Re: [gaia] Video about community network using HF band

[Javier Simó <[e-mail]>]

I'll try to get some info from the people that worked on that. If I 
succeed, I will send it to you.


El 18/3/20 a las 15:31, Rafael Diniz escribió:
> please read "Shannon channel capacity" where I wrote "Nyquist limit".
>
> On 3/18/20 11:27 AM, Rafael Diniz wrote:
>> Hi Javier, but newQPSK in soundmodem, if my memory does not fail, is way
>> wide wide than what we are using in HF, 2kHz. We are using OFDM, I'd say
>> we are closer to Nyquist limit, but of course there is plenty of room
>> for optimization in the MAC and upper protocol layers.
>>
>> Rafael
>>
>> On 3/18/20 6:41 AM, Javier Simó wrote:
>>> 18 years ago we worked on a HF packet-radio based solution and developed
>>> improvements  using OFDM newQPSK; getting up to 9600 bits/s. I don't
>>> know whether I can find the expert who might resemble all the details,
>>> code, etc, but if you feel it could be interesting I can explore that.
>>>
>>> Best
>>>
>>> Javier
>>>
>>>
>>> El 18/3/20 a las 4:31, Rafael Diniz escribió:
>>>> Gracias Luiz!
>>>>
>>>> We carried initial tests of this system in Mexico. The raw throughput,
>>>> in reasonable propagation conditions, is from 500 up to 4k bit/s. In
>>>> "real world" tropical region NVIS trx with hundreds of kilometers of
>>>> distance, with packet protocol and ARQ layers in place, the net
>>>> throughput ranges from 50 to 500 bit/s, depending on many factors.
>>>>
>>>> Abrazo,
>>>> Rafael
>>>>
>>>>
>>>> On 3/17/20 6:23 PM, Luis Martinez wrote:
>>>>> Parabens Rafael !
>>>>> It is wonderful, we are discussing a project like that in Mexico. Can
>>>>> you share what is the speed you are able to achieve ?
>>>>> Obrigado.
>>>>> Luiz
>>>>>
>>>>>
>>>>> On March 17, 2020 at 1:37:42 PM, Rafael Diniz ([e-mail]
>>>>> <mailto:[e-mail]>) wrote:
>>>>>
>>>>>> Hi all,
>>>>>>
>>>>>> Here is the link of our latest developments about HERMES[1]:
>>>>>> https://vimeo.com/398331581
>>>>>>
>>>>>> Cheers,
>>>>>> Rafael Diniz
>>>>>> Rhizomatica
>>>>>>
>>>>>> [1] https://www.rhizomatica.org/hermes/
>>>>>>
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>>> -- 
>>>
>>>
>>> *Francisco Javier Simó Reigadas*
>>>
>>> *Profesor, Director de la ETSIT*
>>>
>>> *Dep**t. Teoría de la Señal y Comunic. y Sist. Telemáticos y Computación*
>>>
>>> Universidad Rey Juan Carlos
>>>
>>> Campus de Fuenlabrada(Madrid), España
>>>
>>> Teléfono: 91 4888167
>>>
>>> [e-mail] <mailto:[e-mail]>| www.urjc.es
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>>>
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-- 


*Francisco Javier Simó Reigadas*

*Profesor, Director de la ETSIT*

*Dep**t. Teoría de la Señal y Comunic. y Sist. Telemáticos y Computación*

Universidad Rey Juan Carlos

Campus de Fuenlabrada(Madrid), España

Teléfono: 91 4888167

[e-mail] <mailto:[e-mail]>| www.urjc.es 
<http://www.urjc.es>| @URJC |