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Interesting upgrade for a Youloop
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Hi Zack,
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Let me start out by saying IMHO, I'm not a believer in Youloops. I think it is a marketing strategy to make the design stand out from the crowd, without it having any firm technical basis for the claims made about it.
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I also have doubts about the company you provided a link to. Although looking like a Western shopfront, they are in fact based in China. Nothing wrong with that, but they don't give their trading address on their website (or at least I couldn't find it), which to me is always a red flag. I do however notice it is on their Facebook page, so why don't they put it on their website ?
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The amplifier itself seems OK, and some thought seems to have been put into the design. They also publish some specifications, and if genuine, they should give some sort of indication regarding the level of performance it is likely to provide, which I would rate as Meh...
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However, the main point of my post is, why do this ?
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The combined cost of an "official Youloop, plus the Balun / amplifier box and Bias Tee, works out as around $100 USD, before shipping and taxes etc.
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An official LZ1AQ switched loop / dipole amplifier, with a very high level of specification works out at around $115 USD, before shipping and taxes etc. Which is only just a little bit more than the previous items.
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https://active-antenna.eu/amplifier-kit/
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"Putting lipstick on a pig" (or something ruder, involving glitter) springs to mind...
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Regards,
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Martin
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On Tue, Oct 29, 2024 at 10:52 PM, Zack N8FNR wrote:
and also found this Youloop upgrade. Anyone tried this? |
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Hi Zack,
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The SMA switch looks to be good enough for your purpose.
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They are using miniature PCB mount relays, which are usually good performers, and can be used for transmit purposes up to a moderate power level.
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My only concerns are the 0-150MHz frequency range, which I would have thought should have been OK up to at least 500MHz (I have used them up to 1GHz), and the amount of isolation between ports, which is as equally important as the value of through loss.? They do publish some performance graphs, but they have not annotated them, so they are not easy to interpret.
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Regards,
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Martin
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On Tue, Oct 29, 2024 at 10:52 PM, Zack N8FNR wrote:
I ordered an SMA switch |
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"YouLoop"? to my knowledge is an acronyme for "Youssef Loop" Youssef Touil is the developer of the airspy SDRs and the programmer of the famous SDR# Software. Because of the exceptionally good sensitivity of the airspy HF+ and Airspy HF discovery SDRs, a passive loop is sufficient to achieve a surprisingly good reception. Youssef Toul proposed a passive moebius-strip type loop and called it "Youloop". Following the demand from customers, he decided to offer the semi-rigid two-turn "YouLoop" as a ready built product that is sold as? "Noise-Cancelling Passive Loop (NCPL)" for portable DX-ing via the airspy distributors network.?
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Meanwhile the majority of YouLoops sold on eBay and Aliexpress? are chinese "copyshop" clones and no genuine Airspy products.
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regards
Fred |
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In conversation with Youssef on the Airspy IO group, during the early days of the Youloop, we argued about the design, and the high impedance "hump" in the middle of the operational frequency range, he then progressively stated several interesting "snippets" of information.
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It requires a receiver with a very good noise figure
The HF discovery input impedance had been optimised for use with the Youloop, and that 50 ohms was not ideal
He featured what he considered to be a suitable pre-amp design, that was based on a guitar pre-amplifier, which had a high value of input impedance
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Youssef is a very bright software engineer, with many talents, but I still don't rate his antenna.
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Just my personal opinion, your mileage may vary.
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Regards,
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Martin |
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On Wed, Oct 30, 2024 at 05:06 PM, Paul White wrote:
Software engineers are often a bit NERD like a and not particularly interested in sales and marketing. However Youssef as developer and president of Airspy seems to be very skilled to put his products and their advantages into the spotlight and made Airspy a worldwide commercial success.
regards, fred |
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When I was working, a sales director once said to me, don't let the customer anywhere near the engineers / developers, as they tend to focus on the negative aspects of our products.
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A purchasing director said to me, if you can, get to speak directly with the engineers / developers, they will tell you what's wrong with their product, how it can be improved, and why their competition's product is better, they just can't seem to help themselves.
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It's all true, I have seen, and heard, of many excellent sale pitches, ruined by careless talk by engineers. They are generally not skilled when presentation and interpersonal skills are required, rather than engineering expertise.
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It is rare to find an engineer or developer that has both sets of skills, and to be really successful you also need to be a psychopath, but that's a conversation for another day...
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Regards,
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Martin
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On Thu, Oct 31, 2024 at 06:54 AM, Fred M wrote:
Software engineers are often a bit NERD like a and not particularly interested in sales and marketing. |
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Hi Paul,
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I also I believe Youssef is very talented, and he has undoubtedly made some significant contributions to the general SDR technology, and I genuinely wish I was as skilled as him.
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I can also think of several other developers who are a brilliant, but somewhat temperamental, and I've been kicked off several groups and mailing lists devoted to specific products, for flagging up problems, with both hardware and software, only to be later proven correct. I've always tried to be factual and non-confrontational, but the bans often remain in place.
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However, IMHO, I still don't rate the YouLoop. It's unnecessarily complicated, and a simple comparison with a similar sized unscreened single turn loop would generally perform as well as, or better than, except perhaps on frequencies below approx 1MHz. From this, I conclude that a lot of users may judge the antenna based on MW broadcast reception, but I may be wrong.
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But, like a lot of antennas, and generally speaking, no one can be bothered to perform any tests, and they just believe whatever they want to believe, without letting anything sway their opinion.
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Have a look at the Antenna reviews on sites like QRZ.com, many of the excellent reviews have nothing to do with the actual product, it's more about self-justifying the purchase, the sales experience, quality of after sales support, and what DX has been worked, without specifying the frequency, mode and power being used. Basically, it's nearly all subjective and emotionally based, rather than being factual.
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To quote Public Enemy - "Don¡¯t Believe the Hype" :-)
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Regards,
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Martin
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On Fri, Nov 1, 2024 at 06:29 AM, Paul White wrote:
At the risk of sounding like a fanboy, I'd add that Youssef is one of those with a special kind of vision. |
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You are correct.? Most RF switches come with BNCs or N connectors.? Heaven forbid the "UHF" connectors.? All are quite common.? I use those available from Alpha Delta and Diawa.? If you want SMA, I'd suggest shopping the professional offerings, but it will cost you.? You might also consider using connector adaptors to go between series.? Dave - W?LEV On Fri, Nov 1, 2024 at 10:06?PM Zack N8FNR via <mrzaax=[email protected]> wrote:
-- Dave - W?LEV |
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Ah Martin, reasoned and down-to-earth as always. One of my pleasures in retirement is belonging to groups like "Loop Antennas" where scientific literates are well represented. ? It's tempting to stray into the fascinating subject of the DSP/SDR developer community with its curious mix of cooperation, rivalry and (possibly) self-imposed restraint in copying or "improving" on others' ideas. That has so many facets and consequences, but is also so off-topic that Grumpy Old Git will self-impose restraint. For now. ? Anyway, unlike you, I rate Airspy's YouLoop very highly indeed. Just because: * My interest is mainly the MW broadcast band (otherwise known as "AM" by those who called a transistor radio a transistor or tranny) where its performance is optimum. * It pairs perfectly with my HF Discovery (at the risk of sounding like a Hi-Fi nutter). * It is relatively immune to the bane of my life, QRM. * My HOA-type location does not allow undoubtedly better antenna options. Plus it's one of the simplest constructions of anything I've tried, even if not at all weatherproof. A perfect example of "horses for courses" and "cutting your cloth...". ? Fun fact: The smart USAF Lieutenant Carl Baum who apparently coined the generic term "M?bius [alt. Moebius] Strip Loop" in his 1964 paper actually spelt the mathematician's name consistently as "Moibus". A bit ironic in the light of his (presumed) heritage. And remind me, was it "Weens(h)teen" or "Wines(h)tine"? Well, nobody else gives a monkey's. ? So-called "social media" have a lot to answer for in fostering the culture of what are now dignified with the title "content creators". Content more akin to the flood of sewage that pollutes our environment, for the most part derivative or daft drivel, and motivated largely by a narcissist's compulsion to feed his own ego. Not much "social" about that, but great for a platform owner's bank balance. ? Never mind QRZ.com, YouTube is the go-to outlet for "reviews" to rack up "views". IMO most of them are not excellent at all, for the reasons you give. The few excellent productions remaining are a joy to watch. ? One thing I find fascinating is the synergy between wannabe reviewers who need "stuff" and China's industry that needs buyers (hello again, @Fred). ? To be fair, China offers a wide range of products that are entirely or nearly unobtanium in the West and by no means all of it is rubbish. But they are on the whole very cheap and in the intersection space are an attractive option for those who are genuinely of limited means. Or just plain stingy, despite having paid thousands for a fancy rig. ? Hence the endless offers of and plugs for "YouLoops" (and even "ORIGINAL YouLoops"), just one example of many. I was suckered into buying a clone YouLoop before my first Airspy version and only later discovered for myself a 3 dB SNR deficit on MW. Not a big deal for many, perhaps, but important to me. And @Zack who started all this may well be about to buy a YouLoop downgrade. Did any "review" highlight that? ? (I was lucky or unlucky enough to be born before the advent of commercial television broadcasting in the UK (RIP BBC), having a low tolerance for hype and an almost pathological resistance to buying products advertised by big names. Hence a complete refusal to succumb to those parroting "they hate it", "they don't want you to know", "they can't stop you" and a host of similar dog whistle idiocies. Amazon gets my money only if there is not a reasonable alternative, which is far too often.) ? But there's no getting away from what seems to me incontrovertible, that the clone industry is fuelled by consumer greed and impatience which are close cousins of the freebie culture. They are one of the drivers of industrial decline (including cottage industries) and ultimately in global balance of power. Phew! No sources for that. ? (Still, that's the way things are. Only half a century ago Japan was the bogey man, later partner. Now, who can afford AOC or buys a second-hand Perseus from there?) ? To try and wrap up this rant, one reason so many get suckered is the wholesale, blatant theft of intellectual property and passing off under others' brand names. Only those with very deep pockets can afford to challenge that abuse and it seems to me most decide it's just not worthwhile even trademarking their wares. ? Daring to upset a respected contributor here, I even have problems seeing a circuit board prominently marked with someone else's callsign - especially in a device that is only a partial implementation of an original design. What is wrong with an explicit "Based on ABC by XYZ"? ? Goodnight, folks. |
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Paul, you mention Carl Baum.? I used to work with him on KAFB in Albuquerque.? Small world........ Dave - W?LEV On Sat, Nov 2, 2024 at 1:29?AM Paul White via <paul=[email protected]> wrote:
-- Dave - W?LEV |