+++++++++++++++ Here the challange is to get a power supply with an adjustable voltage so that the 14.2 volts required to charge the internal K2 battery is present... Otherwise, the adjustment voltage is not important See also Switching Power Supplies +++++++++++++++ Date: Thu, 20 Sep 2001 10:01:54 -0600 From: "Bob Follett" Subject: [Elecraft] P/S for Austrailia -- Batt Charger Gangue: Through the FT817 list, I found reference to a really neat switcher supply. Its an International Power Sources CUP 36-12-1, and I seem to remember the cost was about $43 with shipping from one of their distributors. Why is it good? 13.5V out, 2.4A continious, sealed, and it has about the same volume as a package of cigarettes (different form factor -- longer and skinny). The input is rated as 100V-240V 50-60 cycle. Even has a proper DC-out coax connector on it! So.... Anywhere in the world, no need for a travel adapter, just the plug adapter, and its lighter than a wall-wart, but fully regulated. It is considered by the FT 718 group to be a realtively quiet switcher, but I found that when one uses hotel-style antennas that are close to the radio, some birdies that go to about S8 are found on the bands. On a regular coax fed antenna, it is perfectly quiet, and it has enough momentary power to drive either the K2 or FT 718. When traveling with close antennas -- like wire with a counterpoise, I find it better just to use the P/S to charge the battery -- the voltage is almost perfect. 73, Bob ______________________________ Bob Follett AB7ST 3133 American Saddler Dr. Park City, UT 84060 +++++++++++++++++++ Date: Fri, 21 Sep 2001 08:12:44 -0600 From: "Rod Cerkoney, N0RC" Subject: Re: [Elecraft] Power Connector for K2 Chas, Are you asking about the plug that fits the connector in the radio? Or, the connector in the radio? The plug is 5.0/2.1mm OD/ID respectively. RS has them, but I don't have the P/N. In store packages have size marked on them. The part Elecraft supplies is from Switchcraft and is available from Digikey part number: SC-1052-ND (I think the Switchcraft item is of superior quality) The Connector in the radio (probably Switchcraft) is Digikey item: SC1155-ND Digikey online page for these items is: http://info.digikey.com/T013/V5/177.pdf GL 73, Rod N0RC Ft Collins, CO +++++++++++++++++ Date: Fri, 21 Sep 2001 10:19:20 -0500 From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: [Elecraft] K2 Coaxial Power Connector - More info Rod Cerkoney, N0RC, wrote: >The plug is 5.0/2.1mm OD/ID respectively. RS has them, but I don't >have the P/N. In store packages have size marked on them. The part >Elecraft supplies is from Switchcraft and is available from Digikey >part number: SC-1052-ND (I think the Switchcraft item is of superior >quality). > >The Connector in the radio (probably Switchcraft) is Digikey item: >SC1155-ND > >Digikey online page for these items is: > > http://info.digikey.com/T013/V5/177.pdf More info: Switchcraft #S760, Mouser part #502-S-760 Technical specs: ID .080" (2.03mm), assume 2.1mm OD .218" (5.5mm) See NOTE below Barrel Length .375" (9.52mm) Note: Switchcraft does not list a 5.1mm (0.20") diameter barrel coaxial power connector. It appears that ALL of their coaxial pwr connectors are 5.5mm (0.218") in diameter. I used a caliper to confirm the outside diameter of the barrel of the plug I'd received from Elecraft. 0.218" (5.5mm) on the button. For more info on this Switchcraft connector, go to: http://www.switchcraft.com/ and search for "S760". The plug dimension specs are at the bottom of this page, and if you click on selection #2 (760/S760) from the list at the top of the page, you can download a single-page PDF which shows to detailed engineering drawing of the plug, with references which will match to the specs on the page noted above. I believe this to be the power plug which we are using on our K2s and K1s. They ARE better quality than the plugs available from R/S, if for no other reason that the fact that the center cunductor of the Switchcraft plugs is slightly recessed within the insulator, thus making it more difficult to accidently short the positive lead to ground. The apparent R/S equivalent (at least with regard to dimensions, NOT quality) is their 274-1569 (5.5 x 2.1 mm). The apparent DigiKey part #'s are: Plug SC-1052-ND (as Ron has stated) Socket SC-1153-ND (the SC-1155-ND is SMT) NOTE that the 1998 DigiKey catalog from which I got this info had the Switchcraft part #'s for the plug and jack SWITCHED. However the DigiKey web site (www.digikey.com) had everything listed correctly. Users are urged to RETAIN this information for the future when you will surely need it. And WILL eventually need it... almost guaranteed! Thanks Ron, Tom Hammond N0SS ++++++++++++++++ Date: Mon, 3 Dec 2001 17:46:14 -0800 From: "James Lytthans" Subject: [Elecraft] MFJ Power Supply I'm brand new on the list, having put K2#2195 on the air today for the first time. I don't know if this MFJ power supply has been mentioned here before, but here goes. I purchased the new MFJ switching p/s some time ago to use with my FT-817, and used it today with the K2. At $40 it's quite a supply. Basically a notebook p/s, with some unique features, such as world-wide voltage capability and 13.8V at 2.9A power output. The coaxial power plug (with the FT-817 adapter removed) fits the K2 fine, with no RF hash. I'm taking the radio to Germany this summer, with the supply. My friend Arno, DL6SX, is longing to see the rig, since it's considered to be the best radio available, spec-wise, in Germany. Here is the URL: http://www.mfjenterprises.com/products.php?prodid=MFJ-4103 BTW the K2 is working beautifully. My first contact today was with Maine on 20m, S8+. Quite a rig. 73, Jim - ----- Jim Lytthans K6VRY K2#2195, K1#956 in progress Anaheim, CA http://home.earthlink.net/~lytthans/index.html +++++++++++++++++++++ Date: Sun, 06 Jan 2002 16:58:20 -0800 From: lhlousek To: elecraft list Subject: [Elecraft] K1 linear power supply I generally use my K1 for hotel/P ops or at home. Since AC was always near at hand I didn't want have to carry a charger and futz with charging the batteries. I also wanted to run 5 W on all bands. I tried a number of small switching power supplies but they all put out hash under one condition or another so I put together a little linear power supply. The supply is based on an $8, 15V unregulated DC wallwart from Jameco. A couple of filter capacitors, a low dropout Vreg and a few associated components are mounted in a small Hammond die cast box that fits into the K1 in place of the battery pack. It can also be left outside the K1. This setup provides 12.25 VDC at 1 amp, barely gets warm to the touch during normal operation and provides plenty of juice for 5 watts on 40 thru 15 meters. If you'd like more info let me know. Lou W7DZN +++++++++++++++++ Date: Sat, 26 Jan 2002 00:21:43 -0500 From: "David A. Belsley" To: "John Grebenkemper, KI6WX" , Elecraft Mailing List Subject: Re: [Elecraft] Power Supply for K2 John: I've used the 22-504, and it seems just fine. It's not a switcher and it doesn't make any noise that I've heard. It is a bit big and heavy, of course, relative to the switchers. I've also used the 22-503, switcher. It does make noise: a walking hash about every 100KHz. But it's a problem only if you have open antenna lead near the supply. When I use it at home, where the transmatch is about 25 feet of coax away from the supply, there is no problem at all. The cheapest decent supply I've found is the Elpack WRI4212 that I got for about $12.50 from, I believe, All Electronics. It's voltage is adjustable. They may still have some. It is very quiet, and about half the size and weight of the 22-504. The smallest, lightest supply I've found is the 4.16 amp, 12 volt PhiHong supply, model PSA60W-120. It's available from Mouser, and it's about the size of a pack of cigarettes. Some people said they got noise out of theirs. I've had no such problem unless my antenna lead is wrapped around the power supply. It's voltage is not adjustable. best wishes, dave belsley, w1euy --On Friday, January 25, 2002 7:36 PM -0800 "John Grebenkemper, KI6WX" wrote: > Has anyone used the 3 amp 12V regulated Radio Shack power supply (22-504) > to power their K2? Any problems with noise? Any other recommendations > for an inexpensive K2 AC supply? > -John > KI6WX ++++++++++++++++++++ From: "Jay Rutherford" To: elecraft at mailman.qth.net Date: Sat, 26 Jan 2002 07:26:21 -0500 Subject: Re: [Elecraft] Power Supply for K2 Reply-To: k1uc at adelphia.net John, I will echo Dave's comments on both the 22-503 and the Elpac WRI4212, since he described my experiences with them. Don't know about the 22-504, though, or the PSA60 job. The Elpac is available from http://www.allelectronics.com/ in either new (PS-1242) at $18 or used (PS-1235) at $12.50. On either, the plug needs to be replaced and the voltage cranked up inside for effective use with the K2 with battery. 73, Jay K1UC in Waterbury Center, Vermont, USA GRID FN34 Email: K1UC at AMSAT.ORG K2#1034 +++++++++++++++++++ Date: Sat, 26 Jan 2002 11:40:09 -0500 To: "John Grebenkemper, KI6WX" From: Dave Gingrich K9DC Subject: Re: [Elecraft] Power Supply for K2 Cc: Elecraft Mailing List At 19:36 1/25/2002 -0800, John Grebenkemper, KI6WX wrote: >Has anyone used the 3 amp 12V regulated Radio Shack power supply (22-504) to >power their K2? Any problems with noise? Any other recommendations for an >inexpensive K2 AC supply? John- You didn't say if you have the KBT2 installed. To keep the battery charged you need to end up with 13.8 - 14.2 indicated on the K2 battery display (actual supply voltage about .5 higher). See the battery care and feeding doc on the website. I carry a Phihong PSS-45W-150 laptop style switcher. I think I paid about $25 from Mouser. 15 volts regulated, rated at 3.4 amps, weighs about 6 oz. A diode installed in the cable drops the voltage about .5, and I end up with 13.9 indicated on the K2. The supply does produce a little noise if I connect the antenna directly to the rig (no coax), but no noise is noticeable on any antenna away from the radio. If noise is a problem, I run on the battery and use the supply to charge the battery when not operatng. ================================================ Dave Gingrich, K9DC - Indianapolis, Indiana USA K2 #2211, K1 #931, QRP-L #2376, ARS #1109, FPQRP #389, IRLP #473, k9dc.ampr.org, CCIE #6748 ++++++++++++++++++++ From: "Greg Fischer" To: Subject: Fw: [Elecraft] Power Supply for K2 Date: Sat, 26 Jan 2002 09:47:07 -0800 I picked up a LUXONICS 10a supply from Mountain-OPS (tak pak people). It is tiny, only about 1x3x5. Volt is adjustable from a pot accessed from the bottom and have not noticed any hash from it. I keep it for traveling purposes. Greg AB7R +++++++++++++++++ Date: Sun, 27 Jan 2002 21:22:48 -0800 From: "John Grebenkemper, KI6WX" To: Elecraft Mailing List Subject: [Elecraft] K2 Power Supply Recommendations A few days ago I posted a message regarding AC power supplies for the K2. A summary of the results of the messages I received follows. Radio Shack makes two 13.8 V 3A supplies. #22-503 ($50) is a switching supply and some folks have heard noise from the supply in the receiver. #22-504 ($40) is a linear supply and runs a K2 with no apparent noise, but is bigger and heavier than the switching supply. Mouser (www.mouser.com) has a small 15V 3.4A switching supply. Again, you might get some noise from it if your antenna is close to the supply. The part number is 552-PSS-45W-150 ($38). This is clearly the one to get if small size is important to you. Finally, the cheapest supply is from http://www.allelectronics.com/. The Elpac PS-1242 is $18. Again this is a switching supply and you may have trouble with power supply noise getting into the antenna. Since size was not an issue, I purchased the Radio Shack #22-504 linear supply. It is very quiet; an antenna draped across the supply did not pick up any noise from it. The supply as delivered provided 13.85 volts output, which dropped to 13.75 volts at a 3 amp load. There is a pot on it that can adjust the supply voltage from 13.1 to 14.2 volts. The noise on the output voltage measured 5 mV peak-to-peak with the K2 in receive and increased to 20 mV peak-to-peak with a 3 amp load. Thanks for all of the suggestions. -John KI6WX +++++++++++++++++++ Date: Thu, 14 Feb 2002 20:32:05 +1300 From: Ron ZL1TW To: Elecraft Subject: [Elecraft] Powr supplies for "K" kits. Greetings all, There has been a bit of discussion on and off about suitable power supplies for the K1 and K2 tranceivers. Most appear to be opting for the switchmode supplies which must be tiny units, but still apparently can supply a bit of noise as well as voltage. I decided some time ago to try and make a supply for the rigs I have here that would be safe and relatively easy to cart around without giving myself a hernia. I do have a 30 amp supply (real rupture material to cart around) and a supply I made up with two 12 amp/hr gell cells and trickle charger. (Mild hernia material) However a supply mentioned in the 1996 CDROM version of the ARRL caught my eye and today I just finished it, and it appears to work well on both the K1 and K2 . It is a 5 amp 13.8v supply that uses a LM338K regulator, and 3423 IC in a crowbar circuit to cater for any "nasties" that resulted in overvoltage. The circuit is easy to make and setup, and works well. I have mine mounted in a computer power supply carcase that I have put a decent front panel on. I have this one set to supply 14.4V and the crowbar come into action at 15.25v Cheap to make, has good regulation , and supplies a nice clean DC output. What more could an Elecraft owner want? I quite like the "Pass transistor" type of supplies...even if they are a bit inefficient compared with their switchmode brothers, but I also insist on having that crowbar circuit ......... Possibly worth a look at????.......especially for those suffering from solder fume withdrawal after finishing their kits??? Cheers......Ron ZL1TW ++++++++++++++++++ To: elecraft at mailman.qth.net Date: Thu, 14 Feb 2002 23:56:09 -0600 From: n4so at juno.com Subject: [Elecraft] Power Supply for K Kits A Power Supply for QRP kits -originally published in QST November 1993 and ARRL Handbook 1995 and 1996. A 13.8 v, 5-A Power Supply, ARRL Handbook, ed. 1996- pages 11.28- 11.30 diagram, pictures and parts list, built by Bud Spencer, G4YNM. PC board available from FAR Circuits, 18N640 Field Court, Dundee, IL 60118, latest catalog has it listed as: QST Nov93- 13.5v 5A. SPENCER POWER SUPPLY (Board and MC3423P1) ARRL HB 95 Fig. 11.37. Output voltage adjustable thru an LM338K regulator. PC board/and IC is $6.50. Ken Brown-N4SO Mobile, AL EM50tk Elecraft K1 at 5 watts/4 ele. yagi Keylite Kit keyer ++++++++++++++++++ From: "WA5PB" To: "elecraft list" Subject: Re: [Elecraft] power supply concerns Date: Thu, 21 Feb 2002 21:59:36 -0600 Tom and George, Thanks guys! Found the adjustment, works like a champ! :-D 73 WA5PB Bill Allen ----- Original Message ----- From: "Tom Hammond NØSS" To: "WA5PB" Sent: Thursday, February 21, 2002 22:39 PM Subject: Re: [Elecraft] power supply concerns Bill: There's a PC-mount pot in Astron power supplies hwich will allow you to adjust the output voltage. Should be labeled R5 (1k) and the wiper of this pot connects to pin 4 of the uA734 precision voltage regulator. Tom Hammond N0SS At 09:26 PM 2/21/02, you wrote: >Hey Gang, > >I have the internal battery option for the K2 headed my way, but I have some >concerns about my power supplies. > >Both my Astron RS-20A and Pyramid supplies give me no more than 13.7vdc at >the plug or 13.5 at the dc input of the K2. When I hit display, it gives me >a 13.1-13.2 reading. What can I do short of getting new power supplies so >as to not reduce the life of the internal battery? > >Any help or advice would be appreciate. > >73 >WA5PB >Bill Allen >K2#1068 ++++++++++++++++++ To: elecraft at mailman.qth.net Date: Wed, 27 Feb 2002 13:02:59 -0700 Subject: Re: [Elecraft] K1 build question (batteries) From: Gary L Surrency If you do use a large battery, or any high current capacity DC supply - be sure to fuse the power leads to the K1 or K2 so a short circuit inside the rig does not vaporize the PCB traces. Put the fuse as close as possible to the battery or DC supply terminals. A short inside the DC coaxial connector can instantly destroy the connector and the power cable. Gary Surrency AB7MY On Wed, 27 Feb 2002 11:13:37 EST K4IA at aol.com writes: > I like your idea but a much smaller battery will do the trick and not > be so > heavy to lug around or as expensive. I have used a 4.5 ah battery > for days > and I suspect you could go to a 2.5 ah. NiMH AA's can provide 1.5 > ah for > afternoon outings. > > Radio K4IA > Craig Buck > Fredericksburg, Virginia 22401 USA > > FISTS CW CLUB # 6702 CC 788 Diamond #64 > QRPARCI # 2550 > K1 #470 K2# 2460 +++++++++++++++++ From: "Douglas Westover" To: "ken cubilo electric" , Subject: Re: [Elecraft] re osc problem on kpa100 Date: Sun, 27 Oct 2002 11:32:04 -0800 I had (have?) a very similar problem and tore my hair out trying to solve it. It only occured on SSB and only with a "real" antenna, dummy loads worked fine. My first thought was the bias adjustment which I redid and the problem seemed to disappear. However, since then I've had the "top" off a couple of times and the problem recurrs everytime I put it back together, suggesting that its a loose connection problem or a lead dressing problem. I've not been able to find anything loose, but I do find that if I take the right (as viewed from the front) side panel off when re-installing the top and then dress the interconnects AWAY from the SSB board that the problem goes away. Go figure. 73, Doug W6JD K2/100 #1626 ----- Original Message ----- From: "ken cubilo electric" To: Sent: Saturday, October 26, 2002 12:09 PM Subject: [Elecraft] re osc problem on kpa100 > I did a little more checking into this problem and find that it will > occur at just about anypower level that the pa is switched into the > transmit path, also when the high ref warning goes off pressing the mike > button results in power outputs of 100-150 watts regardless of the power > setting on the front panel, it will reset when you press the mode button > and then reset the high ref alarm, it will not happen with a 50 ohm > dummy load in line. My memory seems to recall someone else on the list > was having a problem like this. anyway it kind of sounds like rf is > getting into the unit somewhere. I just went thru and did a alignment on > both the k2 and the kpa100 and double checked the bias adjustment on the > kpa100. anyone got any ideas? > ken w8ob ++++++++++++++ Date: Thu, 31 Oct 2002 22:57:57 -0500 From: "David A. Belsley" To: Jeff Burns , elecraft_list Subject: Re: [Elecraft] power supply Jeff: I can't give you any info on the MFJ or Astrom, but I've had the SEC-1223 now for several years and it's just fine. I have no hash noise from it at all (although others on this reflector have reported some noise from their units -- don't ask me, I don't know) and it handles the K2/100 with ease. Also, there is a pot, easily accessible, to set the output voltage upwards to 14.1 if you wish to use it with the K2 in a battery configuration. (Be careful, though. There two pots, and you want to be sure to adjust the right one. I don't have the information handy, but if you need it, give me an e-mail and I'll look up which pot). Finally, the price is right for this unit. best wishes, dave belsley, w1euy --On Thursday, October 31, 2002 10:46 PM -0500 Jeff Burns wrote: > I am comparing the MFJ 4125 power supply to the Samlex SEC-1223 and the > Astrom SS-25. Any helpful comments would be appreciated. This will be used > to power a K2/100 eventually. > > Jeff Burns ++++++++++++++ Date: Thu, 31 Oct 2002 22:58:22 -0500 To: "Jeff Burns" From: Dave Gingrich K9DC Subject: Re: [Elecraft] power supply Cc: "elecraft_list" At 22:46 10/31/2002 -0500, Jeff Burns wrote: >I am comparing the MFJ 4125 power supply to the Samlex SEC-1223 and the >Astrom SS-25. Any helpful comments would be appreciated. This will be used >to power a K2/100 eventually. They should all do just fine. I have three copies of the Samlex, one is powering my K2/100. The others are running a UHF Repeater and a remote packet node. No problems with any of them. I also have an Alinco DM-330, no trouble with that one either. +++++++++++++++ From: "Don Brown" To: "Jeff Burns" , "Elecraft" Subject: Re: [Elecraft] power supply Date: Thu, 31 Oct 2002 22:05:10 -0600 Hi I have a 4125, a 4225 with meters i use on my test bench and a 4245 the b= ig 45 amp switcher that runs all of the radios in my shack. They have all= performed well and are very quiet. I do not hear any RF hash in any of m= y K2's or my TenTec 6N2 meter radio. the 4125 will power the K2/100 nice= ly. A properly aligned K2 will pull about 18 amps. The 4125 is rated at 2= 5 amps so you have room to spare. you could also run the KAT100 as it onl= y pulls about 1 amp Don Brown KD5ND +++++++++++++++++ Date: Fri, 01 Nov 2002 04:43:09 +0000 From: "Logan R. Zintsmaster" To: Jeff Burns Cc: elecraft_list Subject: Re: [Elecraft] power supply I have a 4225 and run my K2/100 from it with no problems. I like the meters because I like the feedback that things are working. Logan, KZ6O #1609 +++++++++++++++++ Date: Fri, 1 Nov 2002 09:29:22 -0600 From: "Kenneth E. Harker" To: Elecraft Reflector Subject: Re: [Elecraft] power supply On Thu, Oct 31, 2002 at 10:46:53PM -0500, Jeff Burns wrote: > I am comparing the MFJ 4125 power supply to the Samlex SEC-1223 and the > Astrom SS-25. Any helpful comments would be appreciated. This will be used > to power a K2/100 eventually. There was a Product review article in QST in Jan 2000 that reviewed (I think these very same models of) switching power supplies. The Astron and MFJ supplies performed well. The Samlex supply did not. http://www.arrl.org/members-only/prodrev/pdf/pr0001.pdf -- ---------------------------------------------------------------------------- Kenneth E. Harker "Vox Clamantis in Deserto" kharker at cs.utexas.edu University of Texas at Austin Amateur Radio Callsign: WM5R Department of the Computer Sciences VP, Central Texas DX & Contest Club Taylor Hall TAY 2.124 Maintainer of Linux on Laptops Austin, TX 78712-1188 USA http://www.cs.utexas.edu/users/kharker/ ++++++++++++++++ From: "Don Brown" To: "Mike McCoy" , "Elecraft" Subject: Re: [Elecraft] power supply Date: Fri, 1 Nov 2002 11:11:29 -0600 Hi Linear supplies are better in that they do not generate any RF. The probl= em is they are large, heavy, not very efficient and they are getting expe= nsive. All that iron and copper and large pass transistors that are requi= red for a good linear supply costs a lot of money. With the computer indu= stry using millions of switchers the cost has come down on them and gone = up on linear supplies. Early switchers were terrible in the RF area but t= he newer ones use sine wave switching circuits that do not generate all o= f the harmonics that the early square wave switchers had. Most of the swi= tcher specifically made for ham radio are quite good with little or no ha= sh. However they will never be as good as a linear or a large battery, af= ter all they are nothing but a low frequency transmitter with a rectifier= and a lot of filtering. =20 Don Brown KD5NDB ----- Original Message ----- From: Mike McCoy Sent: Friday, November 01, 2002 10:21 AM To: Elecraft Reflector Subject: Re: [Elecraft] power supply All my supplies are of the linear variety. What is it that makes switchin= g supplies so attractive and/or preferable to a linear design? Wouldn't using a (decent) linear supply solve any/all concerns about hash= ? Mike - K5P ++++++++++++++++++ Reply-To: From: "J. Edward (Ed) Muns" To: "Mike McCoy" , "Elecraft Reflector" Subject: RE: [Elecraft] power supply Date: Fri, 1 Nov 2002 09:17:56 -0800 Switchers are smaller and lighter weight. If you don't need to travel with it (contest or DXpedtions) and have room in your shack, then the linear type is great. I've had the best results with Astron switchers ... and their linear supplies are great, too. 73, Ed - W0YK +++++++++++++++++ From: "Mike McCoy" To: "Don Brown" , "Elecraft" Subject: Re: [Elecraft] power supply Date: Fri, 1 Nov 2002 11:39:55 -0600 > Early switchers were terrible in the RF area but the newer ones=20 > use sine wave switching circuits that do not generate all of the=20 > harmonics that the early square wave switchers had. That's been my (admittedly rather dated) experience with switchers. That = and they don't (didn't?) have the instantaneous current reserve capacity = of a linear and would go into 'overdrive' and/or do funny things if = rapid/sudden demands were placed on them (e.g. CW xmitting). Since my K2 is solar/battery powered I hadn't thought of the necessity = of weight/size considerations when traveling. I have a little Yaesu FP-4 = 4amp linear PS I can easily carry with me anyway. Expense, size, weight & efficiency aside I think I'll stick with linears = in my shack ;) 73, Mike - K5PU +++++++++++++++ Date: Fri, 01 Nov 2002 11:53:38 -0800 From: Jerry Hancock Subject: RE: [Elecraft] power supply To: Mike McCoy , Elecraft Reflector Reply-To: jehancoc at pacbell.net HP 626X series. 0-20v at 0-50a .01% regulation. You can find them surplus. I love it now that I disconnected all the fans. -----Original Message----- From: elecraft-admin at mailman.qth.net [mailto:elecraft-admin at mailman.qth.net]On Behalf Of Mike McCoy Sent: Friday, November 01, 2002 9:52 AM To: Elecraft Reflector Subject: Re: [Elecraft] power supply Speaking of linears, a while back someone posted their recommendation for a 'surplus' high current HP linear power supply. I can't find the post but I sure would like to know the model number of that HP. I'm thinking of getting one nice big fat linear and hooking it up to a Rigrunner so I can completely convert all my gear (including the dinky stuff) to Anderson powerpoles. -Mike +++++++++++++++++ From: "Don Brown" To: "Mike McCoy" , "Elecraft" Subject: Re: [Elecraft] power supply Date: Fri, 1 Nov 2002 13:57:28 -0600 Hi Unless it is very old the hp power supplies are not true linear supplies.= They have a SCR type pre-regulator and a linear regulator following. I = have a hp 6263 0-20 volt at 10 amps and it is like that. I don't use it o= n radios so I'm not sure if its noisy or not. But it could have some swit= ching noise. If you want a bullet proof linear supply try to find a big L= ambda on the surplus market. Very few power supplies will supply their fu= ll rated current at low output voltages without overheating most Lambda p= ower supplies will do this all day long. That is why they are so big and = heavy. Try to find one with discreet transistor regulators. Some of the n= ewer IC type regulator chips are no longer made so it is very hard if not= impossible to repair them if you need a chip (unless you can get a spare= to cannibalize). Don Brown KD5NDB +++++++++++++++ From: "Tony Wells" To: "Indy" , Subject: Re: [Elecraft] power source and noise Date: Sun, 3 Nov 2002 10:35:38 -0000 Fred wrote: > I bought a 35 amp/hr deep cycle battery at a low cost > store for about $22. I've had a similar arrangement with a plain auto lead-acid battery on permanent float charge for several years for my VHF linear.. Only needs an occiasional water topup. The battery is permanently in parallel with a little 5A PSU. No electrical noise, plenty of amps. Tony G7IGG ----- Original Message ----- From: "Indy" To: Sent: Saturday, November 02, 2002 6:27 PM Subject: [Elecraft] power source and noise > Just a thought... It will run the K2 without need for recharge for a > VERY long time, maybe 48 hours of continuous contest style use, or a month > of casual use. Recharging by any of many methods is simple. Won't carry it > with you, but for home use, nothing could be quieter, and very little > cheaper. > > 72 > > Fred > K2 # 700 ++++++++++++++++++ Date: Wed, 20 Nov 2002 13:47:27 -0800 From: Wayne Burdick Organization: Elecraft To: Elecraft Subject: [Elecraft] K2 power output tests at low supply voltages I just completed some preliminary tests to see what the K2 could do with really low supply voltages. On 20 meters, both K2s I tested could easily put out 10 watts in CW mode down to as low as 9.5 volts, and 5 watts down to as low as 9.0 volts. In both cases, there was absolutely no hint of frequency shift or other artifacts, and no change in the CW keying waveform (as observed on a scope). I also listened on a separate receiver, and went back and forth between 9 volts and 14 volts while keying at 5 watts. There was no change in quality or signal strength. On the lowest and highest bands I found I had to reduce power slightly below these levels. Based on these tests, here are my (conservative) recommended maximum power settings vs. DC input voltage: DC VOLTAGE POWER OUTPUT ---------- ------------ 9.0 V 2.0 W 9.5 V 5.0 W 10.0 V 7.0 W 10.5 V 10.0 W These figures should be reassuring to anyone who is planning to operate from batteries. The signal will be perfectly stable at 5 watts well below the recommended usable voltage for a depleted 12-V battery. Even a 9.6-volt, 8-cell NiMH battery pack would work in a pinch. (I'd go with C cells, personally.) We'll be adding this table to the K2 performance comparisons page soon. There are some caveats to keep in mind with low voltage operation: - I was using a 95SQ015 at D10 on the RF board (reverse polarity protection diode), rather than the original SB530. The 95SQ015 type drops about 0.2 to 0.3 volts less on transmit. This diode will be included in the rev A to rev B upgrade kit we're working on. - To ensure accuracy when testing at low voltages, the voltage must be measured right at the DC input jack, in transmit mode. Power cables can drop considerable voltage themselves if they're long and/or use small-gauge wire. To minimize this effect, I use at least #18 wire, no longer than 3-5 feet, when possible. - The KBT2 and other 12-V Gel-Cell batteries should not be used below 10 volts for any length of time, as they can become permanently damaged. (The K2 will give you a LO BATT warning as a reminder--see the owner's manual for more details.) Check your supply voltage as needed using the K2's voltage/current display mode (by tapping DISPLAY). - If you want to use the maximum possible power output at a given voltage, rather than the level in the table above, go for it--but listen to the signal on another receiver first to make sure the keying is still crisp and clean. 73, Wayne N6KR ++++++++++++++++