About the RFX 2400 daughterboard


#1

So I had a few questions about the RFX 2400 daughterboard, and this what
Matt E. had to say in his email…

1.What is the maximum distance I can place two USRPs with the RFX 2400 daughterboards, both communicating with an antenna, to ensure proper transmission, provided they have some line of sight available?

That depends on many many factors, including modulation, antennas, data
rate, environment, other interferers, how well you’ve written your code,
etc. It is impossible to give a proper answer to your question, but I
can tell you that a few feet sounds like you are doing something worng.

  1. I’ve tried adjusting the gain in the receiver (the maximum gain I could use at the receiver for this was 89) and the amplitude in the transmitter (while using the benchmark_tx.py and benchmark_rx.py programs) to maximize this distance, but I can only go as far as a few feet apart. Is there any other way to adjust the gain? Also, the CRC32 was false for all packets received. Is there a way to fix that, or should that not be an issue?

There is a lot of work involved in creating a proper AGC system for your
individual application and system. More gain is not always better.

Finally, I am trying to implement a simple direction finding algorithm using two antennas as receivers in one USRP. Are you aware of any other similar work that has already been done in the field?

Yes, quite a bit of work has been done on this, and I believe at least
one paper was published.

To update on the first question…I was using the benchmark_tx.py to
transmit and benchmark_rx.py on another USRP to receive, with pretty
much default settings and carrier frequency of 2.45GHz.
Any comments on that?


#2

On Tue, Jun 02, 2009 at 09:10:07PM +0200, Ankit S. wrote:

To update on the first question…I was using the benchmark_tx.py to
transmit and benchmark_rx.py on another USRP to receive, with pretty
much default settings and carrier frequency of 2.45GHz.
Any comments on that?

What kind of antennas are you using?

Eric


#3

Eric B. wrote:

On Tue, Jun 02, 2009 at 09:10:07PM +0200, Ankit S. wrote:

To update on the first question…I was using the benchmark_tx.py to
transmit and benchmark_rx.py on another USRP to receive, with pretty
much default settings and carrier frequency of 2.45GHz.
Any comments on that?

What kind of antennas are you using?

Eric

Omnidirectional ones…the standard ones with a black plastic outside.
Looks like this http://www.ciudadwireless.com/images/USR5481BCW.jpg