Ham It Up v1.3 60 kHz Response

The SMA-to-N cables arrived unexpectedly early, so I fired up the spectrum analyzer to see how the Ham It Up Upconverter behaved at 60 kHz (think WWVB), a smidge below its 100 kHz minimum input frequency spec. It’s worth noting that you can’t do a frequency sweep of the 100 kHz to 50 MHz upconverter response using the tracking generator, because the output sits 125 MHz above the input; yes, it took me a while to dope that out…

Anyhow, the 60 kHz sine wave from the (sub-audio-frequency up to 2 MHz, 600 Ω -ish output) signal generator, passed through a 5X attenuator, and terminated in 50 Ω:

Ham-It-Up - 60 kHz input
Ham-It-Up – 60 kHz input

It emerges from the H-I-U in Passthrough mode 3.6 dB lower:

Ham-It-Up - 60 kHz passthru
Ham-It-Up – 60 kHz passthru

In Upconvert mode, the output sits 14 dB below the Passthrough output and 17.6 below the input:

Ham-It-Up - 60 kHz upconvert
Ham-It-Up – 60 kHz upconvert

At that span setting, I don’t trust the frequency resolution of that 125.0605 MHz marker readout.

Cranking the signal generator to produce -10 dBm at the H-I-U output in Passthrough mode brings up a bunch of harmonics:

Ham-It-Up - 60 kHz harmonics passthru
Ham-It-Up – 60 kHz harmonics passthru

In Upconvert, they’re down 13.9 dB from the Passthrough output:

Ham-It-Up - 60 kHz harmonics upconvert
Ham-It-Up – 60 kHz harmonics upconvert13.9

The H-I-U should have about 10 dB conversion loss at 100 kHz, so losing another 4 dB beyond the thing’s rated low end isn’t entirely surprising.

All in all, it works fine…