Category: HF

RTL-SDR E4000 Tuner Trick to Get AM Radio without Mods or Upconverter

YouTube user Superphish has posted a video showing the trick mentioned in this Reddit thread by Anonofish that enables the E4000 tuner to receive a small portion of the broadcast AM band without doing the direct sampling solder mod, or using an upconverter.

It simply involves tuning to a frequency between 3686.6 – 3730 MHz, at which point AM signals start showing up on the spectrum. It isn’t that useful as you can only tune to the very lowest AM stations, but it is still interesting.

RTL-SDR E4000 trick to get some of the AM Band

New RTL-SDR Adaptation for HF and VHF/UHF For Sale

A few months ago we saw a Hungarian hardware developer selling a custom RTL-SDR software defined radio which included an upconverter built into the PCB.

Now a new Brazilian hardware developer has begun selling similar home made RTL-SDR units that can receive HF by default. Note that the page is in Portuguese, but Google translate does a reasonable job at translating.

These units come in a nice box and are capable of receiving between 0 to 1750Mhz.  Attached to the box are two UHF (SO-259) 50 Ohm connectors, one for an HF antenna and one  and a USB port. The developer also provides a CD which seems to come with the drivers, SDRSharp and some plugins. We aren’t sure if this SDR is using direct sampling or an upconverter to get HF signals as there don’t seem to be many details about the modifications made on the page.

The price is $185 Brazilian Reals, which is about $82 USD.

Combined RTL-SDR and Upconverter

The page links to a video showing the SDR in action which is shown below.

Tutorial: HF Decoding Tour with the FUNcube Dongle Pro+

On the FUNcube Dongle blog/store amateur radio enthusiast DK80K (a.k.a Nils) has sent in a link to a 16 page pdf file showing a comprehensive tour on the FUNcube Dongle Pro+’s capabilities on the HF spectrum.

He gives an overview of many digital ham and HF utility modes including DRM, WSPR, RTTY, Olivia, MFSK16, PSK31, Pactor, Packet, Hellschreiben, ROS, SSTV, HF ACARS, SSB, CW, DSC/GMDSS, SITOR-A/B, Globe Wireless, Time Signals, ALE, Baudot, FAX and Stanag 4285.

The FUNcube is a software defined radio similar to the RTL-SDR, but with better sensitivity and noise performance, but at a higher price (around $200 USD). These modes can also be received with the RTL-SDR and an upconverter such as the Nooelec Ham-It-Up upconverter.

Download his pdf here (Mirror)

Tip: Effect of Power Sources on the Ham It Up Upconverter

The Ham-It-Up upconverter uses a 5V USB power input. I discovered that different 5v power sources can cause significant interference with this upconverter, and the same effect will probably occur in other upconverters as well.

When the upconverter was powered by mains power via a phone charger, the signals were almost completely drowned out in noise. Powering it with a PC USB port was better, but the PC USB power introduced some other strong noise sources. Powering it with a battery (used a mobile phone with OTG cable) was the best option. There are still some strong noise sources present, but I can probably solve them with better shielding.

Click continue reading to see some comparison images.

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Receiving SSTV with RTL-SDR

Over on the Radio Antics blog fellow RTL-SDR enthusiast Andrew has been using the RTL-SDR to receive Slow Scan Television (SSTV) amateur signals. SSTV is a method ham radio enthusiasts use to send small images to one another. The images often contain their ham call sign overlaid on the image.

Andrew was able to receive several SSTV images using an R820T dongle tuned to the 27 MHz (11 meter) band. He also used a Funcube Dongle+ and got similar results.

Check out his post for some of the images he received, and his video below for an example of the receiving process.

STANAG 4285 Decoding with RTL-SDR

In this video YouTube user Superphish shows decoding of the French Navy STANAG 4285 test signal. He used an rtl-sdr, Ham-it-up upconverter, SDRSharp and a decoding program called Sorcerer. Watch in HD to read the text, though the text basically just repeats the French equivalent to the quick brown fox, “VOYEZ VOUS LE BRICK GEANT QUE J EXAMINE PRES DU GRAND WHARF” and some test symbols over and over.

Fair warning with the Sorcerer download: Some people report that their virus scanner detects a trojan on some Sorcerer download links. The Sorcerer link above seems to be clean though, as far as my virus scanner reports. An alternative decoder is Sigmira.

STANAG 4285 is the NATO standard for HF communication, and signals can be found all over the HF spectrum.

Stanag 4285 Decoding with RTL-SDR (RTL2832), Sorcerer and SDR Sharp

Integrated RTL-SDR HF Upconverter

Over at KF7LZE’s Blog a post about an upcoming integrated HF upconverter using tiny surface mount components has been posted. It is made by Marty KN0CK and will be for sale on KF7LZE’s site soon.

Marty KN0CK developed a very interesting v1.0 HF converter based on surface mount technology that fits inside the casing of an RTLSDR tuner dongle. He’s recently sent me schematics for the revision, which should offer even better performance.

Cropped HF Upconverter Respin 7

Check out the rest of the post here.