Send and Recieve data like "Hello World"

GNU Radio
1

Hi,

When I have 2 SDR setup, I was looking to send some data/string like
“Hello
World” from one of them and recieve it on the other setup. Are there any
scripts existing already? If not can I get some help on this?

Thanks for any and all response
Meenaktchi

2

I was about to ask a similar question: “Has anyone implemented
a simple RTTY mode?” I suspect keyboard to keyboard RTTY would
be the simplest possible “Hello World” type example.

— Meenaktchi V. [email protected] wrote:

Hi,

When I have 2 SDR setup, I was looking to send some data/string like
“Hello
World” from one of them and recieve it on the other setup. Are there
any scripts existing already?

Chris Albertson
Home: 310-376-1029 [email protected]
Office: 310-336-5189 [email protected]
KG6OMK/AG

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3

When we send and recieve using USRP boards and GNU SDR, on the recieve
side
usrp setup, demodulator connects to gr_correlate_access_code_bb which
connects to framer_sink. framer_sink pushes the assembled packets into
the
target queue. Can we extract the pkt here to read the data? How can we
send
a “Hello World” string on the transmit side usrp sdr setup?

Any suggestions?

Thanks
Meenaktchi

4

Meenaktchi,

You can pack “Hello World” string as paylaod then use send_pkt(payload)
on
the transmiter side. similarly unpack the payload at reciever to convert
into string.

you need to use same formating for pack and unpack at Tx & Rx
respectively.
I am assuming you are using packet radio.

Tarun

5

— Tarun T. [email protected] wrote:

Meenaktchi,

You can pack “Hello World” string as paylaod then use
send_pkt(payload) on
the transmiter side. similarly unpack the payload at reciever to
convert
into string.

you need to use same formating for pack and unpack at Tx & Rx
respectively.

Why not implement a mode that is common in the real
world? Then you can test your receiver by listening
to real signals. No need to have a transmitter working
first

RTTY is the most basic and simple
digital mode possable. There are no frames
and no packets, no protocol and the data rates
is very low, about 45 characters per second
It is just asynchronous FSK
using two tones 1200 Hz apart. See

The technology is so simple it predates computers

There are many programs for doing RTTY on a PC
under Linux or Windows using just a sound card
So you can download and run an example working
system, get it to work, then duplicate it using
gunradio.

The “hello world” should be the simplest thing
that can still work. I think RTTY is that.

Chris Albertson
Home: 310-376-1029 [email protected]
Office: 310-336-5189 [email protected]
KG6OMK/AG

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6

Meenaktchi,

On 7/8/07, Meenaktchi V. [email protected] wrote:

Thanks Tarun.

I am still facing problem with printing the payload as a string. It gets

printed as hex thou i use %s or %r. I checked the parameters passed to the
callback function in …/gnuradio-core/src/python/gnuradio/blksimpl/pkt.py
and payload is converted to a string using to_string() but still when I
print payload it gets printed in hex format.

I think you are not unpacking the received payload before printing it.
Please go through struct — Interpret bytes as packed binary data — Python 3.11.4 documentation . I hope
this would help you.

Any suggestions?

Thanks for any help
Meenaktchi

Regards,
Tarun

7

Thanks Tarun.

I am still facing problem with printing the payload as a string. It gets
printed as hex thou i use %s or %r. I checked the parameters passed to
the
callback function in
…/gnuradio-core/src/python/gnuradio/blksimpl/pkt.py
and payload is converted to a string using to_string() but still when I
print payload it gets printed in hex format.

Any suggestions?
Thanks for any help
Meenaktchi