Hallo Dan, interesting. Could be a possiblity to improve the proceeding.
But I am not familiar with divider chips. Could be, that they work because of their digital function producing some not so wanted effects maybee similiar to such vfos with plls (= phase noise). Up- or Down-converting one has to try it. If You have a very fast spectral analyzer, You could see the effect. You could even use the DREAM-software with from a 12 kHz output, to test. There are other analyzers. Tomorrow I will try to scan some different screens of VFOs with their noise-carpet. Going up or down? There are quartz-oscillators even thermical stabilised, which could do a very sufficent work. On all options, You will need such a circuit, to get good results. It is not cheap. I mention the Barlow-Wadley XCR30 a second time, because this receiver works with a fundamental 1 MHz-quartz and a mixing process. which produces a lot of multiples of the basic 1 MHz. This is filtered from a single circuit. (I will have to look for the circuit plans). And this signal mixes with the incoming frequency to an if of about 42,5 MHz. You have the stability of a collins design with only one quartz for the 1. oscillator. This tuning represents the MHz-scale of the receiver. There is a second one for kHz! (2. VFO)(2. IF is 2.0 to 3.0 MHz). This is working on a 455 kHZ last stage for demodulation and BFO. It could be even necesary to smooth the signal from the divider by a circuit of L and C. Wolfgang --- In [email protected], "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > > Wolfgang: > > One comment you made basically was that over simplification can be a draw back in some cases and this is true. I have thought of ideas such as a single crystal and harmonics of it. > > It seems to me also that if you use a crystal at the highest possible frequency without having to use a harmonic; using a fundamantal crystal as high as possible and then down convert it with a divider chip to a much lower frequency then the phase and drift will be divided and made smaller. Hence much more stable at the resultant frequency. I know thats really not hard. The Soft Rock 40 uses a very high frequency crystal and divides it down twice. And that makes sense. It maybe a idea to keep in mind for later on. > > Dan > > > _____________________________________________________________________ > Call Anyone, Anytime, Anywhere in the World - FREE! > Free Internet calling from NetZero Voice > Visit http://www.netzerovoice.com today! > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
