RFX 900 200mW

Hi everybody,
just a simple question:
does the RFX900 provide 200mW just out of the box? Do I have to take
care of
something in particular in order to obtain them?

Actually, what are the appropriate gain values that I should pass to
subdev.set_gain() n order to maximize correctly the output power?

Sorry for bthering the list with such questions but I was unable to have
them answered in the RFX900 section of the wiki… maybe I’ll add them
myself
once I’ll have fully understood the issue…

thanks and regards to all

Vincenzo P. wrote:

have them answered in the RFX900 section of the wiki… maybe I’ll add
them myself once I’ll have fully understood the issue…

That is a saturated power level. For any linear signal you will need to
back off a bit. In any case, you control the output power by
controlling the amplitude of the signal you send to the USRP. +/-32767
will be the max power but will result in RF clipping. You will need to
find the max power you can get with your particular signal and still
maintain enough linearity. If you need a dB or 2 more, you can bypass
the ISM band filter with a cap of about 100pF and then cut the traces to
the filter.

Matt

Thanks Matt!
really precious answer…
actually, transmitting an 8 MHz wide signal at 820MHz without bypassing
the ISM filter… what kind of attenuation should I expect? …I mean…
just a rough estimate of its magnitude…

thanks

vincenzo

Fantastic… I just had not realized this… (i did not know about the
filter at first) and I wanted to be sure about that…

It actually sounded too good to be true… because I’m already getting a
usable signal (10 m distance indoors) with the filter… therefore I
expect really good performance without it…

Many thanks Matt…

PS.
will the 50 MHz - 1 GHz transceiver be ready for the end of the summer…
I’m looking forward to have one… :slight_smile:

Vincenzo wrote:

Thanks Matt!
really precious answer…
actually, transmitting an 8 MHz wide signal at 820MHz without bypassing
the ISM filter… what kind of attenuation should I expect? …I mean…
just a rough estimate of its magnitude…

What I meant was that if you are working WITHIN the ISM band (902-928
MHz) you could get a couple extra dB by bypassing the filter. If you
are outside of the band, you MUST bypass it. You could be getting as
much as 30 dB off attenuation there.

Matt

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