At 11:45 PM 6/6/04 -0500, you wrote:
> > From: "hwingate" <[EMAIL PROTECTED]>
> > Subject: [Repeater-Builder] Re: Weather Radios
> >
> > The 1050 hz tone is the original arert tone that was used
> > before the SAME system was installed. It is still transmitted
> > with a duration of 8-10 seconds,is not area specific and will
> > give a warning for the whole coverage area of the station, sometimes
> > as much as 5000 square miles.
> > Generating a SAME tone is not for the faint of heart. It is
> > digital and has such oddball parameters as 520.83 bps data rate,
> > a digital 1 = 2083.3 hz , a digital 0 = 1562.5 hz. For more
> > than you ever wanted to know about SAME go here:
> > http://www.nws.noaa.gov/nwr/same.pdf
> >
> > Henry, K4HAL
>
>Henry, I don't think it would be all that hard to build a FSK audio
>oscillator to work with a 1.92 mS wide mark and space tone (which is
>what 520.83 bps translates to) at those frequencies. The
>phase continuity requirement may be a little tricky. though.
Look at the Exar 2206 chip. It was made for the job (300 to 600
baud low power FSK modems). Don't know if it is still made, but
if not there has to be a substitute.
>FWIW, the SAME code definitions are in the referenced PDF. The
>encoderis even somethng that might be worth writing as a sound
>card utility, provided the sound card has the requisite transient response
>and stability.
I'd like to see that as a embedded processor function on a repeater controller
add-on card - in the same sense as the RLC-MOT is a add-on card.
Picture the ability to take a old 160mhz receiver strip - let's say from a
Motrac - something that would normally be considered as a doorstop.
Buy a cheap crystal from somewhere on the local weather channel.
Add this board - call it the Simple-SAME decoder between the audio
output and the repeater controller input. You instantly have a high
performance SAME receiver for the cost of the Simple-SAME and a
crystal.
And it should be a decoder-only device.
We don't need someone parking outside a high school with a laptop,
encoder and HT and setting off the alert RX in the school office.
>Guess I need to dig up the sound libraries and read the furnished
>manual on them.
A sound-card based system is fine for a base station, but I'm not
going to be sticking a laptop at a repeater site.
And if you already have the sound card tied up for a APRS decoder
(AGW Packetengine Pro) do you install another? How many sound
cards can the system support? Hence the universal device - the
Simple-Same - that can talk to a serial port of a desktop, or a repeater
controller. A DB25 jack on the side of it could have both serial
connections and open collector connections.
If your home PC doesn't have an extra serial port, you can add a
USB-to-Serial device.
>de kg7yy
Mike WA6ILQ
PS - if someone makes a Simple-SAME then I want one or two.
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