Re: [Discuss-gnuradio] differences between usrps

[Marcus D. Leech]

On 09/06/2011 08:27 AM, Walter Barmak wrote:
> hi,
>
> as some of you already know, i have a usrp1 with 2 rfx1800 burned to
> rfx900, two small antenas (13db, 60 watts) and a stock clock of 64mhz
> which i'm planning to change for the external clocktamer. however,
> before i do that, i'd like to know which is the best option for me.
>
> 1) as i understand, the main difference between usrp1 and usrp n210 is
> the frequency range. does this have to do with the capacity for
> concurrent calls? is this why the usrp1 can have 7 concurrent calls
> while the usrp n210 can have up to 12 concurrent calls (without further
> modification)?
Not frequency range.  The USRP1 and USRP2/N210 family will operate over 
identical frequency
  ranges for the same daughtercards.  But the *instantaneous bandwidth* 
towards the host is
  higher with the N210 (25Msps vs 8Msps), so depending on the channel 
allocation scheme of
  whatever your application is, this can allow more channels.

> 2) also, i'd like to know what would be the reach of my system in open
> field. i guess, as i now have it, would be around 200 meters, so if i
> would like to improve that i would need either a filter (for transmit
> and receive?) or a duplexer and a higher power antena?
You'd need a power amplifier and duplexor arrangement, likely.  But that 
would take
  an operation that is already on the edge of legality, and make it 
utterly illegal in
  most places, since you'd be interfering with licensed services (the 
GSM operators).


> 3) what is the ethernet connection in the usrp n210 for?
The ethernet connection is how samples go into/out-of the N210.  On the 
USRP1, those samples
  are carried over USB.


> 4) if i would like to increase the number of concurrent calls, i guess i
> would need to buy more usrps, which ones would be better to achieve a
> higher number of concurrent calls? ie, which is designed to be able to
> connect to other usrps and increase the number of concurrent calls?
>
> thanks in advance,
That's a question for the OpenBTS list.  OpenBTS is one of *hundreds* of 
different applications extant for
  Gnu Radio and the USRP family of digital transceivers.  Direct 
OpenBTS questions to the appropriate list.




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