Simple SDR Project

[Robert Hart]

I've been experimenting with a on a simple low-cost SDR design using a
single channel SDR tuned to 10.7Mhz - http://www.hardhack.org.au/dcsdr

The am is to use this as a IF detector stage that can be hacked into
another affordable FM radio that receives a desired frequency. I have
now tried this on few FM Radios and even a UHF VCR and the idea seems to
work quite well in all modulation modes. Recently I bought a small FM
PLL Receiver board on ebay which was designed for VHF with a 0.2uV
sensitivity and It now have a quite workable self-contained VHF SDR
receiver with a 1Mhz channel range and I can watch 64khz of the band
simultaneously using a program called Winrad http://www.winrad.org/ and
most likely more bandwidth with a better sound card.

http://www.hardhack.org.au/vhf_sdr_173Mhz

The problem comes in logging the full output of the receiver over time
as I can't seem to run Winrad http://www.winrad.org/ and Radio-SkyPipe
http://www.radiosky.com/skypipeishere.html on the same computer without
multiple sound cards or two computers and strapping the output of one to
the other which results in reducing the bandwidth and adding noise.

Any comments or suggestions or is this a waste of time?

Robert

[Marcus D. Leech]

Not a waste of time at all.

My recollection is that Jim offers various ways of getting data *into*
Radio-SkyPipe, and if you can
somehow using his API for doing that, you'll have some success.

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

[Jim Sky]

Hi Robert,

I am very interested in your project and in helping you get away for the
data to be picked up by Radio-SkyPipe. Please feel free to contact me
directly at radi...@radiosky.com. I will try to take a look at Winrads
documentation and see if they have someplace I can grab data. (if that
is what you want to do.) Then there is that virtual audio cable thing....

Aloha,
Jim

--
Jim Sky
Radio-Sky Publishing
PMB 242 P. O. Box 7063
Ocean View, HI 96737
USA

http://radiosky.com

[Robert Rolf]

http://en.wikipedia.org/wiki/Virtual_Audio_Cable
http://download.cnet.com/Virtual-Audio-Cable/3000-2168_4-10067766.html

"VAC is intended to connect several audio applications together in real
time. It's like a sound card with hardwired input and output: when an
application sends an audio stream to a virtual cable, other applications
can record this stream from the other cable end. Thus, you can record
and process output of almost any audio application by almost any other
audio application.

Price: Free to try (2-cable trial); $30.00 to buy (more than 2 ports).

The trial version is widely known as Crippleware as a voice can be heard
over all audio streams whispering "trial". It is assumed this is to both
annoy the user and force him or her to buy the full product.
[so much for a 'usable' TRIAL...[R]]

Jim, does RSP have AISO connectivity yet?
http://en.wikipedia.org/wiki/Audio_Stream_Input/Output

Robert, have you considered adding a USB sound card device to the
existing computer? About $40, and you shouldn't be loosing bandwidth if
your source has a low output impedance.
1/8" phone jack splitters (headphone splitters) are cheap, and the
modular ones (little bricks) won't add any noise since there is no cable
length involved.

Do let us know which way you go and how well the VAC program works.

R

[Jim Sky]

>
> Jim, does RSP have AISO connectivity yet?

Not yet. It may happen, but it looks like a big project.
Jim

[Robert Hart]

The VAC looks like it will work quite well. I'll give this a go.

Cheers

Robert