Re: A step at 3GHz?
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Hi Leif, THX for the plots. As a comparison on my ULTRA, I used a ViewTEQ 5-1000MHz noise generator with an in-line 10dB pad and obtained the following plots at 10MHz - 3GHz.? NOTE: This is a calibrated CATV 75 ohm generator, but works fine on 50 oms with a very small dB penalty which in a measurement such as this (or a filter response, is inconsequential). FIG 1 is a dual plot of the Ultra noise floor (green trace) vs the noise generator (red trace). NOTE the response relationship between? the two traces. Response of the 1GHz rated unit is actually out to about 1.352GHz before the rolloff.?
FIG 2 is very interesting and might answer the 5GHz noise plot you are looking at. I increased the frequency set-up to what you used 10MHz-5GHz and low and behold, the noise trace looks very similar to what you are looking at with the "step" at 3GHz, and the following? trace replicating? the lower frequency portion. Could it be that the frequency response of the noise generator is actually lower than 1.5GHz or so? Interesting as to why this might happen. We can assume the ULTRA is at least as flat as the baseline noise shows us, so is it a function of the noise generator? Interesting question which begs more investigation (on another analyzer non ULTRA). AS to the pulse shown with marker 1 @ 2.43GHz, this is direct pickup from my router wifi in close proximity to the analyzer.? FIG 1. 10MHz-3GHz ? FIG 2. 10MHz-5GHz Hope this might help.......Good Luck!! Ted (KD7AQO) ----------------------------------------- From: "Leif M via groups.io"To: [email protected] Cc: Sent: Wednesday January 1 2025 2:39:46PM Subject: Re: [tinysa] A step at 3GHz? Sure, here it comes, all? two of them. Could a Wlan leak
here, I didn't see the 2.4GHz peak? at first when my PC was
off. (Clock on my SA is off.)
 The step shows on? PC too.
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