO-50 at 1828 UTC, but that contact did not generate quite the excitement felt by the operators during that first memorable satellite connection.



Photo D: Nova for Windows display of SO-50 footprint for 1645 UTC pass on November 4, 2006.





The effort to make this contact was successful for a number of reasons.  Both Andy, his crew and Allen are experienced satellite operators, and have experience operating on satellites from cruise ships.  Prior planning, equipment testing and discussion played an essential role.  Orbital prediction programs were used to identify the passes that could be used for the contact, and these passes were ranked and prioritized.  Also, in finest tradition of amateur radio, the other satellite operators on the pass very courteously stood by while the contact was made. 





MacAllister, Andy, 1992, Satellite Contacts on an HT via OSCAR-21: 73 Amateur

            Radio Today, HAMSATS column, October, p. 52.


MacAllister, Andy, 1997, Cruising for AO-27 on the Carnival Sensation: 73 Amateur

            Radio Today, HAMSATS column, March, p. 60.


MacAllister, Andy, 2000, Cruising for Satellites: 73 Amateur Radio Today – Special    

            HAMSATS issue, October, p. 22-28.


Mattis, Allen, 2003, Prior planning - key to a successful DX cruise: The AMSAT Journal,

May/June (Volume 26, No. 3), pp 24-26, (reprinted from Worldradio, 2002, April,

p. 18-21).


Mattis, Allen, 2005a, Satellites and Cruising – A Winning Combination, Proceedings of

            the AMSAT-NA 23rd Space Symposium, p 128-138.


Mattis, Allen, 2005b, HT and AL800 Antenna – An Excellent Portable Satellite Station:

            The AMSAT Journal, March/April (Volume 28, No. 2), p. 21-23.


Mattis, Allen, 2005c, Postscript to HT and AL800 Antenna – An Excellent Portable Satellite

            Station: The AMSAT Journal, May/June (Volume 28, No. 3), p. 17.


Published in The AMSAT Journal, January/February, 2007, (Vol 30, No.1), pp.11-12.

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Created: February 18, 2006 by Allen F. Mattis
Last Updated: March 11, 2007