Hacks SDR

HDSDR OSX version 2.76 released

Once again, with Mario’s permission, I bundled the latest revision of HDSDR to be run on OSX. I also created a new rtl_sdr launcher that should be more stable, easier to use and that incorporates the bleeding edge version of librtlsdr.
I tested this on Yosemite, El Capitan and Sierra. My CPU is a quad i7.

Here is a quick vhf/hf demo that I run using my v3 dongle in direct sampling mode:

In order to download it, please refer to this page.

Latest Release: March 2nd 2017

Hacks SDR

HDSDR on OSX the EASY way – SDRplay edition



Today I updated my HDSDR OSX bundle to include support for SDRplay.
Nothing much has changed… If you want to enjoy SDRplay + HDSDR on OSX, all you need to do is the following:

  1. Install the SDRplay drivers (available here)
  2. Download my bundle
  3. Copy ‘HDSR OSX’ and ‘rtl_tcp SDRplay’ on you hard drive
  4. Run the ‘rtl_tcp SDRplay’ server
  5. Run ‘HDSDR OSX’

As you can see, the bundle still includes the original RTL2832U rtl_tcp server. According to the hardware at your disposal, you can use either use one or the other as their functionalities are practically identical.

The SDRplay support was made possible by the hard work of Tony Hoyle so if you want to thank anybody, please thank him.



Hacks SDR

HDSDR on OSX the EASY way (reloaded!)


Catilina broke everything. Sorry


A while ago I published a bundle that easily allowed anyone to run HDSDR and the RTL2832U on OSX. To my surprise the bundle was quite successful, a demonstration that there weren’t (yet) many available alternatives to use the cheapest (and funniest!) SDR radio in the world on a Mac.

After a few years things have improved a bit and some valid alternatives have surfaced: Gqrx and CubicSDR. Even SDR# has been reported to work under Mono but, believe it or not, neither of them seem to work well on my Mac. Actually they don’t even come close to the level of stability and/or the number of features that can be enjoyed when using HDSDR.

Last week I installed a new active RX antenna and I tried to reopen HDSDR in order to test it. Guess what? I realized that it wasn’t compatible anymore with the most recent versions of OSX. It was time to do it all over again… so here I am.

How to install

1) Download the zip archive and expand it
2) Copy rtl_sdr and HDSDR anywhere you like on your Mac

3) Make sure your RTL2832U is connected
4) Run rtl_tcp

6) Click on Start


At this point, if things go as they should, nothing else is required and you should be ready to go. I have successfully tested Yosemite, El Capitan, Sierra and they work great.

January 19th 2016:  This bundle now also supports SDRplay. More details here.
February 12th 2017: HDSDR updated to 2.76. Improved rtl_sdr
March 2nd 2017: Fixed problem in rtl_sdr (thanks Walter KC1DVT)

Final Considerations

This is an experiment. I cannot guarantee that it will work nor that it will not damage your system or your data. Download and use the bundle at your own risk.
I am not the author of the software and I can be helpful only up to a certain point. All I am doing is bundling a bunch of different packages in a way that is easily executable on a Mac.

HF Portable

K1FM Mini Magnetic Loop 2.0

In the effort of improving my ultra-portable HF antenna setup, I first looked into a Capacitively Coupled Magnetic Loop, better known as the Army Loop (or Patterson Loop). The Army loop performed well. It was so portable that I enjoyed using it before, during and after numerous Tennis matches… Here is one example:

The Army loop, however, sometimes presented a little bit of a challenge because in order to tune you need to operate two capacitors, instead of one. Generally speaking, one capacitor affects resonance while the other affects the coupling impedance. The main problem I found is that even when the SWR is very low, such impedance isn’t always what you would expect it to be (around 50 ohm). You can still match it by operating the second capacitor but there really isn’t a way – while portable – to tell how close you are to the perfect match. That’s the main reason why I decided to look for alternatives.

The idea for my next portable loop came from  the Wonder Loop by Wonder Wand (not to be confused with the ‘G4ILO Wonder Loop’, which is unrelated). Wonder Wand’s Wonder Loop looks like an Army loop, but only has one capacitor. After taking a look inside I was intrigued to see a Toroidal transformer. My first reaction was: WFT?!? Then I remembered seeing something similar on the excellent N4SPP page about loops (probably the best page about magnetic loops actually available). Here is what Frank N4SPP has to say about this coupling method:

N4SPP’s coverage of the toroidal transformer coupling solution

The advantages of such design are two:  no need for a coupler loop and only one capacitor. Precisely what I wanted!
At this point you might ask why don’t  I just use the Wonder Loop. The thing is that the Wonder Loop isn’t simply ultra-portable, it is microscopical. It’s radiator is made of a 1 mm thin copper wire… a bit too much, I guess. All I wanted was the same concept as the Wonder Loop but with a radiator of my choice (and at a smaller price!).

Here is the schematic I started working on:


This time I used a smaller Hammond Enclosure, the 1594ASGY. The capacitor, instead, is a dual gang 266 pF by Mike’s Electronic Parts.  Both gangs are engaged in parallel as well as all the trimmer capacitors (trimmers are used to raise the minimum capacitance and also raise the maximum a little bit). By doing so, the loop covers from 40 to 10 meters. Here is the is the first test item:

And the analyzer results:

As you can see, on 20 meters and above not only the SWR is low but also the impedance is constantly around 50 ohm. No need for a second knob! On 30 and 40 meters, instead, conditions deteriorate considerably but I never expected any good performance from such a small loop on those bands anyways. Below 14 MHz I generally use my loop to listen only. It might happen to make a contact once in a while, but it is rare.

The loop responded as I wanted it to… But was it performing? To find out, yesterday I did the first field comparison of four different foldable loops:

1) Toroidal Coupled Loop 6FT (the antenna I’m writing about today)
2) Army Loop 6FT (the antenna I described last time)
3) Inductively Coupled 6FT Loop (classic design, just smaller than usual)
4) Inductively Coupled 11FT Loop (the classic loop! Practically a photocopy of the Alexloop)

Testing was performed on 20 meters WSPR by sending 3 frames on each antenna starting at 7PM local time. By the time I finished with the last antenna it was already 8PM and it’s possible that during such time propagation conditions evolved. The ideal way to perform this test would be transmitting with all the antennas at the same time, but I am not equipped to do that… At least not yet!
Finally, the gathered data:


As expected, the test shows the 11FT loop constantly being on top of the game. Loop dimensions are critical and on 20 meters there is a considerable difference between 11 and 6 feet circumference. On the other hand, the 6 Feet loops (Toroidal, Capacitive and Inductive) seem to be delivering similar performances. There are no clear winners or losers, which is good news because that means I can keep using the latest version (toroidal) which is smaller and simpler to use.

Future plans include building the biggest toroidal loop possible, as well as making my 11FT inductive loop lighter and easier to transport.

Best 73’s

Alain K1FM


I finally got my HackRF and I have a Mac… Now what?


If you are reading this I can probably imagine what’s going on: You’ve been waiting for a year to get your HackRF and, now that you finally have it, you don’t know what to do with it. The problem is that you have  Mac and – surprise surprise – the only “easy to use” programs (SDR# anyone?) are unfortunately not available for your operating system.

Is there anything you can do? There surely is… Let’s get started.

First of all you need to install MacPorts. If you are already using Homebrew or Fink I’m sorry, you still need MacPorts. If, instead, you don’t even know what MacPorts is just ignore that for now. You will have all the time in this world to find out but, just for now, you don’t really need to know much about it.

After the install is complete, open up a Terminal and run the following commands in it:

sudo port install gr-osmosdr +full
sudo port install gr-fosphor

The install will take hours to complete, so you can open a beer. Maybe two. Hopefully the whole process should complete without incident (I tried on different Macs and so did a few friends and we never had a problem). Once finished, run hackrf_info:

Found HackRF board.
Board ID Number: 2 (HackRF One)
Firmware Version: git-44df9d1
Part ID Number: 0x00594f49 0x00594f49
Serial Number: 0x00000000 0x00000000 0x4xx 0x2xx

If the output of the above command looks like mine (I censored my own serial number) that means your Hackrf is ready to be used. Let’s try:

osmocom_fft -F

After the application loads up, you have a nice looking Spectrum Analyzer that goes from 30 to 7GHz. Play with it. The very first test I have done with it was visualizing the invisible fight that goes on between you Microwave Oven and your Wi-Fi when you prepare Pop-Corn as you surf the net:

In reality, the minimum frequency that you can select (30 MHz) is erroneous. In facts, the HackRF has been reported to be working quite well all the way down to 1 MHz. In order to achieve that, you might patch line 333 of osmocom_fft





The second thing I’d like you to experiment is some sort of a “copy and paste” of the radio spectrum. Let’s say you want to save whatever is going on between 431and 433 MHz, all at once. The hackrf_transfer utility can do that:

hackrf_transfer -r test.bin -f 432000000 -s 2000000

Subsequently you could retransmit the same content  on the same band (or on any other!):

hackrf_transfer -t test.bin -f 432000000 -s 2000000

Here is a demostration:

Another handy tool that is available on the Mac is obviously Gqrx. First you need to install it:

sudo port install Gqrx

Then you can launch it:


Unfortunately Gqrx it still is way less smooth and polished than SDR# or HDSDR but, at least for the time being, if you use a Mac that’s as close as we can get:


Finally, last but not least, GNU Radio.

GNU Radio is the most prominet Open Source SDR framework, an extremely powerful tool that allows you to create any sort of modulators, demodulators and (with the help of your handy HackRF One) also to transmit and receive basically anywhere you want. The possibilities are endless. Is GNU Radio difficult? Very. Is it a good opportunity to lean more? Extremely. As an example, I adapted a generic USB transmitter written by Alex OZ9OEC for the UHD (another SDR device) to work with the HackRF. Here is a screenshot of gnuradio-companion once my modified grc file has been loaded:


here is a screenshot of the actual transmitter while it is running:


And here is another demonstration:

This is as far as I could get in just two days. More to follow!