dk-info
New Member
I am a "digital guy" trying to make his way in the RF world. I am looking for a circuit idea for a stable (over temperature, vibration and battery voltage) FM transmitter in the 88-108 MHz band.
I found several iterations of the LMX2306 + PIC micro-controller design but can't find some of the parts like a BB139 Varicap diode, the LMX2306 itself...
I actually just need a transmitter beacon that say puts out ≈ 2 kHz tone for 500 mSec every 5 seconds or so, then a "Morse" stream with a call sign (I take my technician class test this month) every 5-10 minutes.
I expect to use a simple analog FM radio receiver to track with and hope to get 1,000' in the bush.
Is there a FM transmitter circuit that has a digitally controlled PLL synthesizer that you can actually buy parts for from the Digikey/Mouser/Arrow/Element13 suppliers?
I actually found 4 LMX2306 chips on eBay and now have to find the programming cable interconnect diagram, and pray the codeloader has parallel port drivers that work in Win7!.
I realize stable ≠ simple; is there a off the shelf FM transmitter module I can buy that fits the bill? I would rather build it myself but can't find references that explain the fiddly bits of transistor oscillator topology & operation, not to mention practical VHF buffer design using today's components.
David W
Melbourne, Florida
I found several iterations of the LMX2306 + PIC micro-controller design but can't find some of the parts like a BB139 Varicap diode, the LMX2306 itself...
I actually just need a transmitter beacon that say puts out ≈ 2 kHz tone for 500 mSec every 5 seconds or so, then a "Morse" stream with a call sign (I take my technician class test this month) every 5-10 minutes.
I expect to use a simple analog FM radio receiver to track with and hope to get 1,000' in the bush.
Is there a FM transmitter circuit that has a digitally controlled PLL synthesizer that you can actually buy parts for from the Digikey/Mouser/Arrow/Element13 suppliers?
I actually found 4 LMX2306 chips on eBay and now have to find the programming cable interconnect diagram, and pray the codeloader has parallel port drivers that work in Win7!.
I realize stable ≠ simple; is there a off the shelf FM transmitter module I can buy that fits the bill? I would rather build it myself but can't find references that explain the fiddly bits of transistor oscillator topology & operation, not to mention practical VHF buffer design using today's components.
David W
Melbourne, Florida