[USRP-users] b210 tx power

Marcus D. Leech mleech at ripnet.com
Fri Oct 31 14:02:19 EDT 2014


On 10/31/2014 03:25 AM, Ralph A. Schmid, dk5ras wrote:
>
> 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 JThe 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.
>
You should probably back the baseband magnitude down to about 0.8 or 
less, but that won't make a *huge* difference.


> *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


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

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