Ebay SPF5189Z LNA Gain measurements

1

Hi,
I’ve bought a cheap LNA based on SPF5189Z from ebay.
I’ve installed it on my receiving station to improve the bad NF of RTL2832 dongle.
Here you can find some measurements I’ve done on Vector Network Analyzer: https://iz7boj.wordpress.com/2019/04/11/spf5189z-lna-measurements-on-vna/
I’m tuning the gain of the dongle in order to optimize overall S/N. I’ll let you know at the end how it works.
Best,

Alfredo IZ7BOJ

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2

Hey, Nice!! it would be nice also to make a page about this in wiki.

3

Thank you @azisi. I added a link to my article from the “Build” page, but I think we should create a completely new page for the LNA reviews. How can I do it? I think I can’t create a new page, but only edit the existing ones.

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Log in wiki and then add your page:
https://wiki.satnogs.org/<put_your_page_name>

5

Oh, simpler than I thought.
I’ve just created it: https://wiki.satnogs.org/SPF1589_LNA_measurements

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6

Late to the party, but interesting measurements! Can you please describe the methodology of the measurements with the VNA? How did you account for the noise figure of the LNA? Did you take the datasheet’s values for granted, because not taking the noise figure (i.e. how noisy the LNA is) into account can give inaccurate measurement results.

EDIT: You can do a cross-check of your results with these measurements. They also measure the noise figure! :slight_smile:

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