NT1065_USB3 GPS L1 detection issues

Thread Starter

HAMADA2YOU

Joined Mar 11, 2022
10
Hello everyone,

I'm seeking assistance with the nt1065_USB3 GNSS receiver manufactured by ntlabs. I've been facing difficulties despite my efforts to make it work properly. Here's a breakdown of my setup and the challenges I'm encountering:

Hardware:

Setup: I have connected the active antenna to the GNSS_S14 splitter provided by ntlab, and then connected it to the CH1 input of the nt1065_USB3 receiver using the "config_1.hex" configuration file.

Issue: Unfortunately, I have been unable to detect any L1 signals or satellites despite my efforts. I have tried various active antennas, but the situation remains unchanged.

Successful Test: I did manage to perform a signal tone RF input test, where I input a single tone signal at 1575.42MHz with low power input, and I was able to observe the signal in the output.

I would greatly appreciate any insights or guidance on how to resolve this issue. If anyone has experienced a similar problem or has expertise with the nt1065_USB3 GNSS receiver, your assistance would be invaluable.

Thank you in advance for your help and suggestions.
 

Ya’akov

Joined Jan 27, 2019
9,121
Welcome to AAC.

Just to cover the basics so they aren't overlooked...

Does the antenna have a clear view of the sky?
Are you facing it the right way up?
 

Thread Starter

HAMADA2YOU

Joined Mar 11, 2022
10
Welcome to AAC.

Just to cover the basics so they aren't overlooked...

Does the antenna have a clear view of the sky?
Are you facing it the right way up?
The test I conducted took place during clear sky conditions in the middle of the day. I used two different active antennas: Active Antenna 1 and Active Antenna 2. I successfully operated the splitter and connected Channel 1 of the splitter to Channel 1 of the nt1065_USB3 receiver to receive the GPS L1 signal. The figure below illustrates the output that I obtained:
1685710951124.png

Unfortunately, there were no satellites detected.
 

Ya’akov

Joined Jan 27, 2019
9,121
I don’t understand the plot. The Frequency axis is labeled “MHz” but those numbers are two orders of magnitude too low for GPS/GNSS signals.
 

Thread Starter

HAMADA2YOU

Joined Mar 11, 2022
10
Have you tried connecting your antenna directly to the receiver, i.e. bypassing the splitter?
the
The test I conducted took place during clear sky conditions in the middle of the day. I used two different active antennas: Active Antenna 1 and Active Antenna 2. I successfully operated the splitter and connected Channel 1 of the splitter to Channel 1 of the nt1065_USB3 receiver to receive the GPS L1 signal. The figure below illustrates the output that I obtained:
View attachment 295553

Unfortunately, there were no satellites detected.
Active Antenna 1
Active Antenna 2
nt1065_USB3
 

Thread Starter

HAMADA2YOU

Joined Mar 11, 2022
10
I don’t understand the plot. The Frequency axis is labeled “MHz” but those numbers are two orders of magnitude too low for GPS/GNSS signals.
The nt1065_USB3 receiver utilizes a 2-bit ADC operating at a sampling rate of 53MSps to digitize the incoming signal. Prior to the digitization process, a local oscillator at 1590MHz is employed to downconvert the GPS L1 frequency (1575.42MHz) to an intermediate frequency (IF) of 14MHz. This downconversion allows for effective sampling of the signal at a rate of 53MSps. Here is the additional figure you provided:
1685712252842.png
 

Thread Starter

HAMADA2YOU

Joined Mar 11, 2022
10
Have you tried connecting your antenna directly to the receiver, i.e. bypassing the splitter?
In order to meet the receiver's requirement of at least 15 dB gain before input, the splitter serves the dual purpose of an active antenna DC feeder and splitter. It provides the necessary gain to amplify the signal before it reaches the receiver.
 

seanstevens

Joined Sep 22, 2009
252
Your active antennas require power, is the needed power being fed to the antennas? Is there any way you could check that? I am just trying to cover the basics of the correct signal/level being provided to the receiver. You have already tested with 2 active antennas which require power, the splitter seems to be the power feeder, what is feeding the splitter?
 
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