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#11
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A Beginners Question
Frank I live in a marginal FM area and since I have a Redsun RP2100 I
have no trouble at all getting far distant stations. My other portables and my stereo won't receive them at all. You got good advice for a CC Radio SW, and there is also the cheaper Kaito KA2100, all of which are the same as the Redsun RP2100. A superb performer on FM. See: http://www.universal-radio.com/catal...able/2100.html Universal also do a range of FM antenna's, but I don't have any experience with those. Have a look at: http://www.universal-radio.com/catalog/mwant.html You need to see that the connectors on these devices match the FM radio you have in mind. Good reception John Plimmer, Montagu, Western Cape Province, South Africa South 33 d 47 m 32 s, East 20 d 07 m 32 s RX Icom IC-756 PRO III with MW mods Drake SW8 & ERGO software Sony 7600D, GE SRIII, Redsun RP2100 BW XCR 30, Sangean 803A. Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270 Kiwa MW Loop, PAORDT Roelof mini-whip http://www.dxing.info/about/dxers/plimmer.dx On Dec 5, 1:36 am, "Frank103" wrote: I would like to buy a portable shortwave radio with a whip antenna but I've been holding back because I live in an area that gets mediocre reception on my Sony reciever's FM tuner from stations 20 miles away; so I'm really paranoid about buying a portable shortwave radio. My homeowners association doesn't permit outside antennas. Here are several questions: 1. Can someone recommend a portable shortwave radio for under $200US that works well.? 2. Can I attach an indoor antenna to improve reception? What brand of antenna? 3. I've tried several indoor antennas from Radio Shack to improve my FM reception and none did anything. Can someone recommend a really powerful FM indoor antenna? Thanks in advance. Frank |
#12
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A Beginners Question
On Dec 7, 10:08 am, wrote:
Frank I live in a marginal FM area and since I have a Redsun RP2100 I have no trouble at all getting far distant stations. My other portables and my stereo won't receive them at all. You got good advice for a CC Radio SW, and there is also the cheaper Kaito KA2100, all of which are the same as the Redsun RP2100. A superb performer on FM. See:http://www.universal-radio.com/catal...able/2100.html Universal also do a range of FM antenna's, but I don't have any experience with those. Have a look at:http://www.universal-radio.com/catalog/mwant.html You need to see that the connectors on these devices match the FM radio you have in mind. Good reception John Plimmer, Montagu, Western Cape Province, South Africa South 33 d 47 m 32 s, East 20 d 07 m 32 s RX Icom IC-756 PRO III with MW mods Drake SW8 & ERGO software Sony 7600D, GE SRIII, Redsun RP2100 BW XCR 30, Sangean 803A. Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270 Kiwa MW Loop, PAORDT Roelof mini-whiphttp://www.dxing.info/about/dxers/plimmer.dx On Dec 5, 1:36 am, "Frank103" wrote: I would like to buy a portable shortwave radio with a whip antenna but I've been holding back because I live in an area that gets mediocre reception on my Sony reciever's FM tuner from stations 20 miles away; so I'm really paranoid about buying a portable shortwave radio. My homeowners association doesn't permit outside antennas. Here are several questions: 1. Can someone recommend a portable shortwave radio for under $200US that works well.? 2. Can I attach an indoor antenna to improve reception? What brand of antenna? 3. I've tried several indoor antennas from Radio Shack to improve my FM reception and none did anything. Can someone recommend a really powerful FM indoor antenna? Thanks in advance. Frank- Hide quoted text - - Show quoted text - HeartLandAmerica.Com has the "Silicon Scientific" Multi-Band Digital AM/FM Shortwave Radio RP2000 'On-Sale-For' $49 http://www.hlaimages2.com/prod_images/500/75498.jpg http://www.heartlandamerica.com/brow...adio&PIN=54168 IMHO - This 'appears-to-be' a Redsun RP2100 Radio that has been Re-Branded with the "Silicon Scientific" Name. ~ RHF |
#13
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A Beginners Question
In article EBJ5j.5593$gi7.4456@trnddc04,
"Dale Parfitt" wrote: "Telamon" wrote in message ... In article KCy5j.2781$md.534@trnddc06, "Dale Parfitt" wrote: Yes, for shortwave a 10-20 foot piece of wire can be used. You do not need to spend a lot of money to get started. If noise is an issue, google for 'shielded loop antenna'. You can also buy more expensive antennas. Try, http://www.universal-radio.com/catalog/sw_ant.html Why would a shielded loop receive less noise than, say, a classic wire turn loop? Shielded loops are less sensitive to local inductive E fields. I thought there was enough math/data out there that no one any longer believed this. From the W8JI page- http://www.w8ji.com/magnetic_receiving_loops.htm "Folklore claims a small "shielded" loop antenna behaves like a sieve, sorting "good magnetic signals" from "bad electrical noise". Nothing is further from the truth! At relatively small distances a small magnetic loop is more sensitive to electric fields than a small electric field probe. I would not be quoting some hamıs web site as an authority on electromagnetic theory or folklore. There is a lot of bad information on the net. The areas of electronics and electromagnetism are easy to misunderstand. Part of the problem is that it is also easy to leave questions more open ended than intended and so the answers tend to be ambiguous. So now, I'll be more specific. Maybe it will help. Small loops that have a shield that is split half way around are only sensitive to magnetic fields. The split half way around ensures the E field is canceled for far field and it works pretty well for near inductive fields. I have used this type of probe along with small E field probes in EMI and RFI work so I know they operate as they were designed or I would not have been able to solve problems. Another situation occurs when the shield is not split evenly around the loop and grounded on one end. Here the outer shield picks up the E field and the shielded wire picks up the M field and this configuration will generate about two times the signal the center split shielded loop will generate. So it depends on a number of parameters not least of which is physical size and electrical size for the application. -- Telamon Ventura, California |
#14
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A Beginners Question
I would not be quoting some hamıs web site as an authority on electromagnetic theory or folklore. You might want to Google Tom W8JI and find out who he is. To describe one of the U.S.'s brighter engineers and designers as "some ham" is a real disservice. The fact that he happens to have a ham license is purely a coincidence. His explaination of how the shielded loop functions is embraced by the IEEE group on Electromagnetics and Propagation, Roy Lewellen (writer of EZNEC software) et al. W4OP |
#15
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A Beginners Question
In article ZRm6j.366$3s1.152@trnddc06,
"Dale Parfitt" wrote: I would not be quoting some hamıs web site as an authority on electromagnetic theory or folklore. You might want to Google Tom W8JI and find out who he is. To describe one of the U.S.'s brighter engineers and designers as "some ham" is a real disservice. The fact that he happens to have a ham license is purely a coincidence. His explaination of how the shielded loop functions is embraced by the IEEE group on Electromagnetics and Propagation, Roy Lewellen (writer of EZNEC software) et al. I don't care who Tom and Roy Lewellen are supposed to be. Credentials don't impress me. It's likely either they stated something incorrect or you misunderstood them. You asked a question and I answered it correctly. If you don't like the answer go take it up with those two. And by the way you will be glad to know I'm much more important than the two of them together and yet I take the time to answer your questions. I'm such a nice guy despite being the most important person you will ever deal with. Oh yeah, and your welcome Dale. -- Telamon Ventura, California |
#16
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A Beginners Question
Thanks to all those who replied. I think CCrane - SW is what I'm looking
for. Will also try the Terk Pro. Thanks again. Frank "Frank103" wrote in message news I would like to buy a portable shortwave radio with a whip antenna but I've been holding back because I live in an area that gets mediocre reception on my Sony reciever's FM tuner from stations 20 miles away; so I'm really paranoid about buying a portable shortwave radio. My homeowners association doesn't permit outside antennas. Here are several questions: 1. Can someone recommend a portable shortwave radio for under $200US that works well.? 2. Can I attach an indoor antenna to improve reception? What brand of antenna? 3. I've tried several indoor antennas from Radio Shack to improve my FM reception and none did anything. Can someone recommend a really powerful FM indoor antenna? Thanks in advance. Frank |
#17
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A Beginners Question
On Dec 7, 8:57 pm, "Dale Parfitt" wrote:
I would not be quoting some hamıs web site as an authority on electromagnetic theory or folklore. You might want to Google Tom W8JI and find out who he is. To describe one of the U.S.'s brighter engineers and designers as "some ham" is a real disservice. The fact that he happens to have a ham license is purely a coincidence. His explaination of how the shielded loop functions is embraced by the IEEE group on Electromagnetics and Propagation, Roy Lewellen (writer of EZNEC software) et al. W4OP W8JI's view, as I understand it, is that small shielded loops are no less susceptible to local noise in virtue of their shielding, since the shield, in his view, is part of the antenna. It's probably worth pointing out that, even if this is true, it is still consistent with the view that small loops pick up less noise than other types of antennas in virtue of their directional characteristics. I guess W8JI would then maintain that a shielded loop would be no less susceptible to local noise than an unshielded loop, since in this case both antennas enjoy the benefits of directionality; but he isn't commited to denying that loops are quieter than, say whips when all things are considered. Is this correct or am I missing something here? |
#18
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A Beginners Question
W8JI's view, as I understand it, is that small shielded loops are no
less susceptible to local noise in virtue of their shielding, since the shield, in his view, is part of the antenna. It's probably worth pointing out that, even if this is true, it is still consistent with the view that small loops pick up less noise than other types of antennas in virtue of their directional characteristics. I guess W8JI would then maintain that a shielded loop would be no less susceptible to local noise than an unshielded loop, since in this case both antennas enjoy the benefits of directionality; but he isn't commited to denying that loops are quieter than, say whips when all things are considered. Is this correct or am I missing something here? Correct. Here it is from VE7SL perhaps more concisely: Please note that a 'shielded loop' will not do anything to improve local noise problems that any other type of loop (such as a multi-turn air core loop) might do. Don't confuse the 'shielded' nomenclature with 'noise shielding' as this is not the case. Like any other type of loop, it can be used to null nearby noise sources or signals or turned to enhance desired directions. The shielded loop might more properly be called a 'two-turn' loop or a 'close coupled' loop as this more accurately describes it's behaviour. In actual operation, it is the shield itself that is the active antenna element. Signals picked up by the shield are coupled into the inner conductor, which in turn are coupled back to the receiver via the preamp. The loop is capable of good nulls on both groundwave and skywave signals. The more 'balanced' the loop is (gap placed at exact center), the more balanced the nulls will be. |
#19
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A Beginners Question
In article CoC6j.3689$581.3625@trnddc04,
"Dale Parfitt" wrote: W8JI's view, as I understand it, is that small shielded loops are no less susceptible to local noise in virtue of their shielding, since the shield, in his view, is part of the antenna. It's probably worth pointing out that, even if this is true, it is still consistent with the view that small loops pick up less noise than other types of antennas in virtue of their directional characteristics. I guess W8JI would then maintain that a shielded loop would be no less susceptible to local noise than an unshielded loop, since in this case both antennas enjoy the benefits of directionality; but he isn't commited to denying that loops are quieter than, say whips when all things are considered. Is this correct or am I missing something here? Correct. Here it is from VE7SL perhaps more concisely: Please note that a 'shielded loop' will not do anything to improve local noise problems that any other type of loop (such as a multi-turn air core loop) might do. Don't confuse the 'shielded' nomenclature with 'noise shielding' as this is not the case. Like any other type of loop, it can be used to null nearby noise sources or signals or turned to enhance desired directions. The shielded loop might more properly be called a 'two-turn' loop or a 'close coupled' loop as this more accurately describes it's behaviour. In actual operation, it is the shield itself that is the active antenna element. Signals picked up by the shield are coupled into the inner conductor, which in turn are coupled back to the receiver via the preamp. The loop is capable of good nulls on both groundwave and skywave signals. The more 'balanced' the loop is (gap placed at exact center), the more balanced the nulls will be. This is wrong. I already explained why. Go back and read the part of my post you cut out of the thread. You are being to general in the description of shielded. -- Telamon Ventura, California |
#20
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A Beginners Question
In article
, Steve wrote: On Dec 7, 8:57 pm, "Dale Parfitt" wrote: I would not be quoting some hamıs web site as an authority on electromagnetic theory or folklore. You might want to Google Tom W8JI and find out who he is. To describe one of the U.S.'s brighter engineers and designers as "some ham" is a real disservice. The fact that he happens to have a ham license is purely a coincidence. His explaination of how the shielded loop functions is embraced by the IEEE group on Electromagnetics and Propagation, Roy Lewellen (writer of EZNEC software) et al. W4OP W8JI's view, as I understand it, is that small shielded loops are no less susceptible to local noise in virtue of their shielding, since the shield, in his view, is part of the antenna. It's probably worth pointing out that, even if this is true, it is still consistent with the view that small loops pick up less noise than other types of antennas in virtue of their directional characteristics. I guess W8JI would then maintain that a shielded loop would be no less susceptible to local noise than an unshielded loop, since in this case both antennas enjoy the benefits of directionality; but he isn't commited to denying that loops are quieter than, say whips when all things are considered. Is this correct or am I missing something here? This is wrong. I already explained why. Go back and read the part of my post Dale cut out of the thread. -- Telamon Ventura, California |
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