| Products > Test Equipment |
| Beehive vs. Tekbox EMC probes and amplifier |
| << < (3/5) > >> |
| pdenisowski:
Here are the gain and noise figure of the Tekbox preamp (TBWA2 - 20 dB version, measured with a R&S FSW spectrum analyzer and the FS-SNS (smart noise source) --- End quote --- |
| matthuszagh:
Well it sounds like their "specifications" are more like typical performance and that typical performance really isn't so typical, considering this is a good deal worse than the spec sheet. Good to know... |
| _Wim_:
--- Quote from: nctnico on May 09, 2023, 06:07:34 pm ---@pdenisowski: It would be nice if you could also measure the 'Amazon' pre-amplifier to see how it stacks up. ;D --- End quote --- Hi, a while ago I measured another Chinese preamp (see pictures attached) with an HP8970A & 346B noise source, and it did meet it spec quite reasonable. Spec according to Ali-Express: Gain: typical value 31dB-0.5G input output impedance: 50Ω Maximum output power: P1db 11dBm-0.5G Input signal: <0dBm (>0dBm input signal has been distortion) Bandwidth: 50K-2GHZ (different gain in different frequency) Noise coefficient: 2dB-0.5G As I did not want to bother writing an application for the HP 8970A, I just used in XY plotting outputs. My picoscope does not have a blanking option, so the retrace is also visible. Plot is from 0 to 1.6GHz (so 160MHz per division) Bottom trace is the noise figure (1dB per division): noise figure stays below 2dB up to 1GHz, and never goes above 3dB. Top trace is the gain (4dB per division): gain up to 800Mhz is fairly flat and around 32dB and drops to 25dB at 1600MHz. For only 14€ including shipping, this is quite a useful amplifier. I also have one based on a SPF5189 that looks like the one in the attached picture, when I have some time in the lab I will try to measure this one also. |
| _Wim_:
--- Quote from: _Wim_ on May 14, 2023, 09:08:24 am ---I also have one based on a SPF5189 that looks like the one in the attached picture, when I have some time in the lab I will try to measure this one also. --- End quote --- Also this amplifier seems to reasonable meet is specs (and the specs of the SPF5189). I am picking up some noise in the lab, the spikes on the noise factor come and go. For about 4€ including shipping a very useable device also. |
| pdenisowski:
--- Quote from: _Wim_ on May 18, 2023, 01:00:33 pm ---I am picking up some noise in the lab, the spikes on the noise factor come and go. --- End quote --- Not much you can do about direct pickup, but noise figure is one of the few measurements where I use a proper torque wrench to tighten connectors :) It's very easy to get screwy NF results from environmental noise, especially if your lab is anything like my lab. |
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