AM Radio Loop Antenna in Walnut

[Sullivan]

My latest project - an AM radio loop antenna.  I listen to AM talk radio and a few of the stations I like are not real clear with lots of static.  I was looking into purchasing an external antenna and came across these plans: http://www.mtmscientific.com/loop.html - I fancied up the feet a little.  Works surprisingly well and what is neat is that you do not actually connect it to the radio - just place it nearby and tune it for the best reception.

I made mine from walnut with a BLO and wax finish.

The air variable capacitor that they sell at the site above can also be found on Amazon and eBay but the price with shipping is about the same.

The knob is a Davies Molding 1600BW purchased on eBay.

[fall]

And it looks cool to! Great job.

[stav]

Very cool indeed.  I'll have to check back later when I have time to read the bit on how it works.

[Sullivan]

Very cool indeed.  I'll have to check back later when I have time to read the bit on how it works.

From the plans, the following is a simple explanation of how it works:

"The AM Loop antenna uses the principle of electrical resonance. The copper wire windings form an inductor, and the aluminum plates attached to the tuning dial form a variable capacitor. The inductor and capacitor form a parallel tuned circuit with a specific resonant frequency. Properly tuned, the frequency of loop antenna resonance and the radio station broadcast frequency are equal.

For example, WABC in New York (at dial 770) broadcasts at a frequency of 770,000 Hertz. When carefully tuned, the loop antenna will resonate at exactly that same frequency.

A resonant electric circuit, such as the loop antenna, oscillates in harmony with the electrical impulses from the radio station. The antenna's oscillations can reach relatively large amplitude. In essence, the loop antenna becomes a selective local repeater of the distant radio station's signal.

Portable AM radios contain an internal ferrite core antenna. The internal antenna strongly couples to the loop antenna oscillations when they are physically close together. Of course for reception, the radio must also be tuned to the same frequency as the loop and the radio station."

[Admiral]

Nice Sony ICF 2010, one of the best ever made, love mine. With a simple single wire antenna in a tree I could pull in stations from NYC to listen to baseball games while fishing for pike and walleye at a fly-in cabin in northern Quebec.

[arthropod98]

that is very cool, and definitely something i haven't seen before!  

[Sullivan]

Nice Sony ICF 2010, one of the best ever made, love mine.  With a simple single wire antenna in a tree I could pull in stations from NYC to listen to baseball games while fishing for pike and walleye at a fly-in cabin in northern Quebec.

The radio was a wedding present from my wife when we were married in 1991.  Hard to believe it's almost 30 years old.

[Admiral]

The radio was a wedding present from my wife when we were married in 1991.  Hard to believe it's almost 30 years old.

that's about right, they don't make them anymore, and they are somewhat iconic in the shortwave community.  It's likely worth more now than what she paid for it back then.

[MarkSingleton]

Beautiful. I have a ( plastic , shudder ) "Select-a-Tenna" which does the same thing.

But that is much better looking!!!