For sat ops mobile, you will get the most success out of a 1/4 wave antenna on a good ground plane. It will give you a hemispherical emission pattern so that any direction in LOS is equally covered.
Gregg W5GGW
Sent from my iPhone
On Mar 13, 2011, at 4:28 PM, Ari Kosonen [email protected] wrote:
2011/3/13 Bob- W7LRD [email protected]
Not wanting to reinvent the wheel. Anyone using the FT-8800R mobile for satellites have any hints or sugestions, antennas etc. Email direct-thanks.
Hi,
I am using FT-8900R (practically same as '8800 plus 6m and 10m) for working satellites from my car. My antenna is a Diamond NR770 dualband whip on the trunk lid of my car. While this setup is ok for usual mobile FM operation and APRS, it is probably not optimal for satellite ops. I have got better results on satellites with a dual band mag whip on the roof the my car. Especially when the satellite is below ~60 degrees it can be reached easily when I can hear it (thanks to 50 watts on the uplink). When the sat is higher than that the whip is not so good.
I have been working mainly on AO-51 and I have preprogrammed the uplink/downlink channel pairs with different doppler values so it is easy to follow the sweet spot while the sat first approaches (above the nominal frequency on downlink) and the starts to fly away (below the nominal freq). Programming goes easily with FTB8900 software by G4HFQ. As same channel pairs are available both on the left and right side of the radio, I usually transmit and listen on the left side of the radio and try to listen my own signal on downlink with the right side of the rig. With a single mobile whip the sensitivity of the downlink rx is usually not good enough during the transmission. This might be better with separate antennasa for uplink and downlink.
I have planned to use my Arrow yagi with FT-8900R. As the Arrow's diplexer is rated only max 10 watts, I bought 100w rated separate diplexer to be used with '8900 instead. But I have not tried this combination yet.
73 de Ari OH3KAV / OH7KA Tampere, Finland (grid: KP11) _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb