[Xastir] RDF Units?

[Curt Mills]

On Mon, 28 Mar 2005, James Ewen wrote:

> How short is the transmission period? The DoppleScAnt needs one full spin of
> the antenna matrix worst case... that means 125ms. If you need faster response
> times, you'll need to design around a faster spin rate.

I'm working on that very issue.  I'll either hear back soon on that
question or else run my own experiments to see what the "on" time
is.  I'll know the answer soon enough (regarding the transmitter's
"on" period), then can perhaps modify an existing design to catch
shorter pulses if necessary.

I see that some nice improvements have been made in the PIN-diode
switching arrangement, where you don't need 1/4 wavelength coaxes
anymore, so you can switch bands with ease.  I definitely like that,
but the new design needs 3.5V on the ground side of all the whips,
so they have to be isolated from the car's body.  That's a definite
downside.

I see also that 1/2 wave dipole elements are less prone to
cross-coupling between elements.  I might also go that route.

-- 
Curt, WE7U.				archer at eskimo dot com
http://www.eskimo.com/~archer
  Lotto:  A tax on people who are bad at math. - unknown
Windows:  Microsoft's tax on computer illiterates. - WE7U.
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