If you have a MFJ antenna analyzer such as the MFJ-249 or the MFJ-259, you have a fairly accurate frequency source! Both of these devices have a frequency counter built in. The analyzer has an upper frequency of about 173 MHz. The 16th harmonic (156.25-167.875 MHz) covers the original range of the Drake downconverter (2500-2686 MHz). At 2400, the 15th harmonic should work nicely. I don't own the 70 cm version of this box. It may be even better. Comments from owners? Using this and a *very* old Jerrold Field Strength Meter, I was able to test out the Drake downconverter and the Conifer pre-amp before I made any modifications. I used the analyzer output to set up the Field Strength Meter at 220 MHz (top end of its range). Then I determined what input would give me the output at 220 MHz. Every thing was "right on" frequency. A nice signal level was observed with out the pre-amp. Addition of the pre-amp brought the signal up by about 9 db. I would not like to estimate the voltage levels out of the converter as I don't trust the calibration of the meter (last calibrated in 1965!) ...just nice and strong. I have not tried to radiate the test signal and use the Lance 21 antenna to receive it. That is next if it ever quits raining down here! I have not looked at the output of the analyzer on a spectrum analyzer. I may have time tomorrow to do that. I did try to find "birdies" by tuning the analyzer over a wide range of frequencies. None were observed. Although I am located in the same town as MFJ, I have no connection with them and receive no financial rewards from them. Hope this helps some of you get ready for P3d..73.....Jim....W5VZF. Dr. Jim Akers Dept. of Electrical and Computer Engineering Miss. State Univ.