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HF vs. Sats






>From: "Dave D'Epagnier" <DAVED@ctilidar.com>

>I'm using HF these days primarily as a means to keep in contact with >my 
>sister in law who is a doctor in Malawi. Her village has no >telephones. 
>Her hospital has a solar powered mobile hf rig and a >tower with a 
>tri-bander on it. The gear was all donated. They use 40m >to communicate 
>with people in the capitol city. They also use 10m and >15m to communicate 
>with me and a doctor here in the us to coordinated >medical supplies and to 
>keep in contact with families. So for now, hf >is still their lifeline to 
>the states. Someday they'll get better >equipment for sure (like a phone 
>line >and internet), but for now >they take hf very seriously.
>

Ever hear of KISS?  Keep It Simple Stupid.  This is HF.

HF is inexpensive (compared to satellite equipment), and has little
recurring costs (equipment maintenance only).  But, the trade off is
that availability is unstable, the quality of audio and/or data and
data rate isn't as good. HF is less usuable for DX during solar minimums.  
(From a military or commercial standpoint this isn't as
important than it is for hams.  Most military and many commercial uses are 
NVIS, short range, just over the horizon)

Sats are more reliable, when they work (human factors), for communication, 
and allow wider band transmissions to be passed.

Both satellite and HF have their place in ham radio.

What we ought to be doing with HF is developing better data modems
(PSK31, MT63 are a *great* start).  Systems like HAM ALE would also
be a great project to get running....

What we ought to be doing with SATS are developing high speed doppler
resistant data (yes, even wideband and spread-spectrum stuff).  With the 
proliferation of computers, any analog data can be encoded and passed 
digitally.

There is plenty to invent, develop and improve with both sats and HF.
I'm presently very interested in trying to advance the state of the
art on HF, as some of the newer modems and coding techniques will
allow fairly high speed robust data to be passed on HF.  I can assure
you it is starting to happen commercially.

73,

Fred W0FMS
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