SDRplay testing active loop antennas

[@DXPedro]

We need that experimental mini-loop plans ASAP! that would be perfect for DXing on my apartment! 73s

[@whithamreeve6077]

I would like to see evaluation and comparison of loops and preamps down to the lower frequency limit of the RSPduo or at least down to 10 kHz.

[@jekkodejekkis7372]

I would like to express all my approval to this new project and I just can't wait to see the video comparisons. About the antennas I could suggest the youloop or the ground loop. My only point is the following and I don't know if there is a solution. In open contry there isn't much RFI so all antennas are in best conditions and work really well. But the challenging conditions is to test the antennas in the middle of the town with tons and radios, and TVs, and WIFI, so we are full of RFI. In my opinion only in these conditions we can compare the real power of the Magnetic Loop.

[@dannyshortwave]

As a suggestion, I would like to see the MFJ-1886 receive loop antenna and of course the MLA-30+ active loop antenna. I covered those two on my channel using the RSP DX.

[@michaelagner4355]

Not much of a chance I'm afraid. It seems these folks are living with blinders on insofar as the rest of the world where other loops are available is concerned.

[@hamandshortwaveradioirelan4773]

Looking forward to seeing the rest of the series

[@andrewking3087]

This series looks promising! As a suggestion, please review the MLA-30+.

[@Mike-H_UK]

Good suggestion!

[@jbammi]

+1 for including the MLA

[@d.shortwave4280]

tried a lot of antennas from bonito to miniwhip to Wire and mla30 and only two are staying .. the Wellbrook and the LZ1AQ the rest is way to noisy for my location.

[@jeff2424]

I got the MLA-30+ for MW reception and it was only mediocre at best with the supplied 60 cm diameter loop. I replaced the 60 cm loop with a 6 foot diameter loop with PVC spreaders and it came alive on MW. What a difference!

[@Mike-H_UK]

HI, Mike here who is on the video... I can certainly look at the MLA30+. I don't currently have one myself, and the main difficulty is choosing one to use that gives a fair representation of the product. As I understand it, there isn't just one company that makes the MLA30+ and I often read comments like "The MLA30+ is great, but make sure you get a good one..." Any recommendations on picking one to test that would give a fair comparison?

[@walteredwards544]

I can't wait to see the results. I'm especially interested in that smallest loop with 2 turns. I love to travel and this would be my dream set-up. My concept of operations are to have a very small laptop, my SDR Play and a small but effective antenna that can all be carried in a laptop bag, easily deployable and doesn't take up much space but also has the ability to cover the entire design spectrum of the receiver.

[@DXPedro]

amen! even on more permanent situations, it would be awesome for a lot of people!

[@55Ramius]

Thanks for the information ! Looking forward to more on this. : )

[@marca90210]

Please consider reviewing the minikits version of the lz1aq. It's available in fully built or kitset form and is an improved single loop version of lz1aq.

[@c4715]

Fascinating video. Thanks!

[@LeeDonaghy]

A comparison on what to make the loop out of would be interesting, copper pipe, bicycle wheels and cables like LMR400. loop diameter and thickness.

[@FrancoDX]

Subscribed. I’d like to see the MLA 30+ included as well, I’m not convinced it’s any better than a passive YouLoop but that just might be my location and equipment etc. 👍🏼

[@vk2np]

How about the Pixel 1B ?

[@michaelagner4355]

Not much of a chance I think. They're concentrating on Euro based loops. Very narrow thinking here

[@vk2np]

@@michaelagner4355 Seems so the Pixel is excellent bought before DX Eng bought them out.

[@DonnyHooterHoot]

Have you heard of or tested the GA-450 Radio Antenna Loop?

[@SDRplayRSP]

not familiar with it.

[@Mike-H_UK]

I've read about it. From what I understand, it is a tuneable antenna and therefore only works properly when set up for a particular frequency. This means that the spectral plots that a SDR produces for an entire band will not be possible.

[@DonnyHooterHoot]

Oh well, I'm cheap! Just ordered one of the MLA30+ loops. I have nothing now so I do expect improvement! lol

[@shanerorko8076]

That mini loop are we able to buy it?

[@Dr_Thamminana_KR]

Excellent 👍

[@4X6GP]

Since any differences in noise figure are masked by the atmospheric and manmade noise at HF and lower, and since efficiency is irrelevant in an amplified receive antenna, the significance of your test results is that the winning antenna has a sharper directional pattern. This is helpful if the antenna is rotated, but possibly not if the antenna is in a fixed position.

[@Mike-H_UK]

I have read in several places, but not independently verified, that the directional pattern is almost completely defined by the loop shape, size and number of turns for a wideband (non-resonant) RX loop. By comparing 1m diameter, circular, single turn loops for all of the commercially available products, and aligning the planes and heights of all the antennas, I was hoping to minimise any differences in the directional patterns.

[@4X6GP]

@@Mike-H_UK That certainly makes sense. But if so, then what is the mechanism that explains the differences in s/n ratio? Perhaps some of the antennas are more susceptible to common-mode noise pickup on the feedlines? That could be tested by inserting a common-mode choke in line.

[@Mike-H_UK]

@@4X6GP You raise a key question, maybe the most fundamental question, but if you don't mind, can I hold off answering because this will be a topic in one of the later videos? However, what I can safely say is that some of the major differences between loops/LNAs comes down to amplifier architecture and design, the method of getting power to the amplifier, and the method by which the LNA is linked and interfaced to the receiver. LNA noise may not be totally irrelevant (although a reasonably large loop mitigates this) and common mode pick up definitely needs addressing, as you say. The latest video comparing the LZ1AQ and the Wellbrook ALA1530 show a high level of shared performance but with some discernible differences.

[@AAABTonto]

Very nice, thank you ;-]

[@andyhowlett2231]

Don't forget to test them down to VLF, maybe 16 to 22 kHz. Some loops perform very well across LF, MF and HF but are lacking at the low end. The standard Wellbrook 1530 falls off quickly below about 30 kHz but the 1530 LF extends down to around 15 kHz.

[@Mike-H_UK]

Good point. Have you any particular transmissions in mind that are stable over a period of at least an hour or so and I could use as a benchmark for all antennas?

[@andyhowlett2231]

@@Mike-H_UK I find I get steady daytime sigs on 19.5 and 22 kHz. These are visible at around -110 dBm (s/n 18dB) on the 1530 and around 10dB better (s/n 28dB) on my dedicated LF loop. There are other sigs around this area but some of them are intermittent and always disappear just as I am about to run a test!

[@Mike-H_UK]

@@andyhowlett2231 Where are you based, USA? I should have said, I'm central UK based so will be looking for something that I can receive over here. I'll certainly see what I can find in this frequency range. My obvious concern is that ~20kHz is the land of the switched-mode power-supply, but you are clearly working around this.

[@andyhowlett2231]

@@Mike-H_UK I'm in Cheshire, NW England. I've found that this part of the spectrum is reasonably clear of noise from SMPU's as they tend to run at 40 kHz+ and of course their harmonics are on the high side. The biggest problem seems to be conducted noises from my own gear getting directly in via earth loops. I'm working on chokes and transformers to combat this.

[@Mike-H_UK]

@@andyhowlett2231 Thanks!

[@myballwilson]

I'd sure like to see your conclusion in addition to the methodology. We understand all antennas are compromises but your method has data. Show your work? BTW, I have a Duo but could never afford this experiment. My SDR Play is my most powerful receiver and love it. I only use my Yeasu FTDX 10 transceiver to transmit. All managed by HRD as you explained in an earlier video.

[@prestonclark9563]

Has anyone ever done a video on receiving signal on 6 meter and up to the satellite frequencies

[@M0JHN]

I’d love a decent SDRplay antenna!

[@grahamscanlan9]

I’ve looked at loads of antennas for my SDRUNO and the active loop suits me the best, you can get cheaper ones from ebay that work well. I bought the MLA 30+ @ £35.00 100khz to 30mhz

[@АркадийЛевин-ы6г]

Вы продаете эти антенны?

[@tonymagnier9846]

Try out the W6LVP loop, it's a lot better than the MLA30+

[@michaelagner4355]

Sadly doubtful

[@nallawalla]

The intro is misleading = "taking a look" is literally observing them leaning against a wall. Can a single video be made comparing all the commercially available loops against. say, the Wellbrook? Comparing the Wellbrook with a homebrew design is nice, but not useful for those who are considering buying one off the shelf. As the Americans here have noted, there isn't much LW outside Europe. Please compare something like WWV. 73 de VK3BT

[@SDRplayRSP]

Hi Ash. You raise several interesting points. The purpose of showing the loops leaning against the wall was by way of an introduction to the kind of loops we hope to look at in future videos (they will then be mounted on a stand rather than leaning against a wall). A single video comparing all the commercially available loops would be a mammoth task, so we will likely release comparisons with the Wellbrook one at a time. Where possible we will first share our findings with the designer or company responsible to make sure we aren't misrepresenting them. We're trying to end up with a few recommendations for loops that can be demonstrated to work well in combination with our RSPs and where the loop designer also recommends our RSPs. Regarding US originated designs - several others have mentioned this, and we will explore some of the suggestions. Finally regarding which signals we use for demos, then unfortunately the WWV is not easy to regularly receive in Europe. However its importance is more to do with frequency accuracy so picking alternative signals should still make the comparisons useful.

[@nallawalla]

@@SDRplayRSP Point taken, but choosing a weak HF signal (when you have propagation) is also of interest. You have plenty of time in one clip to cover a range of frequencies, yes? :) At least HF is common to all SDRPlay customers such as myself. Looking forward to the next one.

[@jimshaw8241]

@@SDRplayRSP As asked a couple of comments up, will the Pixel RF Pro-1B be considered? I got one from Pixel probably 6-7 years ago. It's not up now as we've moved, but had it on a TV rotator up ~11 ft in backyard. Very impressed. Used some for MW/LW DX but mostly as a 160-80-40m RX ham antenna. It would drop the noise floor 25-30dB vs my 160-80-40m fan dipole up 50 ft and all these signals would magically appear. I believe it's very similar to the Wellbrook. Thanx! 73 de Jim, AL7BA

[@michaelagner4355]

Here's another observation that no one (as yet) seems to have considered. If they're really serious about doing antenna comparisons, why aren't they using antenna analyzing software - surely there must be something out there that can run on the SDRPlay - for that purpose? To me their so-called recommendations that they will supposedly develop from these so-called tests are nearly worthless. Any one can use their ears to tell if a signal is stronger or weaker - but it takes more than that to do a proper RF evaluation. I kinda have my doubts that the folks running SDRPlay really gave this much serious thought before doing this.

[@SDRplayRSP]

Hi Michael, these tests are not in any way intended as a subsitute for lab based analysis - the loop makers provide their own data to whatever extent they see fit. All we are trying to achieve here is a practical assessment of the antennas under real world conditions which we describe. We will listen to feedback as we progress on this and if there's an overall feeling this is of little use then we will stop doing it - but so far we are seeing a lot of encouragement.

[@shanerorko8076]

Antenna analysers are designed mainly for transmitting antenna. The analayser will fire a signal into the antenna the gauge its feed back just like a multi meter checking a circuit. The issue with active antenna is that you can't fire a test signal into the pre amp so an antenna analyser is utterly useless in testing on an active receive antenna. The only aspects you're after in a receive only antenna is how good the SNR is and how broad band that SNR is. These two factors can be measured just fine with any SDR.

[@michaelagner4355]

As mentioned in passing by a few folks here, it seems you're giving the US listeners the cold shoulder. How about having one of your US based tech staff doing similar reviews here in the US on US based loops, such as the W6LVP, Pixel, Chameleon, etc. Reviews done in Europe don't have very much meaning to us here. Antennas can and sometimes do perform differently in different RF Environments. Very disappointing

[@SDRplayRSP]

Thanks Michael. We are prioritising this activity around popular loop designers/companies who recommend our SDRs - that way both suppliers are on the same page when it comes to providing follow-up support to anyone following our recommendations. Being a non US company, I suspect the US-centric search engines haven't given us as much visibility to the loop guys in the USA but we will reach out to them in the coming weeks.