Marc, I endorse Leigh's suggestion. It is a very simple but effective solution. I use the SA602 myself. Used with an active whip antenna sensitivity is not a problem, and you can receive signals from around the world.
As for the local oscillator, yes you can most certainly use the FE-5650A or FE-5680A, but I don't think that's necessary. If you have a receiver which has suitable stability and can receive 10MHz, then a very good solution is to drive the S602 with a 10MHz OCXO as the LO (the SA602 is very accommodating, and can act as VFO, XO or buffer for an external LO), or even drive it from a 10MHz GPSDO. Bear in mind that any phase noise or modulation will appear on the mixed output (and 1Hz modulation can be a problem with GPSDOs if you're not careful). There is a very neat technique which works well below about 500kHz to give extreme precision to reception. This is 'Clicklock' developed by Peter Martinez G3PLX. Essentially you can receive any signal which has ultra-low drift even if your receiver or converter has drift. It uses harmonics of a 1pps reference compared with the 1pps pulse itself to compensate for receiver drift, and all you need is a 1pps GPS signal and a PC with sound card. The software is then able to provide sufficient phase stability to integrate the received signal synchronously over many seconds, giving incredible sensitivity and bandwidths measured in milliHz. It has enabled me to discern the carrier (and hourly phase advance) of WWVB on 60kHz at a range of 8000km, and for my own 80uW EIRP transmission on 181kHz to be detected 500km away. See http://www.qsl.net/zl1bpu/ZL2AFP/CLICK/click.htm for more information and Clicklock software by Con Wassilief ZL2AFP. 73, Murray Greenman ZL1BPU _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
