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#2
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Also, the 12 kHz filter in this radio sounds great on clear
mediumwave stations, are there any shortwave stations that have clear signals and good audio which I can use this wide filter with (I've been away from the hobby for a while)? Is the excellent audio reputation of the R-1000 from the stock wide filter alone, or is the entire audio circuit what makes it so good? If its just the stock filter, wouldn't any receiver benefit greatly from something wider than the standard 6 kHz filter in the wide slot? While you get great audio with the 12 khz filter, I found it to be on the wide side for my taste, I replaced it with a Kiwa wide filter ( 6 khz ) with little loss on the audio quality but an improvement on selectivity. |
#3
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In article . com,
wrote: Recently I picked up an R-1000 in nice condition, and did a search in this newsgroup, the feeling seems to be that this is basically a decent receiver with good audio but prone to overloading with a large antenna. I have a couple of commercial shortwave antennas which I could use when I get time to put them up, both being about 50' in length, though one can be shortened if need be. I like to listen to the major broadcasters but also enjoy touring the 60 meter band for Africans as well. Can anyone suggest an antenna length that would be best for this receiver? There's a ton of diodes in the front end (it uses diode switched bandpass filters), so if you put too much antenna on it, it's prone to amazing amounts of intermod from nearby medium wave stations. I found that 200 feet was too much, as I'm 5 miles from Seattle's medium wave farm on Vashon Island. About 60 feet seems ok. Also, you can try running it into the 50 ohm coax plug instead of the 500 ohm push terminal, (and remember to flip the back panel switch ;-) ) , without the matching transformer it's less prone to overload. I found that, when I bought a FR-200 portable to play with, that the R-1000 will reradiate this intermod when it's turned off and the diodes in the front end are unpowered. Would the attenuator lose too much signal, or make it an ideal situation? Testing with a short wire wiped out all but the strongest signals, and even they weren't enjoyable then. The 20 dB step on the attenuator makes it useless. There's a mod on the mods.dk site for changing a bunch of resistors to make it 10 dB per step. Also, the 12 kHz filter in this radio sounds great on clear mediumwave stations, are there any shortwave stations that have clear signals and good audio which I can use this wide filter with (I've been away from No, not really. That's why there's the plug/cable setup where you can select for two different selections of wide and narrow for the front buttons. Plugging the three wire harness (at the mddle of the top board) into one socket sets it to 2.1/SSB/6narrow/12wide, the other 2.1ssb/2.1narrow/6wide. (I cheat. I came up with a circuit mod using a CMOS analog switch IC that let's me get all three bandwidths for any mode by pushing in 1,2 or 3 buttons at the same time.) There is also an audio bandwidth spoiler circuit that narrows the bandwidth when the AM-nar button is pressed (or widens it when the AM-Wide is in) regardless of the other configuration. This, I think, could be defeated by popping the connector terminal on one of the top board plugs, but I've never bothered to try that. (Likewise, there's an RF gain spoiler circuit that lowers the sensitivity below 2 MHz.) Both the operation and repair manuals are on the mods.dk web site. the hobby for a while)? Is the excellent audio reputation of the R-1000 from the stock wide filter alone, or is the entire audio circuit what makes it so good? If its just the stock filter, wouldn't any receiver benefit greatly from something wider than the standard 6 kHz filter in the wide slot? I'd go with the filter bandwidth. I'm not impressed with the built in amp and speaker. Not in the same league as an R-5000. You do get pretty good stuff out of the front panel "record" jack, but it's not the ultimate AM receiver. Mark Zenier Washington State resident |
#4
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The 6khz may sound muddy if you are used to the 12, but remember that
you cane tune off center freq. 2 or 3 khz or more to get treble response again. This even works pretty well with filters as narrow (?) as 3 or 4 khz. |
#5
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Thanks to everyone for your help! I'll go with my original antennas
and look into the filter and audio mods. |
#6
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Starman - most of my filters are leftovers from various projects and
scrapped junker receivers and the like. I occasionally type "Murata" into the search box on Ebay and you would be surprised what pops up at times. I got a package of 6 Murata CFW455I filters for about $25 a few years ago. I've since either used most up in upgrades for various people or given them away. I still have a number of 455H and G types I think. You may want to enter "Barend Hendricksen" into a Google search. I think this guy sells all types of filters out of the UK. Frank K3YAZ Tucson starman wrote: Frank, Where are you getting Murata filters these days? TIA wrote: The R-1000 should do well on either of the antennas you mentioned. My R-1000 showed some slight overloading on a 130' wire but did well on a 60' coax/matching xfmr fed wire. I replaced the 12 kHz filter with a 6 khz one (Murata CFW455H) and the audio quality was not degraded significantly but the selectivity sure was better. Removing the top pc board is a hassle the first time, however! Frank ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#7
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Thanks Frank.
wrote: Starman - most of my filters are leftovers from various projects and scrapped junker receivers and the like. I occasionally type "Murata" into the search box on Ebay and you would be surprised what pops up at times. I got a package of 6 Murata CFW455I filters for about $25 a few years ago. I've since either used most up in upgrades for various people or given them away. I still have a number of 455H and G types I think. You may want to enter "Barend Hendricksen" into a Google search. I think this guy sells all types of filters out of the UK. Frank K3YAZ Tucson starman wrote: Frank, Where are you getting Murata filters these days? TIA wrote: The R-1000 should do well on either of the antennas you mentioned. My R-1000 showed some slight overloading on a 130' wire but did well on a 60' coax/matching xfmr fed wire. I replaced the 12 kHz filter with a 6 khz one (Murata CFW455H) and the audio quality was not degraded significantly but the selectivity sure was better. Removing the top pc board is a hassle the first time, however! Frank ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#8
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You should be able to change the front end switching diodes to PIN diodes. A
1N5767 should do the trick. Make sure that they are biased up to at least 15mA. Pete "Mark Zenier" wrote in message ... In article . com, wrote: Recently I picked up an R-1000 in nice condition, and did a search in this newsgroup, the feeling seems to be that this is basically a decent receiver with good audio but prone to overloading with a large antenna. I have a couple of commercial shortwave antennas which I could use when I get time to put them up, both being about 50' in length, though one can be shortened if need be. I like to listen to the major broadcasters but also enjoy touring the 60 meter band for Africans as well. Can anyone suggest an antenna length that would be best for this receiver? There's a ton of diodes in the front end (it uses diode switched bandpass filters), so if you put too much antenna on it, it's prone to amazing amounts of intermod from nearby medium wave stations. I found that 200 feet was too much, as I'm 5 miles from Seattle's medium wave farm on Vashon Island. About 60 feet seems ok. Also, you can try running it into the 50 ohm coax plug instead of the 500 ohm push terminal, (and remember to flip the back panel switch ;-) ) , without the matching transformer it's less prone to overload. I found that, when I bought a FR-200 portable to play with, that the R-1000 will reradiate this intermod when it's turned off and the diodes in the front end are unpowered. Would the attenuator lose too much signal, or make it an ideal situation? Testing with a short wire wiped out all but the strongest signals, and even they weren't enjoyable then. The 20 dB step on the attenuator makes it useless. There's a mod on the mods.dk site for changing a bunch of resistors to make it 10 dB per step. Also, the 12 kHz filter in this radio sounds great on clear mediumwave stations, are there any shortwave stations that have clear signals and good audio which I can use this wide filter with (I've been away from No, not really. That's why there's the plug/cable setup where you can select for two different selections of wide and narrow for the front buttons. Plugging the three wire harness (at the mddle of the top board) into one socket sets it to 2.1/SSB/6narrow/12wide, the other 2.1ssb/2.1narrow/6wide. (I cheat. I came up with a circuit mod using a CMOS analog switch IC that let's me get all three bandwidths for any mode by pushing in 1,2 or 3 buttons at the same time.) There is also an audio bandwidth spoiler circuit that narrows the bandwidth when the AM-nar button is pressed (or widens it when the AM-Wide is in) regardless of the other configuration. This, I think, could be defeated by popping the connector terminal on one of the top board plugs, but I've never bothered to try that. (Likewise, there's an RF gain spoiler circuit that lowers the sensitivity below 2 MHz.) Both the operation and repair manuals are on the mods.dk web site. the hobby for a while)? Is the excellent audio reputation of the R-1000 from the stock wide filter alone, or is the entire audio circuit what makes it so good? If its just the stock filter, wouldn't any receiver benefit greatly from something wider than the standard 6 kHz filter in the wide slot? I'd go with the filter bandwidth. I'm not impressed with the built in amp and speaker. Not in the same league as an R-5000. You do get pretty good stuff out of the front panel "record" jack, but it's not the ultimate AM receiver. Mark Zenier Washington State resident |
#9
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In article ,
Pete KE9OA wrote: "Mark Zenier" wrote in message There's a ton of diodes in the front end (it uses diode switched bandpass filters), so if you put too much antenna on it, it's prone to amazing amounts of intermod from nearby medium wave stations. I found that 200 feet was too much, as I'm 5 miles from Seattle's medium wave farm on Vashon Island. About 60 feet seems ok. You should be able to change the front end switching diodes to PIN diodes. A 1N5767 should do the trick. Make sure that they are biased up to at least 15mA. They're now 1S1587, according to the schematic. I'll have to google and see what that is. Mark Zenier Washington State resident |
#10
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Pete,
I've been thinking of replacing the front-end bandpass switching diodes in my R8B to improve (reduce) the 2nd order response. I can sometimes hear a weak signal on the 25-m band, coming from a very strong station on 49-m. For example, I recently heard a station on 12000-Khz which was actually on 6000-Khz with a +40-db signal. I had a similar problem with my SW8 when it was under warranty. Drake replaced all the front-end switching diodes and this fixed the problem. Do you think the stock diodes can become leaky with age? Would the 5767 be a good choice for the R8B front-end? Thanks Pete KE9OA wrote: You should be able to change the front end switching diodes to PIN diodes. A 1N5767 should do the trick. Make sure that they are biased up to at least 15mA. Pete "Mark Zenier" wrote in message ... In article . com, wrote: Recently I picked up an R-1000 in nice condition, and did a search in this newsgroup, the feeling seems to be that this is basically a decent receiver with good audio but prone to overloading with a large antenna. I have a couple of commercial shortwave antennas which I could use when I get time to put them up, both being about 50' in length, though one can be shortened if need be. I like to listen to the major broadcasters but also enjoy touring the 60 meter band for Africans as well. Can anyone suggest an antenna length that would be best for this receiver? There's a ton of diodes in the front end (it uses diode switched bandpass filters), so if you put too much antenna on it, it's prone to amazing amounts of intermod from nearby medium wave stations. I found that 200 feet was too much, as I'm 5 miles from Seattle's medium wave farm on Vashon Island. About 60 feet seems ok. Also, you can try running it into the 50 ohm coax plug instead of the 500 ohm push terminal, (and remember to flip the back panel switch ;-) ) , without the matching transformer it's less prone to overload. I found that, when I bought a FR-200 portable to play with, that the R-1000 will reradiate this intermod when it's turned off and the diodes in the front end are unpowered. Would the attenuator lose too much signal, or make it an ideal situation? Testing with a short wire wiped out all but the strongest signals, and even they weren't enjoyable then. The 20 dB step on the attenuator makes it useless. There's a mod on the mods.dk site for changing a bunch of resistors to make it 10 dB per step. Also, the 12 kHz filter in this radio sounds great on clear mediumwave stations, are there any shortwave stations that have clear signals and good audio which I can use this wide filter with (I've been away from No, not really. That's why there's the plug/cable setup where you can select for two different selections of wide and narrow for the front buttons. Plugging the three wire harness (at the mddle of the top board) into one socket sets it to 2.1/SSB/6narrow/12wide, the other 2.1ssb/2.1narrow/6wide. (I cheat. I came up with a circuit mod using a CMOS analog switch IC that let's me get all three bandwidths for any mode by pushing in 1,2 or 3 buttons at the same time.) There is also an audio bandwidth spoiler circuit that narrows the bandwidth when the AM-nar button is pressed (or widens it when the AM-Wide is in) regardless of the other configuration. This, I think, could be defeated by popping the connector terminal on one of the top board plugs, but I've never bothered to try that. (Likewise, there's an RF gain spoiler circuit that lowers the sensitivity below 2 MHz.) Both the operation and repair manuals are on the mods.dk web site. the hobby for a while)? Is the excellent audio reputation of the R-1000 from the stock wide filter alone, or is the entire audio circuit what makes it so good? If its just the stock filter, wouldn't any receiver benefit greatly from something wider than the standard 6 kHz filter in the wide slot? I'd go with the filter bandwidth. I'm not impressed with the built in amp and speaker. Not in the same league as an R-5000. You do get pretty good stuff out of the front panel "record" jack, but it's not the ultimate AM receiver. Mark Zenier Washington State resident ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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