AM Radio

[mooremljeff]

The AM radio in my tuner stopped receiving most AM stations. I like to listen to baseball games while working in the garage so this is a big problem Help.

I tried mannualy tuning the station and it still won't come in. I even relocated the loop antenea without any luck.

[Speedbump]

What kind of tuner or radio is this?

[mooremljeff]

Its a 3-4 year old Yamaha tuner. AM 710 Worked great untill I tuned away and could never get it back

[Speedbump]

The only tuners I'm familiar with are the Viet Nam era Tuners we all had. You plugged in your tape deck, turn table and what ever else you had and they all played through it. You could also tune AM/FM, but basically it was just an amplifier.

[HayZee518]

AM signals are vertically polarized out the transmission antenna. a ferrite rod type antenna is highly directional so moving the unit around horizontally should fix your problem. if yours uses a loop antenna [two screws on back] rotate it while tuning it.

[Speedbump]

Another thing about AM signals . After around 7PM in the evening, all AM stations must lower their power a lot to try to avoid too much interference. The bands open up at night and some stations can be heard for hundreds if not thousands of miles away. Unlike daytime when they are local only.

[mooremljeff]

The tuner is modern but basically the same thing described: you plug in your commonents. I'll try moving the tuner horizontally as suggested. I do have a loop antena but the wire fell out of the loop - could that be the problem? I strung out the wire similar to the way the FM wire antena works but maybe the loop configuration is important to tuning?

[Speedbump]

The AM band unlike the FM band needs a much longer antenna. They compensate for length by winding a lot of wire around something. This something is also very directional and must be broadside to the AM station for best reception.

[HayZee518]

an fm antenna is made like a dipole out of ribbon type tv cable rated at 72 ohms. the horizontal element is soldered at both ends and the output is taken off at the exact center of the dipole. a length of 72 ohm flat cable is soldered to the center tap and connected to the screws on the back of the receiver. 24 gauge magnet wire wound around a coil support of an 18 inch diameter and brought out to the am antenna input is highly directional.

[mooremljeff]

but does the wire on the AM need to be wound to work? I currently have the entire length of the AM wire streached out and extended outside on the side of my garage and still no reception.

[HayZee518]

the wire of unknown length is wound around a coil form for portability. a long wire antenna which is what you have now is frequency dependent. each frequency is cut to a certain length to form a half or quarter wave-length for a given frequency. look into an electronics section dealing with antennas and transmission systems.