Finally got a little more time for the 8656.
Pulled out the TDS220 and was able to see some sort of signal up to 350MHz, so that means the high band signal is working. Scratched around and found a 50 ohm terminator and put that on one side of a BNC tee with about 600mm of 75 ohm coax going to the output of the sig gen. Not ideal - but the signal levels were notably more consistent than when there was no termination. (Big surprise, not)
AND I got to transmit to an FM radio! Started out with the internal 400Hz and 1KHz tones and while that was eminently successful, it just didn't satisfy. I dug around and found one of the very first projects I made. I still remember laying out the PCB design on a plane trip from Sydney to Adelaide to visit my great aunt (in my Uni days
). This was a Wien bridge oscillator, complete with real thermistor. Needed some switch/pot cleaning and a joint re-soldered. It worked, but couldn't drive the sig gen. The sig gen had an input impedance of 600 ohms and my oscillator had an output impedance of over 10K (by design). Sigh. Need a buffer amp added and re-housing - with a bit of cleaning up.
Looking for something with better output I grabbed the first thing at hand - my Galaxy S5. Wired up the jack, cranked up the output only for it to decide it was feeding headphones and warned about excessive volume levels. Sheesh! Nanny state frustration set in. I maxed out the peak deviation and got audible reception on the little FM radio.
Mission accomplished, albeit somewhat less than ideal - but I couldn't be bothered pursuing it any further.
Call me a nerd ... I've been running my oscillator against the 8656 modulation output in X-Y mode on the TDS220 for the classic 3:1 Lissajous figure. (Hey, it makes me look like I know what I'm doing
)