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AM Antenna in Eton E1
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AM Antenna in Eton E1
In article ,
"Lenny" wrote: So, how exactly do you use the nulls? Does the ferrite rod move around inside the radio with a control? Lenny "Telamon" wrote in message ... In article , "Lenny" wrote: Thanks Telamon. Lenny "Telamon" wrote in message . .. In article , "Lenny" wrote: OK, I'll admit it. I don't know what people are talking about when they say the E1 doesn't have an AM antenna. People have stated that the E1 does not have an internal "ferrite rod" antenna inside. Doesn't it have a whip antenna. Yes. What more could you want? An internal "ferrite rod" antenna inside. What the heck is a "ferrite rod antenna" anyway? It's a closed loop type antenna utilizing a high permeance core (the ferrite) in order to take up less space. And what does it do differently than the whip? 1. More convenient to use as you don't have to have the long whip sticking out when you carry it around. 2. The whip is omnidirectional and the loop ferrite rod antenna has two nulls in the pattern that you could use to null out a competing station of local noise source, which could improve your reception. 3. The ferrite loop is less susceptible to pick up local noise sources being sensitive to the magnetic field component whereas the whip is sensitive to the electric field. No problem Lenny. #2 Should have been "competing station or local noise source." I need a Usenet editor. Using the photos provided in the thread by weatherall you can see that the coiled ferrite rod goes across the top of the case. The nulls are symmetrical about the rod and exist at the ends of the rod. The "Null" is where the rod antenna will be the least sensitive to a broadcast station. The null off both rod ends is a very small just a few degrees around the rod antenna ends and the maximum reception would be when the rod antenna is broadside to the station. Due to the length and width of the rod antenna this almost always means that the radio front or back should be facing the station. http://www.radiointel.com/review-tecsunpl200.htm How to use this to your benefit? Lets say that either another station or a local noise source is interfering with your reception. You would point the side of the radio toward the interference reducing the level of interference. This will only work if the interference is on a different heading then the station you are trying to hear. The best use of the null will involve acknowledging that we live in an (at least) 3D world so whereas the null will be found is by rotating the radio on a compass heading it can be made "deeper" by aditionally tilting the radio in the vertical axis. Here is an analogy as to what you are trying to accomplish by nulling an interference source. Radio waves are a different frequency of electromagnetic waves same as light waves. It you had a white rod on a black background some distance from you holding a flash light next to your head then the rod would hardest to see when the end of it was pointed at you representing a small dot. If your eyes were the interference then the rod would have the least exposure to you when the end was pointed right at you rotating the rod in the X (compass) and vertical altitude directions so you can only see the very end of it. -- Telamon Ventura, California |
AM Antenna in Eton E1
weatherall wrote: Wrote: Yeah well, if Eton hadn't pushed this receiver into the marketplace at such manic, breakneck speed, then maybe they'd have had time to include a ferrite antenna and make the display quieter. Better to take your time and do it right than launch a product prematurely--even if it means missing a deadline or two. Sarcasm? :) http://www.radiointel.com/review-etone1.htm "Originally unveiled in prototype form at the Consumer Electronics Show in Chicago in 1996 as the Grundig Satellit 900, the E1 has followed a long road from those first mockup models to commercial realization." Yeah, the long and winding road to recall... dxAce Michigan USA |
AM Antenna in Eton E1
On Sat, 28 Jan 2006 07:25:58 -0500, "Lenny"
wrote: Great pix, thanks Weatherall. Does the Ferrite Rod only aid in AM broadcast reception, or does it also aid SW reception? Lenny In most AM/FM radios, the ferrite bar antenna is for AM reception only. A separate whip antenna for FM is reasonably close to a quarter wavelength on the FM frequencies; a 1/4 wave whip antenna on the AM band, 530 to 1700 Khz, would be hundreds of feet long, hence the shortened AM antenna using the ferrite rod. On little radios, the rod is a couple of inches long, on others such as the C.Crane CCRadio or the GE SuperRadio the rod is bigger, about 8 inches long, hence their supposed "DXing" capabilities for AM. On shortwave radios, I'm not sure which frequencies the ferrite bar would be used for, certainly the American AM broadcast band, not sure about others. One disadvantage to the whip antenna, it is vertical, and vertical polarization picks up more manmade interference. Horizontal antennas such as the ferrite bar are a little more immune. Bob k5qwg "weatherall" wrote in message ... Lenny Wrote: OK, I'll admit it. I don't know what people are talking about when they say the E1 doesn't have an AM antenna. Doesn't it have a whip antenna. What more could you want? What the heck is a "ferrite rod antenna" anyway? Hi Lenny: Here are pictures of the insides of a Tecsun PL-200 radio. It's hosted on radiointel.com, a fun & useful site. In some of the pictures you will see tightly coiled copper wire around a bar (that's the ferrite). It's at the top of the radio, and would be on the left side if you're looking at the front. http://www.radiointel.com/review-tecsunpl200.htm -- weatherall |
AM Antenna in Eton E1
Some ferrite rod antennas are round,some ferrite antennas are sort of
flat bar shaped.I have a lot of radios that have flat shaped bar ferrite antennas. cuhulin |
AM Antenna in Eton E1
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AM Antenna in Eton E1
"Bob Miller" wrote in message ... On Sat, 28 Jan 2006 07:25:58 -0500, "Lenny" wrote: Great pix, thanks Weatherall. Does the Ferrite Rod only aid in AM broadcast reception, or does it also aid SW reception? Lenny In most AM/FM radios, the ferrite bar antenna is for AM reception only. A separate whip antenna for FM is reasonably close to a quarter wavelength on the FM frequencies; a 1/4 wave whip antenna on the AM band, 530 to 1700 Khz, would be hundreds of feet long, hence the shortened AM antenna using the ferrite rod. But a SW whip antenna is usually much less than 1/4 wave, as well. The whips can be resonated with additional components, but they usually aren't. It isn't necessary. On little radios, the rod is a couple of inches long, on others such as the C.Crane CCRadio or the GE SuperRadio the rod is bigger, about 8 inches long, hence their supposed "DXing" capabilities for AM. On shortwave radios, I'm not sure which frequencies the ferrite bar would be used for, certainly the American AM broadcast band, not sure about others. Radios with a longwave band would also use the ferrite rod antenna for that band. I've seen radios, such as the Realistic DX-100 which use a ferrite antenna for each of the SW bands. In the case of the DX-100, the antenna is used mostly as the inductance of the input tuned circuit. Nearly all the signal power on SW comes in through a whip or external antenna. Moving the radio has practically no effect on the signal or interference. One disadvantage to the whip antenna, it is vertical, and vertical polarization picks up more manmade interference. Horizontal antennas such as the ferrite bar are a little more immune. Bob k5qwg On most radios, the whip doesn't have to be vertical. Sometimes interference can be minimized by moving the whip, although it often doesn't make much difference. The horizontal ferrite bar radio antenna is magnetically horizontal, but electrically vertical, just like the whip antenna. However, the ferrite antenna is much less prone to capacitive noise pickup from whatever electronic stuff is running. Frank Dresser |
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