Review: HackRF One + PortaPack H2: a Truly Portable SDR

The HackRF One software defined radio (SDR) originally designed by Great Scott Gadgets has been a constant success ever since its introduction a few years ago. A pure open-source development, the HackRF One went through many updates and improvements thanks to an extremely active and supportive community. Not surprisingly, Elektor, itself an early adopter of SDR, endorsed and sold the HackRF One in substantial quantities to both experienced radio enthusiasts of the hardware generation and to those with more confidence in, or affection for, “digital stuff” and equating radio with black magic.

The HackRF One by itself sits between 1 MHz to 6 GHz radio signals "in the aether” and your laptop or lab PC. Using free and again open-source programs running on the PC like GNU Radio, GQRX, SDR#, or SDR Console, the “One” is totally configurable as far as the radio hardware is concerned. If you’re not convinced of the ease of working with the HackRF One as an open canvas for any kind of module that goes into a radio receiver or transmitter, watch Clemens Valens’ video on slapping together a bare-bones but totally functional FM band radio by pulling functional blocks from a library, cheerfully testing and then “assembling” the theoretical configuration, and finally pushing the lot into the HackRF One. The result: a real, playing FM radio with bells and whistles. But… ermm… using a PC connected to the HackRF One.
 

We Want Portability!

Recently, an addon called the Portapack H2 was released that allows the HackRF One to go truly portable, meaning without a PC attached. The PortaPack H2 board is plugged onto the HackRF One like a “hat” or a “shield” in Raspberry Pi- or Arduino-speak, respectively. The combination of the HackRF One and a plugged-on “local console” is great for hunting, hacking, decoding, and recording radio signals in the field, and unobtrusively if needed. This is especially useful for reception of low-power RF signals that are best picked up close to the source, in places or under conditions where it’s undesirable to haul a laptop along.

The new, portable, SDR system thus created includes a 3.2 inch touch-screen LCD, tactile buttons for navigation, a scroll-wheel, a headset jack, a microSD card slot, and two clock connectors. Plus of course the HackRFOne’s USB connector and two tiny pushbuttons for Reset and DFU. The unit is powered by a 2400 mAh, 3.6 V battery which lasts long enough for a full day of radio signal hunting and raw data collecting in the fiels and near transmitters whose aired data you wish to explore or decode. In case you wonder about “headset”, expecting to read “earphones”, well, any SDR can be configured as a transmitter and a microphone signal may be called for.
 

Black Metal

The two PCBs are contained in strong metal case which I have to commend for its ruggedness and overall finish. Tne HackRF one PCB ois marked “cbrtronic 2024” and “cjh”, and the PortaPack, “v.3.6 mmdvm.dub”. I’ve seen the same products on AliExpress et al. supplied in wildly decorated acrylic cases, which is fancy but not functional and even disadvantageous for RF considering stray emissions. The two boards are stacked and held in place by their pinheader connectors and four metal PCB standoffs in the corners. By the way, I do not recommend disassembling the unit as you may find it tricky to put together again. The hardware-curious among you may want to rely on my photographs of the disassembled unit, which I had to take anyway to identify the capacity and type of the two batteries inside (1 LiPo; 1 coin cell).

Although there’s no print on the case with any of the connectors, LEDs, or controls, everything is intuitive to find and operate, except maybe for the two small pushbuttons, one of which is the — occasionally useful — Reset button!
 

The Apps

The pre-flashed Mayhem v.2.0.1 firmware is a further development of the earlier “Havoc” release — splendid names for software produced in open-source spirit.

Perhaps more important to note than the specific function of “apps” made by the Mayhem posse, is the awareness that you can easily perform raw-signal capture in the field, either for instant replay or for offline demodulation, or for analysis and (dare I say it) modification and even replay! With an SD card full of raw data captured off a radio source, the fun starts on the PC cracking it all, nerd-style with beer and pizzas. Also, you can have the SDR constantly scan a range of frequencies unattended and save the results for number crunching later.

So here goes with the apps that come preinstalled on the HackRF One + Portapack H2 combo in one case. The default frequency is indicated in square brackets where applicable, although the desired frequency (range) is user defined through the menu. Most apps provide instant replay, or saving to the SD card.

Receive (RX):

• ADS-B: Receive and analyze ADS-B (Aviation) Signals with the ability to display real-time aircraft locations on a map. [978 / 1070 MHz]
• AIS: Receive and analyze AIS (marine / vessel) signals. [162 MHz]
• BLE Rx: Sniff Bluetooth (BLE) MAC addresses. [2.4 GHz]
• APRS: GPS / weather station / ham radio mobile station positioning. [144.3 MHz]
• ERT Meter: Decode ERT Meter signals. [900 MHz]
• POCSAG: Sniff and decode personal pager (“beeper”) message decoding [166 MHz]
• Audio: Decode WFM/NFM/SPEC/AM [any frequency]
• Level: RF signal level measured by antenna [any frequency]
• Recon: Listen in on any frequency, with any span for scanning [401 – 403 MHz]
• Weather: Sniff and decode RadioSonde (weather balloon / weather station) signals, [402 MHz]
• Search: Basic NBFM receiver / scanner [100 – 400 MHz]
• TPMS Cars: Decode car tire pressure sensors
• SubGHzD: Sniff & capture ISM data easily for [433.920 MHz]

RX apps can be added by downloading from the PortaPack Mayhem wiki and transferring ti the SDR via the SD card.

Transmit (TX)

• ADS-B TX: Spoof ADS-B (aviation) signals
• APRS TX: Transmit APRS packets for GPS, weather stations and telemetry
• BLE Tx: send Bluetooth (BLE) MAC addresses
• OOK: Send (on/off keying) packets
• SSTV: Send slow-scan TV signals
• POCSAG TX: Spoof personal pager ("beeper") signals
• RDS: Send radio data system messages
• Morse: Send Morse code
• BHT Xy/EP: street or public lighting control
• TouchTunes: Control jukeboxes using ASK/OOK
• Soundbrd:  play and transmit .WAV or microphone audio as FM

TX apps can be added by downloading from the PortaPack Mayhem wiki and transferring to the SDR via the SD card. SDR TX output power is in the milliwatts range. Transmitting is subject to legal restrictions applicable in your country or region. The HackRF One is a half-duplex transceiver.
 

 

 

We Want the HackRF Mode!

Despite the multitude of ready-installed apps on the PortaPack H2 — some of which I found esoteric and US centric — I was relieved to see that direct access to the HackRF One is possible simply by touching the HackRF option on the main screen. By disabling the Portapack H2, the PC takes over and you have full support for all common SDR tools and software packages — GNU Radio and others. As a benefit, you have the solid metal enclosure around your HackRF One with all the necessary connectors and controls. Considering the cost of the HackRF One + Portapack H2 + Acessorries as single purchase from the Elektor Store, that’s actually a very good deal with the Mayhem community as the cherry on the cake!

The Antenna Complement

As an old-school licensed radio amateur I am keenly aware of the importance of the antenna (system) connected to any receiver or transmitter. The set of antennas included in the review package indicates that the makers got the point. If you’re new to SDR, it’s good to realize that these receivers are essentially (1) insensitive and (2) “as wide as barndoor”. Likewise, for the SDR’s transmitter function, you get (1) mlliwatt power out and (2) liitle or no harmonics suppression. So, if you can at least grab the correct antenna for a specific frequency range, that’s your first step to optimize reception locally. Later, you can begin thinking about bandpass filters, notches, preamplifiers, and passive or active antennas. For now, the set under review came with an impressive set of antennas:
 

• 1x VHF BLC-TLC, 30 cm, magnetic base, coax cable, SMA connector.
• 1x UHF CLC, 19 cm, magnetic base, coax cable, SMA connector.
• 1x 2.4 GHz WiFi, 15 cm, foldable, SMA connector.
• 1x telescopic rod, 48 cm, SMA connector.
• 1x ADS-B 1-2 GHz, 12 cm, detachable, screw-on, SMA connector.
• 1 x magnetic base, screw top, coax cable, SMA connector.

Where (B/C)LC = base / center loading coil. All antennas are of good quality, neatly packaged, and well worth the investment considering that they can be used for other radio projects too. In my experiments, I did not venture out below 70 MHz or so but found that the bands up to 50 MHz are best served by an outdoor wire or a loop antenna, like the one I proposed in my review of the ATS25 max-Decoder Receiver.
 

 

Fun in the Field

Using the HackRF One and PortaPack H2, and with the assistance of an IT & Communications student I was able to record data/control packets from a vintage 420-MHz TETRA (trunking radio) network still active on the nearby campus. Back in the lab, some clever bit manipulating was done. We went outdoors again with the SDR and using th Replay mode, managed to open and close an electric gate to the Academic Staff Only parking lot using the SDR’s milliwatt transmitter. In my own lab, I also like seeing what’s flying above me using the ADS-B aircraft scanner and the 1-GHz antenna mounted outdoors. I also “cordlessly” measured the tire pressure by walking around some of the newest and expensive cars in my neighborhood. The street lighting in my street I wasn’t able to link to with TPMS — the on/off command is carried over cables I guess.
 

73 & Signing Off

With the arrival of the HackRF One / PortaPack H2 combo in a single, portable enclosure, I entered and overcame the transition area between old-school “discrete components” radio and contemporary software-defined radio, especially for digital modes as opposed to plain broadcast radio. The main reason for the attraction is, frankly, the portability of this particular SDR, which gives me a feeling of being closer to the source of the radio signal I wish to investigate. Others, I gather, are fonder of making their laptops crack and then mimic anything that’s encoded and carried over radio, or working on complex modulation methods.

This new product from the Elektor Store is an example of 1 and 1 equals 3: the HackRF One as a solid base with super credentials, the PortaPack as the perfect, plug-on companion for portable use, and the hospitality of the SDR online community again as the icing on the cake. All three: fully open-source. If SDR ever needed a boost to bond old-school radio fans with software geeks, this is the way to go at an affordable price.

This SDR has an incredible number of options, menus and features, some obvious by turning the large blue-lit knob, others cryptic and deeply hidden. Fortunately, all apps are well documented on the Portapack / Mayhem wiki. For expert advice, do watch the @Sn0ren Youtube channel for a good Portapack H2 tutorial, and the HackRF 101: Day One, Basics if you come from DC but with some software skills. Neither channels are encrypted, Greek, or subject to any decoding. No Monies Returned (Monty Python).