OT: MFJ Quality Issues
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MFJ builds to the lowest common denominator, which is inverse to Elecraft. Each Elecraft is custom crafted, and as of yesterday, If there is a good concern, you can get the actual engineer on the horn - whatever it takes to make it right. I also purchased the 1026 Noise Canceller most recently, but they bend the cabinet sheet metal AFTER it's painted, then (MFJ's term) "adjust" the product with a green magic marker pen. Looks like crap, new out of the box. The same cost savings are applied elsewhere, I installed a small relay in the place of this little light bulb they have for RF circuit protection, and removed many decibels of attenuation. Where do all these cost savings go? Into QST, AES, etc magazine advertising, they have all the money in the world for that!!!! ;-) [Elecraft] OT: MFJ Quality Issues Erik N Basilier ebasilier at cox.net Fri Apr 3 14:04:03 EDT 2009 Previous message: [Elecraft] OT: MFJ Quality Issues Next message: [Elecraft] K2: KPA100 capacitor failures Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] -------------------------------------------------------------------------------- Here is my MFJ score: Over the years I have bought only 4 MFJ products brand new and fully assembled. Of those, only the first one had a problem. That was a tuner purchased over 20 years ago. It had a missing solder joint. My later purchases (noise bridge, RF current sniffer, noise canceler) have been fine. 73, Erik K7TV ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
totally OT, except to the extent that it's QRP: LED lamps
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I just replaced four gas-guzzling incandescent lamps in my dining room
chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. The usual complaint about LED lamps is the cost. But prices are coming down fast: these were only about $4 each at Costco. Each contains 21 white LEDs, and they basically last forever, which means I won't constantly be replacing lamps in this fixture. If the world converts to LED lighting, we won't need to build any more power plants, and we can all use KW amps guilt-free :) Wayne N6KR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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How are the power supplies in these little beasties? Are they noisy? Could
they be? Buck k4ia k3#101 In a message dated 4/3/2009 4:58:06 P.M. Eastern Daylight Time, [hidden email] writes: I just replaced four gas-guzzling incandescent lamps in my dining room chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. The usual complaint about LED lamps is the cost. But prices are coming down fast: these were only about $4 each at Costco. Each contains 21 white LEDs, and they basically last forever, which means I won't constantly be replacing lamps in this fixture. If the world converts to LED lighting, we won't need to build any more power plants, and we can all use KW amps guilt-free :) Wayne N6KR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html **************Hurry! April 15th is almost here. File your Federal taxes FREE with TaxACT. (http://pr.atwola.com/promoclk/100126575x1220714320x1201367638/aol?redir=http:%2F%2Fwww.taxact.com%2F08tax.asp%3Fsc%3D084102950001%26p%3D82) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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I haven't heard any noise from them yet. Since they run directly from
110 VAC, I imagine it's just a bridge rectifier, a resistor, and a filter cap. I wouldn't expect any RF noise. Wayne On Apr 3, 2009, at 2:03 PM, [hidden email] wrote: > How are the power supplies in these little beasties? Are they noisy? > Could > they be? > > Buck > k4ia > k3#101 > --- http://www.elecraft.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by wayne burdick
Sorry, I just can't resist ...
Wayne, that may be fine for your warm California weather, but for other places the wattage benefit is not as great. Consider that, during cold weather, the heating plant must now make up for those 234 watts no longer being dissipated by the bulbs. :-) Actually, we heat our home with geo-thermal energy and have a good solar room, so for those with similar efficient heating systems, those lower wattage lamps may create a good savings for both my electric bill and the planet. 73, Don W3FPR wayne burdick wrote: > I just replaced four gas-guzzling incandescent lamps in my dining room > chandelier with four LED lamps that screw into the same bases. Went > from 240 watts to 6 watts, total. > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by wayne burdick
I don't know about the rest of you but I turn on an incandescent light when I go into my radio room. It gets the chill out of the air. Currently it is snowing and it has been snowing intermittently for the last week. Winter still holds a tight grasp on this mountain. Since I heat with wood not all rooms are the same temperature. The radio room is normally closed so it can be 40 degrees in there when I open the door. That incandescent light has made life much more comfortable at the paddles. Since solid state gear does not throw off as much heat as tube gear I cannot warm my fingers between stints of sending by holding them over the rig. I am very glad I use that light. It is only 60 watts but I can direct it at my hands and it does offer the side benefit of providing extra light ;)
73, Kevin. KD5ONS -----Original Message----- >From: Don Wilhelm <[hidden email]> >Sent: Apr 3, 2009 5:22 PM >To: wayne burdick <[hidden email]> >Cc: Elecraft Reflector <[hidden email]> >Subject: Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps > >Sorry, I just can't resist ... >Wayne, that may be fine for your warm California weather, but for other >places the wattage benefit is not as great. Consider that, during cold >weather, the heating plant must now make up for those 234 watts no >longer being dissipated by the bulbs. :-) > >Actually, we heat our home with geo-thermal energy and have a good solar >room, so for those with similar efficient heating systems, those lower >wattage lamps may create a good savings for both my electric bill and >the planet. > >73, >Don W3FPR > >wayne burdick wrote: >> I just replaced four gas-guzzling incandescent lamps in my dining room >> chandelier with four LED lamps that screw into the same bases. Went >> from 240 watts to 6 watts, total. >> >> >> >______________________________________________________________ >Elecraft mailing list >Home: http://mailman.qth.net/mailman/listinfo/elecraft >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:[hidden email] > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by wayne burdick
On Fri, 2009-04-03 at 13:59 -0700, wayne burdick wrote:
> I just replaced four gas-guzzling incandescent lamps in my dining room > chandelier with four LED lamps that screw into the same bases. Went > from 240 watts to 6 watts, total. > > The usual complaint about LED lamps is the cost. But prices are coming > down fast: these were only about $4 each at Costco. Each contains 21 > white LEDs, and they basically last forever, which means I won't > constantly be replacing lamps in this fixture. > > If the world converts to LED lighting, we won't need to build any more > power plants, and we can all use KW amps guilt-free :) > > Wayne > N6KR Do they really last forever? I have had bad luck with LED night lights gradually getting dimmer over a period of a few months. Do the incandescent replacements have any specs on that? Al N1AL ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by wayne burdick
I hope you have good luck with longevity.
We replaced hundreds of exit light bulbs with LED types at my previous job. They did not last long enough to pay for any energy savings. Granted, that was 10 years ago, maybe technology has improved to a point that they are a viable option. I will be interested to see what your opinion is in a year or two. At my home I have changed over to compact fluorescent bulbs, decent light, good life, the only bad I have found is that they take a few moments to come up to full brightness (temperature really affects this). wayne burdick wrote: > white LEDs, and they basically last forever, which means I won't > constantly be replacing lamps in this fixture. > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
73 de Allen, W1SBY
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Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by Don Wilhelm-4
...and the math is real easy, Wayne, if one lives in an electrically-heated
house. Gary, VE1RGB -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Don Wilhelm Sent: April 3, 2009 6:22 PM To: wayne burdick Cc: Elecraft Reflector Subject: Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps Sorry, I just can't resist ... Wayne, that may be fine for your warm California weather, but for other places the wattage benefit is not as great. Consider that, during cold weather, the heating plant must now make up for those 234 watts no longer being dissipated by the bulbs. :-) Actually, we heat our home with geo-thermal energy and have a good solar room, so for those with similar efficient heating systems, those lower wattage lamps may create a good savings for both my electric bill and the planet. 73, Don W3FPR wayne burdick wrote: > I just replaced four gas-guzzling incandescent lamps in my dining room > chandelier with four LED lamps that screw into the same bases. Went > from 240 watts to 6 watts, total. > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by W1SBY
Hi Allen,
The new LED bulbs are rated for 50000 hours, but this is a guess, because they haven't burned out yet even in accellerated life tests :) Your older LED lamps probably failed because they were using a very small number of LEDs, driven to very high current. Newer LED bulbs use dozens of LEDs, each running at low current. 73, Wayne On Apr 3, 2009, at 2:40 PM, Allen Wisbey wrote: > I hope you have good luck with longevity. > We replaced hundreds of exit light bulbs with LED types at my previous > job. They did not last long enough to pay for any energy savings. > Granted, that was 10 years ago, maybe technology has improved to a > point > that they are a viable option.... --- http://www.elecraft.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by Alan Bloom
There's a Department of Energy report at
http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/lifetime_white_leds_aug16_r1.pdf on white LED lifetime. Their conclusion is that if the LED is properly heat sunk, (heat sinked?) the lifetime should be around 35,000 - 50,000 hours. I suspect that there's a "you get what you pay for" in this regard, in that cheap LED lamps are not going to approach these figures but properly designed and manufactured ones will. I've disassembled a couple of cheap CFLs and I strongly suspect they won't last very long. The ones I disassembled failed for several reasons, including a drop onto the floor, but running them with base up is deadly - apparently the CFLs are designed with the assumption that they will be run base down for proper cooling. Some CFLs are expressly rated for base up operation and should be used when that's the operating mode. Jack K8ZOA Alan Bloom wrote: > On Fri, 2009-04-03 at 13:59 -0700, wayne burdick wrote: > >> I just replaced four gas-guzzling incandescent lamps in my dining room >> chandelier with four LED lamps that screw into the same bases. Went >> from 240 watts to 6 watts, total. >> >> The usual complaint about LED lamps is the cost. But prices are coming >> down fast: these were only about $4 each at Costco. Each contains 21 >> white LEDs, and they basically last forever, which means I won't >> constantly be replacing lamps in this fixture. >> >> If the world converts to LED lighting, we won't need to build any more >> power plants, and we can all use KW amps guilt-free :) >> >> Wayne >> N6KR >> > > Do they really last forever? I have had bad luck with LED night lights > gradually getting dimmer over a period of a few months. Do the > incandescent replacements have any specs on that? > > Al N1AL > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by wayne burdick
Many years ago I managed the optoelectronics portion of a large U.S. semiconductor operation. We weren't very good at what we did and I suffered through several quality issues as a result, so I feel I have some backside expertise in this area. The lifetime of an LED is a function of four things ... the size and density of crystal lattice defects in the chip itself, the current density through the junction, the temperature of the chip, and the reliability of the connections to it. While current density typically determines the temperature of the chip, high current density alone will propagate crystal defects even if the temperature is held very low in a cold liquid. There are various methods for creating the semiconductor junction of an LED and some are more efficient than others in terms of light per watt, but lattice defects negatively affect power out efficiency in all cases, and it is the propagation of those defects that causes the devices to dim over time. In recent years, process design and control has improved to the point where light output efficiency has reached levels I never dreamed were possible, which almost for sure means that lattice defect densities (and therefore device lifetimes) are much improved. And as Wayne says, that higher efficiency allows the devices to be run cooler ... which also would make them live even longer. It seems to me that the life of modern LEDS should mostly be determined by how hard they are being driven (several LEDs driven moderately versus a few being abused), the effectiveness of the heat sinking for the LED package and whatever it is fastened to (I suspect most designs rely on the leads to carry away the heat), and the interconnections to the chip. With reasonable design margins and not too much carelessness on the packagings side, I'd expect them to last a very long time. By the way, I don't think a bridge rectifier is really needed. If I were doing the design, I'd probably just use two strings of LEDs back-to-back across the AC line ... driven slight harder but with an inherent 50% duty cycle. The distributed heat dissipation of several LEDs might be easier to deal with than the dissipation in the single bridge rectifier. It would probably be prudent to include some sort of current limiting to protect against line surges, but since LED forward I-V curves are not very sharp even that might not be needed in some cases. I would bet that there is more variation in individual LED brightness than there is in the forward voltage curves. In my opinion, there are very good reasons why automobile tail lights and traffic signals almost universally use LED lamps now. 73, Dave AB7E wayne burdick wrote: > Hi Allen, > > The new LED bulbs are rated for 50000 hours, but this is a guess, > because they haven't burned out yet even in accellerated life tests :) > > Your older LED lamps probably failed because they were using a very > small number of LEDs, driven to very high current. Newer LED bulbs use > dozens of LEDs, each running at low current. > > 73, > Wayne > > On Apr 3, 2009, at 2:40 PM, Allen Wisbey wrote: > > >> I hope you have good luck with longevity. >> We replaced hundreds of exit light bulbs with LED types at my previous >> job. They did not last long enough to pay for any energy savings. >> Granted, that was 10 years ago, maybe technology has improved to a >> point >> that they are a viable option.... >> > > > --- > > http://www.elecraft.com > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by wayne burdick
I've had two multi-led AC Edison base LED lights fail with exactly half
of the leds off. I suspect some circuit optimization was done in the driver, with a bit of skimping. Leigh/WA5ZNU > Hi Allen, > > The new LED bulbs are rated for 50000 hours, but this is a guess, > because they haven't burned out yet even in accellerated life tests :) > > Your older LED lamps probably failed because they were using a very > small number of LEDs, driven to very high current. Newer LED bulbs use > dozens of LEDs, each running at low current. > > 73, > Wayne > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by wayne burdick
Perhaps the time is now right to replace domestic lighting circuits with 12V
supply, then the cost of the fitments will come down, ie no need for 110/240V conversion to low dc for the leds. Safer, cheaper, more reliable, less raw materials. At those power levels, you could probably keep the original house wiring and just fit a 12V transformer/rectifier. Easier to use alternative power sources, too. Be nice if we had your prices over here. David G3UNA ----- Original Message ----- From: "wayne burdick" <[hidden email]> To: "Elecraft Reflector" <[hidden email]> Sent: Friday, April 03, 2009 9:59 PM Subject: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps >I just replaced four gas-guzzling incandescent lamps in my dining room > chandelier with four LED lamps that screw into the same bases. Went > from 240 watts to 6 watts, total. > > The usual complaint about LED lamps is the cost. But prices are coming > down fast: these were only about $4 each at Costco. Each contains 21 > white LEDs, and they basically last forever, which means I won't > constantly be replacing lamps in this fixture. > > If the world converts to LED lighting, we won't need to build any more > power plants, and we can all use KW amps guilt-free :) > > Wayne > N6KR > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by wayne burdick
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Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by wayne burdick
wayne burdick wrote:
> I haven't heard any noise from them yet. Since they run directly from > 110 VAC, I imagine it's just a bridge rectifier, a resistor, and a > filter cap. I wouldn't expect any RF noise. The LEDs need a constant current supply. Using a resistor to achieve that would significantly compromise power consumption. I would expect them to use a switch mode power supply, regulated for current, rather than voltage. That's how professional LED lighting drivers work. The electronics ought to be very similar to those in CFLs, but it will be easier to get a good ground plane. The current generation of LED bulbs are based on 3W or greater single devices, so a 6 watt device would only drop about 8 volts. A device that achieved 6 watts with large numbers of devices is obsolescent technology, although may well be all that is available on the consumer market (although, for specialised consumer markets, like bicycle headlamps, the state of the art devices are in use, as they are for commercial lighting). -- David Woolley Emails are not formal business letters, whatever businesses may want. RFC1855 says there should be an address here, but, in a world of spam, that is no longer good advice, as archive address hiding may not work. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: totally OT, except to the extent that it's QRP: LED lamps
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In reply to this post by Don Wilhelm-4
On Apr 3, 2009, at 5:22 PM, Don Wilhelm wrote: > Wayne, that may be fine for your warm California weather, but for > other > places the wattage benefit is not as great. Consider that, during > cold > weather, the heating plant must now make up for those 234 watts no > longer being dissipated by the bulbs. :-) You laugh -- But! My father was a Chemistry professor at a small college in West Virginia. In the late 60's they designed and built a new Science building, which opened in 1971. In the mid-70s, during the energy crisis, the college decided to try and save money by turning off all lights in the building at night. This was OK until winter came. They found that the heating system in the new building was running 100% of the time overnight, but the building temperature was still in the low 60s in the mornings. It turns out that the architects of the building had factored the heat output of all the florescent lighting in the building hallways. In fact, the lights were positioned just below the air returns for the HVAC system for this purpose. It was actually a brilliant bit of engineering. So, they ended up leaving all the lights on in the winter. Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email] Web: http://boringhamradiopart.blogspot.com Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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