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[aprssig] RE: [OZAPRS] 434 MHz tracking

Darryl Smith Darryl at radio-active.net.au
Mon Aug 6 00:49:03 UTC 2007


We can use these technologies, but they are not as easy as you think to use
as reliably.

The problem is that a 50W transmitter on 144 MHz takes commonly about 50mSec
to 500mSec to become stable and up to full power, if they are frequency
agile. It takes less time if you don't care about having two PLL's and the
increase in power consumption and cost.

The data rate of 19,200 means that the data is significantly more
susceptible to noise. Close to 20 times more susceptible, since the energy
per bit is so much less. The performance of 10 mW at 19200 is similar to 0.5
mW at 2M. I am just wondering how many people are using this little power on
APRS :-)

One of the ways to get people to use these new technologies, even with their
issues, is to write a paper for the TAPR DCC, or the TAPR PSR newsletter.

Darryl
-----Original Message-----
From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On
Behalf Of Andrew Rich
Sent: Monday, 6 August 2007 9:49 AM
To: Aprssig
Cc: ozaprs
Subject: [OZAPRS] 434 MHz tracking

You know its a pity that we hams could not use the technology of easy radio
on the ham bands.

I see that a 1200 baud packet takes a seconds to send.

On the weekend I was sening 20ms databursts @ 19k2 on 434 MHz at 10mW

I wonder if we are ever going to break the shackles of 1200 baud ?


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