On 07/08/2015 06:02 AM, David Cole wrote:
It occurs to me that the the the RX VFO phase noise would be less influencing, (on phase noise sidebands), than the transmit VFO phase noise... Is that correct? If so, then that would explain why the largest change occurred when K7OLN got his new synthesizer, as opposed to me getting my new synthesizer, as shown in the difference between photos 2 and 3.
I believe the TX and RX phase noise have an equal effect on the interference.
Let's say the phase noise of the new synthesizer is 10 dB better than the old at a particular offset frequency. That is, 1/10 the power.
If you replace one synthesizer (RX or TX) then the total phase noise is reduced by a factor (1 + 1/10) / (1 + 1) = 0.55 or -2.6 dB.
If you replace both synthesizers, then the total phase noise is reduced by a factor (1/10 + 1/10) / (1 + 1) = -10 dB.
I don't think it makes any difference which synthesizer is changed first. Alan N1AL ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
