On USRP and transmitting voice


#1

Hi folks,
I’m a ham that has become interested in SDR in general, and GNU
Radio/USRP. I’m looking to build an SDR that can TX voice (FM & SSB) on
HF/2m/70cm and that could also be a platform for data transmission in
the coming years. I’ve found a good bit of information on the web
regarding reception of SSB & FM at various frequencies, but I’m coming
up short on any voice TX capability. (when I say voice TX, I’m talking
about hooking a mic up to the computer and having it transmit what I
say) Has there been any work done on real-time voice TX (again, NFM/SSB)
with the USRP? Any docs, references, or just writeups? I’m not the
best googler in the world, so apologies if I’ve missed it. Also, are
there any issues to be aware of with USRP TX? I could imagine some
aliasing or perhaps phase or general waveform issues if the software
isn’t set up right, or perhaps some external filtering between the board
and the amp. At any rate, if someone could point me in the right
direction, I’d appreciate it.

Thanks,
Michael Menefee
e: removed_email_address@domain.invalid
w: www.mnetwork.org


#2

I was thinking the same. But then I thought that the USRP is overkill
if you are doing ham type waveforms as they are only 3Khz wide at
mosy. A studio quality computer “sound card” can take 192K samples
per second at 24 bits per channel… GNU radio software can interface
to a high-end sound card

After the sound card you only need a mixer and a VFO. There are a
number of projects that are suplying simple SDR front ends like these.

I may buy smething like USRP later but for now I want to get
on the air for a lot less, About $40 is all you need for a very
limited front end – RX and TX on a crystal bound frequency
once this works my plan is to replace the crystal with a
VFO and then figure out how to switch in filters.

Don’t get me wrong a USRP would be great.

— “Michael C. Menefee” removed_email_address@domain.invalid wrote:

Hi folks,
I’m a ham that has become interested in SDR in general, and GNU
Radio/USRP. I’m looking to build an SDR that can TX voice (FM & SSB)
on
HF/2m/70cm

Chris Albertson
Home: 310-376-1029 removed_email_address@domain.invalid
Office: 310-336-5189 removed_email_address@domain.invalid


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