Category Archives: AM

Travelling and DXing with the Bonito MegActive MA305 antenna

 

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.


Personal firsts

Click here to view on Oxford Shortwave Log

 

Click here to view on Oxford Shortwave Log

 

Click here to view on Oxford Shortwave Log

 

Click here to view on Oxford Shortwave Log

 

Click here to view on Oxford Shortwave Log

 

Radio Tarma, Peru, 4775 kHz

Click here to view on Oxford Shortwave Log

 

Other notable catches

Click here to watch on Oxford Shortwave Log

Click here to watch on Oxford Shortwave Log

Click here to watch on Oxford Shortwave Log

Click here to watch on Oxford Shortwave Log

 

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.

How to build a Milk Crate AM Broadcast Loop Antenna

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.

Jay restores a Panasonic RF-2200

Many thanks to SWLing Post contributor, Troy Riedel, who notes that Jay Allen has just published a post detailing a recent Panasonic RF-2200 restoration. Click here to read Jay’s post.

I recently picked up an RF-2200 at the 2017 Hamvention flea market. Like Jay, I love this particular radio. The thing is built like a tank, but like any vintage rig, 2200s need occasional servicing and cleaning. If you treat a ‘2200 well, it’ll outlast all of us. I’m happy Jay was able to bring this old girl back to life!

DK’s Barn Find: A GE Super Radio II

My good friend, David Korchin (K2WNW), has a knack for finding diamonds in the rough.

He’s been known to find a radio that needs TLC, take it home and restore a bit of its former glory. He’s had some amazing luck in the past.

Recently, DK sent a video of of his recent acquisition: a beat-up GE Super Radio II he purchased for two dollars. This radio will win no beauty contests, but it still plays well.

Check out DK’s video:

Click here to view on YouTube.

Many thanks, DK, for allowing me to post this video. It goes to show you that you should never pass up an opportunity to adopt a Super Radio. Even if the telescopic antenna is all but missing, the internal ferrite bar is where the money is!

Play on!

Back from Xenia: My 2017 Hamvention spoils

I’m finally back from a week of travels which included the 2017 Hamvention held a the Greene County Fairgrounds in Xenia, Ohio.

As an inside exhibitor, I was quite busy at Hamvention–indeed, my voice is only now recovering.

I did manage to sneak away from our table on several occasions to visit with vendors, friends, and check out new innovations (thanks to ETOW volunteers Eric McFadden, Miles McFadden and Robert Gulley!). I also attended the NPOTA (National Parks On The Air) forum on Sunday.

This year, I posted hundreds of photos of the event here on the SWLing Post: both inside exhibits and flea market booths.

I’ve also already started a re-cap/review of the 2017 Hamvention which I plan to post in the next few days. Stay tuned.

In the meantime, though, a number of readers have asked what I brought home from the Hamvention. Though I had no intention to buy stuff this year–seriously–I did manage to come home with a few treasures.

Panasonic RF-2200

If you’ve been reading the SWLing Post for a while, you’ll know I’m a big fan of the ‘2200. On the shortwaves, it’s a great performer even though the analog tuning can be a bit squirrelly.

Where it really shines is on mediumwave, though. It’s easily the best AM portable I own.

My buddy, Eric (WD8RIF), pointed out this RF-2200 (see photo above) in the flea market. Since I already own an RF-2200, I had no intention of buying one.

While taking a photo of it, the seller started telling giving me details. He said he’d never used batteries in it, and only used a small external wire antenna connected on the back (his homebrew connector was still attached). He then mentioned that he also had the original box, manuals, accessories and packing materials.

I put my camera phone away and picked it up to take a closer look. It had obviously been taken care of over the years. The battery compartment was immaculate and the telescoping whip didn’t have any bends or missing sections–it was straight, clean and original.

Out of curiosity, I asked how much he wanted for it.

He wanted $70.

Sold!

With absolutely no hesitation, I reached for my wallet. Sure, I’ve already got an RF-2200, but one can never have too many RF-2200s. Right?

I took a few photos of the RF-2200 this morning:

Without a doubt, this was my exciting 2017 flea market find. .

MFJ-8121 Analog Shortwave Portable

While browsing the inside exhibits late afternoon on Saturday, I spotted this analog portable from MFJ Enterprises.

In truth, I didn’t realize MFJ even had a shortwave portable in their product line.

This particular unit was on the clearance table and was labeled as a “factory second.” The sales person told me it was likely due to the damaged box (the unit inside had no visible blemishes).

At $12, I decided to purchase it.

You see, I get a lot of requests from readers asking for recommendations of simple analog portables. I thought I might eventually review this MFJ unit.

Last night, I popped some AA batteries in the radio and, sadly, it produced no audio. The tuning indicator works, but the speaker doesn’t even produce a hiss. I suspect this is the real reason it was being sold on the clearance table.

I might contact MFJ and let them know about this, or I might simply pop the radio open and see if it’s a broken connection.

HamSource flashlight

And finally–while not a terribly exciting purchase–I did also pick up this CREE LED flashlight at the Ham Source booth. It’s small, bright and runs on one AA battery. It has three settings: high, low and flashing. It appears to be very durable and the beam can be focused. For eight bucks, it’s the perfect flashlight to live in my new Tom Bihn Synapse 25 backpack.

That’s all, folks!

Looking back, I’m quite impressed with my self-control. I really didn’t want to return home with any new finds. If anything, I’m trying to downsize right now.

But a Panasonic RF-2200?  I always have room for another FR-2200!

Post readers: Have you acquired any flea market finds recently?  Please comment!