[amsat-bb] A Fully Rechargeable Satellite Station
n3tl at bellsouth.net
Tue Apr 28 15:14:29 PDT 2009
Over the past 10 months, I’ve made some great new friendships - thanks to AMSAT and its good work to keep amateur radio in space. Many of those friends know that I’ve chosen “a different path to orbit” in my desire to incorporate the concept of emergency communications.
FCC Part 97 is unambiguous in noting that Amateur Radio operators’ abilities to serve the public through provision of emergency communications are, collectively, the lynchpin of the service in the United States. The more I learned about the satellites we all love, the more it became clear to me that it had to be possible to assemble an effective “emergency” station that would be true to that purpose. I began thinking of it as my rechargeable station.
By 03:15 UTC on 27 April, that possibility became a reality. Over the course of the day Sunday and into Monday (UTC), I was fortunate to work multiple contacts in SSB on AO-7, FO-29 and VO-52 using a totally portable (but full-featured) station running on full emergency power. How do I define “full-featured” in this context? My station operates full duplex, incorporates computer-controlled Doppler tuning, and can work CW, SSB, packet and all the digital modes while running on rechargeable batteries.
Sunday started out with a pleasant surprise – DJ8NY in CW on AO-7, making Germany the fourth European country to find Georgia on AO-7 in the past 10-or-so days. Oh … no; I was NOT running full battery power. Given my approach to the antenna here, those low-angle passes of AO-7 call for more than the 5 watts my fully rechargeable station can muster, so I transmit using a Yaesu FT-857D, which provides up to 20 watts out on 70 cm. I need the extra rf muscle because I work AO-7 from my shack, in a second-floor bedroom of my home, and I hand-hold my Elk log periodic antenna. Reaching the satellite when Europe and EM84 share the footprint have me pointing the Elk at a windowless wall, generally at the northeast corner of the house.
The rest of Sunday (and into Monday, UTC), I replaced the FT-857D with a Yaesu FT-817ND for transmitting. Another FT-817ND served as my receiver, as it always does (even with the 857). I use a Diamond MX-72H duplexer to connect both radios to the Elk, and use about 6 feet of RG-8X between the duplexer and the antenna. I have not yet used a receive preamp on either 2 meters or 70 centimeters. Both radios used their internal battery packs for power, as did the Acer Aspire One netbook computer I picked up last fall specifically for radio use. I have been able to configure Orbitron, SatPC 32 and Ham Radio Deluxe (Version 4.1 beta, with the Satellite Tracker software) to provide computer-controlled Doppler tuning.
With multiple CW contacts already in the log on all three satellites using the fully rechargeable station, I wanted to complete the exercise by adding SSB contacts on all three linear satellites in the same day. Thanks to Angelo (N5UXT), Leo (W7JPI), Art (K4YYL), Joe (K3SZH), Bob (KC9ICH) and everyone else I worked Sunday for their signal reports and encouragement. It was pretty neat heading to bed knowing that I had a station I could take down and set up anywhere in a matter of minutes (excluding travel time, of course) that I could use to effectively work virtually any mode available to U.S. amateurs from 40 meters through 70 cm, including all the satellites.
I mention the HF bands and use the phrase “virtually any mode” because I picked up a screwdriver vertical last fall too, and have used it or an end-fed longwire (with a manual MFJ tuner) and a Signal Link USB to make contacts using a variety of sound-card based digital modes, including PSK-31, Olivia, RTTY and SSTV. Having been totally inactive from early 1992 until about 2 years ago, I continue to be amazed at all we amateurs have to enjoy on the air.
My ISS contacts will always be my best QSOs ever. But working Europe on AO-7 and routinely making multiple contacts on passes of all of our satellites running 5 watts rf out or less – all of them with a handheld antenna and many of them from inside – won’t ever get old.
When I told Angelo what I was up to on Sunday during our FO-29 contact, he told me I needed to write it up for the AMSAT-BB. So … here it is.
My primary motivation to share all of this is to suggest to anyone who’s interested that ALL of our amateur satellites are routinely workable from stations that don’t have all the bells and whistles. They don’t even need a lot of power.
Go to the AMSAT Web site (www.AMSAT.org) and look through the descriptions of the satellites we all can work daily. With the exception of the ISS, every satellite we work is transmitting to Earth using QRP power levels – even AO-7. And none of them are using “optimum” antenna systems offering lots of gain and directivity.
Ten months ago today (28 June, 2008), I had my first-ever satellite contact – with KD8ILL in EM99 on AO-51. We both used handheld stations. I never imagined that what started with a brief QSO would have led to so many wonderful contacts and new friendships.
73 to all,
Tim – N3TL
Athens, Ga. – EM84ha
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