ADE-1-24 are double-balanced RF mixers that can be easily found all over eBay, Aliexpress and a few other websites. They are usually available for attractive prices and sometimes might be advertised simply as “ADE-1”.
However, the manufacturer claims that ADE-1-24 is a custom version of the Mini Circuits ADE-1 mixer, built on order for a customer and not necessarily identical to the ADE-1. There are no official specs published for the ADE-1-24. All of the ones available seem to have the same manufacturing date code 628, which means they were manufactured in the 28th week of 2006.
The case and pinout seems to be identical to the ADE1. A quick multimeter measurement showed ~0.1ohm between pin 1 and 6, pin 3 and 4, a diode drop of 221mV @ 1.7mA between pin 2 to 5. Pin 1, 4, 5 are not internally connected.
The spec sheet for the ADE-1 says 0.5-500MHz LO/RF range, +7dBm LO level, 5dB conversion loss, 55dB isolation and 15dBm IP3. An easy check was to test input and output impedance with my homebrew HF Arduino VNA . Unfortunately this is designed for work up to 60MHz so I can’t check it throughout the full range of working frequencies, but it gives us an idea if the ADE-1-24 matches the ADE-1 specs at least for HF equipment.
These are the sweeps for 0.1-60MHz @ +10dBm on the LO (1-6) and RF (3-4) ports.
As you see, it looks like these act quite predictable from 1MHz upwards, with a typical impedance of over 200ohm. I guess they can safely be used down to 500kHz, albeit with slightly reduced performance. The next test is to actually use one in a HF upconverter and see how it does.