[Lowfer] The SDR-IQ Receiver and conditions on 185.300 KHz

[Richard Goodman]

Man ... Life is good!

Conditions on 185.300 KHz were GREAT last night. Last Thursday afternoon I
found the source of 60 Hz related noise that has been giving me trouble for
years! And finally, I got my new SDR-IQ receiver packaged and on line.
Except for a few fairly widely spaced static crashes, reception last night
was incredible!

The SDR-IQ is an amazing receiver! I was fortunate and got one at the
promotional price of $385 out the door including shipping! So far from what
I’ve seen, it does EVERYTHING from about 10 KHz up through 30 MHz extremely
well. I purchased it primarily for LF however and that’s where most of my
experience with it lies.

Here’s what my receiver looks like packaged in a little Radio Shack box:

http://home.comcast.net/~wa3usg/DSC_4821.jpg

I can switch between the two antennas that you see via the link below.

http://home.comcast.net/~wa3usg/DSCF3297.JPG

The AMRAD E-field probe is on the left. My remotely tunable loop is on the
right. The loop has a outdoor utility box under it that contains 9 relays to
switch different capacitors in and out in parallel with the Varactor diode
which is remotely tuned from within the shack. Using this, the loop is
tunable from around 100 KHz up through 500 KHz. I also have a rotor mounted
at the bottom so I can turn it.

http://home.comcast.net/~wa3usg/MVC360X.JPG

I built the E-Field probe because for years, I had 60 Hz related noise on
the loop that I could never quite get rid of. The E-Field probe was much
quieter 
 you could still hear just a little 60 Hz buzz on the Probe but it
was way down in the noise. Solving the noise problem is a totally different
story, but now, both antennas are silent!

The SDR-IQ, as far as I can tell, is absolutely accurate to a fraction of a
Hertz all the way up through 800 KHz (I haven’t tried to determine the
accuracy above that). The front end gain, and gain in the IF are adjustable
from menus on the main control screen on the fly. Likewise, the bandwidth is
adjustable from 100 Hz in the CW mode, all the way up through 20 KHz in the
AM mode. Let me tell you guys 
 this receiver really works well! I have a
strong AM station located about 5 miles from me and until the SDR-IQ, I
always had trouble with it getting in ... no more!!

One of the coolest things about the SDR, is that it has a display that will
let you look at a frequency span of up to 190 KHz around where you are
receiving. The display updates FAST 
 several times per second. The
sensitivity is such that it will display things that are on the threshold of
audibility across the whole span.

When I tune the remote varactor in my loop, you can see the bump in the
noise floor move around and you can put it right where you want it 
 same
way with my tunable preamp 
 I can center the passband of it right where I’m
receiving, If you look at the below display, you can see the loop & preamp
passband is about 25 KHz wide running from about 165 to 190 KHz. Being able
to see & visualize this kinda stuff adds a new dimension to LF reception.
You can also run Argo and the SDR Control program at the same time just
fine. Argo will pick the audio right off your soundcard directly ... no
cables needed.

http://home.comcast.net/~wa3usg/sdr01.jpg


Last night was my first real good night with this setup 
 I’m really anxious
to see what’s around this evening. In case you’re curious about the SDQ-IQ,
I’ll post a link to the RFSPACE website here:

http://www.rfspace.com/sdriq.html

I also wrote a review of this receiver in our Club Newsletter 
 I’ll post a
link to that also (it's 3 Meg):

http://home.comcast.net/~wa3usg/2007_03.pdf

Try it, you’ll like it!

73
Dick, WA3USG