At last summer’s Ham Radio in Friedrichshafen, I was offered a YIG-tuned oscillator at the suspiciously generous price of 5 Euros. Since I’m always on the lookout for cheap instrumentation-grade YTOs, I took it without a second thought. After a brief chat with the friendly operator who sold it, I learned that it came from a recently discarded HP spectrum analyzer, which appears to have been beyond hope. However, he claimed that the oscillator worked ’til the end. Should he read this: thanks for the chat, and for the part :-)
A few months later: Grabbing a spectrum analyzer and a bunch of power supplies shows an indeed very healthy part.
The YTO in question here is Avantek-branded (typical for HP), model AIL 230186. According to its label, it should range from 1.75 to 4.3 GHz. On the casing, it features an SMA port and seven EMI-shielded pins for GND, V+, V-, tuning (+/-) and FM (+/-). In operation, it draws +20 VDC @ 104 mA and -5 VDC @ 109 mA. I did not notice too much of a difference during warm-up, but I guess a rough +20% should be accounted for in the power supply. However, the actual oscillator will only start up once a tuning current is applied to the tuning coil pins, while the FM modulation input can be left unconnected. At an I_tune of 61 mA (~0.91 VDC), it shows stable output of 1.54 GHz at 14.5 dBm. The highest frequency of 4.56 GHz is reached at 190 mA (~2.78 VDC). Beyond, oscillation stops again.
In case anybody needs it, here is a rough outline of the tuning characteristic:
|I_tune / mA||V_tune / V||f_out / GHz||P_out / dBm|
I plan to run it past a precision source analyzer when there’s time, to follow up with some actual performance data.