Saving data in a .txt file using Netcat

we want to send measured values via Wifi to a PC. We are using an ADMP 401 MEMS Microfon. Our Code (client side/ Particle Photon) is working great. We are resiving the data (alterning values between 0 and 10) on the server side via the command window (using Netcat) in “real time”.
But for the Purposes of Analysis we need the measured data in a .txt file.

Does anyone know how to do that using netcat ?

We started writing a small Batch file (we are using Windwos):

cd C:\ncat-portable-5.59BETA1
ncat -v -l 80 > Messergebnis.txt


The code creats a .txt file but without any content.
Thank you in advance.

Best regards

ncat has a dedicated --output option.
You can try this

ncat -l -o Messergebnis.txt 80