asked by
What I'm measuring when the active antenna M-20047 is powered on?

If I connect my VNA to RFO (while powering VCC), what I'm measuring in my VNA is:
a) the LNA Output impedance
b) the M-20047 LNA is bidirectional and I'm reading the whole device impedance including the Antenna?

If a), the only way to measure the antenna tuning is transmitting from another source and measure the power received at RFO, where I can play with L2 until I get the maximum power at my desired frequency right?

Thanks for your answer


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1 Answer

answered by

Hi Eddy,

Here is a visual of where to start tuning the antenna portion of your GPS module. You will not see the 17dB gain of the LNA going into your VNA and will not need to power up VCC for the tuning.

I will send other images as replies to this response due to the limit of the forum responses.

Best regards,

Geoff S.

commented by

Here is the next step

commented by

And here is the next step

commented by

And here is the next step

commented by

And here is the last step

commented by
Once your are sure the antenna is on frequency then you can either take your unit outdoors or use a satellite repeater indoors to see if your GPS receiver is getting a fix on a few satellites.
commented by
Thank you very much Geoff!!
I think this question was not well answered in many previous posts under this forum. But you nailed it! Thanks, now I can tune my antenna correctly.
commented by
Happy to help!!

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Geoff Schulteis

Senior Antenna Apps Specialist at Antenova Geoff is an antenna design-in and OTA measurement specialist. His knowledge of FCC and world carrier requirements is second-to-none.

Steve Bradburn

Senior Antenna Engineer at Antenova With over 25 years’ experience in manufacturing, test and design, Steve has a wealth of RF and measurement knowledge across many industry sectors.


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