I have quite a few of these AT&T manufacturer Dielectric Resonator Oscillators. These were made in the Merrimac Valley Division for their Digital Microwave Radio links. Here are 6 oscillators to choose from (I will delete them as they sell). I figured out a rough schematic and was able to power these, but they also have a built in temp controller. Anyway, these work fine when powered, run off -12 to -15 VDC, power output is +10 to +12 dBm, these have a screwdriver adjust for frequency and are SLIGHTLY adjustable (MHz). Slight output power change with voltage, naturally as I believe these to be reverse channel biased GaAs FETs. Frequencies available are in MHz, 1 each of the following: 7630, 7250, 8310, 6910, 6950, 6044, 6104, 6082, 5993, 6074. I also have a 4020 MHz version of same, slightly larger. Choose which type you want and email me or add this in notes section of purchase. These have remarkably good temperature stability after they reach equilibrium, of the orders of KHz of drift. If you can figure out the temp comp control heater circuit, probably much better than this! Useful for all sorts of experiments where you need a small cheap source. With my crude schematic included! Used, good condition. Several are shown, price is for one. Have fun. Please see my other items for more RF goodies and weird stuff. Remember, I gladly combine items to save you shipping costs, so ask before you pay. I ship worldwide! International buyers: I will check actual cost to send to you, if cheaper I will refund any difference.