Mike those very hard words we heard from Hank W0RLI and others
were not born of a technical consideration, they were from money basis. I
am not at all sure CLOVER works as well as the users would have us
believe, but since the protocal was held secret you could only find out by
buying a CLOVER unit. That was the outcome they hoped for. Instead it was
found that Gateways using the Internet were cheaper and faster.
On Fri, 12 Mar 1999, Mike Bilow wrote:
}
}
} Ron Stordahl wrote in a message to Mike Bilow:
}
} RS> I have been reading this thread and wondering if a
} RS> description, a user level description would be fine, of the
} RS> various modes you have been discussing. Pactor, Pactor I,
} RS> Pactor II, Clover, etc.
}
} Basically, they are various schemes for using FEC (forward error correction),
} ARQ (automatic request for repeat), adaptive modulation, or combinations of
} these techniques. For example, Clover changes its output power, bit rate, and
} modulation format in response to continuous monitoring of link quality, slowing
} down and using more power as the link gets worse.
This you can get from the ARRL Handbook.
}
} RS> Personally I have never understood what is wrong with HF
} RS> Packet that could not be cured by a lower baud rate, perhaps
} RS> a change in modulation method to PSK etc. My impression is
} RS> that the protocol is solid, but that FSK is just not up to
} RS> 300 baud with 200 cycles shift on HF.
}
} No, the protocol is abysmal. FEC and ARQ are essential to reliable HF data
} communications. Adaptive changes to bit rates and output power are nice. The
} actual modulation method is the least of it.
}
Agree.
} RS> I have done a bit of
} RS> HF Packet and believe the thruput would actually increase
} RS> with a lower baud rate.
}
} Sure it would, and less people would be killed in road accidents if the speed
} limit were reduced so that cars could go no faster than pedestrians.
}
} RS> The very effective PSK31 suggests
} RS> to me that a switch to PSK for HF Packet may we warranted.
}
} FSK and PSK are essentially the same thing as far as this issue goes, and you
} can regard FSK as a special case of PSK.
Exactly. This is a hard concept for many people to grasp, but FM
and PSK are in the same units and are the same thing. PSK is usually used
if the phase shift is less than 360 degrees. FM is used when phase shift
is thousands of degrees.
I don't want to get into this issue
} in detail because experience has shown that it provokes religious arguments,
} but the math is clear.
}
Like I say it isn't a religious argument. It is over money.
} -- Mike
}
}
}
Best wishes
- Karl F. Larsen, [EMAIL PROTECTED] (505) 524-3303 -
