RF receive path bandwidth for LimeSDR-USB

Projects LimeSDR
1

Hello everyone,

I’m trying to realize exactly bandwidth for RF ports for the LimeSDR-USB board based on the LMS7002M chip.

According to the source code (https://github.com/Gluttton/LimeSuite/blob/master/src/API/lms7_device.cpp#L721):

  • LNAL - 0.7GHz…0.9GHz;
  • LNAH - 2.0GHz…2.6GHz;
  • LNAW - 0.7GHz…2.6GHz.

According to the LimeSDR Made Simple topic (https://myriadrf.org/news/limesdr-made-simple-part-1/):

  • LNAL - 0.1MHz…1.5GHz;
  • LNAH - 1.5GHz…3.8GHz;
  • LNAW - 0.1MHz…3.8GHz.

According to the Datasheet (https://wiki.myriadrf.org/LimeMicro:LMS7002M_Datasheet or https://github.com/Gluttton/LMS7002M-docs/blob/master/LMS7002M_Data_Sheet_v3.2r00.pdf):

  • LNAL - 0.1MHz…2.0GHz;
  • LNAH - 0.1MHz…3.8GHz;
  • LNAW - 0.1MHz…3.8GHz.

So, what are the correct values?

Thanks in advance!

2

Hi @Gluttton,

Datasheet provides list of frequency ranges for each RF port it is optimized for. It means that you will get best result if you use particular RF port in supported range. But everything depends on RF matching network. RF matching network may be optimized for 900 MHz for instance and connected to any RF Rx input of LMS7002M. Hence the matching network defines frequency ranges.
So, for LimeSDR-USB Rx RF inputs are optimized for these frequencies (it doesn’t mean it will not work at out of range frequencies, but performance will be lower):
LNAL: 700MHz - 900MHz
LNAH: 2GHz - 2.6GHz
LNAW: 700MHz - 2.6GHz

Here is also Rx RF matching network mod if you need better performance at HF:
https://myriadrf.org/news/optimising-limesdr-matching-hf/

1 Like
3

Hi @Zack,

Thank you for the detailed explanation and the provided link!