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Old 13th November 2013, 01:19 AM   #1
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Default FM Antenna Trouble

Hello! After getting into "better than most consumer grade audio" audio about a year ago, I have today wanted to listen to some FM radio on a receiver I have. Now for all of my life using FM I had just used the single wire attached to a high place going to your adverage consumer garbage stereo, but I find this receiver I have is much more complicated.

There is connections for 300 and 75 ohm FM antennas, and I don't know what to do with either of them. I don't have special wire, just normal wire, what can I do to get some radio playing?
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Old 13th November 2013, 01:33 AM   #2
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300 Ohm is the (normally pink) twin wire "T" aerial.

75 Ohm is the co-ax type wire to an appropriate aerial.

As a stopgap you can just use zip wire and make a "T" with the two unconnected ends.
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Old 13th November 2013, 01:35 AM   #3
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Quote:
Originally Posted by KatieandDad View Post
300 Ohm is the (normally pink) twin wire "T" aerial.

75 Ohm is the co-ax type wire to an appropriate aerial.

As a stopgap you can just use zip wire and make a "T" with the two unconnected ends.
Ummm, I don't currently have any sort of antenna, just wire, and I'm not really sure what to do with it.

Can you explain more about this T thing?
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Old 13th November 2013, 01:37 AM   #4
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Using twin core speaker wire, tear one end apart to make a "T" shape.

The width of the "T" needs to be approximately (300 000 000 / f / 4) metres. Where f is the frequency in Hz of the staion you are trying to receive.

The two wires that are still adjacent to each other are connected to the 300R aerial input.

Last edited by KatieandDad; 13th November 2013 at 01:40 AM.
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Old 13th November 2013, 01:41 AM   #5
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Quote:
Originally Posted by KatieandDad View Post
Using twin core speaker wire, tear one end apart to make a "T" shape.

The width of the "T" needs to be approximately (300 000 000 / f / 4) metres. Where f is the frequency in Hz of the staion you are trying to receive.

The two wires that are still adjacent to each other are connected to the 300R aerial input.

I want to receive a wide range of frequencies.

I don't understand why I have to do all of this if a normal consumer grade stereo requires just me placing one wire in a suitable spot to get all of the stations.
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Old 13th November 2013, 01:44 AM   #6
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If you'#ve never seen a ribbon aerial befiore, have a look at FM ribbon Aerial | eBay
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Old 13th November 2013, 01:45 AM   #7
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If you'#ve never seen a ribbon aerial befiore, have a look at FM ribbon Aerial | eBay
Well I just made one of those with maybe 6 foot on each end of the T and it is barely giving me anything more than static on any station.
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Old 13th November 2013, 01:49 AM   #8
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Hi-End receivers are often less sensitive than cheapie ones, they rely on a higher signal strength at the input to reduce FM noise.

Your T aerial will be directional so you will need to turn it round so that it is perpendicular to the transmitter. (ie if you were holding it, you are facing the transmitter).

If the arms of the T are too long or two short it will not be tuned to the station that you are trying to receive. For 90MHz each arm should be about 33 inches.

Last edited by KatieandDad; 13th November 2013 at 01:52 AM.
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Old 13th November 2013, 01:51 AM   #9
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Quote:
Originally Posted by KatieandDad View Post
Hi-End receivers are often less sensitive than cheapie ones, they rely on a higher signal strength at the input to reduce FM noise.

Your T aerial will be directional so you will need to turn it round so that it is perpendicular to the transmitter. (ie if you were holding it, you are facing the transmitter).

If the arms of the T are too long or two short it will not be tuned to the station that you are trying to receive.
Facing the transmitter! Oh god this is getting really picky now, I don't even know where some of these stations are in respect to me.

And the thing is, this is facing one of the transmitters now, and I'm getting a garbage signal.
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Old 13th November 2013, 02:08 AM   #10
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Hi-End receivers often require a decent roof top antenna.
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