Category Archives: AM

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

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.

Muzen Audio handcrafted radios

Many thanks to SWLing Post contributor, John Figliozzi, who writes:

This [company] was mentioned in regard to the CES show out in Las Vegas:

http://www.airsmartaudio.com/

It’s a Chinese company with a rather novel approach to the design of modern radios — AM/FM/Internet Bluetooth, along with the use of tube amplifiers in some models. The web site is almost all in Chinese but the pictures are cool.

Air Smart Audio is the parent company; Muzen Audio the subsidiary.

John also shared the following item from Radio World:

Muzen Audio Group’s founder Dejun Zeng, referred to as the “Father of the Tube Amplifier” in China, is looking forward to the new challenge, saying in a statement: “It is my greatest desire to build a legacy with this organization that will lead customers to say, ‘I am proud to have a Muzen radio.’”

The company received a 2017 CES Innovation Award for their new AM/FM/internet radio and Bluetooth speaker lines, the fifth CES Innovation Award received by Zeng. Muzen Audio also designs a series of vintage-style tube amplifier radios and what the company calls “on-the-road” radios.

(Source: Air Smart Audio)

Thank you, John!

From what I gather, Muzen radios are very much “boutique” radios, thus come with a “boutique” price tag–some models costing as much as $500 US.

Still: it’s refreshing to see a Chinese radio manufacturer marching to their own beat, making handcrafted products in small batches.

According to Twice.com, Muzen recently introduced the  “Classic 1” AM/FM radio with Bluetooth speaker that is powered by a “fluorescent display tube amplifier.” Twice notes:

The Classic 1 is handmade and crafted with real rosewood, and every unit comes with a unique code verifying its hand craftsmanship.

Frequency response of the speaker is 75Hz to 16KHz, of the amplifier, 30Hz to 20KHz.

Pricing and availability will be announced during CES 2017.

I’m looking forward to learning more about Muzen radios! I do love the designs.

Click here to view the Air Smart Audio website (in Chinese). 

Post readers: Anyone familiar with Muzen Audio or own one of their products? Please comment!

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

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.

With loss of Northern Territory service, ABC recommends AM/FM and a satellite phone

Photo: Lisa Herbert via Twitter

Many thanks to SWLing Post contributor, London Shortwave, who shares this tweet from Northern Territory resident, Lisa Herbert.

Read about the cuts to the ABC NT service and Radio Australia by clicking here.

Chris’ Seoul AM Radio Listening Guide now live

Many thanks to SWLing Post contributor, Chris Kadlec, who shares the following announcement about his Seoul AM Radio Listening Guide:

After a long 14 months of work, I’m happy to present the completed Seoul AM Radio Listening Guide, a three-hour documentary broadcast exploring the Seoul AM band one frequency at a time, plus a look at the radio war on the Korean peninsula accompanied by a 115-page guide.

http://www.beaglebass.com/dx/seoul/

In addition to radio broadcasts from across East Asia, the broadcast includes Korean noise jammers and AM, FM, shortwave, and television propaganda broadcasts from both the north and the south, additionally outlined in a 25-page broadcast transcript and 115-page informational guide. It also includes:

* A comprehensive list of 260 East Asian AM stations, including station names, tower locations, distance and direction from Seoul, parallel FM frequencies, broadcast hours, and station website links.

* A full bandscan of 235 regular nightly skywave signals as heard after the sun sets over Seoul.

* Daytime groundwave bandscans taken from eleven different locations in the Seoul metro area, along the North Korean border, beside the sea, and in Korea’s mountainous interior with background information about each location.

* A guide showing stations organized by their network affiliations in addition to privately-owned stations and networks. Alternatively, stations are also shown organized by country, region, and city.

* A chart showing signal strength for each bandscan – day and night – in bar graph format.

* A full colour-coded regional station map covering both skywave and groundwave signals.

* A view of some of Korea’s signal jammers as seen on an SDR (software-defined radio).

* Plus, a complete transcript of the three-hour audio broadcast with additional information on the featured audio clips as well as the songs featured in those clips.

– Chris Kadlec

Brilliant, Chris! I can only imagine the amount of time and effort you’ve put into this guide. Thank you!