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Old August 4th 09, 09:52 PM posted to rec.radio.amateur.antenna
Jim Lux Jim Lux is offline
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First recorded activity by RadioBanter: Mar 2007
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Default INMARSAT Reception Question Re Antenna

Robert11 wrote:
Hello,

Just a typical non-technical sw listener, and frankly now next to nothing re
antennas.
But do like picking up maritime and mil stuff.

Was thinking of trying out a new software Inmarsat program for receiving and
decoding Inmarsat msg's.

Apparently the freq. used is around 2 GHz
My NRD 545 wiuth the converter gets up there, I think.

They mention that you need a parabolic dish antenna, and I think it was an L
type downfeed feed.

Think a Discone antenna and reg. coax would pick up "anything", or not worth
the time to even try ?

Thanks,
Bob



You probably won't have enough SNR without a gain antenna. Doesn't need
to be huge, but you do need more gain than you get from an omni.

Inmarsat operates in C (3.6 GHz down, 6.4GHz up) and L (1.525-1.559 GHz
down, 1.626-1.661 GHz up ) band, not S band. What you heard about was
using a small parabola and an L-band feed for the downlink (at 1.5GHz)

Inmarsat Mini-M uses a very small antenna, and in fact, has the ability
to talk to a satphone with a small antenna (briefcase sized)