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Re: Sony M37 Filter Mod photos uploaded
Gil Stacy
Kevin,
Mike Westfall told me how to do it. He was the first to do it that I am aware of. 73 Gil |
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First (and last) look at the Tecsun DR-920 (Grundig G1100)
satya@...
Hi all:
Despite sage advice to the contrary, I got one of these for quite cheap off of eBay, and ran it through its paces. This receiver has some neat features, including analog tuning with digital readout and that pseudo rubbery case like the E5. Out of the box, the alignment was quite a ways off at both ends. Fortunately it followed the same general alignment procedure as that recently posted by Gary DeBock, and the coil and trimmers were easy to adjust. After a full alignment, my humble verdict is: Plus: really good selectivity (almost as good as the stock Eton e100) and really good nulling (comparable to the WRX-911) Minus: really, really deaf. Plus, it's deaf and noisy. Also, the snap-back of the analog tuning cord causes it to detune, which then triggers the backlight on and off. Finally, it's quite insensitive and deaf. The problem? I got the sense that the digital circuitry was adding a lot of noise, killing off whatever sensitivity it might otherwise have. It's got the same ferrite as the e100 and WRX-911, but the internal circuit noise seemed to be simply too much. Touching the whip or having my hand in certain spots increased the noise. This may be the same analog/digital circuitry in the infamous Tecsun 919/Grundig Mini 300PE, which is also quite a Turkey. FM is no treat either - it seems to overload quite easily and requires that the whip be retracted for urban use, although the selectivity on FM was pretty good. A quick check on shortwave revealed poor sensitivity, plus images here on the low-signal West Coast. In all, I wouldn't recommend this set to anyone for MW DX as there doesn't seem to be any way to correct its fatal sensitivity flaw, or really for anything other than spare parts - run away! Kevin S Bainbridge Island, WA |
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Re: SRF-M37V and SRF-M37W-Performance differences?
Chris Knight <chris@...>
Just a silly question. How hard would it be
to change the I.F. of one of these small radios from 450kHz to 455kHz? Could it
be as simple as changing a mixer IC or a crystal?
73,
Chris Knight
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Re: DT-400W filter mod results comments
Steve Ratzlaff <steveratz@...>
Hi Michael,
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Thanks for your comments. Yes, I used the LTM450HT filter in the DT-400W mod, purchased from the eBay UK seller Mainline. I bought 5 of them and tested several on the bench before installing one. All had the same poor skirt selectivity. Initial skirt depth was about 40 db, not bad at all considering the tiny size of the filter, but it quickly rose to 25 dB about 5 kHz either side of the passband. That's not good enough to give decent adjacent channel selectivity in strong RF environments. The Murata K 455 kHz filter that I've installed in Eton E100's and CCrane SWP's has 75-80 dB skirt depth and it doesn't rise past the passband. It's physically approximately 4 times longer than the LTM filters, and is an example of an excellent ceramic filter, and its performance is reflected by its approximate $50 price. I'm happy the LTM450HT filter mod worked well for your particular RF environment. It didn't produce the desired results for me. Apparently our North American urban RF environments are more challenging than one might think. :) I don't have that problem in the rural area where I live, with no strong stations nearby; I send radios to Gary DeBock to test. He's able to properly evaluate how radios perform in his urban RF environment. 73, Steve ----- Original Message -----
From: "Michael Slattery" <knallebo@...> To: <ultralightdx@...> Sent: Thursday, April 02, 2009 6:47 PM Subject: Re: [ultralightdx] Re: SRF-M37V and SRF-M37W-Performance differences? Whether the 450 kHz filter modification would be useless or not probablyBefore carrying out a mod you have to determine what you expect. As the author of the DT-210L & DT-400W filter mod articles, I find the comment that the mod is 'not worth all the effort' frankly incredible! The mods were not offered as a panacea for turning these radios into 9/10kHz-split DXers machines. That would be impossible with the type of filters (6kHz @6dB BW) used. Rather, the articles were offered in the spirit of improving the usability of these radios in the domestic context. The give-away line in my article was 'the intrinsic quality of the audio remains.' By implication therefore, the mod filter is not especially selective merely an improvement on the original. The moral of the story is to make sure any ULR you intend to mod for 9/10kHz-split DXing has a 455kHz IF system and the ability to tune in at least 1kHz steps or better. 450kHz IF radios are a waste of time since narrow filters with a good shape factor are simply unavailable. Whilst agreeing fully with the remark by Steve about skirt selectivity and filter size, I have to ask: Was the LTM450HT filter used? Nothing else will bring much improvement except for a LTM450IT or even narrower filter, if you could find one. The 'T' suffix in the filter model number is important since these have superior skirt selectivity over those without the 'T' suffix. Living here in the UK I frequently wonder what North American DXers mean by a 'high RF environment'. Amongst others I live within 15 miles of one 150kW & two 400kW MF transmitters & less than 1 mile of two 1kW MF transmitters. The DT-210L & DT-400W filter mods have transformed the reception capabilities of these radios close to these powerful signals. Before the mod, five (9kHz) channels either side of the frequency of one of these strong locals were rendered useless for weak signal reception by the original filter. After the mod I am able to hear weak signals on the immediately adjacent channels (9kHz) with only a small level of adjacent channel interference. Perhaps your RF environment(s) are not really that challenging? Maybe that is the reason you are not reaping the reward from the mod? -- Michael Slattery Sheffield, UK |
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Re: SRF-M37V and SRF-M37W-Performance differences?
--- In ultralightdx@..., D1028Gary@... wrote:
Double bummer!!!!:>( :>( Not only did you rain on my parade, but now you had to drop a wall cloud over it to!!! :>0 :>) Oh well, I can always dream. Well it looks like I'm in the market for acquiring yet another SRF M37V/W to convert in to an M37X??!!! Sort of the way I'm looking for more SRF-39/49/59 to mod up in to a "retro" expedition reciever. Alex N8UCN/KOH8IG |
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GS Ultralight Loggings Apr. 2, 2009
Greg Shoom <shoomg@...>
Ultralight loggings for Thurs. Apr. 2, 2009. All stations logged from Toronto, ON. Dates and times in UTC.
Two more stations added to the ultralight log. Total ultralight count is now: 278. 1420 WIMS IN Michigan City - 02-Apr-2009 0359 UTC - ID at top of hour, then into news. Mixing with WHK. 5 kW. Sangean DT-400W (Poor) --> New station for the overall log. 1690 CJLO QC Montreal - 02-Apr-2009 2345 UTC - Music show, with host saying the record he just played is available at HMV "here in Montreal". Talk about results of university campus elections (CJLO is the campus station of Concordia University). Mixing with presumed WVON (which is not in my ultralight log yet) in null of local CHTO. 1 kW. Sony SRF-59. (Fair). --> New station for the overall log. Best, Greg Shoom VE3LXL |
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Re: Sony M37 Filter Mod photos uploaded
satya@...
Thanks for doing this, Gil! Your tinkering really turned the M37 into a
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capable DX machine. Kevin S Bainbridge Island, WA Check the photos section for before and after photos of filter mods on the |
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Re: SRF-M37V and SRF-M37W-Performance differences?
Michael Slattery
Whether the 450 kHz filter modification would be useless or not probablyBefore carrying out a mod you have to determine what you expect. As the author of the DT-210L & DT-400W filter mod articles, I find the comment that the mod is 'not worth all the effort' frankly incredible! The mods were not offered as a panacea for turning these radios into 9/10kHz-split DXers machines. That would be impossible with the type of filters (6kHz @6dB BW) used. Rather, the articles were offered in the spirit of improving the usability of these radios in the domestic context. The give-away line in my article was 'the intrinsic quality of the audio remains.' By implication therefore, the mod filter is not especially selective merely an improvement on the original. The moral of the story is to make sure any ULR you intend to mod for 9/10kHz-split DXing has a 455kHz IF system and the ability to tune in at least 1kHz steps or better. 450kHz IF radios are a waste of time since narrow filters with a good shape factor are simply unavailable. Whilst agreeing fully with the remark by Steve about skirt selectivity and filter size, I have to ask: Was the LTM450HT filter used? Nothing else will bring much improvement except for a LTM450IT or even narrower filter, if you could find one. The 'T' suffix in the filter model number is important since these have superior skirt selectivity over those without the 'T' suffix. Living here in the UK I frequently wonder what North American DXers mean by a 'high RF environment'. Amongst others I live within 15 miles of one 150kW & two 400kW MF transmitters & less than 1 mile of two 1kW MF transmitters. The DT-210L & DT-400W filter mods have transformed the reception capabilities of these radios close to these powerful signals. Before the mod, five (9kHz) channels either side of the frequency of one of these strong locals were rendered useless for weak signal reception by the original filter. After the mod I am able to hear weak signals on the immediately adjacent channels (±9kHz) with only a small level of adjacent channel interference. Perhaps your RF environment(s) are not really that challenging? Maybe that is the reason you are not reaping the reward from the mod? -- Michael Slattery Sheffield, UK -- Michael Slattery Sheffield, UK |
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London, Ontario Heard in Oklahoma
Kirk Allen <kirk74601@...>
Thanks to some tips from John Bryant, I spent a lot of time listening on 980 khz this morning and managed to log three new stations for the ULR log here in Ponca City. Rob, you'll find one of these stations is in your back yard.
980, KICA, Clovis, NM, 0940-1020, 4/2/09, took a while to finally catch an ID out of this one, and it was the "Grace 980" slogan I finally copied at 1020. Thanks much for the tips on this station. Playing southern gospel mx. I recognized most of the songs they played throughout that 40 minutes. 980, CFPL, London, ON, 1029-1105, 4/2/09, first started hearing mentions of Canada before really trying to zero in on this one. Vy difficult copy here with QRM from an UNID SS sta, KCAB, KMBZ, and at times from KICA plus several other UNIDs were in there too. Finally hrd a lcl trfc report @1102 and very brief tlk abt the weather. Mentions of "AM 980" were also hrd. Mentioned some phone numbers with area code 519. Pretty much all talk from this one. Good ID noted around 1101 UTC. 980, WCUB, Two Rivers, WI, 1110, 4/2/09, this one faded up during a local ad string and most of the ads mentioned Two Rivers...I didn't hear an official ID, but ya know, I do believe it's pretty safe to presume this one's identity! Only audible for a few minutes, so this was a very lucky reception. ULR Station #537 here. 73's to All, Kirk Allen Ponca City, OK Eton E-100 Slider Select-a-Tenna |
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Re: Just for fun!!!
satya@...
Hi Alex:
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When you say "just for fun" I conclude that you don't have Sony's ear on this, but let's pretend you do... I would like them to make a true Ultralight, with the following: - a 5/8" diameter, 4.75" long ferrite with high-count Litz wire on the coil. This size ferrite is just small enough to fit into a 3x5 inch Ultralight case. The ferrite coil is a single movable coil for precise alignment - a DSP IF chip, one that has an alignment trimmer that Gary DeBock finds and realizes that the bias voltage can be adjusted to narrow the bandwidth to any bandwidth desired. That way, a simple alignment would keep it stock, but you would be able to dial the selectivity down to something that only Murata could normally do. - digital tuning with near-continuous tuning steps, readable to 0.1 khz steps. About 50 tuning memories is all I would need. - killer nulling, natch, at least as good as the Kaito WRX-911. - keep the 50 khz IF of the CXA1129N chip so that there are no images - a list price of $59.95 Coming back to reality, sadly Sony is out of designing high-end portables. Still, it would be something! Kevin S Bainbridge Island, WA
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Re: Just for fun!!!
--- In ultralightdx@..., Russ Edmunds <wb2bjh@...> wrote:
I don't know if I'd say 2010, this would be FM,MW,and LW. Not a shortwave receiver with broadcast MW and FM as an after thought, for it would be it's main focus instead. The exotic part is the better than average ability to receive stations under difficult conditions though using the Dxer's choice of design elements. Almost "professional grade" if that could be said. Just as useful to a DXer as it is to a person finding himself in the middle of the desert and wanting to get news or music from "the civilized world". Just a super well made receiver that would be our collective dream. Not that bringing back the 2010 would be a bad thing for the SW side of the house. Alex N8UCN/KOH8IG |
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Re: SRF-M37V and SRF-M37W-Performance differences?
satya@...
Hi Alex/All:
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I have both a stock and a re-filtered M37V. The selectivity on the re-filtered (with the LT450GW) is VERY good, noticeably better than the not-too-shabby SRF-59 and almost that of the stock Eton e100. The stock M37V is an absolute barn door, so it turns a Turkey into something of an eagle. As Gary mentioned previously, it is now an Unlimited class Ultralight, but it really becomes a great little radio. As Steve Ratzlaff mentioned earlier, these little filters cannot be expected to perform like the Murata narrow filter, but it is still a huge improvement and an excellent domestic DXing filter choice. It even dabbles in split frequencies: at the beach this past Tuesday morning, the M37V was able to get good barefoot readability on 774-JOUB from Japan when signals were sufficient, keeping strong stations on 770 and 780 at bay. To change from 9 to 10 khz, first turn the unit off. Power and Clock are the buttons across the top. First push and hold Clock, THEN press and hold Power, and hold both for about 5 seconds. Eventually a 9 or 10 will flash on the screen, indicating to which tuning increment you have just switched. Those 5 seconds seem an eternity... Hope this helps - Kevin S Bainbridge Island, WA Hi Alex, |
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Sony M37 Filter Mod photos uploaded
Gil Stacy
Check the photos section for before and after photos of filter mods on the M37. The larger black boxy filter is the replacement.
73 Gil NN4CW |
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Re: SRF-M37V and SRF-M37W-Performance differences?
Hi Michael,
Thank you for your work in developing the LTM450HT filter
modifications for the Sangean models, and for uploading the information
to DXer.Ca.
Steve and I were working toward the specific goal of transforming
the 450 kHz Sangean models into very effective 9-kHz split DX chasers for
transoceanic reception, such as we had successfully accomplished with the 455
kHz Eton E100 model last summer. We knew before commencing the work that 450 kHz
"consumer-grade" filters are not comparable with the premium Murata
CFJ455K5 filters we used in the E100, but we wanted to try anything available,
since a vastly improved Slider loopstick had already been successfully
transplanted into the DT-200VX (as described in a DXer.Ca article), greatly
boosting the model's sensitivity.
Unfortunately, the project was probably doomed from the start, due to
unrealistic expectations. If you have ever used one of the premium 455 kHz
Murata K filters for transoceanic DXing, you will probably understand how
quickly a DXer can become spoiled with the phenomenal performance. Anyway, we
never meant to be dismissive of your LTM450HT modification for domestic
DXing, and hope you will understand that our 9 kHz-split
DXing performance requirements are far more demanding than those of
the average DXer. We regret any impression to the contrary.
73 and Best Wishes, Gary DeBock
In a message dated 4/2/2009 6:50:21 P.M. Pacific Daylight Time,
knallebo@... writes:
Worried about job security? Check out the 5 safest jobs in a recession. |
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Re: 2009 Seefontein Dxpedition Video on You Tube
Bob Coomler <w6rjc@...>
--- On Thu, 4/2/09, freetodx wrote:
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Re: Just for fun!!!
Russ Edmunds <wb2bjh@...>
--- On Thu, 4/2/09, Jay Heyl wrote: From: Jay Heyl |
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Re: 2009 Seefontein Dxpedition Video on You Tube
Horacio Nigro <hanigrodx@...>
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Re: Just for fun!!!
Jay Heyl
I hope you're not kidding. For MW I'd be pretty happy to see them use the CXA1129N. Though it needs to have far better tuning control than the SRF-59. About ten times better. For FM, they have to use whatever it is they used in the XDR-F1HD. I don't care if it includes HD Radio capability, but it has to use the same non-digital FM circuit. That thing is amazing. Since this is no holds barred and I'd love to see a good portable that can be used for NDB hunting (CW on LW), I want a CW mode with a very narrow filter, 250Hz or less. Even better would be DSP with user selectable filter widths. I also want 1 Hz tuning. I know it sounds like overkill, but it's very useful with beacons. Adjustable BFO would be very nice since I hate the 800Hz offset that's often used. Selectable sideband SSB, passband tuning with steps appropriate to the filter width (i.e. tiny steps with the very narrow filter), notch filter, line out, commonly used external antenna jack (like BNC, or include converters from whatever arcane jack is used to something common). Maybe I'm going a bit overboard. Obviously this would be a bit much for an ultralight. I'm thinking more of a larger portable. -- Jay |
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Just for fun!!!
The AM DXer's in the US, have the venerable "Super Radio" series and the japanese ICF-EX5. Both getting long in the tooth, and both having room for improvment.
With that said the powers that be at Sony, want to make the "ultimate broadcast listeners radio". That being so their going to have two versions a pocketsize radio (ULR) and a bigger portable radio for the home or office. On this radio they will have the FM band, the expanded AM band, and LW for overseas users. They're also making the commitment of going all out, no cutting corners in the quality of the components,circuit design, workmanship. They are willing to use their CXA1129N or an improved version if called for. Now for the good part. There consulting with the domestic broadcast DXer's from around the world, for exactly what they want. And now they've come to you. What would you want?? I'd like to see an improved multiple filtering options, maybe DSP for analog signals, a externial antenna port for AM/LW, Synchronis detection, maybe, even a BFO for CW on LW. An analog dial, with a digital display that can be turned on and off, to see the actual freqency, but shut down to cut off the processor noise. What would you ask for skys the limit. Alex N8UCN/KOH8IG |
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Sony SRF-M37V - Switching between 9 kHz and 10 KHz increments
freetodx
BTW, How do you listen to 9KHZ stations when the M37's are 10 KHz increments. Alex While holding down the clock button, press the power button and hold for 5/6 seconds. Release when you see the 9 kHz /10 Khz in the display. 73, Gary Deacon
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