Default antenna with RFX2400

Hi,

I’m using USRP2 with RFX2400 daughter board. I’m using GRC. By default
which antenna are used for USRP-source and USRP-sink?

PN

On 12/12/2011 08:14 PM, Phone Naing MYINT wrote:

Hi,

I’m using USRP2 with RFX2400 daughter board. I’m using GRC. By default which
antenna are used for USRP-source and USRP-sink?

http://files.ettus.com/uhd_docs/manual/html/dboards.html#rfx-series

-josh

On 12/12/11 11:14 PM, Phone Naing MYINT wrote:

PN

http://files.ettus.com/uhd_docs/manual/html/dboards.html#rfx-series

Hi,

TX is clear, defaulted to TX/RX. RX default to direct conversion, what
does it mean? For receive, using TX/RX or RX2 provides same performance?

PN

On 12/12/2011 08:25 PM, Phone Naing MYINT wrote:

Hi,

TX is clear, defaulted to TX/RX. RX default to direct conversion, what does it
mean?

RFX2400 is a direct conversion receiver and a direct conversion
transmitter. What the docs really should say:

  1. When you tune the transmit chain, the default behaviour is to tune
    the LO away from the desired center frequency.

  2. When you tune the receive chain, the default behavior is to tune the
    LO as close as possible to the desired center frequency.

You can of course, override this behavior:
http://files.ettus.com/uhd_docs/manual/html/general.html#tuning-notes

For receive, using TX/RX or RX2 provides same performance?

TXRX vs RX2 is just a simple switch. You must pick what is most useful
for your application (full vs half duplex). Obviously, for a
receive-only application, either antenna option is good.

-josh

2011/12/13 Josh B. [email protected]

  1. When you tune the transmit chain, the default behaviour is to tune
    the LO away from the desired center frequency.

  2. When you tune the receive chain, the default behavior is to tune the
    LO as close as possible to the desired center frequency.

You can of course, override this behavior:
http://files.ettus.com/uhd_docs/manual/html/general.html#tuning-notes

I would personally reccomend you to use this (and scrap GRC) as soon as
possible.
The RFX2400 board has some problems selecting a center frequency far
enough
off, and you might run into trouble if you are using a digital
modulation
(You can see some of my earlier posts on this)

For receive, using TX/RX or RX2 provides same performance?

TXRX vs RX2 is just a simple switch. You must pick what is most useful
for your application (full vs half duplex). Obviously, for a
receive-only application, either antenna option is good.

If you use the TX/RX as a receiver, you will notice a small attenuation
(~2dB) compared to using RX2.
Also remark, that the attenuation between TX/RX when transmitting and
RX2
is ~65 dB.

-josh


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Best Paul

On 13/12/11 07:59 AM, Paul M. Bendixen wrote:

conversion, what does it mean?

GRC allows you to use advanced tuning–why “scrap GRC” ??