The Airspy Youloop is a freaking brilliant passive loop antenna

Before I start talking Youloop, I have a little confession to make up front:

At the Winter SWL Fest when I gave a presentation about Portable SDR DXing, not only did I give attendees the wrong name of the Airspy Youloop antenna, but I also configured it incorrectly, hence the poor performance via my Miscrosoft Surface Go tablet PC.

I had assumed the the crossover component of the antenna was the transformer component. I realized the mistake I made when I saw some of the first promotional photos of the Youloop antenna a few weeks ago.

The crossover connects both sides of the loop while the tee junction contains the transformer.

Doh! I’m trying to forgive myself for making such an obvious mistake, but in my defence–and in the spirit of full disclosure–my antenna was a very early sample prototype without instructions, diagrams, etc. so I set it up imagining it being similar to the homebrew loop Vlado and I built. (FYI: When I say “Vlado and I built” it, I really mean, “Vlado built it.”) 

So obviously I made a poor assumption.

Once I assembled the antenna correctly? Wow. Just. Wow!

Youloop: The ideal travel antenna for high dynamic range SDRs

The Youloop, Airspy HF+ Discovery, SDRplay RSPdx, and all cables easily fit in my Red Oxx Lil Roy pack.

The Youloop is truly the travel antenna I’ve always wanted for portable SDR DXing. Here’s why:

  • It’s incredibly portable and can be rolled up to fit in a small travel pouch
  • It has all of the low-noise characteristics of other magnetic loop antennas
  • It’s wideband unlike many passive loop designs
  • It requires no variable capacitor or tuner
  • It’s made of quality components
  • It requires no external amplifier nor power source
  • It takes one minute to assemble
  • It’s affordable (~$35 USD shipped)

The only caveat? To take advantage of the Youloop, you must use a high dynamic range receiver.

Airspy HF+ Discovery SDR

I can verify that this antenna works brilliantly with the Airspy HF+ Discovery.

The AirSpy HF+ SDR

It will also pair well with the Airspy HF+  if you shortcut R3 via the R3 modification.

SDRplay RSPdx SDR

I’ve also used it numerous times with the new SDRplay RSPdx while using SDRuno in High Dynamic Range (HDR) mode. With the RSPdx, I can make spectrum recordings of the entire AM broadcast band. Note that HDR mode is only available on the RSPdx at 2 MHz and below, using the SDRuno app.

I have not tested the Youloop with other SDRs yet. I will soon test it with my WinRadio Excalibur.

So how well does the Youloop perform?

Listen for yourself!

I’m doing a little cargiving family members today. Their home is swimming in RFI (radio interference/noise). In the past, I’ve struggled to make good mediumwave recordings at their home–certainly an ideal situation for a mag loop antenna.

This morning, I wanted to record one of my favorite local AM stations (WAIZ at 630 kHz), so I set up the Youloop in the middle of a bedroom, hanging off a large bookshelf set against an interior wall. In other words: not an ideal situation.

When I plugged in the Airspy HF+ Discovery and loaded the Airspy SDR application, I fully expected to see a spectrum display full of broadband noise.

Instead, I saw signals. Lots of signals:

Sure, there’s some noise in there, but it’s low enough I could even do proper mediumwave DXing on most of the band if I wished.

In fact, if you’d like to experience the HF+ Discovery/Youloop pairing in this compromised, less-than-ideal DXing setup, why not tune through one of the spectrum recordings I made?

Click here to download the spectrum file [885.7MB .wav].

The recording was made on March 30, 2020 starting around 10:50 UTC. You’ll need to open this file in AirSpy’s free application SDR# or a third party SDR app that can read AirSpy .wav files.

I can’t wait to try the Youloop in other locations. Since we’re in lock-down due to Covid-19, I won’t be able to try the Youloop in a hotel any time soon. Almost all of my 2020 travel plans have been canceled.

Highly recommend

If you have one of the SDRs mentioned above, go grab a Youloop. At $35 USD, it’s a fantastic deal.

Click here to check out the YouLoop at the RTL-SDR.com store ($34.95 USD shipped).

Click here to check out the YouLoop at Airspy.US ($29.95 + shipping).

Click here to search for AirSpy distributors in your region/country.

If you don’t have a high dynamic range receiver, note that Airspy is exploring the idea of making a pre-amp for the Youloop. If interested, you might drop them a note of encouragement!

Do you have a Youloop? Please share your comments!


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28 thoughts on “The Airspy Youloop is a freaking brilliant passive loop antenna

  1. Pingback: Rob reviews the AirSpy YouLoop antenna | The SWLing Post

  2. Jordan jjdobrikin

    hi
    Does anyone know the nomenclature of the Cable used for the Loops
    It looks like one can use Coax Cable for the two turn loop by connecting the shield and the inner conductor in series .
    Also information on the matching transformer
    Also the practical maximum length of the Coax Feed line

    Reply
  3. davide tambuchi

    Do you have tested this loop with a classic receiver made in the ’70 and ’80 (example: Kenwood R-600, 1000,2000, 5000, Yaesu FRG 7, 7000, 7700, Drake R7 , R8, JRC 515, 525, ecc.)?

    Reply
  4. Roy Hill

    This is a great discussion, I’m afraid I have a really stupid question.

    Can this antenna be used with a older portable SW radio like the Panasonic RF-2200 (It has a twinlead 75 ohm connection.

    Reply
    1. Thomas Post author

      The Panasonic RF-2200 is a fantastic radio, but its receiver would not be able to fully take advantage of this loop design. I’m sure it would work to some degree, but it’s really an antenna designed to pair with high dynamic range receivers like the SDRs mentioned in the article. When I’ve tried this loop on portables, so far, the results are pretty mediocre. On SDRs like the HF+ Discovery and RSPdx, it’s fabulous.

      Reply
  5. Pingback: DIY: How to build a Noise-Cancelling Passive Loop (NCPL) antenna | The SWLing Post

  6. David Tholen

    OK, OK you guys have me totally lost. I will proceed to ask my stupid question. I purchase an SDRPlay RSP1A some time ago now with the hopes of having an effective and inexpensive means to enjoy shortwave and AM longer-range reception. I even thought I might learn something in the process. I eventually shelved the RSP1A for lack of a decent, affordable antenna. Is this an appropriate antenna for the RSP1A?

    Reply
  7. Aaron Kuhn

    I ordered this the instant I saw the price. A low cost high performing antenna has been the missing link for me in wanting to invest in higher end SDRs. I’m really looking forward to using this.

    Reply
  8. Pingback: The SWLing Post Reviews the YouLoop Passive Loop Antenna

  9. Pingback: The SWLing Post Reviews the YouLoop Passive Loop Antenna

  10. Ron F

    > “If you don’t have a high dynamic range receiver, note that Airspy is exploring the idea of making a pre-amp for the Youloop.”

    Can’t see how that’ll do anything to make up for a receiver’s lack of dynamic range. It’ll improve sensitivity, sure (or, rather, make up for the insensitivity of the loop) – but won’t improve the span between ‘minimum detectable signal’ and ‘maximum signal before overload’. Only a better receiver can do that…

    Reply
    1. Andrew

      Well first of all let me say that I agree with you, a preamp will raise the noise as well so it will worsen the S/N ratio, on the other hand, in some cases a LOW gain preamp may still be useful to account for cable signal loss and, if embedding a bandpass, to reduce unwanted offband interferences, other than that a preamp can’t improve a reveiver dynamic range, although … if it embeds a proper AGC capable of both amplificating or attenuating signals it MAY help avoiding RX overload and IMD, but for sure it won’t perform miracles; in this case (loop antenna) such a preamp may be designed to offer high dynamic range and implement an AGC with an adjustable (e.g. a trimmer) output level, in such a case one may adjust the preamp (ok, AGC) output level so that it will be just below the max input level accepted by the receiver

      Reply
    2. Thomas Post author

      I would check with Youssef at Airspy. The only details I have about this are in that Twitter link. If this idea would take off, I’m certain he wouldn’t invest in a pre-amp unless it performed well. His gear is properly engineered.

      Reply
      1. Richard Langley

        Youssef is currently designing a preamp with input from the community. A good conversation is taking place on the Airspy IO group.

        Reply
        1. TomL

          Do you know if Youssef’s preamp will be waterproof? Read through some of the conversation but could not discern much beyond it being +15dB and wideband.

          Reply
        2. Mark Goldhawke

          Just received my youloop…am planning to pair it to a CommRadio cr1…just wondering if my efforts will be for naught though…
          Wanting a truly portable sdr set up for long motorcycle trips

          Reply
    3. Jason

      I’ll hazard a guess that “high dynamic range receiver” requirement is actually a “highly sensitive receiver” requirement. A small passive loop will have very low signal levels, so that dynamic range is being used to reach way down low (no signals are going to be particularly strong). For a RTLSDR, the signal levels would simply be below the noise floor of the receiver it’s self. In this case, a low-noise pre-amp would be needed to make the antenna work with a RTLSDR.

      Reply
      1. Ron F

        That’s my partial guess too – cheap SDRs tend to lack sensitivity at lower frequencies, have a higher internal noise floor than better SDRs (or even a reasonable modern portable), and loops are inefficient anyway (though, as evidenced by my previous comments here and elsewhere, I’m a big fan of them in general when properly designed and used appropriately).

        But many people – including many who ought to know better – seem to conflate or have trouble grappling with the difference between internal & external noise floor, sensitivity, and dynamic range, which is probably where the confusion comes is…

        To address a couple of other responses here, for convenience:
        – What a preamp needs is (a) linearity, (b) high enough compression point (note: not dynamic range, though it factors into it) to not overload on strong signals, (c) dynamic range higher than the receiver following it (to prevent the preamp being the limiting factor for DR), and (d) a low enough noise factor that it doesn’t affect the noise floor too much (i.e. the lower the better).
        – Compression violates (a) – though AGC violates that rule too, a well-designed AGC minimises linearity errors and should not drive the receiver into overload. That’s difficult to do when there’s no feedback (there’s a reason the AGC control is derived from the end of the IF chain, or sometimes post-detection).
        – That aside, the big issue for SDRs is that it’s the sampling stage that is the ultimate limit on dynamic range (e.g. 8 bit sampling = ~50dB DR; 16 bit = ~96dB; etc – at *best*; typically, you can subtract a bit or 2 from that). Other things (e.g. IP – however you want to measure it – in analogue front-end stages, phase noise, etc) will affect DR, but can only make it worse – you’ll *never* do better than the limit set by the # of bits.
        – That said, you can improve the effective number of bits (ENOB) by oversampling/decimating – but at a great cost to sampling bandwidth (each halving of bandwidth adds 1 bit, gaining ~3dB of DR).

        A preamp really doesn’t help with any of those, though it can shift a weak signal up into the available dynamic range ‘window’ so it can be detected (provided there’s no strong signals within the sampling bandwidth that will be driven into overload). But that boils down to “improving sensitivity” – not dynamic range…

        I won’t really comment much about the ongoing preamp design thread, since I’m a bit miserable at the moment due to COVID-related lockdown and some recent dental work. The basic design so far is a long-proven one – I first saw it in the 70’s – but the marketing-like claims are a bit annoying, e.g. the “modern silicon” it “leverages” to obtain “low power, high linearity, low NF” is itself 20+ years old…

        Reply
    4. David J. Ring, Jr., N1EA

      Hi Ron F.,

      A high dynamic range preamp becomes part of the receiver system, being high dynamic range it will receive both extremely weak signals and extremely loud signals without overloading. It becomes the front end of the SDR receiver. You’re right that if the full dynamic range would be sent to the SDR receiver it would still overload, so it would have to be compressed which is similar to what conventional receivers do with automatic gain control circuitry (AGC).

      With the output amplitude reduced, the SDR no longer overloads (for example) in the Medium Wave broadcast band.

      We associate preamp with increasing sensitivity, but it doesn’t have to do just that, it is just an additional independent circuit before the first radio frequency amplifier stage.

      Military communications receivers would overload when the ship was sailing on the Mississippi River, but adding a high quality preamp would clean up the reception, the random noise across the spectrum would disappear and no longer prevent reception if needed signals even though the overall sensitivity of the original receiver was reduced the receiver no longer overloaded which generated noise “hash” throughout the radio’s frequency capabilities.

      Reply
    5. Paul martin

      I’m using a home brew youloop with my RSP1A and it made a huge difference for me. I’m hearing stations I could never touch before.

      Reply
    1. Thomas Post author

      You know, I hadn’t thought about trying the KX3. I’ll have to get on that (and make absolutely sure I can’t trip the TX!).

      Reply
    2. Jake Brodsky, AB3A

      Oh gosh, YES, the Elecraft KX3 has a dynamic range that puts many other receivers to shame. The Youloop would be an excellent receiver antenna for the lower HF bands.

      The big deal about the Youloop is that it provides isolation between the antenna and all the ambient noises near the receiver. These ambient noises are things like switching supplies, noise from computing devices, motor drives (such as what you might have in some ceiling fans), LED lighting, and so on.

      However, that little isolation transformer on the Youloop will not handle significant power. The goal was isolation, not efficiency. So, if you transmit in to it, at the very least you will heat up the RF isolation transformer, and you will probably damage it.

      Reply
  11. Richard Langley

    Got mine last Friday but with online teaching and myriad other duties, haven’t had a chance to try it out yet. Sigh! But soon I hope. Will report back then.

    Reply
  12. slickFDDI

    Can you please use Google drive or something similar to host your I/Q files? Really doesn’t need to take 50+ mins for 900Mb at 60mbps… thx.

    Reply

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