RE: TI-H: Radio Link


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RE: TI-H: Radio Link




Hi Grant!

What modulation scheme are you using (amplitude, frequency, phase, pulse duration, etc) ?  If it costs $80 for a pair, then you must be buying RF modules and building the interface to your calc (or making the whole thing but using a lot of expensive components that you may not need).  If you are getting 38400, you must be using quadrature phase modulation at 2GHz.  Are you using a digital phase locked loop and VCO module?  I know that there is a 902-928MHz band that you can use without a license, but you can't transmit more that 100mW.  Give me more details.  I was going to work on one this summer and would like to see your approach.  My plan is to use the same technique as cell phones.  They transmit a lot of digital data and use few expensive components.

What is your plan for the PCB's?  If you get high data rates you have to control the characteristic impedance of the traces carrying the RF signals.  Do you etch your own boards?  One sided or two?  So many questions...

Mike



-----Original Message-----
From:	Grant Stockly [SMTP:gussie@alaska.net]
Sent:	Saturday, April 25, 1998 7:58 PM
To:	ti-hardware@lists.ticalc.org
Subject:	TI-H: Radio Link


So far I was able to construct a perfect working link that operates at
about 38400 and transmits arround a few miles...  The problem is that 2
cost $80...