Tag Archives: AM

Ed’s Homebrew Fruitcake Tin Radio

Fruit Cake Tin Radio

Many thanks to SWLing Post contributor, Ed Ganshirt, who writes:

I had an old car radio from the 1940’s I salvaged the parts from, and a rudimentary schematic to build by. I decided to re-assemble in the container I stowed away the parts in. Nothing special just another AM broadcast radio in an unusual cabinet (fruitcake tin.)

I love it, Ed! It’s like a broadcast band version of Rex’s Tuna Tin QRP radios!

It must have been a challenge to mount all of the components on that tin.  So how does she play?

Post readers: please comment and consider sharing your homebrew project!

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.

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!

Making broadcast towers safer for birds

(Source: NPR)

It’s likely the only time you really notice one of your neighborhood broadcast and cell towers is at night when they’re lit up with conspicuous bright red lights.

Those lights help pilots see the huge metal structures that can reach 1,000 feet into the air — but they can spell disaster for birds.

In 1976 in Gun Lake, Mich., one tower killed over 2,300 birds in one night, says Caleb Putnam, who works for the Michigan Department of Natural Resources. He says for reasons scientists still can’t quite figure out, birds kept flying headlong into towers.

“If that many are dying at one night at one tower and yet there are thousands of towers across the country and as you go across the world, the numbers are staggering,” he says.

Putnam says in North America alone it’s estimated that 7 million birds smash into towers every year. But until recently scientists didn’t know why it was happening.

[…]”We were able reduce the numbers of bird fatalities on communications towers by simply extinguishing those non-flashing lights,” she says. “Those fatalities were reduced by as much as 70 percent.”[…]

Click here to listen/read this full report on NPR.

With switch from AM to FM, some Polynesians now in the dark

(Source: Southgate ARC)

Some inhabitants of French controlled Polynesia are unhappy at the switch over from Medium Wave AM to VHF FM broadcasting

Radio New Zealand reports Radio Polynesie Premiere switched to an all FM service at the beginning of December, leaving pockets of inhabitants in valleys and on remote atolls without any local radio service.

The broadcaster added five FM transmitters to its network of 48 to improve its reach but in an area the size of Europe, the signal fails to reach all communities.

Concern has been expressed that vital weather warnings are no longer heard.

The mayor of Makatea in the Tuamotus Julien Mai said there is a risk to public safety because people have always been advised to have an emergency kit that includes a radio when severe weather strikes.

Source:
http://www.radionz.co.nz/international/pacific-news/321809/loss-of-am-radio-irks-french-polynesia