Hi Rik i think Stefan wants an "easy" defined LO rejection. He will have to wind transformers for a analogue switch and get the balance right. Probably not difficult. Alan Hello Stefan, Alan, what ab
Hi Alan, Thank you. Yes, i know your website from the early 2000s (as i was young) where i have read all i have found in the web ;-) Yes, a notch filter for 125 kHz is not so critical than a band pas
Hi Stefan why a difficult to get mixer?? the IF port on most DBMs is DC coupled so feed the siganl in there and (i presume) mix up ?? Or is the RF/LO response still too high on the easily available o
Use a fast bus switch like the FS3125, and you may get a slightly better performance than HCMOS can offer. You could adapt the mixer from this upconverter design http://www.g4jnt.com/LFUpconv.pdf
Hi Rik, Very interesting! Looks easy, almost perfect. But i don't know what is the "best" solution now. It gets confusing the more solutions become available. Probably each method can achieve optimal
Hello Stefan, Alan, what about a CMOS analog switch mixer ? Cheap and easy to find. I used a 74HC4053 as mixer in my 3.5MHz to 500kHz transverter. Have a look at http://home4.swipnet.se/~w-41522/lfco
Hi Stefan No, you are right you do need low frequency paths on both sides of the mixer. I have a "lateral" approach to technical questions which starts by saying "why do you want to do it that way"!
Hi Alan, I want to try an alternative to the BF981 which runs in my current LF grabber RX. It downconverts 137 kHz to 12 kHz and feeds the soundcard with this 12 kHz signal. It is running not too bad
