[USRP-users] b210 tx power

Ralph A. Schmid, dk5ras ralph at schmid.xxx
Fri Oct 31 03:25:56 EDT 2014


Magnitude 1, gain something above 100, I did not know the valid range, but in this range nothing changed anymore, so I assumed that everything should be at max. Just a quick and dirty test, I spent only short time on this. Oh, and attenuation of the cable should be small enough, I took one with only 10cm length :) The carrier looked clean, no spurs or IM visible visible when using an 30dB attenuator, and when going directly into the analyzer the usual IM that happens when its input is overdriven.

 

Ralph.

 

From: Marcus D. Leech [mailto:mleech at ripnet.com] 
Sent: Thursday, October 30, 2014 7:52 PM
To: Ralph A. Schmid, dk5ras
Cc: usrp-users at lists.ettus.com
Subject: Re: [USRP-users] b210 tx power

 

On 10/30/2014 02:09 PM, Ralph A. Schmid, dk5ras wrote: 

Here we go:

 

When using OpenBTS, Rangenetworks SDR1 GSM 1800 18 dBm, Ettus B210 GSM 1800 0dBm, GSM 900 6 dBm.

 

With gnuradio and full gain, Ettus B210 plain carrier, 935 MHz 15 dBm, 1877 MHz 9 dBm. 

 

Ralph.

What was the carrier magnitude you used?

What was the actual gain setting on TX?






 

From: mleech at ripnet.com <mailto:mleech at ripnet.com>  [mailto:mleech at ripnet.com] 
Sent: Thursday, October 30, 2014 15:52
To: Ralph A. Schmid, dk5ras
Subject: RE: [USRP-users] b210 tx power

 

The spec sheet for B2xx simply says >10dBm (at max power setting).  In general, the B2xx series produces less maximum power than other products that use daughter-cards.  

See performance data for WBX/SBX/CBX here:

http://files.ettus.com/performance_data/

 

Also, keep in mind that the gain-control range on the B2xx series is larger than on other products, so if you're comparing at the same gain settings as you would on other products, you'll get misleading results.

 

 

 

 

On 2014-10-30 09:40, Ralph A. Schmid, dk5ras wrote:

You can't reliably use "communication range experiments" to measure power.

Sure, but the peak on my analyzer also looked much smaller at 1800 MHz.

Also, don't forget, that the path-loss laws scale with wavelength. You can easily see this with on-line path-loss caclulators.

Still the SDR1 had much higher output power, although both claim to have
similar power.
 
But I will measure it and post the results...
 
Ralph.
 
 
 






-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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