-------- Original Message -------- From: coderman <[email protected]> To: [email protected] Cc: [email protected], [email protected] Subject: Re: Covert wireless (was: A crowdfunding campaign to build a free baseband) Date: Fri, 10 Apr 2015 16:11:15 -0700
> On 4/10/15, [email protected] <[email protected]> > wrote: > > ... I delivered a paper last October regarding the reasons such > > alternatives are > > needed, reviewed recent developments and offered some practical directions > > for future work (some of which I am pursuing): > > > > http://www.paralelnipolis.cz/pp-congress-2014/WWPP.pdf > > > i didn't see mention of MIMO / beam forming systems for both better > throughput and greater privacy. I did not look closely at MIMO due to the lack of inexpensive SDR solutions and their lack of utility at lower bands. > > and as common as HackRF is, there are better kits. why was this unit > in particular chosen? Mainly price and frequency coverage. Since my interest is mainly on apps that require transmitting I did not focus on receviers. Starting at twice the HackRF's cost the USRPs are a best buy at the low end. The HackRF's weakness main weakness is its 8-bit ADC and lack of pre-selector to limit strong out-of-band input signals and reduce out-of-band transmiter spurs. However, it has an internal header to which daughter boards can be added and its CPDL can be reprogrammed for these add-ons and other changes. On the receive side a cheap coax bandstop filter, with acceptable insertion loss, can easily be fabricated to knock down the FM broadcast and pager transmitter signals instead of a pre-selector. What other kits were you thinking of? WW > > hard problems ahead!
