DG4000 Calibration Restoration:
I just finished calibrating my DG4000 for Channel 1 and 2, and the frequency response is flat up to 200 MHz and well within +/- 0.8 dB.
I very tediously calibrated channel 1 and recorded all the levels and frequencies for each of the 60 steps for HFLAT Cal.
And HFLAT is the only calibration routine that I did.
When I got done and checked channel 1 the response was great as noted above. But, I said to myself - WT*. Why? Because in going through the routine I never saw any frequency above 65 MHz, and therefore I never changed changed any of the levels.
So what is calibration? I have concluded that it is removing the un-calibration that you end up with after you install the firmware patch to extend the frequency! That's right. . . Now is that unbelievable, or not.
So to calibrate (or rather restore the previous calibration of) your DG4000:
Press - Utility, Test/Cal, Secure Code, (put in PW) 2010, Enter, Secure OFF, (the result should be) Secure ON, Access gained.
Then for Cal. select HFLAT, Call Point (start at HFLAT 1-1), Measure Value, Input Value, press Save and wait for it to complete (about 3 seconds), select Cal Point for the next step. Repeat for all 60 steps. Then your done and you didn't have to make measurements or level changes. You didn't even have to hook anything up to your DG4000 except for AC power. Hi
Repeat for the remaining channel.
Cheers, Ted