FS: Gigatronics 8651A power meter, 80601A 18GHz power sensor, cable - Page 1
Forum section: electronics / general

author: DaJMasta
author_rank: Super Contributor
timestamp: July 25, 2018, 05:26:29 pm
content: As a bit of an upgrade and a space reduction on the bench (for more equipment, of course), I've switched to a USB R&S NRP-Z22 power sensor and am selling my previous power meter and sensor. The meter, sensor, and cable are in good condition and work well (operation pictures are links below), but I've had trouble with the consistency of low level readings, and I don't know if this is a calibration issue, an ambient EMF issue, or related to the long length of the sensor cable. The 80601A sensor should be rated to -67dBm as its noise floor really only reads stably in my setup down to -28dB or so, though it can be used with lots of averaging below that, detecting signal presence to about -45dBm. In any case, I didn't notice the problem until I started testing to sell it, above -25dBm seems to be extremely stable and has good linearity with the sensor that's replacing it. The cal stickers on the meter and the sensor are intact, but of course are out of date.I'm asking $500 US with free FedEx ground shipping and insurance to the continental US. I can ship elsewhere, but shipping will cost something more and you run into any customs import fees for your country that may be charged on entry.Included is:Gigatronics 8651A single channel power meter (with option 12, 1GHz calibrator)Gigatronics 80601A 0.01-18GHz 200mW modulation power sensorGigatronics 20954-003 Rev. E 3m power sensor cableI'll also include a known-bad 80301A sensor - it would not zero and eventually I took it apart out of curiosity. At least one bond wire to the diode was broken, I think a split ring that was used internally was not put back when reassembled.... but if you needed replacement connector parts or wanted to hack the system a bit, it could be useful, and I have no use for it anymore.To verify performance, I calibrated the sensor on the meter after a warm up period then connected it to my SMIQ06 to test a number of points against the NRP-Z22 that is replacing it on a 0dBm CW tone. None of the instruments used are in cal, but they still seem to agree in terms of linearity, with the NRP-Z22 reading about 0.4dBm under.Freq : NRP-Z22 : 80601a6GHz : -0.55dBm : -0.092dBm3GHz : -0.78dBm : -0.243dBm1GHz : -0.76dBm : -0.323dBm50MHz : -0.71dBm : -0.193dBmUsing the NRP-Z22, I also measured the calibrator signal:50MHz, 0dBm : -0.41dBm measured1GHz, 0dBm : -0.12dBm measuredCalibrating the 80601A with either frequency chosen does not seem to effect the reading (the routine probably uses both)Then I took a 2.5GHz CW tone with averaging set to 8 and turned down the power, taking measurements until the noise of the system was too high for it to be usable (about -45dBm)http://www.medpants.com/pics/8651a/gigatronics%2010dbm.jpghttp://www.medpants.com/pics/8651a/gigatronics%200dbm.jpghttp://www.medpants.com/pics/8651a/gigatronics%20-10dbm.jpghttp://www.medpants.com/pics/8651a/gigatronics%20-20dbm.jpghttp://www.medpants.com/pics/8651a/gigatronics%20-25dbm.jpgThen I started making 1 minute histogram to show the variance in the readings, but the distribution still shows you where the tone is centeredhttp://www.medpants.com/pics/8651a/gigatronics%20-25dbm%20hist.jpghttp://www.medpants.com/pics/8651a/gigatronics%20-30dbm.jpghttp://www.medpants.com/pics/8651a/gigatronics%20-30dbm%20hist.jpgBelow -30dBm I just took histogram measurementshttp://www.medpants.com/pics/8651a/gigatronics%20-35dbm%20hist.jpghttp://www.medpants.com/pics/8651a/gigatronics%20-40dbm%20hist.jpgAnd to give an idea of how varying the lowest signal level appeared, I moved the averaging to 128 and increased the histogram capture time to 2 minuteshttp://www.medpants.com/pics/8651a/gigatronics%20-45dbm%20hist%202min.jpg

author: DaJMasta
author_rank: Super Contributor
timestamp: September 02, 2018, 06:02:30 pm
content: Price drop!