Category Archives: Antennas

Brilliant hard-core DX with the USB-powered Bonito MegActive MA305 antenna

Hi there, you might remember my post from last month focussing on the Bonito MegActive MA305 E-field antenna, kindly supplied to me for testing, by Bonito themselves. That post was essentially a report on my experiences travelling to Crete with the MA305, navigating through security at London Gatwick and Heraklion airports (mostly with relative ease), but more importantly, how well it worked with the equally excellent Eton Satellit portable receiver. Whilst in Crete I managed to copy a number of personal firsts, including CRI on 7295 kHz, via their relay in Bamako, Mali, The Voice of Beibu Radio on 5050 kHz, Nanning, XSL ‘Slot Machine’ on 6251 kHz USB, Ichihara, Japan, S32 ‘The Squeaky Wheel’ on 3828 kHz and NHK World Radio Japan, 11910 kHz. I also copied RTM Wai/Limbang FM on 11665 kHz from Kajang, Myanmar Radio on 5985 kHz and AIR Bhopal on 4810 kHz, amongst others – all of which I would certainly consider to be difficult catches in Europe.

The USB-powered MegActive MA305 is perfect for DXing on the move…

Despite excellent all-round results from the ultra-portable USB powered MA305, there was one signal I copied, which more than any other, demonstrated the DXing credentials of this antenna; Radio Tarma from Peru on 4775 kHz. With a TX power of 1 kW, this is a very difficult station to hear in Western Europe, even with a longwire. To catch this station in Crete, with a 22 cm antenna was incredible and it was at that point during my trip that I realised E-field antennas really can work superbly well for hard-core DXers on the move.

Upon my return to Oxford, I immediately started thinking about a DXpedition to the local woods I use for what I consider serious DXing. For obvious reasons, E-field antennas require an electrically quiet environment to ensure maximum SNR performance. In noisy environments, these types of antennas amplify the signal of interest and the background ‘electro-smog’, thus increasing signal levels but critically, not signal-to-noise. Fortunately, the Oxfordshire wood I have been using for a couple of years is only a 10 minute drive from my QTH as I sort of live in the countryside anyway and the QRM levels there are just about zero. Now, given that this was essentially an experiment to determine the best possible performance from the MA305, I decided to use my best portable radio. It was quite tempting to pack up the Elad FDM DUO which running on a home-brew battery pack has proven itself to be my best (pseudo) portable radio. However, this is supposed to be a real-world test and in this type of scenario, DXpeditions with the Bonito antenna are much more likely to be undertaken with a portable radio. For these reasons I decided to conduct the test with the venerable Sony ICF-2001D. Having proven to be a superb receiver over many, many dxpeditions (check out the evidence on my YouTube Channel Oxford Shortwave Log) and still regarded by DXers as one of the best ever portable radios – possibly the best – it was the obvious choice.

My portable DXing kit comprising the Bonito MegActive MA305 antenna and the Sony ICF-2001D…a bit of a legend in DXing circles…

I ventured out in early June around 23:00 hrs BST (22:00 hrs UTC), parked the car on the edge of the wood and proceeded to set up my cheap camera tripod, slightly modified to accept a 2 metre-long stainless steel tube, into which a slightly thinner 1 metre tube was mounted, topped off with my partially disassembled ‘Selfie Stick’ – which made it back from Crete lol. The antenna was set up in less than 5 minutes and approximately 4 metres above the ground – much quicker and easier than de-spooling 100 metres of wire! With fresh batteries in the Sony and the MA305 powered up using the USB power brick supplied by Bonito, I was ready to start listening. Almost immediately I heard and recorded a personal first; Lao National Radio, Laos, signing on 6130 kHz, with an excellent signal. Hearing them in the UK was only made possible by the annual two week shut down of the PBS Xizang transmitter in Lhasa, Tibet, but hey, I’ll take it. A brilliant start to my listening session.

Over the next two hours I was amazed at what could be heard using this 22 cm amplified antenna. Bearing in mind I have spent many hours at the woods previously, listening via various 100 metre longwires and a 200 metre Beverage, my expectations were, I thought, realistic in that the MA305 coupled to the Sony would catch some very good DX. However, I did believe there might be an absence of at least some of the more exotic low power stations on the Tropical Band – afterall the MA305 is a very short antenna. Clearly I was wrong, because what transpired during the session surpassed anything I thought possible with this set-up. A list of reception videos follows below and further below, a selection of embedded videos. Some of the entries on this list simply stunned me at the time. Rádio Educação Rural for starters is such an incredibly difficult signal to hear in Europe, even with a very large antenna. Thus, to hear them on an ultra-compact set-up felt very special. Radio Mali is another station that is very difficult to catch with any modulation, except on a large antenna and yet there they were – at the first time of trying. Similarly, Rádio Nacional de Angola and Alcaravan Radio are exotics that at best deliver very weak audio – and most of the time no audio. Furthermore, the signals from Emisoras Pio XII, Myanmar Radio and Rádio Clube do Pará were verging on what I would call superb…I’d never heard anything like it previously except via 100 (or more) metres of wire.

The ICF-2001D and MegActive MA305 Rádio Educação Rural transmitter site in Tefé, Brazil

So what’s next? Well it would certainly be an interesting experiment to compare the performance of the MegActive antenna with the Wellbrook ALA1530 active loop in a similar environment. I have used the Wellbrook on DXpeditions several times, with often excellent results, however, it’s not designed to be portable and if SNR performance could be demonstrated as similar between these two products, given a very favourable price delta, the Bonito antenna would add up to be a very compelling purchase decision. More on that to come. In the meantime, thank you very much for reading/watching/listening and I wish you all excellent DX.

Please click on the links below for the reception videos on the Oxford Shortwave Log YouTube channel.

Selected embedded reception videos from the list above:

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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RadioWorld free eBook: Propagation Analysis for Profit

Tecsun PL-310ET: resolving a tight antenna

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Many thanks to SWLing Post reader, Joey (KE4DRJ), who writes:

I was hoping that you or the readers might be able to help me with a problem. I just received my new pl-310et. Which I purchased from anon-co. The issue is with the whip antenna. When I try to rotate the whip, it’s very stiff. I can feel the plastic around the antenna base flexing. I’m worried about cracking the housing. Is there a fix for this issue? Thank you

Thanks for your question, Joey.

I’ve never had to resolve an antenna issue like this and while I do have some ideas, they’ve never been tested. I feel confident, though, some of our readers know tried and true methods that might help. Please comment if you can offer a safe suggestion.

Note, too, that if this issue makes using the PL-310ET difficult, you should also contact Anon-Co as I’m sure they can also help.

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The WDX2RADIO Timeless Classic longwire antenna

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Mike (N1YKH) writes:

Hi Thomas, Just wanted to promote an antenna I sell for a fellow HAM, It sells via http://www.dipolesusa.com/shortwave.html

WDX2RADIO Timeless Classic. 50′ foot longwire antenna kit w/ 25′ foot lead in, quick clip (to click onto a telescoping antenna), wire connector ends to radio, twine, shrink tube for sealing connections, tape, and insulators. Includes instructions. This is very similar to the Shortwave Antennas that were sold at every radio store (incl Radio Shack). Now hard to find. Works with any Shortwave Radio, desktop or portable, new or vintage. I supply all of the clips and lugs necessary.

Perfect for Shortwave, LW, AM DX and General Communications Reception, .05khz to 54 Mhz.. Simple, classic design and installation. Excellent Performer, Big Bang for the Buck and a Super Value. Nothing beats a Longwire Antenna for Shortwave Reception.

Ready to connect to antenna screw on back of set, or to clip onto telescoping antennas on most portables. Everything you need to Mount Outdoors, or in Attic. Easy to follow instructions included.

73 Mike N1YKH

This is certainly a classic wire antenna design–indeed the first wire antennas I ever used for SWLing. And, yes, I purchased it at RadioShack way back when!

Click here to view at Dipoles USA.

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Travelling and DXing with the Bonito MegActive MA305 antenna

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Ok, so officially it wasn’t a DXpedition; it was a well needed vacation in the sun after several hectic months of work, some of which involved travel to slightly more exotic locations. However, these days, I view any travel, whether it be for business or pleasure as a ‘DXpedition’ opportunity! Some of you might remember that I purchased a Bonito Boni Whip at the beginning of 2017 because (a) I needed another antenna and (b) a second Wellbrook loop felt like too much of an extravagance. They’re excellent antennas for sure, but at around £300, I couldn’t justify buying another. Thus, for about a third of the price I bought the Boni Whip. It proved to be an excellent choice – very compact and so perfect for my regular DXpeditions, quick to set up and capable of really excellent DX. There are many videos on the Oxford Shortwave Log YouTube channel that are testament to this. I wrote a couple of articles, published here on the SWLing Post which were seen by Dennis Walter of Bonito, who subsequently contacted me and offered to send over their MegActive MA305 E-field antenna for testing. Dennis made it crystal-clear that I was to ‘do my own thing’…test the antenna in any way I saw fit and publish my findings so DXers/radio enthusiasts could learn more about the capabilities of the antenna – from another DXer. I was happy to agree to this arrangement and the MegActive MA305 duly arrived, complete with two lengths of (bayonet BNC terminated) high quality H-155 coaxial cable.

My portable Dxing kit with MA305 antenna The MA305 power inserter and USB power ‘brick’

The specifications of the MegActive MA305 are very similar to the Boni Whip; they both offer a Gain of +3 dBs, second and third order intercept points of greater than +30 and +50 dB respectively and both tune to 300 MHz. The MA305 is supplied with a longer radiating element and tunes down to 9 KHz (versus the 20 kHz lower limit for the Boni Whip). Obviously this isn’t a specification that is going to concern most radio enthusiasts; both offer fantastically wide operating bandwidths. The way in which these antennas do differ quite significantly however, is in how they are powered. The Boni Whip operates from 12 to 15 V, whilst the MA305 operates from 5 to 15 V. Bonito’s design philosophy regarding this feature is based on the increasing difficulty in procuring reasonably priced analogue external plug-in power supplies (they are no longer allowed to be produced due to power consumption restrictions).

Interestingly, when the power supply for my Wellbrook ALA1530 packed up, I called them to purchase a replacement and was told they only have limited stocks remaining. Thus, a solution for powering active antennas with a suitable low-noise supply is an issue that needs resolving. The guys at Bonito figured a USB power source was suitably quiet and with USB ‘power bricks’ almost ubiquitous these days for charging mobile phones and other portable electronic devices on-the-go, the idea could be applied to their active antennas. The result is the MegActive MA305, designed to operate at 5 Volts with no loss of performance. As a DXer who probably spends more time listening on DXpeditions than I do in my shack at home, the USB power solution was perfect. I myself often carry a cheap Chromebook laptop to use as an additional power source for my camera phone when I’m DXing, so Bonito’s design approach resonated with me completely.

Travelling with the MegActive MA305

Ok, so the MA305 is very compact and very light indeed – perfect for a trip to Crete! However, I know from many conversations with my YouTube friends and followers that some of us feel a slight sense of trepidation carrying shortwave radios and antenna systems on board flights, be they national or international. I myself wasn’t really concerned other than if my bag got pulled from the X-ray machine, there’s often quite a long wait whilst the security staff work through the queue of luggage requiring er…human intervention! Predictably, my rucksack did get pulled and I waited patiently until it was my turn to explain the contents! Looking back on this retrospectively, it’s hardly surprising. Other than the usual holiday paraphernalia, my rucksack contained:

A 10.0 metre length of H-155 coaxial cable
A 1.0 metre length of H-155 coaxial cable
Eton Satellit receiver
MA305 Coaxial Power Inserter
MA305 Antenna Amplifier
Bonito USB ‘Power Brick’
Bonito USB Power Cable
NooElec RTL-SDR dongle
NooElect ‘Ham It Up’ upconverter
Various screened cables and connectors
10 metres of equipment wire

I explained to the (friendly) security chap that I was a shortwave radio hobbyist and identified the various pieces of equipment for him, as he removed them from my rucksack. He confirmed my X-ray had ‘lit up’ (in blue as it happens) with metallic/electronic items and was even kind enough to swivel his monitor to show me the mess of items strewn across the screen – just as I had thrown them all into my rucksack! However, after quickly swabbing some of the items, he said all was fine and hoped that I enjoyed my holiday and listening. Service with a smile at Gatwick Airport – and I was on my way. My outbound experience got me thinking whether it would be possible to pack my DXing kit in such a way that it wouldn’t alarm airport security. Thus, for the trip home, I packed all of my cables into my (checked-in) suitcase. I figured it would be obvious there was no security risk associated with cables alone. I then packed my RTL-SDR, upconverter and all of the MS305 components very neatly into a single box and put that in my carry-on rucksack. Now, some might argue that security measures at Heraklion International Airport in Crete differ a little from London Gatwick, but I observed staff at the X-ray machine very carefully monitoring every piece of luggage passing through it – including my own and I passed straight through without a problem. All I did was take my laptop out as usual, and put it in a separate tray. Job done.

DXing with the MegActive MA305

My listening post in Crete, with the brilliant Eton Satellit receiver

My apartment in Crete was on the second floor and a large balcony provided a decent outdoor location for DXing. As regards electrical noise, the location was much quieter than my shack at home, but it certainly wasn’t perfect, thus a good test of the MA305 in a real-world pseudo-urban environment. in an attempt to improve SNR, I bought a cheap ‘Selfie Stick’ and some tape and managed to construct a mount for the amplifier, increasing the overall height above ground by about 1.5 metres and displacing the radiating element an additional 2 metres thereabouts from the building. I’m not sure whether it made much difference, but it seemed like the sensible thing to do for less than 10 Euros.

During my week-long stay, I managed to fit in several listening sessions and copied some really excellent DX from this ultra-compact, USB-powered set up. In fact, the MA305 coupled to the Eton Satellit performed so well, I managed to copy a number of personal firsts, including CRI on 7295 kHz, via their relay in Bamako, Mali, The Voice of Beibu Radio on 5050 kHz, Nanning, XSL ‘Slot Machine’ on 6251 kHz USB, Ichihara, Japan, S32 ‘The Squeaky Wheel’ on 3828 kHz and NHK World Radio Japan, 11910 kHz. I also copied RTM Wai/Limbang FM on 11665 kHz from Kajang, Myanmar Radio on 5985 kHz and AIR Bhopal on 4810 kHz, amongst others – all of which I would certainly consider to be difficult catches in Europe. To hear them with an 18 cm antenna felt pretty special. African shortwave stations were also very well represented and I managed to copy a number of them including Radio Hargeysa on 7120 kHz, Voice of Tigray Revolution on 59150 kHz, Radio Oromiya on 6030 kHz, Radio Fana on 6110 kHz, Radio Ethiopia on 7235 kHz, Radio Sonder Grense on 3320 kHz and Radio Guinée on 9650 kHz. I expected to hear all of these stations, except for Radio Guinée, which is farther away from Crete than the UK. So, all-in-all an excellent result.

Despite hearing a lot of excellent DX whilst in Crete, there is one signal I copied, which more than any other, demonstrates the DXing credentials of the MA305 – and Eton Satellit for that matter. In the early hours of the morning (00:59 hrs UTC) I copied and recorded Radio Tarma from Peru on 4775 kHz. With a TX power of 1 kW, this is a very difficult station to hear in Western Europe, even with a longwire. To catch this station in Crete, at all, was incredible on an ultra-compact set-up. It was at this point during the trip that I realised E-field antennas really do work superbly well for hard-core DXers on the move. It inspired me to conduct further tests back home in the Oxfordshire countryside, where electrical noise is absent. This I did a few days ago, with some quite amazing results on the Tropical Band. More on that to come in my next post. In the meantime, please find text links and embedded videos for selected reception recordings, below. Many more recordings are available on the Oxford Shortwave Log YouTube channel and please don’t hesitate to contact me if you require further information on the MA305 or the Eton Satellit. Thanks for reading/watching/listening and I wish you all excellent DX.

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How to build a Milk Crate AM Broadcast Loop Antenna

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Many thanks to SWLing Post contributor, James Townley, who shares the following guest post originally posted on his Shortwave/Medium Wave blog:

540 kHz to 1700 kHz Loop Antenna (Click to enlarge)

AM Broadcast Loop Antenna

by James Townley

Several years ago, I became interested in medium wave DXing. One of my limitations was the size of my yard, so I developed an interest in tuned loop antennas to compensate, because setting up a beverage antenna was out of the question. I experimented with different sizes of loops, and found that the bigger the aperture, the more gain the loop would have. The tuned loop antenna is also very directional, which allows you to reject, or null out interference from either noise or other stations. Loops are considered bi-directional in that they receive to the front and back, but not to the sides. The tuned loop antenna quickly became my weapon of choice for medium wave DXing.

Recently when the weather began allowing me to enjoy the outdoors, I decided to make another smaller loop antenna from a plastic milk crate I had lying around. I saw the idea on the internet when I observed that someone had used a milk crate for their loop. Click here to see a variety of tuned loop antennas that others have made. Whichever material you decide to make your loop antenna from, just make sure that it is not a conductive material. Wood, plastic, and cardboard seem to be popular materials for loop making. In the photo above, I am using my Sony ICF-2010 to listen to WCCO on 830 kHz. This station is nearly 200 miles south of me, but I am able to receive it with 9 LEDs lit on my signal strength meter while using the loop. There is no direct connection of the loop to the radio, it is inductively coupling with the radio’s own ferrite rod antenna.

If you are interested in making a loop antenna like mine, here are the materials you will need:
120 ft of 18ga insulated wire (I bought a 100 ft spool of cheap speaker wire and pulled the 2 conductors apart):

1 – Plastic milk crate
1 – 15 to 365 pF air variable capacitor (found in many old radios, or a google search to buy one from an internet store)
1 – Tuning knob. Any knob will do as long as it fits the shaft on the variable capacitor.
1 – Tape or wire ties. I used tape to secure the wire while winding, then hot glue when finished.

When you begin to wind your coil, use tape or a wire tie to secure the wire, and leave about a foot of wire. This extra foot of wire will later be soldered to the frame on the capacitor. As you wind your coil, pull the wire snugly and with each turn leave about a quarter inch spacing between each turn. The spacing isn’t critical as long as the spacing is consistent. I wound 21 turns on my crate. This may differ for you, depending on the size of your crate, or the value of you capacitor. If you find that the bottom frequency isn’t low enough, you can add more wire to make a few more turns. This will lower the bottom frequency for you.

After winding the coil, you can solder each end of the coil to your capacitor. The beginning of the loop gets soldered to the frame of the capacitor, and the other end of the coil to the rotor solder lug on the side of the capacitor. If you do not have a soldering iron, you can use alligator clips to connect your loop coil to the capacitor as well. I secured my capacitor to the inside corner of the crate with hot glue. I put a generous amount of the hot glue onto the bottom of the capacitor frame, and held it to the crate until the glue cooled enough for the capacitor to stay on it’s own. I used enough to get the job done, but not so much that it interfered with the plates in my capacitor. The hot glue seemed to adhere very well. I then checked the spacing of my coil turns, and secured them with the hot glue as well.

I was very impressed with the results after spending some time with the loop. It’s small enough to maneuver around easily, but big enough to give it some gain, so I can listen to daytime DX. I may make another tuned loop using two crates to see how much more gain I get with the larger aperture.

Happy DXing,
James Townley

Many thanks, James, for sharing your project with us! This loop appears to be relatively simple and accessible even to those with little knowledge of soldering or homebrewing. I’m now wondering how a loop made of four milk crates might perform!

Click here to view James’ Shortwave/Medium Wave blog.

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