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.

bofh · ‎2026-03-03

@bofh wrote:
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.

Removing 56pF C8 solved the problem.

56pF at 1.5GHz results in an impedance of approximately 2 ohms, which causes significant signal attenuation.

A truly silly mistake by mikroe.

Andrew Neil · ‎2026-03-03

@bofh wrote:
A truly silly mistake by mikroe.

Be sure to feed that back to them!

I have found them to be receptive to comments on their forum:

https://forum.mikroe.com/viewforum.php?f=12&sid=629d7067dfc15314f937872095b14d9d

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.

GalaxyQuest · ‎2026-03-03

Glad you were able to resolve this.

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 sent a message to support, don't want to register "yet another forum".

bofh · ‎2026-03-03

@jamessmite wrote:
It sounds like the LIV4F is struggling with passive antennas, even when the environment and placement seem fine, while the MAX-M10S works reliably. This could be due to the LIV4F’s sensitivity or internal LNA limitations.
If you need pin-compatible alternatives, here are two options often suggested:

this wording smells very much like AI slop. Even if not, it is inappropriate IMNSHO.