Re: [Discuss-gnuradio] Re: Help required tunnel.py

[Tuan Ta]

I finally found a setting that actually works. So the real problem I think lies in the bit rate. I had no communication whatsoever in low bit rate (~250k). I started to have unreliable comm. at 500k and at 1Mbps I got no packet drops for tunnel.py. However, even at 1Mbps I still got about 5% drops using benchmark_* (always at the end).

My theory is that lower bit rate corresponds to lower signal bandwidth. I think in some mixer/filter stage the frequency offset is too large thus push all of my useful bandwidth out of the passing band. With higher bandwidth, a large path of the useful bandwidth remains in spite of the frequency offset, thus the receiver was able to pick up some thing. Lower bandwidth works fine for Chuck so he might not have the frequency offset problem.

Let me know if anyone has a better explanation. 

Tuan

On Thu, Jul 8, 2010 at 11:12 AM, chuck lorres <address@hidden> wrote:

-How far apart are your boards?
1meter apart

- What options did you use to run tunnel, benchmark_ofdm_*, benchmark_*.

default with 2.41G frequency.

- When you run benchmark_*, did you get a lot of packet drops at the end of transmission (about 15%)?

perfect reception was observed. 0 packets were dropped.

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Date: Thu, 8 Jul 2010 11:09:30 -0400

Subject: Re: [Discuss-gnuradio] Re: Help required tunnel.py
From: address@hidden

To: address@hidden; address@hidden

That's pretty much the same settings that I have. Can you clarify a bit more:

- How far apart are your boards?

- What options did you use to run tunnel, benchmark_ofdm_*, benchmark_*.

- When you run benchmark_*, did you get a lot of packet drops at the end of transmission (about 15%)?

Thanks a lot,

Tuan

On Thu, Jul 8, 2010 at 10:55 AM, chuck lorres <address@hidden> wrote:

I am using RFX 2400,  gnuradio 3.2.2,  ubuntu 9.10 and 9.04 on another

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Date: Thu, 8 Jul 2010 10:48:24 -0400
Subject: Re: [Discuss-gnuradio] Re: Help required tunnel.py
From: address@hidden
To: address@hidden
CC: address@hidden

Chuck,

What hardware are you using?

On Thu, Jul 8, 2010 at 10:38 AM, chuck lorres <address@hidden> wrote:

Hi,
I have successfully run digital folders tunnel.py.
However, I am not receiving anything when i run the ofdm folder tunnel.py.
Whereas the benchmark_ofdm_tx+rx.py is running perfectly.
I have varied almost all the available parameters but to no avail.
Please help me out.
Thanks in advance.
Chuck.

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