Question about radio antennas

master7045

Senior member
Jul 15, 2005
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I just hooked up a "vintage" amplifier (vintage = 1970 or 1980s, I"m not really sure) to a pair of klipsch speakers in my office. I would like to hook the only AM/FM radio antenna I have in the house to this receiver, but there are some odd connections to me. First the antenna, it is a powered AM/FM antenna and there is a single two wire connection marked AM and a single F-connector for FM. The back of the receiver has a 300 Ohm connector for FM split to two posts or there is a single FM, GRND, & AM connector. Is there an easy way to hook up this antenna by using a splitter or adapter? Currently I have 1 of the wires going to the AM post and the other going to the FM post. The F-connector is hanging loose not connected to anything. I get decent FM reception and pretty crappy AM selection. Any tips?
 

CallMeJoe

Diamond Member
Jul 30, 2004
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Not sure about the AM connection on your receiver, but the FM needs a balun (transformer) to convert the 75-ohm f-connector to 300-ohm twin-lead. Check Radio Shack.

What make and model receiver? It might help in figuring out the AM connection.
 

master7045

Senior member
Jul 15, 2005
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Thanks for the links/replies. THe first amazon link is what I need for the FM, but the AM still puzzles me. I'll have to take a closer look when I get home, but I swear there was only 1 post for the AM antenna. The bank panel had was set up like: FM Grnd AM all screw posts right next to each other. Above those three was the FM 300 ohm dual post connectors. Does the loop for AM contain a ground? I'm no electrical whiz, but to me, that would not make a loop.
Anyway, I'm going to head out to radio shack on my lunch and see what I can find. I don't have the model # of the amp but it's an old JVC model probably from the 70s or 80s, analog dial w/ green backlight, equalizer on one side, particleboard/mdf sides and a metal cover. I'll snap a picture tonight.
 

sdifox

No Lifer
Sep 30, 2005
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Thanks for the links/replies. THe first amazon link is what I need for the FM, but the AM still puzzles me. I'll have to take a closer look when I get home, but I swear there was only 1 post for the AM antenna. The bank panel had was set up like: FM Grnd AM all screw posts right next to each other. Above those three was the FM 300 ohm dual post connectors. Does the loop for AM contain a ground? I'm no electrical whiz, but to me, that would not make a loop.
Anyway, I'm going to head out to radio shack on my lunch and see what I can find. I don't have the model # of the amp but it's an old JVC model probably from the 70s or 80s, analog dial w/ green backlight, equalizer on one side, particleboard/mdf sides and a metal cover. I'll snap a picture tonight.

In your case, the ground is shared between fm and am.
 

master7045

Senior member
Jul 15, 2005
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Here is the picture of the back of the amp. I used the 75 to 300 Ohm adapter to connect the FM portion to the top two posts on the left side of the amp (as your looking at the back of it. The three posts below that are (from Left to Right as you look at the picture; FM GND AM. I have the two leads from the wire labeled AM going to AM & GND. I get both AM & FM so I guess I'm doing it correctly. IF anyone has any suggestions, I'm all ears!
IMG_6943.jpg


Also, model # is JVC R-S33
 
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master7045

Senior member
Jul 15, 2005
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I just uploaded the picture to photobucket and attempted the link again, hopefully it works now.
 

sdifox

No Lifer
Sep 30, 2005
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from your description you are fine. Are you getting better reception than the ferrite antenna that is built in? The black tube is the antenna.
 

master7045

Senior member
Jul 15, 2005
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After reading some of the links you provided, I figured out that was the AM antenna, which was not very good. The new one I've attached seems to work pretty well. I live near St Louis and last night I was able to pick up (although noisy), a Chicago sports station & 1 station from Atlanta & another from New Orleans. My ultimate goal is to pick up WGN radio 720 & 890 from Chicago, so I can listen to the Cubs & Bears games when they aren't on TV