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.
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 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:
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:
Generic USB Audio device - to transfer baseband I/Q signal, as an audio stereo stream
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.
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.
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.
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
We have recently been able to obtain a small number of YouLoop HF/VHF portable receive only passive antennas that were produced by the owner of Airspy. The YouLoop is available in our store priced at US$34.95 including free worldwide shipping. It comes with the balun "tee" connector, coax inverter, 2x 1m semi-rigid coax cables for a ~60cm loop, and 1x 2m semi-rigid coax for the feedline. Note that US customers may wish to purchase from airspy.us as they have local US stock. We are focusing on non-US orders for this product and we only have very limited stock at the moment - UPDATE: Now out of stock. We have reordered more and should be back in stock by end of March.
YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF
If you don't know what a "YouLoop" is, it is a simple passive magnetic loop antenna design which consists of a ring of coax cable and a low loss 1:1 or 4:1 balun. The design was recently popularized by Youssef (prog) the owner of Airspy, and he has put up a page explaining how the design works here. Many users on Twitter have been reporting good results with HF reception with the design. It appears to be especially useful in urban environments where there is lots of local noise.
Left Discovery with YouLoop Antenna, Rigth Discovery with HF Hoxin Vertical Antenna.
Same configuration in sdr#, both in roof with 25m RG213 cable.
A lot of noise in the vertical antenna, Barcelona noisy city. pic.twitter.com/NNYdpsmNTo
Being passive, it has no amplification and so it works best with a low noise SDR like an Airspy HF+. However we have also found decent results with SDRplay SDRs, and a standard RTL-SDR Blog V3 running in direct sampling mode, although RTL AGC mode needs to be turned on for an extra boost. Improved results can be obtained by using a low cost HF amplifier on the front end, and even our wideband LNA which is advertised as working down to 50 MHz still does actually give a decent boost from 5 MHz and up.
Also the design has some advantages in that it has very low electrical interference pickup, and has no electronics that can overload from signals that are too strong. Overloading from strong signals is something that can easily affect cheap magnetic loop antennas like the MLA-30, and even higher end loop antennas too. Being a magnetic loop, it also naturally filters out electric field interference which is extremely common in urban environments, and is the reason why e-field antennas like miniwhips often perform poorly.
The antenna is designed to be extremely portable, being lightweight and easy to assemble/disassemble. As such it is not designed to be weatherproof, so if you do decide to mount it permanently please make use of weatherproofing tape.
Unlike fixed magnetic loops, the YouLoop design is also easy to experiment with. By using longer coax cables you can easily create a larger loop which can result in stronger signals. We found that replacing the 1m loop cables with 2m lengths gave quite nice results for us. If you have the space you could try even larger loops too.
The design also doubles as a great VHF antenna with reception up to 300 MHz possible when used in a folded dipole configuration. To do that, simply flatten the loop into a dipole shape.
Finally, if you prefer the YouLoop can also be constructed by yourself. The Twitter post below shows the basic design. Search Twitter for "YouLoop antenna" for more discussion on the design too.
A few days ago we posted about the release of the new NooElec Ham-It-Up Nano upconverter which sells for US$49.95 on their store and Amazon. Upconverters enable SDRs that cannot tune in the HF bands to receive HF by shifting the low HF frequencies "up" into a range receivable by most VHF/UHF capable SDRs.
In his latest video Techminds reviews the Nano together with an E4000 tuner based RTL-SDR with built in bias tee. In the video he demonstrates it working with the SDR# software, and shows how to set the Shift parameter to ensure that the correct frequency offset it set. He goes on to demonstrate reception through the various HF bands confirming that the unit works as expected.
