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#1
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Hi everyone,
I am new here, so please excuse my ignorance about antennas, or if I am in the wrong ng. I could not find any help getting the answer to my question by googling. I have a cheap boom box radio that I recently bought at Walmart and it plays great music, and cd's, and cassettes. Unfortunately it will not play my favorite FM oldies station (97.5 MHz) either in my workshop, or my house (it plays several other stations fine). My other boom box will play the station (and its 20 years old), and they are both of relatively equal value (the older one is a brand name - Panasonic). If anything, I would think the new one should have 20 year newer technology in it, and it should play at least as good - dunno. They both have a telescopic whip antenna (I hope that is the right terminology), and the new one will not play the station I want by either rotating the antenna, or moving the radio to different positions. I have tried everything. The only way it will play the station I want, is to put my hand on the antenna (or even around the antenna - ie I don't even have to touch it - interesting - I guess my body makes a real good antenna - I have always wondered about this phenomena). I tried touching it with other metallic devices (eg, wire, coat hanger etc), and it has no effect. The only way it will play the station is by getting near the antenna with my hand. I see no way of mounting an FM antenna to the receiver (ie the antenna is factory mounted to the back of the radio. I have a couple of questions if you will allow me : - Is there anything I can do to the existing telescopic whip antenna (such as wrap it in aluminum foil or something else weird like that) that will enable the radio to pick up the station I want. And also, please explain why it plays the station I want when I put my hand on or around the antenna. - I thought AM and FM antennas were different technologies (so to speak - eg amplitude modulation versus frequency modulation). How come portable AM/FM radios only have a single telescopic whip antenna (please excuse me if that is the wrong terminology). Is the whip for FM, and the AM is inside the radio, or it uses the cord (just a guess). Any comments would be greatly appreciated. Thanks...Pete |
#2
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take it back to wallmart its a bummer nmb
I have a cheap boom box radio that I recently bought at Walmart and it plays great music, and cd's, and cassettes. Unfortunately it will not play my favorite FM oldies station (97.5 MHz) either in my workshop, or my house (it plays several other stations fine). My other boom box will play the station (and its 20 years old), and they are both of relatively equal value (the older one is a brand name - Panasonic). If anything, I would think the new one should have 20 year newer technology in it, and it should play at least as good - dunno. They both have a telescopic whip antenna (I hope that is the right terminology), and the new one will not play the station I want by either rotating the antenna, or moving the radio to different positions. I have tried everything. The only way it will play the station I want, is to put my hand on the antenna (or even around the antenna - ie I don't even have to touch it - interesting - I guess my body makes a real good antenna - I have always wondered about this phenomena). I tried touching it with other metallic devices (eg, wire, coat hanger etc), and it has no effect. The only way it will play the station is by getting near the antenna with my hand. I see no way of mounting an FM antenna to the receiver (ie the antenna is factory mounted to the back of the radio. I have a couple of questions if you will allow me : - Is there anything I can do to the existing telescopic whip antenna (such as wrap it in aluminum foil or something else weird like that) that will enable the radio to pick up the station I want. And also, please explain why it plays the station I want when I put my hand on or around the antenna. - I thought AM and FM antennas were different technologies (so to speak - eg amplitude modulation versus frequency modulation). How come portable AM/FM radios only have a single telescopic whip antenna (please excuse me if that is the wrong terminology). Is the whip for FM, and the AM is inside the radio, or it uses the cord (just a guess). Any comments would be greatly appreciated. Thanks...Pete |
#3
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On Tue, 3 Apr 2007 19:07:47 -0400, "Pete" wrote:
- Is there anything I can do to the existing telescopic whip antenna (such as wrap it in aluminum foil or something else weird like that) that will enable the radio to pick up the station I want. And also, please explain why it plays the station I want when I put my hand on or around the antenna. Hi Pete, Neil's terse comment of taking back may ulitmately prove beneficial. On the other hand you can just string up a lot of wire (higher is always better) and simply wrap one end around the telescoping antenna. Insulated wire or not shouldn't matter. 73's Richard Clark, KB7QHC |
#4
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Richard Clark wrote:
On Tue, 3 Apr 2007 19:07:47 -0400, "Pete" wrote: - Is there anything I can do to the existing telescopic whip antenna (such as wrap it in aluminum foil or something else weird like that) that will enable the radio to pick up the station I want. And also, please explain why it plays the station I want when I put my hand on or around the antenna. Hi Pete, Neil's terse comment of taking back may ulitmately prove beneficial. On the other hand you can just string up a lot of wire (higher is always better) and simply wrap one end around the telescoping antenna. Insulated wire or not shouldn't matter. 73's Richard Clark, KB7QHC Thank you Richard...that is the kind of comment I was looking for (I took Neil's with a grain of salt-there is absolutely nothing wrong with the radio). I was trying to be polite in my post, but I am way smarter than that. I will try wrapping the wire around the antenna tomorrow and let you know what happens (is it okay to use phone wire which has several individually insulated wires in it). BTW could you please tell me why the reception comes in when I put my hand around the antenna (ie what is my body doing to the signal), and also answer my second question about one antenna for both AM and FM. Thanks again...Pete |
#5
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On Tue, 3 Apr 2007 23:06:19 -0400, "Pete" wrote:
Thank you Richard...that is the kind of comment I was looking for (I took Neil's with a grain of salt-there is absolutely nothing wrong with the radio). I was trying to be polite in my post, but I am way smarter than that. Hi Pete, No, it is still advice to consider. Your new radio does have the performance of a lemon in comparison to your old set. I will try wrapping the wire around the antenna tomorrow and let you know what happens (is it okay to use phone wire which has several individually insulated wires in it). BTW could you please tell me why the reception comes in when I put my hand around the antenna (ie what is my body doing to the signal), and also answer my second question about one antenna for both AM and FM. Thanks again...Pete Yes, it is a mystery still.... Your body is a conductor, admittedly a very poor one, but the power levels we are talking about, and the currents involved don't ask very much. The wavelengths involved for FM are about your height. If we shift to AM, you would have to be the Jolly Green Giant (hence hand waving usually doesn't do much good). That you don't even have to touch the antenna is also an indication in the small power necessary, it is more about your height and proximity. Multi wire, such as you have, will make little difference. However, this is not to say that things won't remain marginal. You do have the experience with another radio that works in the identical environment, so that suggests some hope. There are "magic" lengths of wire, but you can escape that discussion by crafting various different lengths by bending, trimming, but still keeping things high (all of this is predicated on putting the antenna into the sight of the transmitter). The same antenna is NOT for both bands. The AM antenna is undoubtedly the old stand by we call the loopstick. This is a long rod of ferrite material with a coil or wrapping of wire - you've probably seen these before. A car antenna certainly does double duty, but this is not generally found in portable radios. This is because the car radio sits inside a metal cage that demands an external sky hook. 73's Richard Clark, KB7QHC |
#6
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Richard Clark wrote:
On Tue, 3 Apr 2007 23:06:19 -0400, "Pete" wrote: Thank you Richard...that is the kind of comment I was looking for (I took Neil's with a grain of salt-there is absolutely nothing wrong with the radio). I was trying to be polite in my post, but I am way smarter than that. Hi Pete, No, it is still advice to consider. Your new radio does have the performance of a lemon in comparison to your old set. Hi Richard...Make sure to read Michael Black's interesting info in this thread. I definitely believe the radio (cheap as it may be) is doing exactly what it is designed to do. I do not believe it is a lemon, and there is no doubt in my mind the older Panasonic has better circuitry in it (it is a better set and has a graphic equalizer also - the newer one doesn't even have bass/treble controls but it sounds good), but they are roughly comparable. Actually, the old one probably costs quite a bit more (on a relative basis) considering how cheap you can buy this stuff these days compared to the price twenty years ago. Just for your info, I have an old Electrovoice stereo receiver downstairs (with dials/knobs) and it still works fine after 36 years. Also FYI, I have a new Sherwood stereo receiver upstairs (with the fm antenna that came with it installed), and it also picks up the station I am talking about weaker than the other stations, but I was able to tweak the antenna and it comes in acceptable. It is interesting that the old Panasonic boombox has no trouble. Sorry if I am going off on a tangent. I have more comments below :-) ....Pete I will try wrapping the wire around the antenna tomorrow and let you know what happens (is it okay to use phone wire which has several individually insulated wires in it). BTW could you please tell me why the reception comes in when I put my hand around the antenna (ie what is my body doing to the signal), and also answer my second question about one antenna for both AM and FM. Thanks again...Pete Yes, it is a mystery still.... Your body is a conductor, admittedly a very poor one, but the power levels we are talking about, and the currents involved don't ask very much. The wavelengths involved for FM are about your height. If we shift to AM, you would have to be the Jolly Green Giant (hence hand waving usually doesn't do much good). That you don't even have to touch the antenna is also an indication in the small power necessary, it is more about your height and proximity. Multi wire, such as you have, will make little difference. However, this is not to say that things won't remain marginal. You do have the experience with another radio that works in the identical environment, so that suggests some hope. There are "magic" lengths of wire, but you can escape that discussion by crafting various different lengths by bending, trimming, but still keeping things high (all of this is predicated on putting the antenna into the sight of the transmitter). The same antenna is NOT for both bands. The AM antenna is undoubtedly the old stand by we call the loopstick. This is a long rod of ferrite material with a coil or wrapping of wire - you've probably seen these before. A car antenna certainly does double duty, but this is not generally found in portable radios. This is because the car radio sits inside a metal cage that demands an external sky hook. 73's Richard Clark, KB7QHC Thanks again Richard for all the good info. I kind of knew about the loopstick stuff but just wanted to make sure. You guys have been great...Pete |
#7
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Pete,
The real difference between antennas and receiving FM stations versus AM stations has nothing to do with the modulation, but with the frequency on which these signals are transmitted. For optimal reception, you need an antenna that corresponds to the wavelength of the transmitted station. For AM radios, that is usually a real long length of wire wrapped around a magnetic rod within the radio. For FM, it is usually a telescoping whip antenna. If you find yourself with two radios that are similarly-equipped in terms of antennas, but one gets your favorite stations while the other does not, then the one that does not is either broken or has designed-in lousy sensitivity. How can you compensate for lousy sensitivity? If the low-sensitivity radio is _close_ to working (evidenced by its being able to hear your favorite station by putting your hand near the antenna) then you may be able to substitute a slighter better, directional antenna for the telescopic whip and get the stations you want. A cheap-and-dirty experiment would be to purchase a Radio Shack "Dipole FM Antenna [$3.00] and connect one lead to the whip (fully collapsed) and the other lead to a nearby ground connection in your workshop (center pin of a 3-prong electric outlet). Elevate the antenna as high as possible, and stretch the "T" sections horizontally. The best signal reception will be from the sides of the "T" -- so if you know the location of your favorite station's transmitter, you can rotate the ends of the T for best signal capture. THEN AGAIN... you may just want to take it back to Wal-Mart for an exchange. Experiment with the available radios by collapsing the whip antennas and seeing which one gets the most stations and has the least "buzz" from the store's fluorescent lights. -larry K8UT "Pete" wrote in message ... Hi everyone, I am new here, so please excuse my ignorance about antennas, or if I am in the wrong ng. I could not find any help getting the answer to my question by googling. I have a cheap boom box radio that I recently bought at Walmart and it plays great music, and cd's, and cassettes. Unfortunately it will not play my favorite FM oldies station (97.5 MHz) either in my workshop, or my house (it plays several other stations fine). My other boom box will play the station (and its 20 years old), and they are both of relatively equal value (the older one is a brand name - Panasonic). If anything, I would think the new one should have 20 year newer technology in it, and it should play at least as good - dunno. They both have a telescopic whip antenna (I hope that is the right terminology), and the new one will not play the station I want by either rotating the antenna, or moving the radio to different positions. I have tried everything. The only way it will play the station I want, is to put my hand on the antenna (or even around the antenna - ie I don't even have to touch it - interesting - I guess my body makes a real good antenna - I have always wondered about this phenomena). I tried touching it with other metallic devices (eg, wire, coat hanger etc), and it has no effect. The only way it will play the station is by getting near the antenna with my hand. I see no way of mounting an FM antenna to the receiver (ie the antenna is factory mounted to the back of the radio. I have a couple of questions if you will allow me : - Is there anything I can do to the existing telescopic whip antenna (such as wrap it in aluminum foil or something else weird like that) that will enable the radio to pick up the station I want. And also, please explain why it plays the station I want when I put my hand on or around the antenna. - I thought AM and FM antennas were different technologies (so to speak - eg amplitude modulation versus frequency modulation). How come portable AM/FM radios only have a single telescopic whip antenna (please excuse me if that is the wrong terminology). Is the whip for FM, and the AM is inside the radio, or it uses the cord (just a guess). Any comments would be greatly appreciated. Thanks...Pete |
#8
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Thanks Larry...You top posted, so I will to. I really am a technical person
and know a little bit about this stuff, and there is no doubt that the tuner/antenna circuitry in the older Panasonic is more sensitive (ie better). I will try Richards comments and let you guys know what happens. And if that doesn't help than maybe I will try your suggestion. Thanks for taking the time to comment. Have you ever been to Walmarts. You are lucky if you are able to plug anything in. Believe it or not I did plug the display of the one I bought in. Most of them are all a mess and you can't plug anything in :-) . Pete Larry Gauthier (K8UT) wrote: Pete, The real difference between antennas and receiving FM stations versus AM stations has nothing to do with the modulation, but with the frequency on which these signals are transmitted. For optimal reception, you need an antenna that corresponds to the wavelength of the transmitted station. For AM radios, that is usually a real long length of wire wrapped around a magnetic rod within the radio. For FM, it is usually a telescoping whip antenna. If you find yourself with two radios that are similarly-equipped in terms of antennas, but one gets your favorite stations while the other does not, then the one that does not is either broken or has designed-in lousy sensitivity. How can you compensate for lousy sensitivity? If the low-sensitivity radio is _close_ to working (evidenced by its being able to hear your favorite station by putting your hand near the antenna) then you may be able to substitute a slighter better, directional antenna for the telescopic whip and get the stations you want. A cheap-and-dirty experiment would be to purchase a Radio Shack "Dipole FM Antenna [$3.00] and connect one lead to the whip (fully collapsed) and the other lead to a nearby ground connection in your workshop (center pin of a 3-prong electric outlet). Elevate the antenna as high as possible, and stretch the "T" sections horizontally. The best signal reception will be from the sides of the "T" -- so if you know the location of your favorite station's transmitter, you can rotate the ends of the T for best signal capture. THEN AGAIN... you may just want to take it back to Wal-Mart for an exchange. Experiment with the available radios by collapsing the whip antennas and seeing which one gets the most stations and has the least "buzz" from the store's fluorescent lights. -larry K8UT "Pete" wrote in message ... Hi everyone, I am new here, so please excuse my ignorance about antennas, or if I am in the wrong ng. I could not find any help getting the answer to my question by googling. I have a cheap boom box radio that I recently bought at Walmart and it plays great music, and cd's, and cassettes. Unfortunately it will not play my favorite FM oldies station (97.5 MHz) either in my workshop, or my house (it plays several other stations fine). My other boom box will play the station (and its 20 years old), and they are both of relatively equal value (the older one is a brand name - Panasonic). If anything, I would think the new one should have 20 year newer technology in it, and it should play at least as good - dunno. They both have a telescopic whip antenna (I hope that is the right terminology), and the new one will not play the station I want by either rotating the antenna, or moving the radio to different positions. I have tried everything. The only way it will play the station I want, is to put my hand on the antenna (or even around the antenna - ie I don't even have to touch it - interesting - I guess my body makes a real good antenna - I have always wondered about this phenomena). I tried touching it with other metallic devices (eg, wire, coat hanger etc), and it has no effect. The only way it will play the station is by getting near the antenna with my hand. I see no way of mounting an FM antenna to the receiver (ie the antenna is factory mounted to the back of the radio. I have a couple of questions if you will allow me : - Is there anything I can do to the existing telescopic whip antenna (such as wrap it in aluminum foil or something else weird like that) that will enable the radio to pick up the station I want. And also, please explain why it plays the station I want when I put my hand on or around the antenna. - I thought AM and FM antennas were different technologies (so to speak - eg amplitude modulation versus frequency modulation). How come portable AM/FM radios only have a single telescopic whip antenna (please excuse me if that is the wrong terminology). Is the whip for FM, and the AM is inside the radio, or it uses the cord (just a guess). Any comments would be greatly appreciated. Thanks...Pete |
#9
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"Larry Gauthier \" ) writes:
If you find yourself with two radios that are similarly-equipped in terms of antennas, but one gets your favorite stations while the other does not, then the one that does not is either broken or has designed-in lousy sensitivity. Actually, it might be the reverse, depending on what exactly is happening. I have a all in one stereo I got at a garage sale. It had lousy reception of a non-local station that is always receivable here on other radios, even lousy ones. I naturally thought the antenna was the problem. But I did something and realized I likely was attenuating the signal, and the issue wasn't "not enough antenna" but too much. I took off the whip antenna, and that thing gets perfect reception on that non-local station, whereas before it was noisy. Clearly, the stereo was being overloaded by local signals, which impacted on it's ability to receive the strong but comparatively weaker non-local station. Removing the antenna attenuated the local station(s) enough that the stereo didn't overload, but the non-local station was still strong enough to be received fine. Most consumer broadcast receivers are too sensitive if anything, because they don't handle strong signals that well, yet the strong signals overloading them make them useless for receiving distant signals. A less sensitive receiver wouldn't be as good for distant reception, but the local signals wouldn't mask those distant signals with overload. I don't know if this is the case here, but it is worth looking into since it's the last thing people generally expect. I notice when I got a Grundig portable sw receiver at a rummage sale in September, the manual specifically states to keep the whip antenna shorter when on the FM broadcast band (the antenna being longer for the shortwave bands), and having been prompted by the manual and experience, I do notice that not so great reception on the FM band is improved when I shorten the whip antenna. Michael VE2BVW |
#10
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Michael Black wrote:
"Larry Gauthier \" ) writes: If you find yourself with two radios that are similarly-equipped in terms of antennas, but one gets your favorite stations while the other does not, then the one that does not is either broken or has designed-in lousy sensitivity. Actually, it might be the reverse, depending on what exactly is happening. I have a all in one stereo I got at a garage sale. It had lousy reception of a non-local station that is always receivable here on other radios, even lousy ones. I naturally thought the antenna was the problem. But I did something and realized I likely was attenuating the signal, and the issue wasn't "not enough antenna" but too much. I took off the whip antenna, and that thing gets perfect reception on that non-local station, whereas before it was noisy. Clearly, the stereo was being overloaded by local signals, which impacted on it's ability to receive the strong but comparatively weaker non-local station. Removing the antenna attenuated the local station(s) enough that the stereo didn't overload, but the non-local station was still strong enough to be received fine. Most consumer broadcast receivers are too sensitive if anything, because they don't handle strong signals that well, yet the strong signals overloading them make them useless for receiving distant signals. A less sensitive receiver wouldn't be as good for distant reception, but the local signals wouldn't mask those distant signals with overload. I don't know if this is the case here, but it is worth looking into since it's the last thing people generally expect. I notice when I got a Grundig portable sw receiver at a rummage sale in September, the manual specifically states to keep the whip antenna shorter when on the FM broadcast band (the antenna being longer for the shortwave bands), and having been prompted by the manual and experience, I do notice that not so great reception on the FM band is improved when I shorten the whip antenna. Michael VE2BVW Thanks a lot for the great info Michael...I love technical stuff, and I find your comments very interesting. You guys have been very helpful. Thanks again to all of you...Pete |
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