Category Archives: Accessories

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.

CC Buds-Pro: new in-ear phones from C.Crane

Many thanks to SWLing Post contributor, Troy Riedel, who shares the following sales flyer from C.Crane:

NEW! CC Buds-Pro

Designed and built for voice clarity and less listening fatigue

A recent post from The Wall Street Journal indicates “An estimated 30 million Americans have some degree of hearing loss and the numbers are growing. A study published last month by John Hopkins University researchers, predicted that the number of U.S. adults with hearing loss will nearly double by 2060…”

Buy Two CC Buds Pro and get the Third pair FREE!

I will plan to grab a pair of these in the near future. I keep a pair of the original CC Buds in my Elecraft KX2 go-kit–I find that they’re well-suited for ham radio work and the audio fidelity is quite good for music as well.

I used the original CC Buds on at least 80 National Parks on the Air activations last year. They’re a great choice for sound isolation–more than once I had to set up next to a road and the in-ear buds eliminated all of the noises from passing cars so that I could focus on working pile-ups!

Thanks for the tip, Troy!

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!

Powering the Sony ICF-SW7600GR with USB rechargeable packs?

Many thanks to an SWLing Post reader who recently asked the following question:

Hi Thomas:

I rely on my SONY Shortwave in case of emergency, but it’s occurred to me that relying on the alkaline batteries inside to be fully charged and not corrode wouldn’t make sense.

I am thinking it would be great to be able to power the radio’s 6V 700ma off of the multiple USB rechargeable power sticks I have around the house.

What I need is a cable from the USB stick to the radio.

As a hobbyist project, any ideas for an existing cable or how to make such a cable with the appropriate power circuit?

Many thanks.

I know a power cord can be created as long as polarity and the coaxial plug match what the Sony requires. I’ve never used the Sony on a 5 VDC source–I assume it’s within tolerance and RX sensitivity wouldn’t be affected?

Post readers: If you’ve ever created or purchased a USB power cable for the Sony ICF-SW7600GR, please comment!

What are your favorite radio apps?

As I mentioned in a previous post, I’ve been browsing the Google Play store this morning in search of an Android app that would help one of our readers decode HF digital modes.

I suggested Tivar, which is essentially FLdigi for Android devices. The app was originally created by Dave (W1HKJ) and published on Google Play by Stephen Cooper. According to the description, the app does not have a dedicated developer, but based on reviews, it seems to work for many.

I assume this is the best (or only?) app for decoding broadcasts like the VOA Radiogram, DigiDX, etc?

Searching Google Play–and noticing a number of new apps–made me realize that it’s been a while since I’ve done a proper updated of my list of Android, iOS and Windows apps for radio enthusiasts.

What’s in your phone or tablet?

Post readers: I could use your help…

If you have a moment, please browse my list of apps and comment (on this post) with suggestions of any that you love, but I haven’t recommended.

I’ll check out each app and update the list accordingly over the next few weeks.

It would be very helpful if you note what you like about the app and if it’s available on multiple platforms (iOS, Android and/or Windows). I imagine there are many I’ve yet to check out!

Thank you in advance!