Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Yes, that's true. But there is an IF filter for FM that could be changed out On Jan 4, 2008 3:43 PM, Gil Stacy <[EMAIL PROTECTED]> wrote: > Mike, > Is it accurate to say that the filter change does not affect FM operation? > Gil -- Mesa Mike LA de NM ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Mike, Is it accurate to say that the filter change does not affect FM operation? Gil ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Hi Les, $100 would be way too much. If you can locate a suitable filter and send it and the radio to me, I'll do it for free (um.. plus shipping). I've been looking around for a source of those ceramic filters, but they don't seem to be readily available. I've sent off a request to RadioLabs.com for a price quote, though. They service Sangean radios, so I figure they gotta have replacement parts, if they're willing to sell 'em. If you can find a SFP450I or a SFP450J from a dead Sangean (or radio shack, or other) radio, that would be what we need. I currently have a SFR450K in my radio, but it's so narrow that the audio sounds a bit muffled. On Jan 4, 2008 1:31 PM, Les Rayburn <[EMAIL PROTECTED]> wrote: > Mesa Mike, > > Any chance you'd be willing to perform this mod for hire? Like some on the > list, my eyes are not what they used to be...but I'd love to > improve my SRF-37V. > > Would $100 bucks cover it? -- Mesa Mike LA de NM ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Mesa Mike, Any chance you'd be willing to perform this mod for hire? Like some on the list, my eyes are not what they used to be...but I'd love to improve my SRF-37V. Would $100 bucks cover it? Les Rayburn, director High Noon Film 100 Centerview Drive Suite 111 Birmingham, AL 35216 205.824.8930 205.824.8960 fax 205.253.4867 cell -- From: "Mike Westfall, Lost Almost NM" <[EMAIL PROTECTED]> Sent: Wednesday, January 02, 2008 4:19 PM To: ; <[EMAIL PROTECTED]> Subject: [IRCA] Vast selectivity improvement for my SRF-M37V > This is for you experimenters out there that are complaining about the > poor selectivity of the Sony SRF-M37V Walkman mighty-mite ultralight. > > It turns out that the SRF-M37V does not use the same chip as the > SRF-59. I don't know where I ever got the idea that it did. > I took my SRF-M37V apart and there is a TA737A5 at its heart. Of > course, I couldn't find a datasheet anywhere for it. I guess it's a > Toshiba part, though. > > Anyway, there is a small 450 kHz ceramic filter on the circuit card > next to the main chip, which I unsoldered and replaced with a SFP450I > ceramic filter from a dead DX-440 that I had laying around. > > The results were simply staggering! I can now receive the very weak > KABR on 1500 kHz, despite the fact that my local KRSN is right next > door on 1490! Impossible to do on my car radio, even!. > > For even more selectivity, I might have tried to use the narrower > SFR450K from the same DX-440, but it's a little bigger, and wasn't > sure it would fit, but the filter I used gives great selectivity. > > Taking the radio apart isn't too hard. After removing the four screws, > the case pops right apart, without using fingernails, etc. There are > two circuit boards inside, one for the keyboard/microcontroller, and > the other for all the analog stuff. Yoiu have to unsolder on red wire > to get the two to unfold from each other. Then you have to unsolder a > couple spots on a copper foil shield which is covering the TA737A5 in > order to get to the solder pads for the ceramic filter, which is > marked "50J". Remove the the filter and clean out the holes. The new > filter has to be laid on its side, and small wires run from it's pins > to the holes where the old fiter was (no, it's not a drop-in > replacement!). AFter you fold the two circuit boards back together, > it's in there nice and cozy, and won;t be going anywhere. If you're > worried about movement weakening and breaking your wires, I guess you > could dab some RTV under the new filter to hold it in place, but I saw > no need for that. > > > NOW I have a sensitive, selective little DX monster that can switch to > 9kHz tuning! > I can't wait to try it with my RS Loop later! > > -- > Mesa Mike > LA de NM > ___ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the > original contributors and do not necessarily reflect the opinion of the > IRCA, its editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > > ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V (Mike Westfall, Lost Almost NM)
--- "John H. Bryant" <[EMAIL PROTECTED]> wrote: > > > Hey, Mike... > > Great work on the improved selectivity of the M37V I'm sure that > it will qualify as an Ultralight and there are VERY FEW record > holders in the "Super Modified" class right now. Go to work with > that hummer and keep good records for a week or ten days until we can > > sort this out... You got a Tiger By The Tail... and one in the Tank, > too! > > I for one would seriously consider purchasing a suitably-modified SRF-M37V. I haven't been able to work on miniature circuits since I started needing bifocals over ten years ago, so I wouldn't think of trying it myself. I figure if I'm going to do this ultralight thing, I might as well jump in with both feet. Russ Edmunds Blue Bell, PA ( 360' ASL ) [15 mi NNW of Philadelphia] 40:08:45N; 75:16:04W, Grid FN20id <[EMAIL PROTECTED]> FM: Yamaha T-80 & Onkyo T-450RDS w/ APS9B @15' AM: Hammarlund HQ-150 & 4' FET air core loop Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V (Mike Westfall, Lost Almost NM)
Hey, Mike... Great work on the improved selectivity of the M37V I'm sure that it will qualify as an Ultralight and there are VERY FEW record holders in the "Super Modified" class right now. Go to work with that hummer and keep good records for a week or ten days until we can sort this out... You got a Tiger By The Tail... and one in the Tank, too! John B. Stillwater, Oklahoma, USA Rcvrs: WiNRADiO 313e, Eton e1, NRD-535(kiwa-mods) Antennas: 700' NE/SW mini-Bev, Wellbrook Phased Array (pre-production version) ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Mesa Mike, This is a phenomenal improvement that will make a huge difference in the SRF-M37V's DX capability! During the recent (2007) Shootout, the SRF-M37V would have been the clear winner except for its selectivity issue. Your modification provides a method for this highly sensitive and digitally advanced unit to truly become a ultra-mean DX Machine. On behalf of the deeply appreciative Ultralight Tech Trio (Steve, Nick and I), may I express our deepest appreciation for your outstanding contribution to the Ultralight DX cause. Now, start tearing up the bands with your tiny little terror! 73, Gary DeBock **See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop000304) ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Hi Bert The hard part eill be obtaining a ceramic filter, I think. Anybody know where to buy 450 kHz ceramic filters? On Jan 2, 2008 4:33 PM, Ira Elbert New, III <[EMAIL PROTECTED]> wrote: > > What will you charge for the technically inept amongst us to render this > service? Must we provide our own filters too?!?!? Here's hoping for a > cheerful answer... -- Mesa Mike LA de NM ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Gil, I think that's probably too big to fit. On Jan 2, 2008 4:53 PM, Gil Stacy <[EMAIL PROTECTED]> wrote: > Bert, > The cost of my filter was $5 more than the cost of an SRF59. > Mike, > My filter is a five pin filter, three pins ground and input and out put > pins. I'd probably lay it on its side as this will give a height of .25". > The length is .375" and about .375" wide. Any room inside the boards for > this one? > Gil > > ___ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the original > contributors and do not necessarily reflect the opinion of the IRCA, its > editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > > -- Mesa Mike LA de NM ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Perhaps then, I will dance with what brung me... Bert New Watkinsville, Georgia Proudly Serving You Since 1964! > Date: Wed, 2 Jan 2008 18:53:06 -0500 > From: [EMAIL PROTECTED] > To: irca@hard-core-dx.com > Subject: Re: [IRCA] Vast selectivity improvement for my SRF-M37V > > Bert, > The cost of my filter was $5 more than the cost of an SRF59. > Mike, > My filter is a five pin filter, three pins ground and input and out put > pins. I'd probably lay it on its side as this will give a height of .25". > The length is .375" and about .375" wide. Any room inside the boards for > this one? > Gil > ___ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the original > contributors and do not necessarily reflect the opinion of the IRCA, its > editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > _ Share life as it happens with the new Windows Live. http://www.windowslive.com/share.html?ocid=TXT_TAGHM_Wave2_sharelife_122007 ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Bert, The cost of my filter was $5 more than the cost of an SRF59. Mike, My filter is a five pin filter, three pins ground and input and out put pins. I'd probably lay it on its side as this will give a height of .25". The length is .375" and about .375" wide. Any room inside the boards for this one? Gil ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
What will you charge for the technically inept amongst us to render this service? Must we provide our own filters too?!?!? Here's hoping for a cheerful answer... Bert New Watkinsville, Georgia Proudly Serving You Since 1964! > Date: Wed, 2 Jan 2008 15:19:35 -0700 > From: [EMAIL PROTECTED] > To: irca@hard-core-dx.com; [EMAIL PROTECTED] > Subject: [IRCA] Vast selectivity improvement for my SRF-M37V > > This is for you experimenters out there that are complaining about the > poor selectivity of the Sony SRF-M37V Walkman mighty-mite ultralight. > > It turns out that the SRF-M37V does not use the same chip as the > SRF-59. I don't know where I ever got the idea that it did. > I took my SRF-M37V apart and there is a TA737A5 at its heart. Of > course, I couldn't find a datasheet anywhere for it. I guess it's a > Toshiba part, though. > > Anyway, there is a small 450 kHz ceramic filter on the circuit card > next to the main chip, which I unsoldered and replaced with a SFP450I > ceramic filter from a dead DX-440 that I had laying around. > > The results were simply staggering! I can now receive the very weak > KABR on 1500 kHz, despite the fact that my local KRSN is right next > door on 1490! Impossible to do on my car radio, even!. > > For even more selectivity, I might have tried to use the narrower > SFR450K from the same DX-440, but it's a little bigger, and wasn't > sure it would fit, but the filter I used gives great selectivity. > > Taking the radio apart isn't too hard. After removing the four screws, > the case pops right apart, without using fingernails, etc. There are > two circuit boards inside, one for the keyboard/microcontroller, and > the other for all the analog stuff. Yoiu have to unsolder on red wire > to get the two to unfold from each other. Then you have to unsolder a > couple spots on a copper foil shield which is covering the TA737A5 in > order to get to the solder pads for the ceramic filter, which is > marked "50J". Remove the the filter and clean out the holes. The new > filter has to be laid on its side, and small wires run from it's pins > to the holes where the old fiter was (no, it's not a drop-in > replacement!). AFter you fold the two circuit boards back together, > it's in there nice and cozy, and won;t be going anywhere. If you're > worried about movement weakening and breaking your wires, I guess you > could dab some RTV under the new filter to hold it in place, but I saw > no need for that. > > > NOW I have a sensitive, selective little DX monster that can switch to > 9kHz tuning! > I can't wait to try it with my RS Loop later! > > -- > Mesa Mike > LA de NM > ___ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the original > contributors and do not necessarily reflect the opinion of the IRCA, its > editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > _ Don't get caught with egg on your face. Play Chicktionary! http://club.live.com/chicktionary.aspx?icid=chick_wlhmtextlink1_dec ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
If it's for a 450 kHz IF, go ahead and try it if it's not too big. The one I used was the same size as a modern Murata CFULA series ceramic filter. On Jan 2, 2008 3:29 PM, Gil Stacy <[EMAIL PROTECTED]> wrote: > Mike, > That's good news. I have a spare Kiwa 6.2 kHz filter for my FRG-7. Any > reason not to use it?? > 73, Gil > > > > On 1/2/08, Mike Westfall, Lost Almost NM <[EMAIL PROTECTED]> wrote: > > > > This is for you experimenters out there that are complaining about the > > poor selectivity of the Sony SRF-M37V Walkman mighty-mite ultralight. > > > > It turns out that the SRF-M37V does not use the same chip as the > > SRF-59. I don't know where I ever got the idea that it did. > > I took my SRF-M37V apart and there is a TA737A5 at its heart. Of > > course, I couldn't find a datasheet anywhere for it. I guess it's a > > Toshiba part, though. > > > > Anyway, there is a small 450 kHz ceramic filter on the circuit card > > next to the main chip, which I unsoldered and replaced with a SFP450I > > ceramic filter from a dead DX-440 that I had laying around. > > > > The results were simply staggering! I can now receive the very weak > > KABR on 1500 kHz, despite the fact that my local KRSN is right next > > door on 1490! Impossible to do on my car radio, even!. > > > > For even more selectivity, I might have tried to use the narrower > > SFR450K from the same DX-440, but it's a little bigger, and wasn't > > sure it would fit, but the filter I used gives great selectivity. > > > > Taking the radio apart isn't too hard. After removing the four screws, > > the case pops right apart, without using fingernails, etc. There are > > two circuit boards inside, one for the keyboard/microcontroller, and > > the other for all the analog stuff. Yoiu have to unsolder on red wire > > to get the two to unfold from each other. Then you have to unsolder a > > couple spots on a copper foil shield which is covering the TA737A5 in > > order to get to the solder pads for the ceramic filter, which is > > marked "50J". Remove the the filter and clean out the holes. The new > > filter has to be laid on its side, and small wires run from it's pins > > to the holes where the old fiter was (no, it's not a drop-in > > replacement!). AFter you fold the two circuit boards back together, > > it's in there nice and cozy, and won;t be going anywhere. If you're > > worried about movement weakening and breaking your wires, I guess you > > could dab some RTV under the new filter to hold it in place, but I saw > > no need for that. > > > > > > NOW I have a sensitive, selective little DX monster that can switch to > > 9kHz tuning! > > I can't wait to try it with my RS Loop later! > > > > -- > > Mesa Mike > > LA de NM > > ___ > > IRCA mailing list > > IRCA@hard-core-dx.com > > http://montreal.kotalampi.com/mailman/listinfo/irca > > > > Opinions expressed in messages on this mailing list are those of the > > original contributors and do not necessarily reflect the opinion of the > > IRCA, its editors, publishing staff, or officers > > > > For more information: http://www.ircaonline.org > > > > To Post a message: irca@hard-core-dx.com > > > > > ___ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the original > contributors and do not necessarily reflect the opinion of the IRCA, its > editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > > -- Mesa Mike LA de NM ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
If it's for a 450 kHz IF, go ahead and try it if it's not too big. The one I used was the same size as a modern Murata CFULA series On Jan 2, 2008 3:29 PM, Gil Stacy <[EMAIL PROTECTED]> wrote: > Mike, > That's good news. I have a spare Kiwa 6.2 kHz filter for my FRG-7. Any > reason not to use it?? > 73, Gil > > > > On 1/2/08, Mike Westfall, Lost Almost NM <[EMAIL PROTECTED]> wrote: > > > > This is for you experimenters out there that are complaining about the > > poor selectivity of the Sony SRF-M37V Walkman mighty-mite ultralight. > > > > It turns out that the SRF-M37V does not use the same chip as the > > SRF-59. I don't know where I ever got the idea that it did. > > I took my SRF-M37V apart and there is a TA737A5 at its heart. Of > > course, I couldn't find a datasheet anywhere for it. I guess it's a > > Toshiba part, though. > > > > Anyway, there is a small 450 kHz ceramic filter on the circuit card > > next to the main chip, which I unsoldered and replaced with a SFP450I > > ceramic filter from a dead DX-440 that I had laying around. > > > > The results were simply staggering! I can now receive the very weak > > KABR on 1500 kHz, despite the fact that my local KRSN is right next > > door on 1490! Impossible to do on my car radio, even!. > > > > For even more selectivity, I might have tried to use the narrower > > SFR450K from the same DX-440, but it's a little bigger, and wasn't > > sure it would fit, but the filter I used gives great selectivity. > > > > Taking the radio apart isn't too hard. After removing the four screws, > > the case pops right apart, without using fingernails, etc. There are > > two circuit boards inside, one for the keyboard/microcontroller, and > > the other for all the analog stuff. Yoiu have to unsolder on red wire > > to get the two to unfold from each other. Then you have to unsolder a > > couple spots on a copper foil shield which is covering the TA737A5 in > > order to get to the solder pads for the ceramic filter, which is > > marked "50J". Remove the the filter and clean out the holes. The new > > filter has to be laid on its side, and small wires run from it's pins > > to the holes where the old fiter was (no, it's not a drop-in > > replacement!). AFter you fold the two circuit boards back together, > > it's in there nice and cozy, and won;t be going anywhere. If you're > > worried about movement weakening and breaking your wires, I guess you > > could dab some RTV under the new filter to hold it in place, but I saw > > no need for that. > > > > > > NOW I have a sensitive, selective little DX monster that can switch to > > 9kHz tuning! > > I can't wait to try it with my RS Loop later! > > > > -- > > Mesa Mike > > LA de NM > > ___ > > IRCA mailing list > > IRCA@hard-core-dx.com > > http://montreal.kotalampi.com/mailman/listinfo/irca > > > > Opinions expressed in messages on this mailing list are those of the > > original contributors and do not necessarily reflect the opinion of the > > IRCA, its editors, publishing staff, or officers > > > > For more information: http://www.ircaonline.org > > > > To Post a message: irca@hard-core-dx.com > > > > > ___ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the original > contributors and do not necessarily reflect the opinion of the IRCA, its > editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > > -- Mesa Mike LA de NM ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
Re: [IRCA] Vast selectivity improvement for my SRF-M37V
Mike, That's good news. I have a spare Kiwa 6.2 kHz filter for my FRG-7. Any reason not to use it?? 73, Gil On 1/2/08, Mike Westfall, Lost Almost NM <[EMAIL PROTECTED]> wrote: > > This is for you experimenters out there that are complaining about the > poor selectivity of the Sony SRF-M37V Walkman mighty-mite ultralight. > > It turns out that the SRF-M37V does not use the same chip as the > SRF-59. I don't know where I ever got the idea that it did. > I took my SRF-M37V apart and there is a TA737A5 at its heart. Of > course, I couldn't find a datasheet anywhere for it. I guess it's a > Toshiba part, though. > > Anyway, there is a small 450 kHz ceramic filter on the circuit card > next to the main chip, which I unsoldered and replaced with a SFP450I > ceramic filter from a dead DX-440 that I had laying around. > > The results were simply staggering! I can now receive the very weak > KABR on 1500 kHz, despite the fact that my local KRSN is right next > door on 1490! Impossible to do on my car radio, even!. > > For even more selectivity, I might have tried to use the narrower > SFR450K from the same DX-440, but it's a little bigger, and wasn't > sure it would fit, but the filter I used gives great selectivity. > > Taking the radio apart isn't too hard. After removing the four screws, > the case pops right apart, without using fingernails, etc. There are > two circuit boards inside, one for the keyboard/microcontroller, and > the other for all the analog stuff. Yoiu have to unsolder on red wire > to get the two to unfold from each other. Then you have to unsolder a > couple spots on a copper foil shield which is covering the TA737A5 in > order to get to the solder pads for the ceramic filter, which is > marked "50J". Remove the the filter and clean out the holes. The new > filter has to be laid on its side, and small wires run from it's pins > to the holes where the old fiter was (no, it's not a drop-in > replacement!). AFter you fold the two circuit boards back together, > it's in there nice and cozy, and won;t be going anywhere. If you're > worried about movement weakening and breaking your wires, I guess you > could dab some RTV under the new filter to hold it in place, but I saw > no need for that. > > > NOW I have a sensitive, selective little DX monster that can switch to > 9kHz tuning! > I can't wait to try it with my RS Loop later! > > -- > Mesa Mike > LA de NM > ___ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the > original contributors and do not necessarily reflect the opinion of the > IRCA, its editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > > ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
[IRCA] Vast selectivity improvement for my SRF-M37V
This is for you experimenters out there that are complaining about the poor selectivity of the Sony SRF-M37V Walkman mighty-mite ultralight. It turns out that the SRF-M37V does not use the same chip as the SRF-59. I don't know where I ever got the idea that it did. I took my SRF-M37V apart and there is a TA737A5 at its heart. Of course, I couldn't find a datasheet anywhere for it. I guess it's a Toshiba part, though. Anyway, there is a small 450 kHz ceramic filter on the circuit card next to the main chip, which I unsoldered and replaced with a SFP450I ceramic filter from a dead DX-440 that I had laying around. The results were simply staggering! I can now receive the very weak KABR on 1500 kHz, despite the fact that my local KRSN is right next door on 1490! Impossible to do on my car radio, even!. For even more selectivity, I might have tried to use the narrower SFR450K from the same DX-440, but it's a little bigger, and wasn't sure it would fit, but the filter I used gives great selectivity. Taking the radio apart isn't too hard. After removing the four screws, the case pops right apart, without using fingernails, etc. There are two circuit boards inside, one for the keyboard/microcontroller, and the other for all the analog stuff. Yoiu have to unsolder on red wire to get the two to unfold from each other. Then you have to unsolder a couple spots on a copper foil shield which is covering the TA737A5 in order to get to the solder pads for the ceramic filter, which is marked "50J". Remove the the filter and clean out the holes. The new filter has to be laid on its side, and small wires run from it's pins to the holes where the old fiter was (no, it's not a drop-in replacement!). AFter you fold the two circuit boards back together, it's in there nice and cozy, and won;t be going anywhere. If you're worried about movement weakening and breaking your wires, I guess you could dab some RTV under the new filter to hold it in place, but I saw no need for that. NOW I have a sensitive, selective little DX monster that can switch to 9kHz tuning! I can't wait to try it with my RS Loop later! -- Mesa Mike LA de NM ___ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
