Category: HF

Testing the YouLoop on VLF & LF Reception with an Airspy HF+ Discovery

Over on his YouTube channel Frugal Radio has been testing his YouLoop passive magnetic loop antenna on VLF and LF reception with his Airspy HF+ Discovery. In the video Frugal Radio browses the VLF & LF spectrum, making note of some interesting signals, and showing how well the combo receives.

The YouLoop is a low cost passive loop antenna for HF and VHF. It is based on the Möbius loop design which results in a high degree of noise cancelling. However the main drawback is that it is a non-resonant design, which means that it needs to be used with ultra low MDS receivers like the Airspy HF+ Discovery. We have YouLoop stock available in our shop for $34.95 with free worldwide shipping.

Airpsy YouLoop passive antenna review on VLF & LF with an HF+ Discovery and SDR# during storms!

Tech Minds: Decoding GMDSS Maritime Distress Messages

In a recent YouTube video Tech Minds shows how to decode GMDSS (Global Maritime Distress and Safety System) messages which are broadcast on MW and HF. In the video he explains the DSC (Digital Selective Calling) which allows calls to be made to individual ships, a group or all stations. He goes on to demonstrate the YADD GMDSS DSC decoder running via the HF audio piped in from SDRUno and received with an SDRPlay RSPdx.

How To Decode Maritime Distress Messages GMDSS DSC

Tech Minds: Review of the MLA-30 Active HF Loop Antenna

Over on YouTube Tech Minds has uploaded a new video where he reviews the MLA-30 active HF loop antenna. In the past we have posted about the MLA-30 antenna a several times on the blog as it is the cheapest active loop antenna available on the market, can be powered by the RTL-SDR Blog V3's bias tee, and generally loop antennas can give good HF performance in a small package. In the video he compares the MLA-30 against an end-fed halfwave antenna and concludes that the MLA-30 works well at the lower frequencies, but not so well in the higher bands.

MLA-30 Active HF Loop Antenna

The YouLoop Passive Loop Antenna Reviewed on HF Reception

Thank you to Robin from the "Frugal Radio" channel on YouTube for submitting his latest video which is a review of the Airspy YouLoop antenna that we currently have for sale on our store for $34.95 including shipping.

The YouLoop is a low cost passive loop antenna for HF and VHF. It is based on the Möbius loop design which results in a high degree of noise cancelling. However the main drawback is that it is a non-resonant design, which means that it needs to be used with ultra low MDS receivers like the Airspy HF+ Discovery. However, a high performance HF pre-amp will be available in the future which will allow it to work well with other radios too.

In his video Robin tests the YouLoop on the HF bands with an Airspy HF+ Discovery and he demonstrates excellent noise free reception from his location. In terms of his setup he notes:

I am running Spyserver on a 10 year old Windows 7 laptop in the loft. The same laptop is also running 3 x SDRSharp instances (following 2 digital trunking systems). It runs 4 x  simultaneous Zello instances each providing a high quality audio feed to my Network Radio / phone.
 
In terms of noise-creating equipment nearby, there is
  • a second laptop used for other duties
  • a Pi 3B used for ADS-B reception, feeds & a second instance of spyserver 
  • a Pi 3A with MMDVM module performing as a hotspot
  • a Motorola HT charger
  • 5 x base station scanners
This means there are 10 x switched mode power supplies constantly running, as well as 4 x 24/7 WiFi devices.
All this equipment is within 10ft of the YouLoop antenna, was one of my primary reason for choosing a passive loop. 
 
Since making the video, cable clips have been added provide support to the antenna which means it is now in the correct shape of a loop.  That means I am unable to rotate the antenna to make use of the nulls when receiving. However I am very pleased with the performance based on the location, noisy environment, and frugal pricing :-)

$35 Airspy YouLoop Passive Antenna Review : tested on HF using Airspy HF+ Discovery SDR

AFEDRI LAN-IQ: Standalone 12-bit 30 kHz to 1.7 GHz SDR with LCD Screen for $339

AFEDRI have recently begun shipping their new software defined radio called the "LAN-IQ". The LAN-IQ is a full standalone SDR with good advertised specifications and a very decent price of only US$339. The advertised specs from the Afedri LAN-IQ website are pasted below:

  • 30 kHz to 1700.00MHz continuous frequency range
  • Direct sampling
  • DDC - Digital Down-Conversion
  • 12- bit 76.8 MSPS A/D conversion
  • Stand Alone mode (AM, CW, SSB, NFM, WFM stereo, BPSK, QPSK demodulators)
  • Up to 2.2MHz recording and processing bandwidth
  • Waterfall display functions, when used with appropriate software
  • Recording and playback, when used with appropriate software
  • Sensitivity -  MDS -136 dBm at 500Hz bandwidth (0.03MHz-35MHz)
  • Sensitivity -  MDS -143.5 dBm at 500Hz bandwidth (50MHz-435Mhz)
  • USB 2.0 (Full Speed) interface
  • LAN interface for remote access
  • Compatible with: Linrad, Winrad, HDSDR, Studio1,  SDR Console (SDR-radio), CuteSDR, SdrDX, Quisk, PowerSDR_mrx
  • Powered from USB or external power supply 7-10VDC
  • Dimensions 120mm deep x 78mm wide x 27mm high
  • Unit cost - $339
The Afredi LAN-IQ SDR
The Afredi LAN-IQ SDR

They go on to elaborate on the specs:

LAN-IQ SDR is stand-alone, direct sampling Software Defined Receiver (see picture above)  it has ability to send it's received I/Q stream in three different modes:

  • Stand-Alone (Digital processing, filtering , decoding is implemented inside SDR)
  • Network (LAN)
  • USB

LAN-IQ SDR has the following specification:

  • Frequency Coverage: 0.03MHz-35MHz & 35MHz-1700MHz
  • Noise Figure: ~11dB (for 1MHz-35Mhz range and maximum RF gain 35dB)*
    *input VGA (Variable Gain Amplifier) has variable Gain from -10dB up to +35dB
  • Noise Figure: ~3.5dB (for 50MHz-435Mhz range and maximum LNA/MIX gain )
  • MDS: -136 dBm at 500Hz bandwidth (0.03MHz-35MHz)
  • MDS: -143.5 dBm at 500Hz bandwidth (50MHz-435Mhz)

Output data format: two 16-bit I/Q channels (audio stereo stream emulation)

Maximum Receiving Bandwidth:

  • BW = up to 2200kHz (for 2400kHz sample rate) -  using Network connection
  • BW = up to 706kHz (for 768kHz sample rate) -  instand-alone mode
  • BW = up to 230kHz (for 250k samples/s sample rate) -  using USB connection

RF ADC sampling rate: 76.800 MHz

Power Supply Voltage Requirements:

  • 5V (supplied from the PC's USB bus or from external) or  from external power supply able to provide 5VDC +/-0.2V).
  • 7.0-10V DC to the DC power connector.

Power Supply Current Requirements:

  • up to 850mA (max. LCD brightness, network cable connected, VHF/SHF band)

The LAN-IQ SDR is designed to be used in stand-alone mode , i.e. without need to use  any additional computer and software.

In same time the SDR can be connected and used with  Personal Computer (PC) by two interfaces:

1. Ethernet Network connection.

This can now provide up to 2400 kHz sample rate

2. Full Speed USB

From PC point of view, the SDR-Net can be used alternatively as:

1. Network device using two IP protocols: TCP and UDP.

  • TCP protocol is used to control the SDR parameters.
  • UDP protocol is used to send received I/Q stream from SDR to PC

2. Or exactly like the  AFEDRI SDR-Net -USB Composite Device, that contains two USB functions:

From the Afedri Groups.io forum we've learned that by default the unit will come without the tuning knob, but a knob can be requested if preferred, although it comes with some limitations.

Ordering of the LAN-IQ is done via email only, and the email address can be obtained at the end of their ordering page. They accept PayPal, and shipping costs anywhere from $18 - $32 depending on the country. Also regarding shipping they note that deliveries may be delayed due to COVID-19 which is of course the case for every global delivery right now.

From the SWLing Post blog post we've also learned of a short demonstration video created by Fenu-Radio which is shown below. We are also awaiting his full review which will be posted on fenu-radio.ch.

Afedri LAN-IQ in Action

In a second video Fenu-Radio compares the LAN-IQ against the Malahit-DSP which is another similar low cost standalone SDR which we posted about back in November 2019.

Malahit-DSP & Afedri LAN-IQ "Head to Head"

More videos of the LAN-IQ in action can be found on the Afredi-SDR YouTube channel.

The K-180WLA: A New Low Cost Battery Powered Active Loop Antenna

We've recently seen a few submissions about a new low cost active magnetic loop antenna called the K-180WLA which sells for around US$50 - US$60 over on eBay and Aliexpress. While it appears to be very similar to the well known MLA-30 loop, it's main defining feature is that it's power feeder is battery powered via a built in Lithium ion cell which would make it useful for portable operation. It also advertises a wide usable frequency range of 0.1 - 180 MHz with an amplified gain of 20 dB. They note it can also be pushed up to 450 MHz with reduced gain of 8.9 dB. The battery run time or power draw is not advertised. They write:

  • The P.BOX feed box has a built-in 3.7V 18650 flat-head lithium battery with integrated power supply module. It is the only active antenna that does not require an external power supply and integrates a charge management chip. The MICRO USB charging port is compatible with the 5V charging head of Android phones. And charging cable, very easy to use.
  • UHF low-noise preamplifier is used. The gain flatness is very good within the ultra-wide operating frequency of 0.1-180MHZ. It provides a gain of about 20DB, even when working to 450MHZ gain, there is still about 8.9DB.
  • The receiving frequency covers long wave, medium wave, short wave, FM broadcasting band and VHF aviation band. The small ring diameter 55CM is simple to set up. It can be set up outside the window, balcony, terrace and roof. Lovers erected.
  • All the screws of the antenna are made of 304 stainless steel, and the preamplifier box is fully waterproof, which can be used for long-term outdoor wind and rain.
  • Suitable models include Desheng S-2000 PL-660 PL-880 ICOM R71E YAESU FRG-8800 and all short-wave receivers, especially for SDR receivers.

    Note:

    The antenna is equipped with a dual SMA male adapter cable, an SMA to 3.5 plug adapter cable, and an S2000 BNC adapter, which means that your radio can be used with SMA female, BNC, and 3.5 jacks. Requires additional accessories. Receivers and radios with other interfaces need their own adapters.

We've ordered a unit and plan to compare it against the MLA-30, Wellbrook and YouLoop (with optional HF amplifier that is to be released soon) in a future post. This loop is also being discussed over on the SWLing Post Blog.

The K-180WLA Loop Antenna
The K-180WLA Loop Antenna

SWLing Blog: Building a Homemade YouLoop (Noise-Cancelling Passive Loop) Antenna

Over on the SWLing Post Blog Thomas has uploaded an excellent tutorial showing how you can build your own YouLoop (aka a Noise-Cancelling Passive Loop). If you've been following our previous posts you'll know that we recently started selling the "YouLoop" which is designed and produced by Youssef from Airspy. The YouLoop is a passive loop antenna designed for HF reception, but also works well up until VHF. The main catch is that you need to use it with a receiver with a low noise figure front end, like the Airspy HF+ Discovery (SDRplay units should work well too). The RTL-SDR Blog V3 in direct sampling mode does somewhat work with it to an extent, but RTL-SDRs relying on upconverters for HF will probably see poor results.

We are selling the loop in our store for $34.95 including free shipping to most countries. Batch 2 is currently in preorder, but is almost sold out and should begin shipping soon. Batch 3 will also be available for preorder soon and is about 2 weeks away from shipping. We also expect there to be a high quality pre-amp available for sale in a few months too which will help those with higher noise figure radios or longer feed line runs. 

Alternatively, as the YouLoop is a relatively simple and openly shared design it is possible to homebrew your own if you want to. Over on the popular SWLing Post blog, author Thomas has written up a full tutorial on hombrewing your own. The parts you need include coax cable, a BN-73-302 wideband 2-hole ferrite core, magnet wire, heat shrink tubing and electrical tape. The guide takes you through the process of winding the balun and constructing the loop using simple tools and a soldering iron.

The SWLing Post Reviews the YouLoop Passive Loop Antenna

Over on the SWLing (Short Wave Listening) Post blog Thomas has just uploaded his review of the YouLoop in a post titled "The Airspy Youloop is a freaking brilliant passive loop antenna". If you weren't aware, we are currently selling this loop in our store for US$34.95 incl. free worldwide shipping to most countries. Sales are currently in pre-order as our first batch of units ordered sold out within a day, but we're soon going to receive the second batch in the next few days. 

Thomas is a seasoned shortwave listener who has used many antennas, and in the review he notes that he is extremely impressed with the performance. In his review he tests the antenna in a location that is swimming with RFI and places the loop in the middle of a bedroom. Although the situation is not ideal, Thomas was surprised at the number of signals he was able to receive.

To work properly the YouLoop requires a low noise figure radio like the recommended Airspy HF+ discovery, but Thomas notes that he's also had excellent success with the SDRplay RSPdx running in HDR mode.

YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF
YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF