[Hackrf-dev] Is my new (old) HackRF Deaf?

Tue Jul 11 15:29:28 EDT 2017

Depending what your looking to transmit, not really. I know the creator of
SDRConsole mentioned on the LimeSDR list that he was working on it.
Certainly there is the gnuradio windows port, that you could use to create
whatever waveform you want, and then use hackrf_transfer to play. (Assume
you have that command line utility working if you have the hackrf working
in sdrsharp.) The hackrf driver utilities might even come in the windows
port, I think they do actually. (As does, I believe gqrx) with these you
should have osmocom_siggen, which you can use to generate basic
sine/sawtooth/chirps etc.

However for testing the hackrf, the best way would be to boot to Pentoo,
and use gqrx to test rx and use osmocom_siggen to test tx, both have GUIs
that make them easier for a beginner. Pentoo can be easily installed to a
USB stick and comes with everything you need to get started. No
installation or compiling needed (other than running the program to copy it
to a blank USB stick). Then if you want to experiment with getting
everything up and running on alternate operating systems, you'll do so
knowing the problems you encounter are not related to the device, or at
least have a good baseline of the devices behavior to know that a problem
is or isn't part of the device. (Obviously as I said in previous email,
these comparatively cheap, wideband devices do come with tradeoffs, only
you can tell if those are a problem for your use case.)

For transmit, the device is essentially a fast D2A converter, and mixer,
with USB connectivity. I don't know if it's obvious, but the hackrf has no
concept of a modulation. It clocks in samples, and passes them up to the
computer. With SDR, all the mod/demod and any other stuff like FEC or
vocoding is done on the computer. So I think most people end up using GR or
integrating with the driver directly into their code and using libraries
like liquiddsp, fftw, or gnuradio to do the DSP behind it all. The awesome
part about the SDR stuff is how the radio really doesn't matter much,
assuming it meets basic requirements for BW, noise, etc.

I know there has been much interest from the traditional ham community in
getting a transciever console that supports usual ham analog modulations
and perhaps a few digital ones, and much discussion, but I'm not aware of
anything easy to point to and say that does it. Lots of RX, but not much on
the TX side. Part of it is interfacing with the various SDRs out there.
Soapy and osmocom is what most people use on the Linux side as middleware.
But this has to abstract away devices with no TX like the RTL sticks, half
duplex devices like hackrf, 1TX/1RX like the USRP B200, 2x2 MIMO like the
LimeSDR, and in the end everyone has atleast 1RX so that's what's commonly
built towards.

As an aside,
I use SDR almost exclusively for TX for testing other equipment or software
I write. So mainly  to provide know waveforms. I use GR, but mainly in
Python code, so I can add in a few things that would be hard to add in from
the gnuradio-companion GUI.

So it doesn't sound like you want a transciever console, what are you
trying to transmit? What bandwidth? Just tones or something digitally or
analog modulated?

-Anon

On Jul 11, 2017 1:27 PM, "Jerry" <jsternmd at att.net> wrote:

Hi Anon,

Many, many thanks for the thoughtful summary.  It’s very much appreciated.
I sheepishly have to admit my primary goal is to use HackRF as a signal
source up to 6GHz and only secondarily for any SDR receive function.  As
such, learning the nuances of Linux for installation or watching hours of
tutorials was something I ranked as secondary after I first confirmed basic
operation of the HackRF for both TX and RX.   However, as I have been
digging into it, the entire breadth of SDR functionality has peaked my
interest so that I will put my energies into those secondary tasks as
well.

BTW, are you aware of any Windows software that can provide a GUI for TX
functions?

Jerry NY2KW

*From:* Anon Lister [mailto:listeranon at gmail.com]
*Sent:* Tuesday, July 11, 2017 3:42 AM
*To:* Jerry <jsternmd at att.net>
*Cc:* hackrf-dev at greatscottgadgets.com; Gavin Jacobs <
apriljunkbox at hotmail.com>

*Subject:* Re: [Hackrf-dev] Is my new (old) HackRF Deaf?

Hey,

So, a little DSP background.

------

Keep in mind pretty much all the SDRs now output complex (I/Q) / Quadrature
samples. This means two things. Nyqust BW = Sample Rate, and everything is
centered at 0 frequency digitally. Basically, where you would think of a
bandwidth control before, use sample rate now. Bandwidth usually refers to
a filter applied to the sample_rate (remember, bandwidth=sample rate) sized
chunk of spectrum.

The SDR takes that original spectrum (10M of complex bandwidth centered at
90Mhz in your case, down converts it to baseband, and sends it to the PC.
GR is plotting [-5M, 5M] (but helpfully overlaying the original tuned
frequency for you, since you have told it where that is in the QT GUI sink.)

Also, unlike your (probably) superhet recievers, most SDR devices,
including the hackrf are direct conversion. This type of receive has a
couple drawbacks over the superhet ones. (There are pros too usually
size/weight/power/cost.) One con is DC leakage. That is the bigger spike
you see at the center. You can avoid it by offset tuning. I think the ham
folks would call this a VFO. Basically it, in software, will take the
spectrum from a point not at 0, shift it down to 0, and bandpass filter it.
Then do the FM/AM/ec demod. (You can also simply overpower the spike with
your carrier, if possible, but the hackrf has a rather large amount of
leakage vs others so it's not always practical, and it would need to be at
the antenna power, not post digitization.)

If you insist on using Windows I think SDRConsole might work a bit better
for you, and is probably setup to be a little more friendly to someone
coming into the SDR thing from a ham background or someone who is not very
used to a Linux environment. However setting it up requires using zadig,
but if you got it working with sdr#, it should already be setup. Also I'll
say if you want to do hammy things, like receive AM, N/WB FM, SSB, etc.
these software packages are what your looking for, not something like
gnuradio. They usually have the point and click VFO/offset tuning setup, so
you pick you modulation, click on the center, drag the box or enter the
bandwidth you want for the demod, and you get data. Gnuradio is more akin
to a box of wires, components, and tools you will need if you want to build
your own radio, and many pages of manuals for each independent piece. Its
an awesome tool if you want to experiment with building different kinds of
radios, perhaps a bit overkill or a bit much if you just want to use one.
(At least till you get your feet wet in the SDR world, and start thinking,
man wouldn't it be cool if sdr#/SDRConsole/gqrx could do XYZ, and then
realize GR provides you the tools to do just that.)

I'll also mention there is a Pentoo live USB stick image you can download
and boot into with all the drivers and such ready to go for a Linux setup.
Just plug it in and boot off it. If you do try this the best (imho) Linux
version of the SDR#/SDRConsole radio receiver app flavor, is gqrx, which
should come on the Pentoo image by default.

If you do keep playing with GR, you should sign up for the discuss-gnuradio
mailing list which is very active, and can help with some of your gnuradio
questions.

----

So for your current setup:

BW will control the digital bandpass filter on the hackrf. It will not do
what you want. Try setting that equal to the sample rate(samp_rate by
default), and changing the sample rate to something like 4M. From your FFT
it looks like you have possibly two weakish FM carriers visible, but your
bandpass is set to only a meg or two, so you might be missing some on the
side, that are higher power.

You'll need to adjust the gain sliders. The help documentation(or see [1])
should describe what they mean for the hackrf, of which there are three.
"RF gain" is a toggle for the rf amp. Leave this one off/0. The other two,
the bb and if gain I believe, you can play with, setting both to about 16
should be ok to start, however I find setting the if gain to 32 and the bb
to about 4 seems to work better for me.

[1]https://www.reddit.com/r/hackrf/comments/49aa2i/using_
gain_controls_with_osmocom_sourcesink_in/

-Anon

On Jul 11, 2017 12:36 AM, "Jerry" <jsternmd at att.net> wrote:

Jake

Thanks for the sound advice.  I have had spectrum analyzers and learned
early to be careful with nearby RF sources ☹

Right now I am getting a wide confluence of signals between 98.5 and 101.5
on the FFT.  If it were my SA I would narrow the bandwidth to improve the
signal resolution but on the Osmocom Source changing Ch0 Bandwidth from 10
Hz to 500 Hz doesn’t appear to change the FFT display noticeably.

Attached is a picture.

Jerry NY2KW

*From:* HackRF-dev [mailto:hackrf-dev-bounces at greatscottgadgets.com] *On
Behalf Of *Gavin Jacobs
*Sent:* Monday, July 10, 2017 6:22 PM
*To:* hackrf-dev at greatscottgadgets.com
*Subject:* Re: [Hackrf-dev] Is my new (old) HackRF Deaf?

Jerry,

Learning how to use Ubuntu, and Gnu, and HackRF is a challenge! I went down
that path about a year ago. The issue you describe hits every new user.
When you are running GNU radio, you have to turn up the IF gain to about 40
- it defaults to 0. Also, turn up the BaseBand gain to about 30. Leave the
RF gain at 0 (that setting is confusing; a value of 0 just means the RF LNA
is left off; 14 means it is on; but you rarely need it on).

Also, a word of caution. Since you are a ham, you likely have an HT or a
base station. You have to take care to never exceed the maximum field
strength anywhere near the HackRF. I don't recall the exact spec, but
basically if you transmit with a 5 Watt HT, right next to HackRF, you can
fry the RF front end.

Hope that helps.

Jake

------------------------------

*From:* HackRF-dev <hackrf-dev-bounces at greatscottgadgets.com> on behalf of
Jerry Stern <jsternmd at att.net>
*Sent:* July 10, 2017 2:54:16 PM
*To:* hackrf-dev at greatscottgadgets.com
*Subject:* [Hackrf-dev] Is my new (old) HackRF Deaf?

Is my HackRF deaf?  I am a ham radio hobbyist and I bought a HackRF One to
enhance my deeper learning of SDR but also as a broadband RF source.  To my
dismay, installing the software has become days of learning Ubuntu basics
and dealing with instructions that are at times outdated or nuanced towards
a person with much more than basic Linux skills.  So, I gave up on Ubuntu
only because it was faster for me to install and test with Windows 7.   My
HackRF One (GreatScott) must have been a leftover as the firmware was dated
2014(August).  I installed the latest version HackRF tools and updated the
firmware to Feb 2017.  I followed Mike's video tutorial for creating a
basic GNU flow for FM and also installed SDR#.  I have very strong FM
broadcast stations in my area which I can easily demodulate with my Rigol
Spectrum analyzer using the ANT500. However both with GNU and SDR# my
HackRF appears deaf in FM broadcast mode.  I read that a few years back
there may have been some issues with cold solder joints on the HackRF
pcb....  I have a lot of test equipment - from RF generators up to 2 GHz,
etc but before I go that route is there something I am perhaps missing in
my setup.  Not sure where or what details to provide here without
overloading my question further .

Thanks

Jerry

Sent from my iPhone

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