Comments on: Designing and building a Manned Beacon or MEPT, part 1 of many http://on3jt.byze.be/designing-and-building-a-manned-beacon-or-mept-part-1-of-many Blog and website of a Belgian ham radio operator who likes to build antennas and other projects. Tue, 16 Feb 2010 12:36:01 +0100 http://wordpress.org/?v=2.8.4 hourly 1 By: Janne OH1SDR http://on3jt.byze.be/designing-and-building-a-manned-beacon-or-mept-part-1-of-many/comment-page-1#comment-91 Janne OH1SDR Tue, 16 Feb 2010 12:36:01 +0000 http://on3jt.byze.be/?p=253#comment-91 Cheers mate, long time no see! I think you might have some big troubles stabilizing the LTC1799. If you have not built oscillators before, you might want to know few basics: LC oscillator can be made really stable, VCO with over decade cannot. Especially when it doesn't seem to have shielded inductance. Also VCO with such wide range will usually introduce terrbile amount of phase noise. According to LTC1799 specs, the temp drift is awfull. With just few C of temp change, you would have kHz drift at 10 MHz. You would be better of with traditional Hartley etc LC-oscillator. But I suspect that even LC-oscillator would not provide the long term stability required by the MEPT. Crystal oscillator, or programmable crystal oscillator might be the solution. http://www.amateurradio.org.za/SOTA.doc Good luck with the project! 73 de Janne OH1SDR Cheers mate, long time no see!

I think you might have some big troubles stabilizing the LTC1799. If you have not built oscillators before, you might want to know few basics: LC oscillator can be made really stable, VCO with over decade cannot. Especially when it doesn’t seem to have shielded inductance. Also VCO with such wide range will usually introduce terrbile amount of phase noise.

According to LTC1799 specs, the temp drift is awfull. With just few C of temp change, you would have kHz drift at 10 MHz. You would be better of with traditional Hartley etc LC-oscillator. But I suspect that even LC-oscillator would not provide the long term stability required by the MEPT. Crystal oscillator, or programmable crystal oscillator might be the solution.

http://www.amateurradio.org.za/SOTA.doc

Good luck with the project!

73 de Janne OH1SDR

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