LIV4F less sensitivity compared to MAX-M10S?

bofh · ‎2026-03-03

Hi all,

to evaluate LIV4F and MAX-M10S, I use Mikroe "GNSS 9" and "MAX" click boards with a passive antenna (Quectel YEGT001W1AM).

While the MAX click board with the MAX-M10S gets a fix in less than one minute, the MAX 9 board with the LIV4F doesn't get a fix. Even when starting with an active antenna to get a fix and then switching to the passive antenna, the LIV4F stops operating. Sporadically, the GSV sentence shows then one or two weak (~20) signals while the MAX-M10S has >10 satellites with signals in the range 20..44.

From my understanding of the data sheets, both the LIV4F and MAX-M10S should have similar performance without an external LNA, isn't it?

Is there any known issue with the Mikroe GNSS 9 click board?

Or a possible misconfiguration of the LIV4F I could fix?

bofh · ‎2026-03-03

@GalaxyQuest wrote:
Also looking at Mikroe GNSS9 board the RF line is powered, therefore, can you please remove R3 - 10 ohm to isolate the DC offset on RF_IN line and retest with passive antenna

R3 likely doesn't harm as stated above, but if there is really the 56pF capacitor C8, this would dampen the signal quite much. I'll remove it and report back.

View solution in original post

Andrew Neil · ‎2026-03-03

@bofh wrote:
Is there any known issue with the Mikroe GNSS 9 click board?

You'd have to ask Mikroe about that: it's their board - nothing to do with ST!

https://www.mikroe.com/support

@bofh wrote:
Or a possible misconfiguration of the LIV4F I could fix?

You'd need to show your code to know that.

How to write your question to maximize your chances to find a solution

How to insert source code

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

bofh · ‎2026-03-03

@Andrew Neil wrote:
You'd have to ask Mikroe about that: it's their board - nothing to do with ST!

asking for known issues in the ST community doesn't require that the product has "something to do" with ST. But MikroElektronika is official partner https://www.st.com/content/st_com/en/partner/partner-program/partnerpage/MikroElektronika.html

To me, the board looks unsuspicious - maybe the 6.8n series inductor isn't perfect... I could add 3.9pF to GND to match the network shown in the X-NUCLEO-GNSS1A1 docs. Or remove it at all.

@Andrew Neil wrote:
@bofh wrote:
Or a possible misconfiguration of the LIV4F I could fix?
You'd need to show your code to know that.

no code by me, I'm using the LIV4F with factory settings.

GalaxyQuest · ‎2026-03-03

What voltage are you providing to the board? LIV4F needs 3V3.

I would start with an active antenna and make sure the gain is less than 36 dB.

From Datasheet

Teseo-LIV4F has built-in LNA and SAW. It is recommended to use an active antenna with gain less than 36 dB
and the noise figure less than 1.5 dB

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bofh · ‎2026-03-03

the operating voltage is 3.29V .

As I stated in the OP, the LIV4F works with an active antenna but stops as soon as I change the antenna.

The application needs to work with a passive antenna. The MAX-M10S does so even it the antenna is inside my office window, so antenna and location seem to be good. The LIV4F doesn't work even if I place the antenna 1m outside the office.

I would appreciate very much to have two alternative pin-compatible sources of GNSS modules.

GalaxyQuest · ‎2026-03-03

That is very strange on Mikroe board, let me look at the schematics of the board.

However, I tried testing with a passive antenna - L1 only - and I am sitting in my home office with a poor view of sky. I can see signals with Teseo Suite - see attachment.

Can you please read out the firmware for me?

Send the command,

$PSTMGETSWVER,255

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GNSS-LeaT · ‎2026-03-03

We don't normally support the Mikroe boards. However, I took a quick look at them on their web site. The GNSS 9 has an antenna power supply connected to the AON pin. If a passive antenna is being used, power should not be supplied to that pin or it will reduce performance.

The Max 2 board looks like it does not have an antenna power supply, which, to me, means it is designed for a passive antenna.

I recommend contacting Mikroe and asking their recommendations for using the GNSS 9 board with a passive antenna.

GalaxyQuest · ‎2026-03-03

For my passive antenna test, I am using the EVB-LIV4F which is an ST Eval board, schematics are found here EVB LIV4F Schematics

Also looking at Mikroe GNSS9 board the RF line is powered, therefore, can you please remove R3 - 10 ohm to isolate the DC offset on RF_IN line and retest with passive antenna

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

bofh · ‎2026-03-03

I hope I got the complete response:

$PSTMVER,GNSSLIB_9751cbebbec0c_ARM*5C
$GPTXT,DEFAULT PVT CONFIGURATION*2A
$PSTMVER,FreeRTOS_V10.4.3_ARM*57
$PSTMVER,BINIMG_STA8041_4.6.8.5.11_ARM*34
$PSTMVER,SWCFG_86065331*62
$GPTXT,DEFAULT PVT CONFIGURATION*2A

bofh · ‎2026-03-03

@GNSS-LeaT wrote:
If a passive antenna is being used, power should not be supplied to that pin or it will reduce performance.

supplying power to a passive antenna doesn't harm (unless the antenna is a DC short, but this is not the case). The DC signal is decoupled via 56nH which shouldn't attenuate the RF signal.

@GNSS-LeaT wrote:
The Max 2 board looks like it does not have an antenna power supply, which, to me, means it is designed for a passive antenna.

I'm using a "GNSS MAC Click" board which provides antenna power (R2, L1) and works with active antennas.