[USRP-users] b210 tx power

Marcus D. Leech mleech at ripnet.com
Thu Oct 30 08:57:11 EDT 2014


On 10/30/2014 07:21 AM, Ralph A. Schmid, dk5ras via USRP-users wrote:
> Hi,
>
>> I don't have measurements for the b210, but the ones for the b200 tx
> (which
>> should be pretty identical to the b210) indicate that the variation of TX
> power
>> between 100MHz and 2GHz is about 6dB max (for the 30dB gain case). So,
>> depending on what you consider to be remarkable, you might call this a
> My estimation was near 10dB, but OK, 6dB are possible, too.
>
>> remarkable drop; however, I don't think TX power is that critical for GSM;
>> what are the operational differences you see at 1.8GHz?
> At least the operational range drops significantly, even on line of sight.
> The Rangenetworks SDR1 delivers at 1.8GHz about the same downlink range like
> the B210 at 900 MHz, while the B210 at 1.8GHz only has half or a third of
> the SDR1 range. Of course with identical antennae, identical location,
> identical phone.
>
> This discussion makes me curious, I will measure it with my old HP and tell
> about the results.
>
>> Another thing that happened to me a few times and made me question my
>> sanity was connecting to the wrong port of my USRP (that was with N210s,
>> though).
> Oh, yes, you are mentioning here a not so bright spot of my experiments,
> when coverage ended at the door of my office. WTF?! Took me a while to
> figure out. This resulted in putting red caps onto the usually unused ports
> of my B210 :-)
>
>> Greetings,
>> Marcus
> Ralph.
>
>
>
You can't reliably use "communication range experiments" to measure power.

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




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





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