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.
I threw one together yesterday using 1 meter of Flexi 4XL, which is a variant of 9913, but any 50 Ohm coax should be similar in performance. I used a random ferrite ring harvested from a computer power supply, 15 turns on primary and secondary, so it’s a 1:1. I don’t know how that affects performance over the 2-hole ferrite, but mine is working fine for strong signals, in that it is allowing me to listen to transmissions that would otherwise be unbearably noisy. I DO have to turn on the maximum pre-amp setting on the Icom 7300. Stations that I simply could not listen to with a G5RV or mini-whip are 99% noise free on the loop. Signals are nowhere near as strong on the loop, but if the noise is gone, does it really matter? My Frankenstein of this loop is working well for the AM broadcast band and up to 17 MHz which is the highest frequency I have tested in on so far. Once I procure the correct ferrite, I will absolutely be adding a total of 2 of these loops to my antenna switcher. (two because they are directional, and they will each be oriented differently.)
OOPS!!! I used 1 meter PER SIDE of the loop.
Is the youloop antenna usable for old analog receivers like Yaesu FRG7, 7000, 7700, Kenwood R600 and R1000 and so on?
I built one too, using a Mini-Circuits ADT1-6T+ 1:1 transformer and generic TV coax cable, together with a classic LNA4HF, right after the transformer. Works really well on an RTL-SDR V3 with an upconverter, it’s also pretty good with direct sampling. Really happy with the performance, and being a loop, having the option to null out local RFI by rotating the loop is fantastic.
I created my own version 90 cm in diameter and some random ferrite ring. Works best in range 5 – 14 MHz with rtl-sdr v3 and another direct sampling rtlsdr stick that I have. Also shows decent performance in MW and I see some station in LW (but v3 is not as good as another dongle without bias-tee circuit). LW/MW performance could be boosted with resonance antenna (loop of the same 90 cm diameter and variable capacitor). I used lan cable to build MW/LW loops (it has 8 wires and available in almost any store). For MW 12 turns of single wire from lan cable, for LW 32 turns (but 40 should go to lower frequency, or you may have to use slight larger capacitor), small 20-320 pF capacitor from old cheap radio. You could get approximate calculation here – https://earmark.net/gesr/loop/joe_carr_calc.htm though it works for square loops.
Just put diy youloop near resonant loop, tune to desired frequency and get SNR boost for 6-12 dB.
Also noticed that VHF lna not stated for those frequencies may boost snr up to 4-6 dB as well, so with LNA and resonant loop v3 could receive something on LW.
Interesting ideas, though with all of those turns of LAN cable, it seems like you have built a traditional loop antenna, not a magnetic loop.