VARA - How it works in layman's terms.
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Most amateur digital discussions these days will come around to talking about the VARA mode by EA5HVK.
VARA has been in development for many years and is now a mature format used by many Hams around the world.
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What "it" is - VARA is a audio modem that sends and receives tones over the air which convey data.
VARA continuosly adjusts the data level to match conditions, getting the most out of the path between the stations.
It is one of the fastest methods in both HF and VHF/UHF communications via voice radios to date.
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Perhaps the simplest way to explain would be to compare to something you can visulize like a orchestra.
Most amateur modulation methods are single tone at a time, like a single instrument playing away.
VARA is like the whole orchestra playing with the ability to hear each instrument individually.
VARA HF uses from 2 to 58 different tones called carriers.? VARA-FM uses 14 to 116 carriers.
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At this point, we owe a debt to mathmatical wizards who theorized if tones could be produced with enough accuracy
and carefully chosen to be mathmatically orthogonal, these tones would not interfere with each other when played at the same time.
No filters, just math.
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Like any modem, VARA is meant to be used by another application to communicate.
For example, Winlink which is essentially an email program with several options for delivery, including using VARA.
Reminicant of the dial up Internet days, if the user wishes to send or check their email on Winlink, they open a modem program.
From there, it's up to the user to choose and connect to a gateway station, then exchange email.
73's
Mike N0QBH
N0QBH Mike Berg