FM antenna made simple

I have to agree with Sgmlaw here for the most part. Getting a good outdoor antenna mounted up high with a low loss feedline that is carefully routed is what we should all be striving for. A large Yagi on a rotor would be optimum, but well beyond what most folks require for decent reception. If that's not possible, you may be stuck with one of the indoor antennas or the homebrew that i described. One of the advantages that the design that i mentioned has is that it is vertical rather than horizontal. If you don't think that this makes a difference, take a listen to your car stereo sitting out in front of the house. Chances are, the stock Delco, Ford or Mopar "sound system" with an external body mounted antenna just might be able to pick up stations that your high dollar tuner with great specs and amplified indoor antenna can't seem to pull in. There are two reasons for this. The car antenna and the vertical dipole that i suggest are both omnidirectional whereas many of the amplified antennas and the "T" antennas are cross polarized (both vertical and horizontal) and relatively directional. This means that they are highly susceptible to multi-path and far more sensitive to "aiming". With the vertical dipole, you shouldn't have to fuss with orientation as long as you keep the entire antenna vertical and mount it as i described. If your trying to pick up a specific station but are having a hard time doing it, you can make the vertical dipole somewhat directional by playing with the orientation and direction of the ground (bottom) wire. Another reason that the center fed dipole works well is that the antenna is naturally resonant at the lengths that i mentioned (between 28" and 32"). It therefore offers gain over an "untuned" or "non-resonant" antenna that is of random length or design. One more comment is that sometimes what we attribute to being a poor incoming signal is actually TOO much signal. This can cause front end overload. Signs of this are that the station has a "ragged edge" to it and always sounds like it is not exactly on center channel. While this might sound like the symptoms of a weak or distant station, the difference is that these stations come in quite loud and can be tuned in over a wider frequency range than normal. The signal is so strong that it is actually bleeding over onto adjacent frequencies. This can be caused by being very close to the transmitter or having an amplified antenna system turned up way too much. In some extreme cases, you might even need to install an inline attenuator. This "eats up" some of the signal coming into the tuner, reducing it's strength to a level that the the receiver section can more easily deal with. Keep in mind that if you do have a "mast mounted" amplifier near the antenna, the indoor section of this device MUST be located BEFORE any splitters are put into the system. In other words, you would need to have the outdoor antenna connected to the mast mounted amplifier section, a piece of coax coming down into the house, the control section of the amplifier and then any splitters that were absolutely necessary. Placing a splitter between the mast mounted amp and the control panel could either reduce or absolutely kill the performance of the amplifier, making it useless and sometimes even detrimental to the system. This is often overlooked or not fully understood by inexperienced installers. For those that desire the best performance from their FM systems, you might want to check into the Magnum Dynalabs Signal Sleuth. This acts as both an amplifier and filter and is commonly referred to as a "pre-selector" in the RF field. This makes the signal both stronger and sharper sounding while rejecting outside interference. Hope this helps. Sean >

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Bmpnyc- I am referring to a device about 4-5' long and approx. size of a 2x4. I don't have any significant multipath problems here, I put it in the attic (20' above grade) and I didn't hook up the amplifier, and was pulling in many, many stations without even a good physical connection to my HT receiver (the Yamaha has something that almost looks like a Pal type connector, can't thread the f connector on, but just placed it so the "hot" center lead touched, or even came very close) to the center of the amp connector). Didn't do any critical listening, it was just an experiment on the TV antenna I was going to return. Have no idea how it performs under more difficult conditions.

Well I have tried two of your suggestions. First I moved the T attenna to a different inside wall that faces the direction that I suspect most local signals are coming from and most stations are were received more consistently and clearer.

Sean, I made up the vertical dipole you so completely outlined above. I was able to solder the wires and as an initial trial ran in outside and tacked it behind a wooden shutter on the first floor of our wooden shingle covered home. The stations coming from this side of the house(north) are coming in beautifully, considerably clearer than with the T.
Another local station that I suspect comes from the west is not coming in as well as it did with the T. I am planning to move it higher on a east facing wall to see if that will help.

Glad that it is working out a little better for you. The reason that i said to mount it in the window was for specific reasons. If it is mounted in the middle of a window, it is not REAL close to any metal that might detune it plus it is still indoors. This protects the wire from being exposed to the weather and will keep both it and all of the connections from corroding. As mentioned previously, this basic design is omnidirectional, i.e. it should pick up all directions relatively equally as long as the entire antenna is vertical. If you've got aluminum siding, the wooden shudder is near a large metal frame for the window or you have conduit or wiring located closely to the antenna in the wall behind it, this could cause both detuning and directionality. If you can, you might want to run another wire dipole on the west side of your house and then simply hook up an antenna switchbox that you can get from Rat Shack. This would give you the best of both worlds at the flip of a switch. Sean
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