Auf seiner Forschungsreise durch Ispra entdeckte Wolfgang Back das Institut für Schutz und Sicherheit des Bürgers (Institute for the Protection and the Secur…
Video Rating: 5 / 5
Software Defined Radio is it today, right? So why no SDR handhelds? And for all their high-tech wizardry, why no SDR cell phones? Mostly it’s power consumpti…
Video Rating: 5 / 5
Chris is talking about an SDR HT. David W2LNX asked about OFDM (at 32:45).
Put the two together. Will this be the HT that can send/receive digital
data at high speed (say >1mbps)??? Without being networked?
of course in the bandwidth, under 1Ghz also includes 222Mhz and 900Mhz. I
guess it might take more effort to add the filtering for those bands. Plus
he talks about the higher frequencies being a lot less stable right now.
Code & schematics are on github under the user testaco/whitebox. Also, look
for the project on Facebook as the handle “whiteboxradio”. YouTube won’t
let me link directly but hopefully you can find it. 73, Chris KD2BMH
Actually, looking more at OFDM @yandan8, I’d like to defer to someone who’s
more of an expert as to the theoretical limit of what 2MHz can bring. It
seems like there’s plenty of tradeoffs in there.
Homepage?
@RSwrightMD – Thank you very much 🙂 You can keep up to date by following
my twitter @testa, or my blog at blog.testa.co . I now have it transmitting
off of 4AA batteries. @yandan8 – The RF chip (CMX991) has a maximum receive
bandwidth of 2MHz, so depending on channel width and spacing you do have a
hard limit. ~1mbps should be possible but I have to work out the math
still. Also, I believe, you have to get OFDM into the band plan, which I
bet would take some time to get locked down.
My project is greatly inspired by the architecture of the smartphone. In
fact, I’d say what I built is an open source hardware Qualcomm Gobi modem,
though I do not know the specifics of their architecture at all. Only what
I can see when I rip an iPhone apart. I talked about this at the TAPR Forum
this year at Hamvention. The slides are available on the website slideshare
under the handle “whitebox-hamvention2013” 73, Chris KD2BMH
D-Star uses GSM, which is a pretty simple quadrature mode to implement. It
does not contain many subcarriers like OFDM.
D-Star is GMSK
There are examples of OFDM on the amateur bands. Programs such as EasyPAL
are implementations of the Digital Radio Mondiale standard. I wouldn’t be
surprised, but don’t know, if D-Star uses OFDM. D-Star is allowed on the
band-plan for 2m as a “Digital Mode”.
This is an amazing presentation about a new prototype for a SDR handheld
transceiver. The DCC/TAPR conference is cutting edge.
It was just me (the host) who introduced the idea of “not many” SDR cell
phones, based on what I saw at the SDR forum at the 2009 Hamvention. Chris
was just looking at the Flex-style ham equipment. The cell-phone thing
seemed like an interesting connection. Of course technology isn’t black and
white, either/or, and I’m not surprised if there’s SDR in anything. But can
you supply some details that I can use in a future show? How much “SDR” is
in the iPhone 5 or Glaxay SIII?
Not to distract from Chris’s great presentation, but the opening premise
that there are no “SDR handhelds or cellphones” is clearly wrong, I had
first hand involvement in SDR based cellular basebands 20 years ago. Try
finding any portable complex wireless device these days where the radio
datapath doesn’t use significant SDR technology. Completely agile SDR
portable radios? Much rarer, but still been in service with the Military
for many years.
Great talk about ham radio SDR.
#sdr #ham