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On Sat, 2 Aug 2003 15:28:00 -0500, "John R. Strohm"
wrote: "Allan York" wrote in message . com... Hi, I am looking for advice on how to integrate a PIC microchip with a ham radio transciever. I will use this in a robot. I am looking for 100 - 300 mile range. I have a ham radio license. Thanks for the help Y'know, this is the first ham radio operator I've ever encountered who DIDN'T sign a radio-related post with his callsign. Makes ya wonder, doesn't it??? Not really. I've got one but I don't shout about it. Chiefly because I frequently ask seriously ***dumb*** questions the nature of which I should already know. Saves embarrasment. :-) -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
On Sat, 2 Aug 2003 15:28:00 -0500, "John R. Strohm"
wrote: "Allan York" wrote in message . com... Hi, I am looking for advice on how to integrate a PIC microchip with a ham radio transciever. I will use this in a robot. I am looking for 100 - 300 mile range. I have a ham radio license. Thanks for the help Y'know, this is the first ham radio operator I've ever encountered who DIDN'T sign a radio-related post with his callsign. Makes ya wonder, doesn't it??? Not really. I've got one but I don't shout about it. Chiefly because I frequently ask seriously ***dumb*** questions the nature of which I should already know. Saves embarrasment. :-) -- "I believe history will be kind to me, since I intend to write it." - Winston Churchill |
Me neither.
"Keith Poindexter" wrote in message ... No.. "John R. Strohm" wrote in message ... "Allan York" wrote in message om... Hi, I am looking for advice on how to integrate a PIC microchip with a ham radio transciever. I will use this in a robot. I am looking for 100 - 300 mile range. I have a ham radio license. Thanks for the help Y'know, this is the first ham radio operator I've ever encountered who DIDN'T sign a radio-related post with his callsign. Makes ya wonder, doesn't it??? |
Me neither.
"Keith Poindexter" wrote in message ... No.. "John R. Strohm" wrote in message ... "Allan York" wrote in message om... Hi, I am looking for advice on how to integrate a PIC microchip with a ham radio transciever. I will use this in a robot. I am looking for 100 - 300 mile range. I have a ham radio license. Thanks for the help Y'know, this is the first ham radio operator I've ever encountered who DIDN'T sign a radio-related post with his callsign. Makes ya wonder, doesn't it??? |
I've done a fair amount of playing around with PIC16F876's. They
have two built in PWM generators. You set the overall carrier frequency by writing to a register and then control duty cycle as you need it. Turns out to be very low overhead. Hope this helps. Bruce/ND8I "xpyttl" wrote in message ... I'm pretty disappointed at the amount of flame this posting generated. snip Secondly the shape of the waveform is an issue. It's real easy to generate square waves from the PIC, but in most cases, these will generate lots of spurious output. Depending on the application and the sort of encoding you will use, you will need to come up with nice sine waves. There really are 3 ways to do this ... in many applications you can simply get away with a good low pass filter between the PIC and the radio. This will take a bunch of tweaking, though, and you will need a good scope, and preferably a spectrum analyzer to get it right. You can also generate the sine wave by having the PIC output the sine wave using pulse width modulation and a little filtering. In my experience, you can get extremely good sine waves this way, BUT the PIC is 100% dedicated to the task, which means your data rates will need to be low. The third approach is to build an oscillator that you can control with the PIC. Given that you will probably need only two frequencies, this may not be such a bad approach. snip |
I've done a fair amount of playing around with PIC16F876's. They
have two built in PWM generators. You set the overall carrier frequency by writing to a register and then control duty cycle as you need it. Turns out to be very low overhead. Hope this helps. Bruce/ND8I "xpyttl" wrote in message ... I'm pretty disappointed at the amount of flame this posting generated. snip Secondly the shape of the waveform is an issue. It's real easy to generate square waves from the PIC, but in most cases, these will generate lots of spurious output. Depending on the application and the sort of encoding you will use, you will need to come up with nice sine waves. There really are 3 ways to do this ... in many applications you can simply get away with a good low pass filter between the PIC and the radio. This will take a bunch of tweaking, though, and you will need a good scope, and preferably a spectrum analyzer to get it right. You can also generate the sine wave by having the PIC output the sine wave using pulse width modulation and a little filtering. In my experience, you can get extremely good sine waves this way, BUT the PIC is 100% dedicated to the task, which means your data rates will need to be low. The third approach is to build an oscillator that you can control with the PIC. Given that you will probably need only two frequencies, this may not be such a bad approach. snip |
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