Re: [Elecraft] KPA500 Noise While Off
My KPA500 makes a noticeable hum/thump when the laser printer that is on the same circuit draws a lot of current. 73, Matt NQ6N On Wed, Jun 27, 2018 at 12:58 PM Jim Brown wrote: > On 6/27/2018 10:37 AM, Richard Wade wrote: > > If I had to venture a guess, I would say that somehow the unpowered > KPA500 > > was picking up noise on the shack wiring. Very strange. Is that > possible?? > > It is if equipment in your shack is not properly bonded together, and to > house grounds that are also properly bonded together. Study N0AX's > recent ARRL book on the topic, to which I contributed, or the slides for > a tutorial talk I've done at several hamfests. > > http://k9yc.com/GroundingAndAudio.pdf > > 73, Jim K9YC > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to m...@nq6n.com > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA1500 ATU - ability to handle more than two antennas
I think this is a very important aspect of station design and a big consideration for any future amp purchase I make. I'd like to respectfully suggest that Elecraft consider designing a bulletproof 16x2 antenna switch rated for 5KW and 10:1 SWR (and lots of isolation between ports) that integrates seamlessly with the amp and tuner. There is typically a need to switch both antennas and high power bandpass filters, or at least the high cost of high power bandpass filters makes using only one for each band (via switching) very useful. So when the amp QSYs to 40m the ideal scenario allows the switching in of a 40m bandpass filter after the amp, and then whichever antennas are usable on 40m, with the tuner knowing which antenna was chosen so that it can switch to the previously known settings for instant TX. 73, Matt NQ6N On Fri, Jan 26, 2018 at 1:45 PM, K9MA <k...@sdellington.us> wrote: > How about using an external switch to select which ATU settings the amp > uses? Perhaps with a digital INPUT line? > > Scott K9MA > > > On 1/26/2018 11:15, Wayne Burdick wrote: > >> This is definitely doable from the amp. All it takes is an external >> antenna switch with a control port compatible with RS232, Ethernet, USB, or >> one of the amp’s multi-purpose digital output lines. (These have other >> uses, too, such as SWR alarm output.) >> >> To select among antennas from the amp, you could do any of the following: >> >> - tap the ANT switch to go between two or more antennas in rotation >> >> - tap ANT then use the UP/DN switches >> >> - assign two frequently-used antennas to the front-panel PF1 and PF2 >> switches >> >> In all cases, the LCD would show your selection from among N external >> antenna jacks. >> >> We can adapt the firmware to handle any such scenario. >> >> Wayne >> N6KR >> >> >> On Jan 25, 2018, at 7:58 PM, K9MA <k...@sdellington.us> wrote: >>> >>> I'm concerned about the same issue: Multiple antennas on one band. I >>> have an automated antenna selection system. In addition to following the >>> band data from the transceiver, there are switches to select antennas. I >>> frequently have to very quickly switch antennas, so it must involve only a >>> single switch. Using a mouse with the computer is nowhere near fast enough >>> and I really don't want to make it dependent on the computer, anyhway. >>> However, my antennas have different impedances, so require different ATU >>> settings. So, how can I tie the KPA1500 ATU into my antenna control switch >>> so it automatically switches settings? All the antenna switching is >>> external to the amp, so only a single amp output is used. The ideal would >>> be a control line to the amp, controlled by the same switch that selects >>> antennas, which would select ATU settings. I really don't want to make it >>> dependent on the computer. I expect others have the same issue. Can the >>> KPA1500 be made to do something like this? >>> >>> 73, >>> Scott K9MA >>> >>> -- >>> Scott K9MA >>> >>> k...@sdellington.us >>> >>> __ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Elecraft@mailman.qth.net >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to n...@elecraft.com >>> >> > > -- > Scott K9MA > > k...@sdellington.us > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to m...@nq6n.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Operation of K Line Over LAN
One other note: there is also a remotehams Android app which can also be used for operating the rig via rcforb on phone. On Thu, Jan 11, 2018 at 7:10 PM Matt NQ6N <m...@nq6n.com> wrote: > Remotehams rcforb works nicely and is easy to set up especially if you > already have a sound card connection for digital modes. > > It does require one pc near the rig and another near the bed. > > You can easily connect up a paddle using a serial port or usb serial > adapter. > > 73, > Matt NQ6N > > On Thu, Jan 11, 2018 at 7:06 PM Tom Richardson <n4we@gmail.com> wrote: > >> I will be bed-ridden with a broken leg for a few weeks. Does anyone >> know of any straightforward methods for operating my K3S and KPA500 >> over my wireless LAN using my laptop plus Ham Radio Deluxe or another >> software package? >> >> Thanks, >> Tom >> N4WE >> __ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to m...@nq6n.com >> > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Operation of K Line Over LAN
Remotehams rcforb works nicely and is easy to set up especially if you already have a sound card connection for digital modes. It does require one pc near the rig and another near the bed. You can easily connect up a paddle using a serial port or usb serial adapter. 73, Matt NQ6N On Thu, Jan 11, 2018 at 7:06 PM Tom Richardson <n4we@gmail.com> wrote: > I will be bed-ridden with a broken leg for a few weeks. Does anyone > know of any straightforward methods for operating my K3S and KPA500 > over my wireless LAN using my laptop plus Ham Radio Deluxe or another > software package? > > Thanks, > Tom > N4WE > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to m...@nq6n.com > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] [KX3] Re: KX2 as a remote front panel for another KX2, KX3, or K3S?
I would very much like to be able to use my KX2 as a remote control head for my K3. Some usage details below: - Use the RCForb software (remotehams) to control my K3. So if the KX2 supported terminal mode, I believe it would be able to remote control any rig via RCForb. - Having the built-in paddles send CW via the KY commands (and also ideally by having them generate the RTS/DTR serial port signals used by RCForb for local paddles) would be great as well. Local side tone generated by the KX2 would also be great. - In my opinion, integrating the audio back through the KX2 speaker is not important at all, the computer audio works fine. - Even though the KX2 control set is smaller than that of the K3, it would still be very nice to see the display and use some of the knobs/buttons to access some of the more useful controls. The KX2 is designed with a lot of pragmatic attention to conserving space, so those knobs are typically all I use most of the time anyway. I'd be happy with any subset of the above features. I currently use a K3/0 Twin which takes up a fair bit of desk space, and would prefer to use my KX2 for controlling the remote station most of the time, particularly for casual operating or DXing. The operating position where I operate from when using the remote setup is a smallish desk with a slim iMac and not much extra space. 73, Matt NQ6N On Fri, Dec 22, 2017 at 7:09 PM, kevino z z_kev...@hotmail.com [KX3] < kx3-nore...@yahoogroups.com> wrote: > > > I’d really like to be able to use my KX2 to control my KX3.. Is that an > option or is only the K series the lucky one? > > > No trees were killed in the sending of this message. However, a large > number of electrons were terribly inconvenienced ! > > > On Dec 21, 2017, at 20:42, Wayne Burdick <n...@elecraft.com> wrote: > > > > A number of KX2 owners have asked whether they could use the rig as a > “terminal” to control a remote radio. This may be possible to a limited > degree. > > > > This can already be done with a K3, K3S, or K3/0-Mini. All three can do > 100% control of a remote K3 or K3S, including 1:1 display mapping. > > > > On the smaller end of the scale, you can use a KX3 in “RIG CTRL” mode to > do limited control of a remote KX3, K3, or K3S. Page 28 of the KX3 owner’s > manual provides more information on this. A small number of basic functions > is provided, including VFO, band change, mode change, AF gain, etc. > > > > The rigs can be connected together with a null-modem TTL/RS232 cable (2 > wires + ground) or through a simple server app. Receive audio, mic, and > keyer paddle must be handled separately from the control stream. > > > > The question is whether there’s enough interest to justify adding such > functionality to the KX2. Like the KX3, the KX2 would only provide certain > basic controls. > > > > We’re open to discussion about this (on the list or to me privately). > Please include a short description of the application you have in mind. It > could be as simple as this: using a KX2 on one side of a large shack to > control a K3/K3S on the other side. This would be my motivation, since my > primary work computer is out of reach of the K3S setup. > > > > 73, > > Wayne > > N6KR > > > > > > > > __ > > Elecraft mailing list > > Home: https://nam01.safelinks.protection.outlook.com/?url= > http%3A%2F%2Fmailman.qth.net%2Fmailman%2Flistinfo% > 2Felecraft=02%7C01%7C%7C0cf3eaf9fb5644f7720308d548dd349c% > 7C84df9e7fe9f640afb435%7C1%7C0%7C636495037259355786= > rdOhIZ6eqsKha9nF4YEU0EiO0Cw1ptqTU05S%2F1wDSTY%3D=0 > > Help: https://nam01.safelinks.protection.outlook.com/?url= > http%3A%2F%2Fmailman.qth.net%2Fmmfaq.htm=02%7C01%7C% > 7C0cf3eaf9fb5644f7720308d548dd349c%7C84df9e7fe9f640afb435 > %7C1%7C0%7C636495037259355786=HgjO1wsbRpFmLmjma4p6c9PUO9DQCK > 2bt9vuEljKBFg%3D=0 > > Post: mailto:Elecraft@mailman.qth.net > > > > This list hosted by: https://nam01.safelinks. > protection.outlook.com/?url=http%3A%2F%2Fwww.qsl.net=02%7C01%7C% > 7C0cf3eaf9fb5644f7720308d548dd349c%7C84df9e7fe9f640afb435 > %7C1%7C0%7C636495037259355786=vZAfx4QrEzj2zDYebuPfFdBW2463EG > 1loK6V8MnsRUk%3D=0 > > Please help support this email list: https://nam01.safelinks. > protection.outlook.com/?url=http%3A%2F%2Fwww.qsl.net% > 2Fdonate.html=02%7C01%7C%7C0cf3eaf9fb5644f7720308d548dd349c% > 7C84df9e7fe9f640afb435%7C1%7C0%7C636495037259355786= > opv7mnolZHw6gER%2Be6%2BJ%2FfJQs7ub836bxNf4dS%2Bz4mg%3D=0 > > Message delivered to z_kev...@hotmail.com > __._,_.___ > -- > Posted by: kevino z <z_kev...@hotmail.com> >
Re: [Elecraft] WSJT-X K3/K3s hanging as Tx
I'd experienced this problem, also not due to RF in the shack, and since I switched to using PTT via RTS or DTR the problem has not recurred. The problem began when I had been using RCForb and a virtual serial port with CAT control of PTT for WSJT-X, so the explanation Joe offers makes sense based on my experience. Unless WSJT-X had some provision for reviewing all state changes to the K3 that might occur "unexpectedly" due to other CAT "clients" of the K3, it would not be able to guarantee that its own state matched that of the K3, which could seemingly result in the sort of behavior being experienced. 73, Matt NQ6N On Tue, Nov 14, 2017 at 8:07 AM, David Bunte <dpbu...@gmail.com> wrote: > I won't take a lot of time weighing in on this thread. I am a newbie to > FT8, with only a little over 100 Qs. I am using my K3 with a DigiKeyer II, > and have never experienced the problem. > Dave - K9FN > > On Tue, Nov 14, 2017 at 8:58 AM, Gordon LaPoint <gordon.lapo...@gmail.com> > wrote: > > > Bert, > > I also have the problem, and it IS NOT rf getting into the shack. It > > will happen with 1 watt. It is a function of wsjt-x and may be related > to > > using split. I have never seen the problem when NOT using split. The > > problem usually appears when clicking on a new station to answer a CQ, > and > > the split has to change. > >The systems will return to normal in the next 15 second segment if > > nothing else is touched, or somtimes will return to normal sooner if the > > "halt tx" button is clicked on. > >I also see the problem when using other radios than the K3, I have an > > IC-7000 and ANAN-10E that also get used for wsjt-x. > > The problem has occured in wsjt-x versions 1.8 rc2, rc3 and release > > 1.8 I not remember seeing the problem before version 1.8 rc2, but can > not > > be sure. > > I now have about 1,500 FT8 contacts in the log, so I use FT8 a lot. > > Gordon - N1MGO > > > > On 11/13/2017 07:00 PM, Bert Garcia N8NN wrote: > > > >> The CAT and PTT are on different COM ports, per the installation > >> instructions for the microKEYER II when using WSTJ-X. And it's not a > stray > >> RF problem as I have all the equipment bonded together, ferrite cores on > >> the audio and control lines, a line isolator in the feedline where it > >> enters the house, and line isolators between the rig and amp and between > >> the amp and antenna tuner. The lockup happens when running only 30 > watts > >> with FT8. It never happens when running a KW on many other modes. I > run > >> RTTY, PSK and other digital modes with no problems. > >> > >> Thus, I suspect the issue is associated with the WSRJ-X software as the > >> same issue occurs with various transceivers in multiple locations. > >> > >> Bert N8NN > >> > >> -Original Message- > >> From: Don Wilhelm [mailto:donw...@embarqmail.com] > >> Sent: Monday, November 13, 2017 3:17 PM > >> To: n...@earthlink.net; g...@ka1j.com; Elecraft@mailman.qth.net > >> Subject: Re: [Elecraft] WSJT-X K3/K3s hanging as Tx > >> > >> Bert and Gary, > >> > >> Have you looked for a computer problem? Such as having both PTT via > >> command and via an RS-232 signal line? Do you have both VOX on and > another > >> means of keying the transceiver? > >> > >> 73, > >> Don W3FPR > >> > >> On 11/13/2017 3:07 PM, Bert Garcia N8NN wrote: > >> > >>> This problem is not unique to the K3. My Yaesu FT-1000mp does the > >>> same thing -- locks up in transmit mode with no RF output and I have > >>> to turn it off to regain control. The lock up is intermittent, and > >>> some days it never happens. Rebooting everything works for a while, > >>> but when I least expect it, the lockups will start again. > >>> > >> __ > >> Elecraft mailing list > >> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >> Help: http://mailman.qth.net/mmfaq.htm > >> Post: mailto:Elecraft@mailman.qth.net > >> > >> This list hosted by: http://www.qsl.net > >> Please help support this email list: http://www.qsl.net/donate.html > >> Message delivered to gordon.lapo...@gmail.com > >> > > > > > > -- > > Gordon - N1MGO > > > > __ > > Elecraft mailing list >
Re: [Elecraft] On CW
I'm comparatively young (41) but I appreciate the musings about CW. I still remember the first CW QSO I observed at a demonstration at a Red Cross building in Michigan when I was 11 years old. I'd had a pair of plastic FM walkie talkies as a young child that had the dots and dashes of Morse embossed onto the front, but I had not expected the thrill that I felt as an actual CW QSO was made before my eyes. I was licensed a few months later. Another memorable CW QSO for me was the first time I sat in front of a friend's K3. The audio sounded so clear and beautiful that I soon ordered my own. I think there is something very special about the art form of CW and the kind of craftsmanship and passion that it inspires. Thanks to Wayne and everyone at Elecraft, the CWOps, etc, for keeping the magic alive. 73, Matt NQ6N On Tue, Oct 31, 2017 at 1:26 PM, <rkr...@johngalt.biz> wrote: > > On 10/31/2017 2:02 PM, engineercm wrote: > >> Thank you so much for articulating the magic about CW. >> > > As a teen I tried to learn Morse Code and never was able to get very far. > With Morse as a condition for getting a license, I never thought about > getting a Ham License although I was very heavy into electronics and got my > First Class Radiotelephone License. (To show my age, the testing only had > one transistor question; all the rest were tubes.) > > When I discovered that Morse Code had been removed as a requirement (2014 > or so) I began studying for my tests and made Extra within a few months. > > I have K3S that I am about to put on the air, on SSB to begin because > that is what I currently understand. > > I have had CW recommended, but am unwilling to repeat the head banging > experience I went through 50+ years ago. > > Now that I've given the history, my question to those of you who are > gung-ho on CW is; how did you begin the learning process? Is there some > secret that I missed? > > 73 > > Ray > KK4WPB > > > -- > Furthermore, I believe that islam must be destroyed. > If there must be trouble, let it be in my day, that my child may have > peace.--Thomas Paine > III% Molon labe. > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to m...@nq6n.com > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] For Sale: One excellent condition, late serial number K3
Hello, Because most of my operation has been remote lately, I am selling one of my two K3 transceivers. Both are in superb condition. I only need one and will be keeping the one that does not sell. If interested, please contact me off list and I will send you the specs for both. The serial numbers are 5530 and 6066. I am the original purchaser of both rigs and both are in superb working order. 73, Matt NQ6N __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] [KX3] Re: Kx2 paddle issue
I have had this issue with my KX2 paddle and have two observations: On my paddle, the screw that is meant to hold the standoff to the plastic body will actually screw tightly into the plastic body *without* the standoff. When this happens, additional torque applied with a screwdriver has no effect on the standoff. When my paddle got loose I tightened the screw with a screwdriver, but then later (after it got loose multiple times) I realized that the screw felt tight because the threads were *gripping the plastic. *The connection with the standoff was still fairly loose, the torque I put on the screwdriver was blocked by the tight fit of the screw's threads to the plastic. The solution I used was to turn the standoff while jogging the screw back and forth with a screwdriver until I felt the standoff grip against the other side of the plastic, then continue to jog the assembly while tightening the screw about another quarter turn, to the point where the screw was nice and tight against the standoff and *also* tight against the plastic. This approach has kept the screw and standoff stable without the need for glue. I think that if future releases of the paddle were manufactured with a slightly larger hole in the plastic, then it would be easier to achieve a tight fit between the screw and the standoff. I'd also be curious if a small lock-washer on the standoff side might help make the assembly more immune to vibration. 73, Matt NQ6N On Tue, Jul 25, 2017 at 11:12 AM, Ron D'Eau Claire <r...@cobi.biz> wrote: > It's useful to remember that a screw (or bolt) is a spring. When tightened > it stretches lengthwise. Like any spring, it offers the best "grip" when > subjected to the right range of pressure. > > Way back in my High School days (1950's - before Mercury was a toxic > substance) I watched a demonstration using a bolt and nut made of frozen > Mercury. Mercury is not elastic. Liquid Mercury was poured into molds for a > nut and bolt and hardened with liquid nitrogen. Using gloves, the > demonstrator assembled the nut and bolt using a large wrench to apply a > great deal of torque. That done, anyone could loosen it without a wrench by > just twisting the nut or bolt with minimal finger pressure (inside the > gloves of course). There was no resistance since Mercury does not stretch. > > It's easy to over torque (stretch) small screws. That's why the Elecraft > kit > assembly manuals do not recommend using power screwdrivers. The Elecraft > factory in Watsonville is equipped with special torque-limiting power > screwdrivers to allow quick assembly with screws not so tight they are > damaged or broken. > > Since a screw is basically an inclined plane that stretches the screw when > tightened, vibration will allow the screw to turn (slide along the plane of > the threads), hence the use of lock washers or chemical compounds in such > environments to stop any movement. > > Perhaps the issue with the KX2 paddles is the vibration as the contacts > collide allowing the screws to turn. Working remotely on the Elecraft > manuals I've not been directly involved with the issue, so that is pure > speculation. > > 73, Ron AC7AC > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to m...@nq6n.com > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] using the KX2 as a remote control head for K3
I seem to recall this being discussed with the KX3, but I haven't been able to find the relevant discussion. I'm curious if the KX2 can be used to control the K3 remotely in the same way that a K3 can be used to do so. Any tips or links to help me figure this out would be much appreciated. I am using RCForb connected to the K3 in the shack, but also have an RRC remote unit and would consider any other options. 73, Matt NQ6N __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA500 Hum when off?
I had this happen and discovered that the laser printer I had was plugged into the same ac circuit and was causing voltage drop periodically. Moving the printer to another wall outlet fixed the problem. Matt NQ6N On Jun 11, 2013, at 5:03 PM, Eric Swartz - WA6HHQ, Elecraft e...@elecraft.com wrote: This is normal and is due to the small low voltage transformer and rectifiers that provide power to the front panel microprocessor. turning off the rear switch will turn everything off, including this transformer. Eric elecraft.com On 6/11/2013 10:13 AM, Stan AE7UT wrote: I have a kit-built KPA500 that has the same issue. It's well grounded and all the bolts are tight. The humm is barely noticeable when off but definitely there. 73 Stan AE7UT -- View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-Hum-when-off-tp7575069p7575086.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
