[Lowfer] MP on ZLW-1 mixer

[Michael Sapp]

Mitch & All: I'm testing a 3.000 MHz IsoTemp OCXO127-19 with the MiniCIrcuits ZLW-1 +7dBm Double Balanced Mixer this afternoon. OCXO on for about 90 minutes.  Total system drift .06Hz/hr for first hour according to ARGO with Meinberg running in the background (not sure that really makes much difference)....and a few furnace "on" cycles in the test period. MP is audible here with a peak in mid -33 range this afternoon. In front of the ZLW-12 mixer I have an efficient 1:1 LF isolation transformer (BN73-202 variety) and my VE7BPO&W7ZOI design MF low pass filter. No preamp. Listening on the NE transformer of my 18x70x18ft EWE antenna.

Specs on the OCXO127-19 are 4V p-p into 50 ohms output (+17dBm) so I have a 10 dB pad between it and the ZLW-1 +7 LO port.  Oscillator draws 23.7 ma @ 15 volts. Oven runs 27V and starts around 300ma, then settles down to around 70~80ma. I'm running it on 24 volts presently (available on my bench supply).  RF output check with my HP141T showns second harmonic down 44 dB, third harmonic down 58 dB and +17 out at 3MHz.

http://i1296.photobucket.com/albums/ag19/wa3tts/mp3714a_zpsee3bd96f.jpg

The LO is wrapped in cloth to limit drafts, but no serious environmental management attempt for initial testing...


EAR and MLS tests to follow unless DK7FC is active on 137 this evening.....

73  Mike wa3tts