Category Archives: Antennas

Urban DXing: testing the Bonito Boni whip against a 30 metre longwire & the Wellbrook ALA15030

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Hi there, if like me, you live in an urban environment, chances are QRM is having a negative impact on the quality of the signals you’re receiving at home. The presence of electrical noise makes antenna choice very important, particuarly if you’re planning to spend more than a few £££s on something more sophisticated than a length of wire. Recently I was considering the the purchase of a second compact antenna, for use at home in my shack and out and about on DXpeditions. I already had the excellent Wellbrook ALA1530 H field antenna, but at more than £250, it’s very costly and thus it seemed rather extravagent to buy a second one, if I could find something with similar performance for less expense. Space is at a premium at home and of course I take much of my equipment out on DXpeditions, so the Bonito Boni whip active antenna appeared to be an ideal choice. A wideband active antenna (from 20 kHz to 300 MHz) operating from 12 to 15V DC, with a very compact form-factor definitely ticked all the boxes. Furthermore, with reasonable second and third order intercept points of +55 and +32.5 dBm respectively, the Boni whip, on paper at least, looked like a pretty good buy at around £100.

 

Now, clearly, an E field antenna such as the Boni whip is not going to match the SNR provided by the H field Wellbrook ALA1530 in a noisy, urban environment. I have uploaded a few reception videos to my YouTube channel to demonstrate this, making a direct comparison of the two. However, what about the performance of the whip versus a simple longwire in an urban environment? Is there a delta in performance? The value proposition of the whip is primarliy in it’s performance, coupled with portability I suppose, but that must be considered a secondary requirement. The whip might be 10 or 15 times more expensive than a reel of cheap equipment wire, but will the reception justify the cost delta?!

Text links follow directly below, with embedded videos thereafter; you will find 3 reception videos comparing the whip and a 30 metre longwire, on shortwave and one each for LW and MW. At the end of each video there’s a section with the Wellbrook loop, just to calibrate where the longwire and whip are in terms of a much more effective H field antenna. The result? Well, there’s not much to separate the longwire and Boni whip, except on LW, where the whip prevails. A friend told me recently, if reception is rubbish at home under a blanket of QRM, don’t blame the antenna, the noise is the real problem. He was right. So, the next tests are to be undertaken out in the field, where the whip has a real chance to shine. I’m rooting for it because to have an antenna that performs as well as, or close to my loop out in the woods, yet can be packed away into a small case would be brilliant. Thanks for reading/watching/listening.

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

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The company and history behind the Boeing 707 HF antenna coupler

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(Source: Boeing)

Many thanks to David Giba who shares the following via the Gary J. Cohen’s Shortwave Listeners Global Facebook page:

The Boeing 707 is my favorite commercial jetliner. If one looks at the tail they will see a probe pointing forward off the top of the tail. That is the HF shortwave antenna.

(Source: VIP Club)

It was matched by an antenna tuner/transmatch much like we have in our HF radios. This is the story of the Univac Coupler. Very interesting.

Click here to read on the VIP Club website.

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Klaus demonstrates his folding mag loop antenna

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Many thanks to SWLing Post contributor, Klaus Boecker, who follows up after our recent post showcasing his homebrew magnetic loop antenna.

One of the cool things about Klaus’ antenna is that he can easily position it vertically (see above), or fold it over into a horizontal position (see below).

While one would think Klaus would get optimal performance from his loop while vertically-oriented, it’s not always the case. Klaus has discovered that on some frequencies, placing the antenna in the horizontal position lowers the noise level and increases the target signal’s strength.

To demonstrate, Klaus made the following short video for us:

https://youtu.be/pP0e7wnAjEY

Click here to view on YouTube.

That’s a pretty amazing difference, Klaus! I’m no antenna expert, but perhaps what’s happening is you’re eliminating noise that is polarized in the plane of your antenna, thus the signal “pops out” much better when oriented horizontally?

I’m curious if any readers can explain this.   I know very little about loop antennas–especially small loops since so much of their surroundings affect their performance.

Thanks for sharing, Klaus!

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Oxford Shortwave Log: Sony ICF-SW77 vs ICF-SW55 vs Tecsun PL-310ET

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Hi there, I recently posted an article regarding a couple of recent DX catches with the Sony ICF-SW77 receiver and went on to explain the background to a multi-receiver test I had started conducting, comparing it with its stablemate of the time the ICF-SW55 and, just for the hell of it, a more modern, yet modest portable in the shape of the brilliant little Tecsun PL-310ET.                                                Sony ICF-SW77

The initial results confirmed the performance of the Sony receivers to be very similar and thus the justification for the original price delta of £100 in the UK to remain in question. The first target signals chosen and in the original post were ABC Northern Territories on 4835 kHz and Radio Mali on 9635 kHz.

Sony ICF-SW55                                                        Tecsun PL-310ET

The initial results reinforced my view that the PL-310ET is a great portable for relatively small money; it managed to copy both signals, something you might not expect from what is essentially a budget receiver.

Below are links to the next 6 reception videos on the Oxford Shortwave Log YouTube channel and once again, featuring all three radios. I have used two different antennas during the testing – a 75 metre longwire and the Wellbrook ALA1530 active loop, running on batteries. The accompanying text description to the videos indicates which antenna was used.

Although the PL-310ET clearly struggled with the more ‘hard-core’ DX signals amongst those detailed below, the fact is, for less than £40 in the UK (and I’m certain even less elsewhere), Tecsun have delivered us a portable radio that really is capable of real DX. With DSP, a number of audio bandwidth filter options and great sensitivity, it’s a winner for beginners to DXing and to ‘old hands’ who want a radio in their pocket when they take the dog for a walk for example (something I do all the time – you never know when you’re going to come across the next barbed wire fence!). As for the Sonys, well I’m still not convinced one way or the other that the £100 price delta on the original price of the ICF-SW77 was worth the money – the ICF-SW55 is pretty close to it in terms of delivering discernible audio across all of the below reception videos. I’d be interested in your views and note there will be a final posting on this 3-way receiver comparison to wrap things up. In the meantime, thanks for reading/watching/listening and I wish you good DX!

Enbedded videos follow below.

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

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Sony ICF-SW77: recent DX & comparing performance with the ICF-SW55 & Tecsun PL-310ET

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Some of you might remember the extensive tests I conducted last August, comparing this great portable receiver against the model it was introduced to replace – and arguably one of the best-ever portables – the Sony ICF-2001D/ICF-2010. I conducted a back-to-back series of comparison tests at the very quiet wood in Oxfordshire I use for my DX’peditions, using the same antenna for both recievers – the excellent Wellbrook ALA1530 active loop. In total, I made fourteen reception videos comparing the ICF-2001D and ICF-SW77 and posted them to my Oxford Shortwave Log YouTube channel. Both receivers performed very well, delivering excellent reception on the Tropical Band and elsewhere on the shortwave spectrum, however, the ICF-2001D proved to be the clear winner, with what proved to be far superior synchronous detection.

But that wasn’t the end of the road for my ICF-SW77. It remains a very capable receiver (one of my all-time favourite portables) and one which I continue to use regularly. However, every now and then, it surprises me with something exceptional. Since conducting the tests against the ICF-2001D, the SW77 has brought in my best-ever indoor reception of Radio Verdad, Guatemala on 4054.8 kHz….and when I say best-ever, I really do mean it; the audio was significantly clearer than anything I had copied previously at home with the Elad. More recently, I copied Zambia NBC Radio 1 on 5915 kHz on a DX’pedition with a far superior signal to anything I’d previously heard, with any other reciever, including the ICF-2001D and the Elad FDM DUO. Some of this of course is down to short-term conditions of propagation, however, the SW77 continues to prove why it has such a loyal following and continues to command premium prices on eBay. Text links and embedded videos to both reception videos on Oxford Shortwave Log follow below:

Further to these recent catches, I promised some of my YouTube subscribers that I would conduct another, similar test with the ICF-SW77, but against it’s cheaper ‘sibling’ the ICF-SW55. A review at the time of the ICF-SW55’s introduction concluded that the price premium of the ICF-SW77 may not be justified since the performance of the two receivers was very similar, despite the SW55 lacking synchronous detection. As someone who has extensive experience with the SW55 out in the field – it was my mainstay DXpedition receiver for more than a year – I was just as interested as my subscribers in how these two vintage Sonys would measure up against each other. The lineage is all very obvious from their respective industrial designs, but the lack of Synchronous detection on the SW55 might have been the one element of functionality resulting in poorer performance, particularly in challenging band conditions and in the presence of adjacent channel QRM etc. To mix things up a little, I have also thrown the brilliant Tecsun PL-310ET into this test. Such a sensitive and selective receiver for less than £40, it has provided more surprises with regard to it’s performance than just about any other radio I’ve owned. How would the Tecsun compare to these two vintage, but high-end Sony portables? Stay tuned to find out! Two reception videos follow, using signals from ABC Northern Territories (4835 kHz) and Radio Mali (9350 kHz), with more to follow on Oxford Shortwave Log and a further posting on swling.com/blog. Thanks for watching/reading/listening.

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

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Klaus’ magnetic loop antenna in “urban camouflage”

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Many thanks to SWLing Post reader, Klaus Boecker, who originally posted these images of his homebrew magnetic loop antenna on the Shortwave Radio Station Listening Facebook page.

I love the design of his mag loop which easily allows for a vertical or horizontal orientation.  Kaus has discovered, in certain cases, places the loop in a horizontal position dramatically decreases the noise level.

Having a little fun with what I call “urban camouflage” Klaus recently decorated his antennas to match the neighborhood flower boxes!

I’m sure more than one neighbor may be wondering what sort of creative floral arrangement Klaus has planted! 

Klaus notes that the vertical to the left of the loop is a a 2m / 70cm J-Antenna.

Thank you again, Kalus, for allowing me to share your images here on the SWLing Post.  I imagine your modest home-grown antenna farm works some serious DX on occasion!

Thanks again for sharing!

Readers: Have you camouflaged or decorated your antenna(s)?  Please share your photos!

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