Audiophile FM stereo antenna

[electra225]

I admit to not being the brightest bulb in the lamp sometimes, but, please, 'splain this to me. How is an "Audiophile" FM stereo antenna different from a common old FM or TV antenna? How does this contraption make stereo better? Built in Mesa, so it must be good.

https://phoenix.craigslist.org/evl/ele/ ... 16862.html

[TC Chris]

You're right. In fact, a folded dipole, properly stretched out, would likely be better in dealing with multipath because it's directional. Multipath can make for very lousy sound. That antenna looks like an omni, which will not deal with multipath gracefully. On the other hand, any antenna will reduce noise and make things sound better.

Chris Campbell

[William]

I know I'm not the brightest bulb in the lamp. I'm guessing this is an antenna built for city folks. Us country folks need something outside and much bigger.

Bill

[Motorola minion]

I cannot be silent on this subject, since I had engineering class EL-440 (Antennas and Propagation) over 35 years ago. Nothing is new here, I use rabbit ears for FM using twin lead not coax, so this is half the solution for most folks. A single length of 18-12 gage copper wire is an antenna, insulated or not. All the FM I need is within 50 miles of my house and shop, but issues of co-channel are getting worse as translators multiply.

I do not like indoor FM antennas because just walking around a room affects reception but not everyone has an attic or roof access. Most FM is horizontally and vertically polarized for both home and auto reception respectively. Many broadcast more power in the horizontal plane, hence outdoor antennas are mainly horizontal.

The dimension 31 inches is the dimensional compromise over the 20 MHz bandwidth of FM. Many times, rooftop TV antennas were marketed as including FM, but only 1-2 of the arrayed dipoles were about this length. These had one advantage - its directional and one disadvantage - tuned/cut not just for FM 88-108 but also VHF 54-88, 180-216 Mhz.

An outdoor, roof mounted FM-only antenna is the best because:

1. Up high, outside and unobstructed path is where the strongest signal is!

FM directional 2.jpg (5 KiB) Viewed 1175 times

Compromise: Attics are great for a poorly constructed but effective antenna, even home made ones but a metal roof and objects like spouting in the can affect it.

2. Directional means forward gain is maximized and co-channel interference is minimized.

Compromise: Omni-directional antennas often take form of folded dipoles in an S or circular shape. Mounting them on a wall may work if on the "signal side" of the wall.

[William]

Thanks, Dave. In my fringe area it definitely works best with an outside antenna. Growing up we had self supporting tower in the backyard right behind the house. Mounted to that tower were two antennas. One for FM, the other for TV. There was a rotor to turn them in the direction of the signal, mostly for TV. They were the biggest antennas that Wingard built. It looked like we were trying to communicate with Mars. Of course back then there was only three TV stations that we could receive. CBS, ABC, and, NBC. The big TV antenna with it's booster pulled them in with no problem. There was a certain FM station that my Mom like. It was located in Grand Rapids which was 90 miles away. The big FM antenna had no problem pulling that station in, and, Mom was very happy.

I'm glad you posted the Antenna 101 info today. Living in the same fringe area I will do some experimenting to see what I can do to improve FM reception.

Bill

[Firedome]

So I guess Yagi antennas are most appropriate for cell reception?

[TC Chris]

When I moved to my current house, I connected up my Metz whip antenna and heard mush on my favored station. It was basically tons of multipath. So just for fun I took a DIY article from the Audio Amateur magazine and built a little Yagi intended for indoor (attic) use--copper tubing, wood boom--and popped it up in my living room. Wow, problem solved. So I bought a Radio Shack Yagi and popped it up on the gable end of the house. Out in the shop, I have a turnstile omni in the garage attic area. The little Zenith table radio next to my computer uses a folded dipole hung where it seems to work best (vertically for this one). In the kitchen the GE Superradio II has another folded dipole, horizontal under the kitchen cabinet. Sometimes my body messes with the signal (depends on the weather). The bathroom Panasonic portable, tuned to the NPR news station, uses its own telescoping whip. My little house has foil-faced foam under the vinyl siding, and I suspect that affects signal strength significantly indoors. The other problem here is that radios with no tuned RF amp (the Panasonic & the Zenith) do get bleed-through from the big transmitters up on the ridge NE and SE of me. On the Panasonic I just telescope the antenna inward to reduce signal strength so the front end isn't overloaded. That's also what I do on the Ray Jefferson RDF tht I use for its FM band on the local sailboat. You can see the transmitting towers right over my mooring, so if I extend the whip all the way it way overloads. Push it down and the radio has an easier time sorting things out. At home the rooftop Yagi is fed by coax so the downlead isn't acting as an antenna. On the Zenith, I just try to ignore the damned preacher who's usually spouting at this time of night and polluting my music. It's not an alternate channel nor an adjacent channel so I think it's just front end overload.

Chris Campbell