So the BFO has a fixed value of 11.9985 or 12..0015mhz, it is up to the user to whack at L5 and C103 to set the appropriate frequency.
Your BFO values work if using the Raduino with a VFO output freq of 5mhz. ?They get swapped if the VFO is at 19mhz.. I believe the SDR Kits VFO doesn't know about "negative offset", so the best way to receive a 7mhz signal is to have it emit a 19mhz VFO signal.
> ?vfo is what you see on the display,?
I assume the display is showing 7mhz. ?And that the Raduino VFO is actually sending out 5mhz. ?If you are talking about the SDR Kits VFO and some sketch for that beast, I have no idea what it is displaying.
> Your SDR kit has to generate the bfo value nothing more and you enter it on the BITX40 at the place of L4 (which has to be removed).
Your SDR kit is generating the VFO, ?not the BFO. ?The BFO is set by L5 and C103. ? But yes, the SDR kit is doing nothing more than injecting a 19mhz VFO signal into the DD connector near L4.
?
I think.
Jerry
On Thu, Feb 9, 2017 at 09:09 am, ron van doremalen wrote:
bfo-(vfo * SI5351_FREQ_MULT)
vfo is what you see on the display, the multiplier is there for getting it ready for the SI5351 library to understand it to be unsigned long value.
Bfo has the values:
LSB = 1199850000ULL;
USB = 1200150000ULL;
?
Your SDR kit has to generate the bfo value nothing more and you enter it on the BITX40 at the place of L4 (which has to be removed).
?
?
