Re: [Elecraft] Switching Supplies
On Jul 8, 2008, at 8:40 AM, Jan Erik Holm wrote: Mike Penkas wrote: I have 2 SEC1223's and no hash. I also have an Astron RS35 and RS50 linear supplies. Sometimes the magnetic hum from them drives me crazy. The little cork pads Astron puts in them to alleviate this does not help much. I keep them under the closed console on the floor. Mike WA8EBM Sorry to disagree but the SEC1223 is far from quiet. However it can be made much better by modifications. The DC side needs much better filtering, also some work can be done on the AC side. I bought a used SEC-1223 at a hamfest to power my K2. I found it reasonably quiet on all bands except 160m. I added ferrite beads and bypassing to the DC output, and more ferrite to the AC leads and all but knocked the birdies completely out of the picture on 160m. Bill Coleman, AA4LR, PP-ASELMail: [EMAIL PROTECTED] Quote: Not within a thousand years will man ever fly! -- Wilbur Wright, 1901 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Switching supplies and the K3
Hi Thomas, I'm not sure what your operating style is but if you are looking for 100w on CW and SSB then I recommend the Gamma Research HPS-1a. I have one and run my K3-100 with it all the time in a portable fashion. Here is a link to Fred's site: http://www.gammaresearch.net/ It has a very small footprint, weighs only 1.25 lbs and has no problem supplying my K3 @ 100w for CW. Fred recommends cutting back to 25 or 30 watts for continuous key down type ops. I've read others who state they run it at 40 watts for PSK ops without problems. Some reviewers commented on the fan and some excessive noise, but I've never been bothered by it at all. It is indeed not as quiet as the K3 fans, but certainly not loud IMO. I've heard no noise or hash on the K3 either. I made a short cable that plugs into the HPS-1a connector (supplied) to APP's to fit the K3. If you're looking for a linear replacement, this may not meet your needs. But for portable or just CW SSB ops it certainly has worked fine for me. Take care 73, Dave W8FGU -Original Message- From: [EMAIL PROTECTED] [mailto:elecraft- [EMAIL PROTECTED] On Behalf Of Thomas Kuehl Sent: Monday, July 07, 2008 5:24 PM To: elecraft@mailman.qth.net Subject: [Elecraft] Switching supplies and the K3 Hi, I am back on the Elecraft list after being gone for quite a while. I have a K3/100 coming in the next month or 2, and now I am thinking about how it is best to power it. The K3 has a nice small footprint and that will be much welcomed in my small operating area. And, I don't want to dwarf the available space with a big linear power supply. Therefore, I am considering a switching power supply with its small size as well. Switching supplies have come a long way relative to the RF hash generation issue and I am considering going that route. I sure don't want to degrade the K3'3 outstanding performance with a noisy supply, so I am still cautious. The eHam reviews for switching supplies provides a lot of different opinions for the various products. One in particular, the Jetstream JTPS28, seems to get high marks from its users. Is anyone on the list using this particular supply to power the K3? If so, what are your impressions of its performance? Or should I skip the switching power supply idea altogether? Thanks, Thomas - AC7A ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Switching supplies and the K3
Same here. I have two of these supplies, and have yet to hear a peep of RF noise from them. 73 Stewart G3RXQ On Mon, 7 Jul 2008 21:50:08 -0400, Bruce McLaughlin wrote: I am having very good performance from the SEC 1223 which is the same supply I use with the K2/100. If it does generate any noise I have yet to hear it. Bruce-W8FU -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Thomas Kuehl Sent: Monday, July 07, 2008 5:24 PM To: elecraft@mailman.qth.net Subject: [Elecraft] Switching supplies and the K3 Hi, I am back on the Elecraft list after being gone for quite a while. I have a K3/100 coming in the next month or 2, and now I am thinking about how it is best to power it. The K3 has a nice small footprint and that will be much welcomed in my small operating area. And, I don't want to dwarf the available space with a big linear power supply. Therefore, I am considering a switching power supply with its small size as well. Switching supplies have come a long way relative to the RF hash generation issue and I am considering going that route. I sure don't want to degrade the K3'3 outstanding performance with a noisy supply, so I am still cautious. The eHam reviews for switching supplies provides a lot of different opinions for the various products. One in particular, the Jetstream JTPS28, seems to get high marks from its users. Is anyone on the list using this particular supply to power the K3? If so, what are your impressions of its performance? Or should I skip the switching power supply idea altogether? Thanks, Thomas - AC7A ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com Internal Virus Database is out of date. Checked by AVG. Version: 8.0.101 / Virus Database: 270.4.3/1529 - Release Date: 7/1/2008 7:23 PM ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching supplies and the K3
Thomas Kuehl wrote: small size as well. Switching supplies have come a long way relative to the RF hash generation issue and I am considering going that route. I sure don't want to degrade the K3'3 outstanding performance with a noisy supply, so I am still cautious. I don't like switchers. I have a Diamond GSV3000 25A linear supply. It is about the same width and depth as the K3, and slightly lower than it when it is up on the tilt bail (which it normally is.) The fan, when it comes on, is just as quiet as those in the K3. It has two meters on the front showing current and voltage. This power supply is also sold by Yaesu as the FP-1030A. - Julian, G4ILO K3 s/n: 222 K2 s/n: 392 G4ILO's Shack: www.g4ilo.com KComm for K2/K3: www.g4ilo.com/kcomm.html -- View this message in context: http://www.nabble.com/Switching-supplies-and-the-K3-tp18326982p18335407.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching supplies and the K3
Same here - nice quiet PSU. I would buy one again without any hesitation. Simon Brown, HB9DRV -- From: G4ILO [EMAIL PROTECTED] I don't like switchers. I have a Diamond GSV3000 25A linear supply. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching supplies and the K3
Based on my own personal experience, I would recommend a linear supply. I use the Astron RS-35A. Yes, it is as big as the K3, but it is rock solid, well-filtered, and RFI-free, and has over-voltage and over-current protection. In addition, the Astron has heavy-duty output terminals that will better handle the peak current. 5-way binding posts are fine for QRP but I like the larger terminals for QRO. (all IMHO of course). Buy the power supply from R and L Electronics for a low price and quick delivery. (They carry switchers, too). John W2XS Thomas Kuehl wrote: Or should I skip the switching power supply idea altogether? Thanks, Thomas - AC7A ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com -- View this message in context: http://www.nabble.com/Switching-supplies-and-the-K3-tp18326982p18337652.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching Supplies
I have 2 SEC1223's and no hash. I also have an Astron RS35 and RS50 linear supplies. Sometimes the magnetic hum from them drives me crazy. The little cork pads Astron puts in them to alleviate this does not help much. I keep them under the closed console on the floor. Mike WA8EBM - Original Message - From: [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Tuesday, July 08, 2008 6:28 AM Subject: [Elecraft] Switching Supplies Pardon me if someone has already pointed this out (I have not followed the entire thread)- my past experience with linear supplies reveals an all too often failure mode of either shorted pass transistors or blown control chips (LM-723). In either case the output voltage from the supply can rise to the unregulated DC filtered voltage (usually 20+ volts) and cook anything attached. A fast and effective crowbar, if designed correctly, will clamp this voltage before it destroys your expensive equipment. With switchers my experience has been that one or more of the switching FETs or high speed diodes fail and the supply just dies (no output). Which one would you rather have connected to your brand new K3 if it failed? 73 Rodger N4NRW counting down the day till the K3 arrival! ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching Supplies
Mike Penkas wrote: I have 2 SEC1223's and no hash. I also have an Astron RS35 and RS50 linear supplies. Sometimes the magnetic hum from them drives me crazy. The little cork pads Astron puts in them to alleviate this does not help much. I keep them under the closed console on the floor. Mike WA8EBM Sorry to disagree but the SEC1223 is far from quiet. However it can be made much better by modifications. The DC side needs much better filtering, also some work can be done on the AC side. 73 Jim SM2EKM ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching supplies and the K3
Thomas Kuehl wrote: Hi, I am back on the Elecraft list after being gone for quite a while. I have a K3/100 coming in the next month or 2, and now I am thinking about how it is best to power it. Thanks, Thomas - AC7A I bought the Alinco DM-330MW to power my K3. It's pretty small and there's no fan noise and not a peep under load. There are some birdies occasionally but they are the 'wandering' type and drift away very quickly and have never caused any problems; in any case you can tune them away with the 'tune' control on the front panel.. All in all I think this is a pretty good companion to the K3. 73, Stewart Rolfe, GW0ETF (K3 #145) -- View this message in context: http://www.nabble.com/Switching-supplies-and-the-K3-tp18326982p18338697.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching Supplies
I believe that all new SEC1223's have the mods fitted. 73 Stewart G3RXQ On Tue, 08 Jul 2008 14:40:27 +0200, Jan Erik Holm wrote: Mike Penkas wrote: I have 2 SEC1223's and no hash. I also have an Astron RS35 and RS50 linear supplies. Sometimes the magnetic hum from them drives me crazy. The little cork pads Astron puts in them to alleviate this does not help much. I keep them under the closed console on the floor. Mike WA8EBM Sorry to disagree but the SEC1223 is far from quiet. However it can be made much better by modifications. The DC side needs much better filtering, also some work can be done on the AC side. 73 Jim SM2EKM ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching supplies and the K3
I have a GSV3000 as well and can confirm the lack of rfi. In my opinion switch mode supplies have no place anywhere near the ham shack - its bad enough the neighbours having them all over the place but they don't know or care - we should know better. As an aside if anyone has any doubts about whether or not switch mode supplies cause rfi get one of these devices and check it http://www.winradio.co.uk/home/erd.htm I got one some years ago after a tip on the FlexRadio list and its been extremely useful in tracking down sources of interference - just hold it near to a wall wart supply, or usb cable for instance and be astonished with the amount to radiation being generated. The rfi being produced might not be falling directly within the hf ham bands, but, its unwanted radiation nonetheless and is not something you want in or around the shack. 73 to all Trevor G0KTN ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching supplies and the K3
The early Samlex switching power supplies were on the noisy side but they have corrected that problem years ago. I personally use the Samlex SEC 1235M switching supply with my K3 and certainly do not get any noise from it. 73 from Fern VE7GZ with K3 #412 - Original Message - From: Phil Debbie Salas [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Tuesday, July 08, 2008 7:56 AM Subject: [Elecraft] Switching supplies and the K3 Same here. I have two of these supplies, and have yet to hear a peep of RF noise from them. 73 Stewart G3RXQ I am having very good performance from the SEC 1223 which is the same supply I use with the K2/100. If it does generate any noise I have yet to hear it. Bruce-W8FU I'm using a SEC-1235. It is also RF quiet and works well. I modified mine by adding Powerpole connectors to the back, and changed the fan circuitry so that the fan runs at slow speed all the time (still full speed if/when necessary). Info is on my website in the Equipment Modification section at www.ad5x.com. Phil - AD5X ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com -- Internal Virus Database is out-of-date. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 270.4.3/1528 - Release Date: 7/1/2008 7:26 AM ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching supplies and the K3
This discussion gives me the opportunity to correct an opinion that I earlier posted on this list. Some long time ago I said I didn't much like the Watson W25-XM switched supply because of RF noises which always contrive to arrive on frequency at the worst possible moment. I advised someone on this list to think twice before purchasing a Watson switched supply. However I now have the tiny Watson Power Mite NF, a surprising and very thoughtful birthday gift from my wife. It is much quieter in RF emissions and anyway has a front panel control to shift the switching frequency in case hash does arrive on the operating frequency at a bad moment. The variable-speed fan is moderately quiet too. This supply powers the K3 (or K2) just fine. I would prefer to have a big linear PSU, of course, but my present operating conditions are much better served by this small and very light switcher. 73 Neill F5VLD / G4HLX K2/100 #2425 K3/100 #289 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Switching supplies and the K3
Trevor Smithers wrote: supplies have no place anywhere near the ham shack - its bad enough the neighbours having them all over the place but they don't know or care - we should know better. But we should also know about conversion efficiencies, power factors and power line harmonics! As an aside if anyone has any doubts about whether or not switch mode supplies cause rfi get one of these devices and check it http://www.winradio.co.uk/home/erd.htm Without a specification for near field sensitivity below a few hundred kHz, its difficult to be sure whether this is measuring anything useful in terms of radiated RFI. -- David Woolley The Elecraft list is a forum for the discussion of topics related to Elecraft products and more general topics related ham radio List Guidelines http://www.elecraft.com/elecraft_list_guidelines.htm ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
re.: [Elecraft] Switching Supplies
I also have an Astron RS35 and RS50 linear supplies. Sometimes the magnetic hum from them drives me crazy. The little cork pads Astron puts in them to alleviate this does not help much. I keep them under the closed console on the floor. Mike WA8EBM - Original Message - I have my RS 35M on the floor also. I shorted it out once momentarily an exciting moment. The problem is that the transistor cases that you see sticking out of the back on the heat shield are at V+ level. If something like a ground braid (this was my case) touches the transistors or the 12V output terminal you have a short. I ended up finding a cardboard box and cut the top and front off and most of the sides off. What is left is a cardboard back shield with lots of ventilation to prevent accidental connections to the wire maze I have down there on the floor. Mike Scott - AE6WA Tarzana, CA (DM04 / near LA) K3-100 #508/ KX1 #1311 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: re[Elecraft] .: Switching Supplies
Hello all, I am using the MFJ-4125 25A switcher with my K3. I have no RF hash or birdies from the power supply at all. I find it unbelievable that popular and supposedly quality power supplies like the Astron would leave exposed transistor cases at elevated voltage above ground. The MFJ fan, which is always running, isn't whisper quiet, but not really noisy either. This switcher faired very well in the ARRL review a few years back, in fact it was one of the most quiet ones tested. Knut - AB2TC Mike Scott-7 wrote: I also have an Astron RS35 and RS50 linear supplies. Sometimes the magnetic hum from them drives me crazy. The little cork pads Astron puts in them to alleviate this does not help much. I keep them under the closed console on the floor. Mike WA8EBM - Original Message - I have my RS 35M on the floor also. I shorted it out once momentarily an exciting moment. The problem is that the transistor cases that you see sticking out of the back on the heat shield are at V+ level. If something like a ground braid (this was my case) touches the transistors or the 12V output terminal you have a short. I ended up finding a cardboard box and cut the top and front off and most of the sides off. What is left is a cardboard back shield with lots of ventilation to prevent accidental connections to the wire maze I have down there on the floor. Mike Scott - AE6WA Tarzana, CA (DM04 / near LA) K3-100 #508/ KX1 #1311 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com -- View this message in context: http://n2.nabble.com/re.%3A-Switching-Supplies-tp395807p395863.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: re.: [Elecraft] Switching Supplies
Here's a plug for the MFJ-4225MV which I'll be using with my K3 any day now ... It should go well because it's small and light (I guess most switchers can make that claim though). I have not noticed any RF noise when using it with my IC-706 or alongside my now departed FT-1000. It has a fan that runs continuously. Fairly quiet but I don't like hearing fans at all. I'm thinking of doing some sort of temperature controlled mod so the fan only runs if needed. 73--Nick, WA5BDU ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: re[Elecraft] .: Switching Supplies
I find the fan noise on my MFJ-4125 unacceptable. If I ever use it again it will have to be put behind the desk. 73, Tony W7GO ab2tc wrote: Hello all, I am using the MFJ-4125 25A switcher with my K3. I have no RF hash or birdies from the power supply at all. I find it unbelievable that popular and supposedly quality power supplies like the Astron would leave exposed transistor cases at elevated voltage above ground. The MFJ fan, which is always running, isn't whisper quiet, but not really noisy either. This switcher faired very well in the ARRL review a few years back, in fact it was one of the most quiet ones tested. Knut - AB2TC Mike Scott-7 wrote: I also have an Astron RS35 and RS50 linear supplies. Sometimes the magnetic hum from them drives me crazy. The little cork pads Astron puts in them to alleviate this does not help much. I keep them under the closed console on the floor. Mike WA8EBM - Original Message - I have my RS 35M on the floor also. I shorted it out once momentarily an exciting moment. The problem is that the transistor cases that you see sticking out of the back on the heat shield are at V+ level. If something like a ground braid (this was my case) touches the transistors or the 12V output terminal you have a short. I ended up finding a cardboard box and cut the top and front off and most of the sides off. What is left is a cardboard back shield with lots of ventilation to prevent accidental connections to the wire maze I have down there on the floor. Mike Scott - AE6WA Tarzana, CA (DM04 / near LA) K3-100 #508/ KX1 #1311 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: re[Elecraft] .: Switching Supplies
On Tue, 2008-07-08 at 17:02, ab2tc wrote: Hello all, I am using the MFJ-4125 25A switcher with my K3. I have no RF hash or birdies from the power supply at all. I find it unbelievable that popular and supposedly quality power supplies like the Astron would leave exposed transistor cases at elevated voltage above ground. The MFJ fan, which is always running, isn't whisper quiet, but not really noisy either. This switcher faired very well in the ARRL review a few years back, in fact it was one of the most quiet ones tested. Knut - AB2TC And the cheapest of all the ones tested, as I recall. I bought it because of the price and the small size and weight. When I go on a trip I can throw it in a suitcase with the K3 and still have room left over for clothes. The only complaint I have heard about the MFJ-4125 is the fan noise. While it is definitely audible, I personally don't find it objectionable. For those who do, placing the unit under the operating table should solve the problem. Al N1AL ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] Switching supplies and the K3
I am having very good performance from the SEC 1223 which is the same supply I use with the K2/100. If it does generate any noise I have yet to hear it. Bruce-W8FU -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Thomas Kuehl Sent: Monday, July 07, 2008 5:24 PM To: elecraft@mailman.qth.net Subject: [Elecraft] Switching supplies and the K3 Hi, I am back on the Elecraft list after being gone for quite a while. I have a K3/100 coming in the next month or 2, and now I am thinking about how it is best to power it. The K3 has a nice small footprint and that will be much welcomed in my small operating area. And, I don't want to dwarf the available space with a big linear power supply. Therefore, I am considering a switching power supply with its small size as well. Switching supplies have come a long way relative to the RF hash generation issue and I am considering going that route. I sure don't want to degrade the K3'3 outstanding performance with a noisy supply, so I am still cautious. The eHam reviews for switching supplies provides a lot of different opinions for the various products. One in particular, the Jetstream JTPS28, seems to get high marks from its users. Is anyone on the list using this particular supply to power the K3? If so, what are your impressions of its performance? Or should I skip the switching power supply idea altogether? Thanks, Thomas - AC7A ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com Internal Virus Database is out of date. Checked by AVG. Version: 8.0.101 / Virus Database: 270.4.3/1529 - Release Date: 7/1/2008 7:23 PM ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
