I would like to humbly request support for hackrf antenna power in gr-osmosdr. At runtime preferably, or at least an init string flag to control it
(hackrf=0,antenna_power=1 for example). The function call seems to be hackrf_set_antenna_enable() but it's not exposed in gr-osmosdr as far as I can tell.
I have some dev experience (but not in C) but I'm falling short trying to understand the code and add the feature myself. If someone wants to provide some "ELI5" guidance I'll be happy to give it another go.
Having this feature would open up the powered antenna feature to users of gr-osmosdr such as gnuradio, gqrx, and the list goes on (big win!)
Reference:
https://www.mail-archive.com/hackrf-dev@greatscottgadgets.com/msg00423.html
Thanks!
Brad
What's the "right way" to call rtlsdr_* functions while receiving samples
via rtlsdr_read_async()?
e.g. to change frequency or gain mid-run.
You can't call them directly from the async callback as you're within a
libusb callback at that point and libusb will self-deadlock if you do
anything that needs a synchronous transfer. Plus even without the
self-deadlock you really don't want a recursive callback happening if
another bulk transfer turns up..
You can't call them from a separate thread because librtlsdr isn't
threadsafe.
The only way I've found that's reliable is to call rtlsdr_cancel_async()
from within the async callback, wait for rtlsdr_read_async() to return, do
your work, then call rtlsdr_read_async() again. This is ugly and can drop
samples. rtlsdr_read_async() is also a bit buggy in that sometimes it will
take up to a second after cancellation has completed before it returns (it
calls into libusb to handle more events even if all xfers have completed
cancellation, and then you've got to wait for that to time out..)
What's the right way to do this?
Oliver
Dear Osmocom.org project members,
I'm happy to be able to announce the annual incarnation of OsmoDevCon.
The Date is set for March 27 through 30. Venue: As usual, IN-Berlin
e.V. in Berlin, Germany.
Further details can be obtained from
http://openbsc.osmocom.org/trac/wiki/OsmoDevCon2015
Attendance, as usual, is restricted to people with an active history in
the Project by contributions in terms of code, patches, discussions,
documentation or in other form.
= Registration =
If you have wiki access, please add yourself to the #Requested section.
Alternatively, you can send me private e-mail about it.
After review, your (nick)name will be listed in the #Confirmed section.
Looking forward to meeting all of you again soon!
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
It seems a Russian developer created a fork of rtl-sdr that has software
decimation. "The decimation feature allows you to sacrifice some
bandwidth for increased ADC bit resolution."
This may be a reimplementation of the sdr-sharp version of decimation
according to this story:
http://www.rtl-sdr.com/new-sdr-rtl-sdr-driver-lnamixervga-gain-settings-dec…
The driver also features manual settings for the LNA/Mixer and VGA gain
stages and is based on Oliver Jowet’s modified driver.
The source code is here:
http://sourceforge.net/projects/sdrr820tmanualgainsettings/files/ if
anybody wants to see if there are any notable changes worthy of making a
patch or pull for as it may contain other fixes or features.
Hi All,
The rtl-sdr library from Osmocom uses R820T with an
IF filter bandwidth of 5 MHz. This means that the
peak amplitude of all the signals within this bandwidth
has to be below the point of saturation for tha ADC.
To accomplish that on a crowded FM band it is necessary
to turn down the gain which means that weak stations
can not be heard because of the degraded NF.
It is possible to do much better. The IF filter which
actually is a low pass filter and a high pass filter
can be set for a bandwidth of 300 kHz. Dynamic range
increases by something like 30 dB for the second next
channel 400 kHz away. It is also possible to get some
more improvement by changing the gain distribution.
Sampling should remain at 2.4 MHz because the stop band
attenuation is not very high and if sampling at 300
kHz one would get aliases from signals outside the filter
if they are strong.
Here is a video showing the difference between the Osmocom
library and a modified library:
https://www.youtube.com/watch?v=btDiWHuI730
Amusing that the cheap dongle has lower phase noise than
the low noise synthetized generator from Hewlet Packard.
An oldfashioned vacuumtube generator is needed to find
the performance of the dongle...
The modified library can be obtained like this:
git clone https://github.com/dl8aau/librtlsdr
A dll for Windows is available here:
https://drive.google.com/file/d/0B9m6SAaGpewQeWtyS0lzdW1xVmM/view?usp=shari…
Linrad-04.04 will soon become available here:
http://www.sm5bsz.com/linuxdsp/linrad.htm
Regards
Leif