bring your baofeng/handheld to activity day please

[Randall Wayth]

Hi all,

There was an interesting thread on wahams a week ago about the spectral
purity of Boafeng handhelds. I just measured mine using my specan, and it
would be interesting to get a larger sample. I will bring my specan to the
activity day today, so please bring along your handheld, and any adapter
needed to put a BNC connector into the antenna socket if necessary.

Cheers,
Randall.

Re: multi file Tx/Rx over OFDM

[Moath Sulaiman]

Any kind feedback on this case?

Best Regards,
Moath Sulaiman

On Thu, Jul 13, 2023, 11:43 AM Moath Sulaiman  wrote:

> Hey all,
> trying to send a text file using B200 and receive it using B210 or PLUTO
> over OFDM Tx/Rx blocks.
> the setup works fine, but I need this setup to be repeated for 100
> different text files. So, I modified the python code to read, send and
> transmit the files one by one. the code works good for the first two
> (sometimes three) files and after that the files written at receiver side
> are all of size zero byte. I used another SDR on a nearby machine and could
> detect that there is transmission going there.
> attached is :
> - the flow graph to illustrate the idea
> -python code files (main one is ofdmrx_processor)
>
> I wonder if it is related to buffering issues, you kind help is
> appreciated.
>
> Moath Sulaiman
>
>
>

Re: Missings packets on OFDM system simulation

[Johannes Demel]

Hi Jorge,

a couple of observations first:
- the "throttle" block needs to be part of the actual flowgraph to have 
any effect. You might want to remove your null source -> throttle -> 
null sink chain.
- for the sake of a Minimum Working Example (MWE) I suggest to remove 
the file sink and virtual sinks as well.
- Did you check the actual sample level on the "OFDM Transmitter" output 
port? I suspect these values do not have a mean energy of 1 but way 
less. In your case probably 1/sqrt(64). You'd need to adopt the "Noise 
Voltage" parameter in your "Channel Model" block accordingly.

- How did you compute your SNR value?
- As long as there's noise, you'd eventually lose packets.

Cheers
Johannes

On 13.07.23 20:08, JORGE GONZALEZ ORELLANA via GNU Radio, the Free & 
Open-Source Toolkit for Software Radio wrote:

As you can see, it's the basic implementation of OFDM.
My goal it's to measure the BER, but as I mentioned earlier, below 
certain level or SNR (20dB)


El jue, 13 jul 2023 a las 8:05, Marcus Müller (>) escribió:


Hi Jorge,

yes, please share your flowgraph. It's moot even beginning talking
about it without
knowing it.

Best regards,
Marcus

On 12.07.23 20:53, JORGE GONZALEZ ORELLANA via GNU Radio, the Free &
Open-Source Toolkit
for Software Radio wrote:
 > Hello everyone, I have some question related with a OFDM
transmission simulation, in
 > particular, about losing packets.
 >
 > I am using the OFDM Transmitter and Receiver blocks to do the
transmission (if you need
 > more details, I can upload an image of the flowgraph).
 >
 > The problem that I get is when put some noise (to get some level
of SNR), when I have
 > about 20dB (or more) of SNR I don't lose any packet, but if I put
less than 20dB of SNR,
 > almost all packets gets lost, (just 1 or 2 packets are received),
all of this happen over
 > simulation.
 >
 > Any suggestions on why this might happen?



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