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Is FM performance on modern PLL radios "rap" with a capital "C"?
http://www.home.earthlink.net/%7Esrw...rundig-100.htm
"FM? Whazzat? After 25+ years in that business, we no longer listen to any FM broadcasting. Why; when we have 9,000 classical CDs, an eight-foot grand piano, a Yamaha Clavinova, and a harpsichord?! In order to be useful to readers who might, however, want to know about the FM performance, we did tune to the band and TRY to pick up a station. Surely the only one we would ever want to hear, from our home in San Jose, would be classical KDFC, 102.1, in San Francisco. It was absolutely unreceivable. Ditto via the Radio Shack DX-397; and there is almost no trace of it either using the Sony 7600GR. But a late-60's Grundig Music-Boy germanium transistor radio (original manual at left) picks it up quite clearly! This shows the sad deterioration of FM radio design over the decades; the old discrete-component radio, with excellent selectivity, could pull KDFC out of the hiss and mush; the new ones, with their short whip aerials and IC cookbook designs, just did not have the power and discrimination." I'm wanting a pockety sized PLL radio that will, on FM performance, actually equal, at least an, old Grundig radio for sensitivity, cross-modulation and image rejection! |
This web site lists some of the best portable fm receivers:
http://www.geocities.com/toddemslie/...sedbydxers.htm I have found the best fm stereo dx setup to be a combination of a small rooftop antenna with rotor and a stand alone FM tuner like the Denon TU1500. http://www.radioshack.com/product.as...t%5Fid=15-2163 http://www.fmsystems.net/sp_tu1500.htm Jim On Wed, 31 Dec 2003 18:07:15 -0000, "Richard" wrote: http://www.home.earthlink.net/%7Esrw...rundig-100.htm "FM? Whazzat? After 25+ years in that business, we no longer listen to any FM broadcasting. Why; when we have 9,000 classical CDs, an eight-foot grand piano, a Yamaha Clavinova, and a harpsichord?! In order to be useful to readers who might, however, want to know about the FM performance, we did tune to the band and TRY to pick up a station. Surely the only one we would ever want to hear, from our home in San Jose, would be classical KDFC, 102.1, in San Francisco. It was absolutely unreceivable. Ditto via the Radio Shack DX-397; and there is almost no trace of it either using the Sony 7600GR. But a late-60's Grundig Music-Boy germanium transistor radio (original manual at left) picks it up quite clearly! This shows the sad deterioration of FM radio design over the decades; the old discrete-component radio, with excellent selectivity, could pull KDFC out of the hiss and mush; the new ones, with their short whip aerials and IC cookbook designs, just did not have the power and discrimination." I'm wanting a pockety sized PLL radio that will, on FM performance, actually equal, at least an, old Grundig radio for sensitivity, cross-modulation and image rejection! |
"Richard" wrote in message ... http://www.home.earthlink.net/%7Esrw...rundig-100.htm Holy Moly!! Two images on a single conversion radio!!! I'd ask Major Armstrong what's happening here, but he checked out before I checked in and my old pal, Fred Terman, has been quite silent over the last couple of decades, or so. Is there a mathmetical formula for this image frequency stuff? Please tell me how this happens, oh wise one! "By now, we had also acquired a Grundig FR-200 "crank" radio, which has the typical problems of other single-conversion Grundigs we've tested, such as the Model 350: noticeable and very irritating images on the broadcast and SW bands, 910 kHz above or below the proper station frequency. This means, for example, no less than THREE instances of "WWV, 10 MHz": one below, one on, and one above the correct frequency. And stations that are very strong cause hetrodynes when their images land right on top of one you want to tune in." Frank "Trailer Park" Dresser |
"R.F. Collins" wrote in message ... This web site lists some of the best portable fm receivers: http://www.geocities.com/toddemslie/...sedbydxers.htm I have found the best fm stereo dx setup to be a combination of a small rooftop antenna with rotor and a stand alone FM tuner like the Denon TU1500. http://www.radioshack.com/product.as...t%5Fid=15-2163 http://www.fmsystems.net/sp_tu1500.htm Jim I should have put portable in the subject header! I'm also thinking in terms of the worldband portable as well! What resonated with me, is the idea that FM performance of many of your PLL portables, worldband or not, cannot even match a late 1960's Grundig. |
This is a common problem with single conversion. If your front end is
too sensitive as on some Grundigs, you can overload the IF and get a mixing product generated at 2 x IF frequency (455kHz) = 910 kHz. This gives you the image at 910kHz above and below the actual frequency. This is why more expensive radios are dual and triple conversion. Jim On Wed, 31 Dec 2003 19:38:56 GMT, "Frank Dresser" wrote: "Richard" wrote in message ... http://www.home.earthlink.net/%7Esrw...rundig-100.htm Holy Moly!! Two images on a single conversion radio!!! I'd ask Major Armstrong what's happening here, but he checked out before I checked in and my old pal, Fred Terman, has been quite silent over the last couple of decades, or so. Is there a mathmetical formula for this image frequency stuff? Please tell me how this happens, oh wise one! "By now, we had also acquired a Grundig FR-200 "crank" radio, which has the typical problems of other single-conversion Grundigs we've tested, such as the Model 350: noticeable and very irritating images on the broadcast and SW bands, 910 kHz above or below the proper station frequency. This means, for example, no less than THREE instances of "WWV, 10 MHz": one below, one on, and one above the correct frequency. And stations that are very strong cause hetrodynes when their images land right on top of one you want to tune in." Frank "Trailer Park" Dresser |
If you scroll down on the first link, there is a section on portables.
The Panasonic is no longer made. The Yacht Boy 400 is still in production and the Satellit 700 is now the 800 but these should give you idea as to who manufactures the best FM portable. Jim On Wed, 31 Dec 2003 20:54:23 -0000, "Richard" wrote: "R.F. Collins" wrote in message .. . This web site lists some of the best portable fm receivers: http://www.geocities.com/toddemslie/...sedbydxers.htm I have found the best fm stereo dx setup to be a combination of a small rooftop antenna with rotor and a stand alone FM tuner like the Denon TU1500. http://www.radioshack.com/product.as...t%5Fid=15-2163 http://www.fmsystems.net/sp_tu1500.htm Jim I should have put portable in the subject header! I'm also thinking in terms of the worldband portable as well! What resonated with me, is the idea that FM performance of many of your PLL portables, worldband or not, cannot even match a late 1960's Grundig. |
"Richard" wrote in message
... http://www.home.earthlink.net/%7Esrw...rundig-100.htm "FM? Whazzat? snipped I found FM performance to be excellent from my old Grundig Satellit 1400 (c.1983). Got many a continental European from up here in Scotland, during Sporadic 'E' lifts in the summer. -- Ian Smith, Renfrew, Scotland. 55.868733°N 4.399517°W, 7m asl |
R.F. Collins wrote:
If you scroll down on the first link, there is a section on portables. The Panasonic is no longer made. The Yacht Boy 400 is still in production and the Satellit 700 is now the 800 but these should give you idea as to who manufactures the best FM portable. Jim Are you trying to say there's some connection between the Satellit 700 and the 800, or just that the 800 is a good FM DX portable, in the same league as the 700? The radios are of course unrelated. I don't know anything about the 800 except what I read on the net, and I don't recall having read anything extreme one way or the other about its performance on FM, but the 700 is one great FM radio. |
"Ian Smith" wrote in message ... "Richard" wrote in message ... http://www.home.earthlink.net/%7Esrw...rundig-100.htm "FM? Whazzat? snipped I found FM performance to be excellent from my old Grundig Satellit 1400 (c.1983). Got many a continental European from up here in Scotland, during Sporadic 'E' lifts in the summer. -- Ian Smith, Renfrew, Scotland. 55.868733°N 4.399517°W, 7m asl Yep. Reading some comments about the Sony ICFM33RDS, and the bit I text I quoted to start the thread, I've somehow got the impression that many modern portable PL sets are "rap" with a capital "C"on FM. Radio Shack DX-397 and the Sony 7600GR quoted as not being that good. Not sure how expensive these radios are, but, the ICFM33RDS is only£35, so maybe poorish FM performance is to be expected for this set. If I pay say £80 or £100 for a PLL radio, maybe FM performance would get to as good as the old Grundig. I don't want the RX to be deaf on FM, or have images from localstations all over the band. I wonder then if I need double conversion on FM.I bet ICFM33RDS is not double. Thats actually just a two band RX. I probably should spend a bit more and go for worldband. I vacillate between worldband and not worldband. :c) |
"Larry Ozarow" wrote in message ... R.F. Collins wrote: If you scroll down on the first link, there is a section on portables. The Panasonic is no longer made. The Yacht Boy 400 is still in production and the Satellit 700 is now the 800 but these should give you idea as to who manufactures the best FM portable. Jim Are you trying to say there's some connection between the Satellit 700 and the 800, or just that the 800 is a good FM DX portable, in the same league as the 700? The radios are of course unrelated. I don't know anything about the 800 except what I read on the net, and I don't recall having read anything extreme one way or the other about its performance on FM, but the 700 is one great FM radio. I've put narrower IF filters in my Sat 800 and the result is quite impressive on FM. Good sensitivity with the whip antenna, handles a larger antenna well (actually better than most radios I've tried on FM). Definately worth considering for FM DX if you limit yourself to radios actully in production. craigm |
"R.F. Collins" wrote in message ... This is a common problem with single conversion. If your front end is too sensitive as on some Grundigs, you can overload the IF and get a mixing product generated at 2 x IF frequency (455kHz) = 910 kHz. This gives you the image at 910kHz above and below the actual frequency. This is why more expensive radios are dual and triple conversion. Jim Images have nothing to do with overloading. I read the linked web page and it says: "Earlier in the year 2003, we made the mistake of taking seriously some very enthusiastic posts on rec.radio.shortwave -- "the trailer-park shortwave newsgroup" according to one of our acquaintances -- by dim-wits who were overjoyed with a ten-dollar multiband radio with the unexpected brand name "Bell & Howell"" "dim-wits"? "the trailer-park shortwave newsgroup" ? As far as images go, there's only one. The signal mixes with the local oscillator. Either the sum or difference signal is the desired signal. The other signal is the image. There may be other false signals from oscillator harmonics. But these will be totally out of band, even VHF signals. The page's insults and cheap shots on cheap radios continue: http://www.home.earthlink.net/~srw-s...rundig-100.htm It's just one crackpot's opinion, but I find insult humor unimaginative. There's is a another image at the bottom of the page: "by Steve Waldee, retired broadcast consultant, AM-FM transmitter engineer, and audio specialist;" If the original poster is still reading this, I'll suggest the problem with FM DXing has little to do with PLLs and more to do with stereo. It takes a lot more signal to get adaquate quieting with FM stereo. I used to receive a Green Bay public radio station from Chicago with a DX-440 on a semiregular basis. No more, the local stations around 88 - 89 Mhz are broadcasting almost full time now. All the radios on the webpage, aside from the old Grundig, were bottom end in both price and performance. There might be a pattern there. Frank "trailer park" Dresser |
"Richard" wrote in message ...
"Ian Smith" wrote in message ... "Richard" wrote in message ... http://www.home.earthlink.net/%7Esrw...rundig-100.htm "FM? Whazzat? snipped I found FM performance to be excellent from my old Grundig Satellit 1400 (c.1983). Got many a continental European from up here in Scotland, during Sporadic 'E' lifts in the summer. -- Ian Smith, Renfrew, Scotland. 55.868733°N 4.399517°W, 7m asl Yep. Reading some comments about the Sony ICFM33RDS, and the bit I text I quoted to start the thread, I've somehow got the impression that many modern portable PL sets are "rap" with a capital "C"on FM. Radio Shack DX-397 and the Sony 7600GR quoted as not being that good. Not sure how expensive these radios are, but, the ICFM33RDS is only£35, so maybe poorish FM performance is to be expected for this set. If I pay say £80 or £100 for a PLL radio, maybe FM performance would get to as good as the old Grundig. I don't want the RX to be deaf on FM, or have images from localstations all over the band. You've made a classic mistake, that because shortwave receivers carry relatively high price tags, that they then offer superior FM broadcast reception. In the first place, a higher price tag may reflect the limited interest in shortwave. If you have to design something out of the ordinary, it will cost more than an average design. And if fewer people are interested, then you have to recoup the cost by a higher price. But more important, any design concerns will be put into what the radio is intended for, ie shortwave. And for anyone who understands radio design, there is virtually no overlap between what's good for an FM broadcast receiver in the 88 to 108MHz range, and a shortwave receiver. One is for FM reception, the other is for AM reception. One is for wideband signals relative far apart in a part of the spectrum that is at least three times the upper frequency of the other, while the other is for narrow signals with narrow spacing between channels and still at a relatively low frequency. Shortwave and the FM broadcast band are not close together. All of this means that there is very little where the designs overlap. What you are buying is a shortwave radio (and maybe/likely that circuitry is used to tune the AM broadcast band since the frequencies are adjacent and the mode and signal bandwidth would be the same) and an FM broadcast radio in the same box. Traditionally, shortwave radios did not include an FM band, with a few exceptions; it changed as small shortwave receivers from Asian companies became the norm. In other words, the FM BCB section is thrown in as a marketing matter. Since that FM section does nothing for the main selling point of the radio, that shortwave reception, then any money put into that section will take away from the design of the shortwave section. So realistically, one might as well put in as cheap an FM section as possible, since it's just added circuitry, and one can so very easily pick the same sort of circuit that is in any average FM radio. Buying a shortwave radio will not automatically give better FM reception, and depending on specific design, it may be inferior to what you could find elsewhere. Car radios are often good, because they require sensitivity yet also the ability to withstand strong signals. FM reception is a key part of the design, so it gets the attention. I have various digitally tuned Delco car radios around the house, and they are the best FM radios I've ever had. I have no idea of the absolute performance, just that in my passing contact with relatively low end receivers the FM section is great. On FM, the PLL is well designed so I don't get spurious responses. The sensitivity seems good, yet it doesn't overload. It is rare to find a station where it doesn't belong. Selectivity is pretty good. The other day, conditions were great and a non-local station was booming in. It's adjacent to another non-local station but which comes in regular (though it's strength varies). There was no problem that day from adjacent channel interference. FM broadcast receivers intended for good performance will also be good contenders. Note that you have to go for something with a beyond average design. Just as in those shortwave radios, FM (and AM even moreso) are considered not so important in a "hifi" situation, so they put little money into the tuner section. You would have lousy FM radios in consumer equipment twenty and thirty years ago, and you have it today, whether they are digitally tuned or not. Such receivers are intended for local reception (who would be interested in that noisy signal from a bit further out, especially since the ads and traffic reports aren't local?) so weak signal reception is not a concern in the design. And as with a lot of FM receivers, they tend to be too sensitive, but that never becomes useful for weak signal reception because that sensitivity also means a tendency to overload on the local and strong signals. Michael |
In article , Richard says...
http://www.home.earthlink.net/%7Esrw...rundig-100.htm "FM? Whazzat? After 25+ years in that business, we no longer listen to any FM broadcasting. Why; when we have 9,000 classical CDs, an eight-foot grand piano, a Yamaha Clavinova, and a harpsichord?! In order to be useful to readers who might, however, want to know about the FM performance, we did tune to the band and TRY to pick up a station. Surely the only one we would ever want to hear, from our home in San Jose, would be classical KDFC, 102.1, in San Francisco. It was absolutely unreceivable. Ditto via the Radio Shack DX-397; and there is almost no trace of it either using the Sony 7600GR. But a late-60's Grundig Music-Boy germanium transistor radio (original manual at left) picks it up quite clearly! This shows the sad deterioration of FM radio design over the decades; the old discrete-component radio, with excellent selectivity, could pull KDFC out of the hiss and mush; the new ones, with their short whip aerials and IC cookbook designs, just did not have the power and discrimination." Apparently, there are several kinds of FM signals being used. Vertical, horizontal, and circular polarized signals. Don't ask my for a technical explanation. I'm wondering if an FM stations signal type can affect how well you can get the station with a generic FM radio. I'm wanting a pockety sized PLL radio that will, on FM performance, actually equal, at least an, old Grundig radio for sensitivity, cross-modulation and image rejection! I have the same 'want' as you....pocket sized PLL FM that's designed from the get-go as a good FM receiver. I just prefer FM to AM and don't consider myself a DX'er in the traditional sense. I have a Sony ICF 2010, 7600GR, RS DX-396, DX-402, Panasonic RF B300. They all PALE in comparison to my Superadio II for FM performance. Not digital, no PLL, no memory presets but it brings in FM stations that the others can't hear. I guess when all is said and done, a "good" analog radio is hard to beat, especially when it's an older model. Amazingly enough, my BEST FM receiver is an AM/FM/stereo amplifier from Radio Shack that was made in 1985. It picks up the hard to get FM stations WITHOUT AN ANTENNA. Zero...nada...zippo connected to the FM antenna lugs. Before I got my Superadio, I stopped BARELY receiving my favorite FM stations on my 2010. I actually thought the station had gone off the air (I even sent an email to the station asking when they'd return to normal broadcasting...never got a reply). I finally turned on that old Radioshack amp, and the station came in like it was next door. I've taken out of the attic an old car AM/FM/FM stereo cassette digital radio from Panasonic that's at least 25 years old. My plan is to put it on batteries to see how well it works as a desktop. Unfortunately, at 5 pounds (without batteries and speaker), it won't be 'pocket sized'. elfa BTW, I'm also bay area....30 miles north of SF. Just tried your KDFC and got it fairly good on the Sony 2010. Tried it on the Superadio and it boomed right in, crystal clear. Try my favorite SF FM station....KKSF...103.7....light jazz. |
"elfa" wrote in message ... Apparently, there are several kinds of FM signals being used. Vertical, horizontal, and circular polarized signals. Don't ask my for a technical explanation. I'm wondering if an FM stations signal type can affect how well you can get the station with a generic FM radio. Nearly all FM's now use circular polarization for their main antennas. Circular polarization is less efficient, power wise, than a simple dipole, but they do tend to penetrate better into crowded urban areas than either horizontal or vertical polarization. |
In article , Brenda Ann says...
"elfa" wrote in message ... Apparently, there are several kinds of FM signals being used. Vertical, horizontal, and circular polarized signals. Don't ask my for a technical explanation. I'm wondering if an FM stations signal type can affect how well you can get the station with a generic FM radio. Nearly all FM's now use circular polarization for their main antennas. Circular polarization is less efficient, power wise, than a simple dipole, but they do tend to penetrate better into crowded urban areas than either horizontal or vertical polarization. Thanks Brenda Ann.... I know I can rely on you to come up with an explanation that makes sense. elfa |
Michael Black wrote:
You've made a classic mistake, that because shortwave receivers carry relatively high price tags, that they then offer superior FM broadcast reception. In the first place, a higher price tag may reflect the limited interest in shortwave. If you have to design something out of the ordinary, it will cost more than an average design. And if fewer people are interested, then you have to recoup the cost by a higher price. But more important, any design concerns will be put into what the radio is intended for, ie shortwave. And for anyone who understands radio design, there is virtually no overlap between what's good for an FM broadcast receiver in the 88 to 108MHz range, and a shortwave receiver. One is for FM reception, the other is for AM reception. One is for wideband signals relative far apart in a part of the spectrum that is at least three times the upper frequency of the other, while the other is for narrow signals with narrow spacing between channels and still at a relatively low frequency. Shortwave and the FM broadcast band are not close together. All of this means that there is very little where the designs overlap. What you are buying is a shortwave radio (and maybe/likely that circuitry is used to tune the AM broadcast band since the frequencies are adjacent and the mode and signal bandwidth would be the same) and an FM broadcast radio in the same box. Traditionally, shortwave radios did not include an FM band, with a few exceptions; it changed as small shortwave receivers from Asian companies became the norm. In other words, the FM BCB section is thrown in as a marketing matter. Since that FM section does nothing for the main selling point of the radio, that shortwave reception, then any money put into that section will take away from the design of the shortwave section. So realistically, one might as well put in as cheap an FM section as possible, since it's just added circuitry, and one can so very easily pick the same sort of circuit that is in any average FM radio. Buying a shortwave radio will not automatically give better FM reception, and depending on specific design, it may be inferior to what you could find elsewhere. Car radios are often good, because they require sensitivity yet also the ability to withstand strong signals. FM reception is a key part of the design, so it gets the attention. I have various digitally tuned Delco car radios around the house, and they are the best FM radios I've ever had. I have no idea of the absolute performance, just that in my passing contact with relatively low end receivers the FM section is great. On FM, the PLL is well designed so I don't get spurious responses. The sensitivity seems good, yet it doesn't overload. It is rare to find a station where it doesn't belong. Selectivity is pretty good. The other day, conditions were great and a non-local station was booming in. It's adjacent to another non-local station but which comes in regular (though it's strength varies). There was no problem that day from adjacent channel interference. FM broadcast receivers intended for good performance will also be good contenders. Note that you have to go for something with a beyond average design. Just as in those shortwave radios, FM (and AM even moreso) are considered not so important in a "hifi" situation, so they put little money into the tuner section. You would have lousy FM radios in consumer equipment twenty and thirty years ago, and you have it today, whether they are digitally tuned or not. Such receivers are intended for local reception (who would be interested in that noisy signal from a bit further out, especially since the ads and traffic reports aren't local?) so weak signal reception is not a concern in the design. And as with a lot of FM receivers, they tend to be too sensitive, but that never becomes useful for weak signal reception because that sensitivity also means a tendency to overload on the local and strong signals. Michael Points: I think some of the the points you raise are probably applicable to any radio that is not FM only. I do not think I can buy a PLL FM only RX, and besides I'd want AM broadcast band at least, in addition. One would imagine a portable that was just FM and broadcast band (no shortwave) the money would be spent on better FM performance. But, I suspect that in many cases that might not be the case. Not sure whether poor FM perfornance is related to PLL. Maybe not, but generally to use of IC's. Maybe biggest reason that the the ICFM33RDS FM performance at FM might not be that good is because it's an inexpensive set. Maybe. Maybe no modern worldband RX will be that good on FM. Then again maybe some are at least as good as (say) an old Grundig. Perhaps the likely candidates would be FM/Broadcast band ony RX. Or the more expensive worldband. As usual, you get what you pay for. Bottom line for me I guess is that I'd like to feel that if I went ahead an spent say £80 to £100 on a PLL radio, that FM performance would be as good as an old Grundig. Worldband RX or no. Or is it the case that I could spend much more than this and still not get the old Grundig performance. If that was the case, surely that would say something about modern FM design? I could end up with two radios, a FM/Broadcast band RX. Plus a worldband set. That article really does scathe rec.radio,shortwave"!! Ha!! That was just unfortunate, I was not concentrating on that part of the article. Just came with the bit I was interested in.:c) |
"Richard" wrote in message ...
http://www.home.earthlink.net/%7Esrw...rundig-100.htm "FM? Whazzat? After 25+ years in that business, we no longer listen to any FM broadcasting. Why; when we have 9,000 classical CDs, an eight-foot grand piano, a Yamaha Clavinova, and a harpsichord?! In order to be useful to readers who might, however, want to know about the FM performance, we did tune to the band and TRY to pick up a station. Surely the only one we would ever want to hear, from our home in San Jose, would be classical KDFC, 102.1, in San Francisco. It was absolutely unreceivable. Ditto via the Radio Shack DX-397; and there is almost no trace of it either using the Sony 7600GR. But a late-60's Grundig Music-Boy germanium transistor radio (original manual at left) picks it up quite clearly! This shows the sad deterioration of FM radio design over the decades; the old discrete-component radio, with excellent selectivity, could pull KDFC out of the hiss and mush; the new ones, with their short whip aerials and IC cookbook designs, just did not have the power and discrimination." I'm wanting a pockety sized PLL radio that will, on FM performance, actually equal, at least an, old Grundig radio for sensitivity, cross-modulation and image rejection! While it is certainly unfortunate that KDFC is the only classical station left in the SF Bay Area, you overlook (perhaps deliberately?) a few of the root causes of this problem: More stations jammed onto the band as close together as permitted, most of them using higher power than the good old days, and the fact that stereo requires a better signal to get through. You really cannot blame the receivers for this mess. |
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Another effect is from the quality and expertise of the broadcast engineers
for various radio stations. A free-lance radio engineer named Fulgham used to tweak several of the stations in the Jackson, Mississippi area (could be he still does -- I've lost track of him). He was the best I've ever seen. Driving up from the New Orleans area, the difference in audio quality of some the Jackson stations was noticably several notches above the stations I listened to in New Orleans. It would have you thinking "I didn't know my car stereo could sound that good." -- Stinger "elfa" wrote in message ... In article , Brenda Ann says... "elfa" wrote in message ... Apparently, there are several kinds of FM signals being used. Vertical, horizontal, and circular polarized signals. Don't ask my for a technical explanation. I'm wondering if an FM stations signal type can affect how well you can get the station with a generic FM radio. Nearly all FM's now use circular polarization for their main antennas. Circular polarization is less efficient, power wise, than a simple dipole, but they do tend to penetrate better into crowded urban areas than either horizontal or vertical polarization. Thanks Brenda Ann.... I know I can rely on you to come up with an explanation that makes sense. elfa |
"Richard" wrote in message ... Yep. Reading some comments about the Sony ICFM33RDS, and the bit I text I quoted to start the thread, I've somehow got the impression that many modern portable PL sets are "rap" with a capital "C"on FM. Radio Shack DX-397 and the Sony 7600GR quoted as not being that good. Not sure how expensive these radios are, but, the ICFM33RDS is only£35, so maybe poorish FM performance is to be expected for this set. If I pay say £80 or £100 for a PLL radio, maybe FM performance would get to as good as the old Grundig. I don't want the RX to be deaf on FM, or have images from localstations all over the band. My DX 440 is a PLL portable and it's a good FM DXer, although I rarely get to FM DX due to the crowed frequencies here. I was picking up a small station, maybe 5kW or less, almost 200 miles away when conditions were good. Shirt pocket portables have some problems the larger portables don't. Most small portables use the headphone cord as an antenna. The antenna may be off it's ideal length. Stretching the cord out straight makes it a better antenna and a poorer headphone cord. Small portables have to use small batteries, so power consumption becomes an important issue. It's a bit of an oversimplification, but a RF stage which operates a high power is less prone to overloading than a RF stage which operates on minimal power. The power consumption issue becomes more important on radios which use power hungry PLL circuits. So I suppose small PLL radios might starve the RF amp to preserve the batteries. But that's just speculation. I wonder then if I need double conversion on FM.I bet ICFM33RDS is not double. Thats actually just a two band RX. I probably should spend a bit more and go for worldband. I vacillate between worldband and not worldband. :c) The normal 10.7 Mhz IF is OK. You'll get an extra set of images with each conversion. A poorly done double conversion radio is worse than a single conversion radio. You might want to consider radios larger than shirt pocket size. In my expirence, the larger portables are the better performers. Frank Dresser |
"Richard" wrote in message ... [snip] That article really does scathe rec.radio,shortwave"!! Ha!! That was just unfortunate, I was not concentrating on that part of the article. Just came with the bit I was interested in.:c) My mistake, Richard. I was hoping you were the "former broadcast engineer", posting under a false name. I'd really love to have learned more about this undocumented double image superhet effect. And what is the exact number of bargain basement radios a really sharp consumer needs to buy before he realizes that they don't perform as well as expensive older radios. Well, maybe the "former broadcast engineer" will start posting here on rec.radio.trailer_park. Always room for another, well -- you know. Frank Dresser |
Frank Dresser wrote:
You might want to consider radios larger than shirt pocket size. In my expirence, the larger portables are the better performers. Yea true. I've actually got I've got a DX-392, (Roberts RC818) so my focus has been on the shirt/pocket size. And it could be that with pocket-sized radios the chances of getting good FM performance is reduced. Made worse if it's cheap as in cost, like the Sony ICFM33RDS is. One could in theory say then, that generally speaking pocket portables will not have particularly good performance on FM. That is different from saying modern PLL portables generally speaking have not particularly good FM performance. But even if this was true, that PLL portables in general (not pocket) have not good FM performance, it could be price sensitive. And you can probably always find something that does not fit the general case. We are always looking out for these. :c) Or pay the higher price, which may translate to no option but to go for bigger than pocket portable. But, sometimes you really want a pocket portable. I must suss out the right pocket portable in my price range (say up to £80 ($120-ish). Whether I can get good FM performance for this cost I know not yet. If it is true that FM performance is mediocre for modern pocket-sized PLL RX's, then I'll not find what I'm after.Unless I were to find an exception in that price bracket. |
Frank Dresser wrote:
"Richard" wrote in message ... [snip] That article really does scathe rec.radio,shortwave"!! Ha!! That was just unfortunate, I was not concentrating on that part of the article. Just came with the bit I was interested in.:c) My mistake, Richard. I was hoping you were the "former broadcast engineer", posting under a false name. I'd really love to have learned more about this undocumented double image superhet effect. And what is the exact number of bargain basement radios a really sharp consumer needs to buy before he realizes that they don't perform as well as expensive older radios. Well, maybe the "former broadcast engineer" will start posting here on rec.radio.trailer_park. Always room for another, well -- you know. Frank Dresser To be honest, I don't know the details of the sets he claims were not up to a late 1960's Grundig. I got the drift though, rightly or wrongly that todays FM portables (especially pocket?) are pretty poor on FM. Deaf and maybe full of spurious stations in vicinity of local FM channels. Was re-inforced by what I read previously about the Sony ICFM33RDS: http://forum.digitalspy.co.uk/board/t/98752/ds.html ---------------------- "Anybody got one of these personal radios? [Richard: He's talking about a Sony srf 59 personal radio bought for about $30] I've just brought one, and I really don't rate it. I get a 'ghost' radio 4 signal up and down the FM band, and there is a fair amount of hiss with the radio on and the volume right down, the same on both AM and FM so I don't think it's radio interfernce- more likely coming from the internal circuitry? OK so 20 quid isn't a kings ransom, but it is considerably more than a Bush or Alba walkman-which has tape too. I've been a 'fan' of Sony's radios for a while, and this is the first time I've been disappointed by one Anyone else out there happy/disappointed with one? --------------------- [Richard: Kev replies:] my ICF-M33RDS does the same - except in my case it's 96 Trent FM below 96.2, Faza until 97.1 and radio Nottingham from 87 - 103.8 and 107.2FM --------------------- [Richard: Later UNcabled says:] I find that budget Sony radios have too much sensitivity in the FM band, and consequently there is always a certain amount of overloading which causes ghost stations (it's always Radio 1 in my experience), and a station 'pile up' around the 100MHz point. Their AM performance however is usually really good, especially if you live in a city where the signals are clean and strong. --------------------- What strikes me now is that this is all in relation to cheap (cost wise) radios. Have I managed to tar all pocket radios re FM performance with the same brush? Wrongly? I thought not somehow when I read at: http://www.home.earthlink.net/%7Esrw...rundig-100.htm |
Tivoli Model One has the best tough-signal performance of any 3 digit
FM radio I've run across. I can get 3,000 Watt stations 40+ miles away perfectly. http://www.tivoliaudio.com/pM1CLA.htm On Wed, 31 Dec 2003 18:07:15 -0000, "Richard" wrote: I'm wanting a pockety sized PLL radio that will, on FM performance, actually equal, at least an, old Grundig radio for sensitivity, cross-modulation and image rejection! |
"Richard" wrote in message ... Yea true. I've actually got I've got a DX-392, (Roberts RC818) so my focus has been on the shirt/pocket size. And it could be that with pocket-sized radios the chances of getting good FM performance is reduced. Made worse if it's cheap as in cost, like the Sony ICFM33RDS is. One could in theory say then, that generally speaking pocket portables will not have particularly good performance on FM. That is different from saying modern PLL portables generally speaking have not particularly good FM performance. But even if this was true, that PLL portables in general (not pocket) have not good FM performance, it could be price sensitive. And you can probably always find something that does not fit the general case. We are always looking out for these. :c) Or pay the higher price, which may translate to no option but to go for bigger than pocket portable. But, sometimes you really want a pocket portable. I must suss out the right pocket portable in my price range (say up to £80 ($120-ish). Whether I can get good FM performance for this cost I know not yet. If it is true that FM performance is mediocre for modern pocket-sized PLL RX's, then I'll not find what I'm after.Unless I were to find an exception in that price bracket. A good performing small PLL portable may be hard to find. People tend to treat shirt pocket radios as disposable items. I can't offer much advice on buying a good shirt pocket PLL radio, but I have an old Sony Walkman SRF-19W analog AM-FM radio which is at least a decent performer. It suffers from the usual headphone cord/antenna problem, and it would be better with a FM stereo switch. The radio autoswitches back and forth between stereo and mono on weak FM signals. There used to be a few FM mono stations on the low end of the band and the Walkman worked well there. So, I suppose a FM stereo/mono switch would be a clue to the radio's DX ability. Frank Dresser |
Just to encapsulate:
It's either true or false to say: 1 All modern PLL portables are not good FM performers. 2 All modern pocket-sized PLL portables are not good FM performers. 3 All budget pocket-sized PLL portables are not good FM performers. It could be that only 3 is generally true. And if that were to be the case it would be a matter of buying a non-budget pocket portable, worldband or otherwise. If all were true, then I'm stuck!! :c) Because I want a digital PLL. (I'm hoping some one is going to sayonly 3 is true! :c) 3 is probably true in general, but I wondered whether 1 & 2 is true. That's why the subject header says,"Is FM performance on modern PLL radios "rap" with a capital "C"?") |
Richard wrote:
Just to encapsulate: It's either true or false to say: 1 All modern PLL portables are not good FM performers. 2 All modern pocket-sized PLL portables are not good FM performers. 3 All budget pocket-sized PLL portables are not good FM performers. It could be that only 3 is generally true. And if that were to be the case it would be a matter of buying a non-budget pocket portable, worldband or otherwise. If all were true, then I'm stuck!! :c) Because I want a digital PLL. (I'm hoping some one is going to sayonly 3 is true! :c) 3 is probably true in general, but I wondered whether 1 & 2 is true. That's why the subject header says,"Is FM performance on modern PLL radios "rap" with a capital "C"?") BTW, when I say pocket portable I mean small enough to perhaps fit in a pocket, not one made to go in your pocket!! I'm after a radio about 6" x 4" x 1" ish. With telescopic antenna. That's what I have called a pocket portable. |
David wrote:
Tivoli Model One has the best tough-signal performance of any 3 digit FM radio I've run across. I can get 3,000 Watt stations 40+ miles away perfectly. http://www.tivoliaudio.com/pM1CLA.htm On Wed, 31 Dec 2003 18:07:15 -0000, "Richard" wrote: I'm wanting a pockety sized PLL radio that will, on FM performance, actually equal, at least an, old Grundig radio for sensitivity, cross-modulation and image rejection! Great :But not PLL or small portable.:c) |
"Frank Dresser" wrote in message
I read the linked web page and it says: "Earlier in the year 2003, we made the mistake of taking seriously some very enthusiastic posts on rec.radio.shortwave -- "the trailer-park shortwave newsgroup" according to one of our acquaintances -- by dim-wits who were overjoyed with a ten-dollar multiband radio with the unexpected brand name "Bell & Howell"" "dim-wits"? "the trailer-park shortwave newsgroup" ? Who is the *real* dimwit here? You would have to be the original dimwit to really expect a $10 radio to actually be very useful. Good grief...I've never seen one, even the picture, and I know it sucks just from the description. They DO NOT build good shortwave radios and sell them for $10. I have to good sense not to believe otherwise...Mamma didn't raise no "trailer park" fool. The page's insults and cheap shots on cheap radios continue: "clipped from that site"... If someone posts an enthusiastic comment about one particular brand of sw radio or scanner, this is immediately "rebutted" (allegedly) by those who disagree. This is, as I state in my Icom articles, a futile act. Everyone is entitled to the enjoyment of the hobby and to appreciate his or her own radio. By telling an enthusiast that his "radio is bad" or that his or her taste is faulty, nothing positive is accomplished.... OK, let me get this right...He's complaining because no one would say the B@H was a piece of dime store junk, but now he's complaining because some might or did in other cases with other brand radios...Hell, I think most all portables are basically junk. I've never seen one that was really worth a hoot for anything serious. I wouldn't buy any of them. That's my opinion, and I'm sticking to it. I don't care if I'm chased out of this house, and forced to a trailer park to live next door to the guy that wrote that web page. Normally, I never comment on specific radios, unless it's a question on own I actually own. I realize not all people need radios that cost several hundred dollars or more to listen to VOA or whatever. I don't normally comment on other peoples radios, unless they start developing incorrect delusions regarding some aspect of it's performance, and even that is rare. I know the B@H would be useless to me, but there is no point on raining on someone elses parade just to act radio snobbish. That's why I never add to threads like that. If the poster likes the thing, more power to him. He's certainly a lot less lighter in the pocket than I am with my various models. MK |
It's not overly amazing that particularly simple radios aren't overly
impressive on FM; my ICF-7601 is an example for such a design: After an antenna matching circuit, signals are fed directly to an IC that does mixing to 10.7 MHz, has stuff filtered by a single IF filter (280 kHz or whatnot) and then demodulates it with the help of a 2nd filter for discrimination. The sensitivity to overload depends entirely on the IC used, and with only one filter, selectivity isn't great. The ICF-SW7600G(R) already uses a better design with an FM pre-amp and two cascaded filters (though both are still rather wide at a spec'd 280 kHz). It can still overload quite a bit (that's the downside of the rather good sensitivity), but fitting narrower filters (I had mine changed to 110 and 150 kHz parts, respectively) improves selectivity significantly, allowing some DX. (Same goes for the ATS-909, which, modified with two 110 kHz filters, seems to be quite a popular choice among FM DXers here.) I can only recommend such a modification if you're regularly using the FM part. (The YB-400 apparently uses better filters out of the box.) Grundig's Satellits, BTW, used three cascaded FM IF filters. (The old Sony ICF-5900 - along with the older ICF-5500 - also did, but these were rather wide at - guess what - 280 kHz.) For top performance, nothing beats a bunch of cascaded filters and discrete components, of course. High-end FM tuners use(d) as much as four cascaded filters. Stephan -- Home: http://stephan.win31.de/ | Webm.: http://www.i24.com/ PC#6: i440BX, 2xCel300A, 512 MiB, 18 GB, ATI AGP 32 MiB, 110W This is a SCSI-inside, Legacy-plus, TCPA-free computer :) Reply to newsgroup only. | See home page for working e-mail address. |
Stephan Grossklass schrieb:
(Same goes for the ATS-909, which, modified with two 110 kHz filters, seems to be quite a popular choice among FM DXers here.) And for real DX work, even narrower filters exist - 95 kHz, 80 kHz or even 60 kHz. (Apparently for RDS to work properly with 80 kHz filters, realignment of the receiver is necessary. Below 60 kHz, you obviously get distortion - but which real DXer cares about that? ;).) Still, for normal needs 110 kHz should be fine. A nice thing about that particular receiver seems to be that you can also receive in the OIRT band (used to be situated at 67 ... 73 MHz) used in Eastern Europe and Russia. Stephan -- Home: http://stephan.win31.de/ | Webm.: http://www.i24.com/ PC#6: i440BX, 2xCel300A, 512 MiB, 18 GB, ATI AGP 32 MiB, 110W This is a SCSI-inside, Legacy-plus, TCPA-free computer :) Reply to newsgroup only. | See home page for working e-mail address. |
The Sangean ATS606A has very good FM but I've never tried to DX with
it. On Thu, 1 Jan 2004 21:24:36 -0000, "Richard" wrote: David wrote: Tivoli Model One has the best tough-signal performance of any 3 digit FM radio I've run across. I can get 3,000 Watt stations 40+ miles away perfectly. http://www.tivoliaudio.com/pM1CLA.htm On Wed, 31 Dec 2003 18:07:15 -0000, "Richard" wrote: I'm wanting a pockety sized PLL radio that will, on FM performance, actually equal, at least an, old Grundig radio for sensitivity, cross-modulation and image rejection! Great :But not PLL or small portable.:c) |
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