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#2
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#3
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On Thu, 23 Feb 2006 21:51:09 -0500, Ken Scharf
wrote: Gary Schafer wrote: I have a homebrew project that I need some crystals for. Need the following: 3.300 mhz 3.500 mhz 10.5 mhz 17.5 mhz 24.5 mhz Prefer HC6 holders if you have them. Any help out there? Thanks! Gary K4FMX Please reply to Building a 2B clone eh? Kind of. It is a converter for a BC453 (Q5er) that I built many years ago. It now uses only one 3.5 Mhz crystal, dual conversion, for all bands. Trying to clean up some of the image problems. 73 Gary K4FMX |
#4
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Gary Schafer wrote:
On Thu, 23 Feb 2006 21:51:09 -0500, Ken Scharf wrote: Gary Schafer wrote: I have a homebrew project that I need some crystals for. Need the following: 3.300 mhz 3.500 mhz 10.5 mhz 17.5 mhz 24.5 mhz Prefer HC6 holders if you have them. Any help out there? Thanks! Gary K4FMX Please reply to Building a 2B clone eh? Kind of. It is a converter for a BC453 (Q5er) that I built many years ago. It now uses only one 3.5 Mhz crystal, dual conversion, for all bands. Trying to clean up some of the image problems. 73 Gary K4FMX Since all the frequencies in question are harmonics of 3.5mhz (except 3.3mhz) you could use a PLL to generate them by phase locking a vco to the harmonics of a 3.5mhz oscillator. Use a divide by N circuit to divide down the vco output to 3.5mhz and have a phase detector compare the output of the divider with the 3.5mhz oscillator. Properly shielded, this pll would be as clean as the crystal oscillator. |
#5
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Ken Scharf wrote:
Since all the frequencies in question are harmonics of 3.5mhz (except 3.3mhz) you could use a PLL to generate them by phase locking a vco to the harmonics of a 3.5mhz oscillator. Use a divide by N circuit to divide down the vco output to 3.5mhz and have a phase detector compare the output of the divider with the 3.5mhz oscillator. Properly shielded, this pll would be as clean as the crystal oscillator. Since they are low order odd harmonics, is a PLL even necessary, or could a square wave sort of buffer, a filter at the desired frequency and then an amplifier tuned there do the trick? With a PLL, you will still need to switch components for each frequency range - generally you get less than an octave (factor of two in frequency) out of a single VCO, but changing the inductor and/or fixed capacitors for each band shouldn't be too hard. |
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