Recommended K3 Cal Schedule
Locked
 
|
Are there any recommended schedule or guidelines for when to recalibrate a
k3? 73 de Fred KC2QFR K3 SN 2266 ______________________________________________________________ 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 |
|
|
Just completed my second K3/100 and am in the process of integrating them
into the former FT-1000 SO2R station. I'm using the DX Doubler for SO2R switching. I bought the K3 cables from them, and hooked up both radios to DXD. When I plug the headset into the DXD phone socket, I hear a hummy sidetone and low-level hum on both radios. With a headset plugged into either the front or rear K3 phones sockets, I don't hear it. So, it sounds like something that's occuring as a result of whatever's going on inside the DXD. For now, I'm planning to isolate the audio output going to the DXD using 1:1 isolation xfmrs. But has anyone else had a similar problem? If so, how did you cure it? I had a similar problem (and used the same solution) with the FT-1000s and the DVD. I thought it was a Yaesu issue, but maybe not.... Rob K6RB ______________________________________________________________ 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 |
|
|
This is a common problem with DXDoubler due to differences in chassis potential between transceivers. TopTen Systems have even published an application note concerning the issue: http://www.qth.com/topten/apnote9.htm Their solution, as you have already discovered is to add two transformers in the headphone line between one of the transceivers and the DXDoubler. The recommended transformers will have approximately 3 dB of insertion loss ... it will be necessary to "turn up the volume" on the transceiver with the transformers in line. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of > [hidden email] > Sent: Monday, March 15, 2010 4:41 PM > To: [hidden email] > Subject: [Elecraft] DX Doubler/K3 issue > > > Just completed my second K3/100 and am in the process of > integrating them into the former FT-1000 SO2R station. I'm > using the DX Doubler for SO2R switching. I bought the K3 > cables from them, and hooked up both radios to DXD. When I > plug the headset into the DXD phone socket, I hear a hummy > sidetone and low-level hum on both radios. With a headset > plugged into either the front or rear K3 phones sockets, I > don't hear it. So, it sounds like something that's occuring > as a result of whatever's going on inside the DXD. For now, > I'm planning to isolate the audio output going to the DXD > using 1:1 isolation xfmrs. But has anyone else had a similar > problem? If so, how did you cure it? > > I had a similar problem (and used the same solution) with the > FT-1000s and the DVD. I thought it was a Yaesu issue, but > maybe not.... > > Rob K6RB > > > > > ______________________________________________________________ > 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 |
|
|
Would bonding the two chassis together with thick wire or braid work?
73 -- Joe KB8AP On Mar 15, 2010, at 4:44 PM, Joe Subich, W4TV wrote: > > This is a common problem with DXDoubler due to differences > in chassis potential between transceivers. ... > 73, > > ... Joe, W4TV > > > > >> -----Original Message----- >> From: [hidden email] >> [mailto:[hidden email]] On Behalf Of >> [hidden email] >> Sent: Monday, March 15, 2010 4:41 PM >> To: [hidden email] >> Subject: [Elecraft] DX Doubler/K3 issue >> >> >> ... >> When I >> plug the headset into the DXD phone socket, I hear a hummy >> sidetone and low-level hum on both radios.... >> Rob K6RB >> ______________________________________________________________ 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 |
|
|
Bonding the chassis of each transceiver to DXDoubler is recommended by TopTen Systems but their application note also says that bonding alone may not always be enough. I've always recommended bonding every piece of equipment (including the computer) to a single common reference (ground) point, generally the same point at which all feedlines enter the shack. 73, ... Joe, W4TV > -----Original Message----- > From: Joe Planisky [mailto:[hidden email]] > Sent: Monday, March 15, 2010 8:47 PM > To: Joe Subich, W4TV > Cc: [hidden email]; [hidden email] > Subject: Re: [Elecraft] DX Doubler/K3 issue > > > Would bonding the two chassis together with thick wire or braid work? > > 73 > -- > Joe KB8AP > > On Mar 15, 2010, at 4:44 PM, Joe Subich, W4TV wrote: > > > > > This is a common problem with DXDoubler due to differences > > in chassis potential between transceivers. ... > > > 73, > > > > ... Joe, W4TV > > > > > > > > > >> -----Original Message----- > >> From: [hidden email] > >> [mailto:[hidden email]] On Behalf Of > >> [hidden email] > >> Sent: Monday, March 15, 2010 4:41 PM > >> To: [hidden email] > >> Subject: [Elecraft] DX Doubler/K3 issue > >> > >> > >> ... > > >> When I > >> plug the headset into the DXD phone socket, I hear a hummy > sidetone > >> and low-level hum on both radios.... > > >> Rob K6RB > >> > ______________________________________________________________ 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 |
|
|
In reply to this post by Joe Subich, W4TV-4
On Mon, 15 Mar 2010 19:44:31 -0400, Joe Subich, W4TV wrote:
>This is a common problem with DXDoubler due to differences >in chassis potential between transceivers. TopTen Systems >have even published an application note concerning the issue: >http://www.qth.com/topten/apnote9.htm >Their solution, as you have already discovered is to add >two transformers in the headphone line between one of the >transceivers and the DXDoubler. They also suggest a low resistance bond between one transceiver chassis and the other BEFORE resorting to transformers. That's my fundamental recommendation as well. It also helps to get power for both radios from the same AC outlet, or from outlets whose green wires are bonded together (for example, multiple outlets in the same steel backbox). There are two common causes of this problem. One is the potential difference between the two radios. Bonding and using the same outlet will fix that. The second common cause is a magnetic field that couples into the loop between the two radios and the DXDoubler. That field is most often is established by a big power transformer very close to the rig (either the linear supply for the rig(s) or the power transformer for the power amp. The field is coupled to the audio two ways. First as the induced voltage, and second as current flowing into a pin 1 problem at either (or both) end(s). Magnetic field coupling can be minimized by reducing the loop area. In this case, the loop consists of the audio cable shields and the radio bonding path. This may sound counter-intuitive, but that means making one of those cables longer so that the cable for radio two follows a path from the DXDoubler to radio one and then along the bonding conductor to radio two, and lacing the cables together with ty-wraps. Adding transformers can also break that magnetic loop, but if the transformers are unshielded (and most inexpensive transformers are unshielded) the transformers may pick up the magnetic field and couple it as a differential signal. 73, Jim Brown K9YC ______________________________________________________________ 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 |
|
|
> There are two common causes of this problem. One is the
> potential difference between the two radios. Bonding and > using > the same outlet will fix that. > > The second common cause is a magnetic field that couples > into > the loop between the two radios and the DXDoubler. That > field is > most often is established by a big power transformer very > close > to the rig (either the linear supply for the rig(s) or the > power > transformer for the power amp. The field is coupled to the > audio > two ways. First as the induced voltage, and second as > current > flowing into a pin 1 problem at either (or both) end(s). There actually is a much more common and much more severe issue that gets almost totally ignored, dc current paths from external power supplies. The high supply current radios draw causes a ground loop when we use low voltage supplies that have the negative supply voltage grounded at the power supply or any other point in the system other than at the radio. When the radio has any sort of amplitude varying RF output, the rapidly varying dc input current creates a pretty good voltage drop across the negative supply lead. Since that lead is grounded at more than one point, it drives the supply negative to a different potential at different points in the system, and the rig's chassis and other chassis "wiggle around" at different potentials at the RF envelope's modulation rate as PA current varies from quiescent to 20 amps or more peak current on envelope peaks. The effect is almost indistinguishable from rectification of the RF envelope. As a matter of fact many blame this problem on RFI because it sounds like RFI even though it is "AFI". While bonding all the chassis helps a great deal, the real issue is a design shortfall in the negative rail wiring of the power supply and our equipment. The best fix for this problem is to not have common chassis grounds on low voltage sensitive signal leads, a good design isolates the sensitive signal leads with isolation transformers. This problem is a whole lot like the problem we create in vehicles when we run the negative radio lead to the battery negative post. People designing gear have to learn to not create a harmful path. I can't imagine having an audio interface device that connects audio and signal lead grounds all together at low frequencies or dc! The voltage induced this way is typically hundreds of times higher in magnitude than voltage induced by flux leakage from power transformers. Worse yet, it is an extremely low impedance source making it very difficult to "bypass". 73 Tom ______________________________________________________________ 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 |
|
|
Tom
You mention bonding in vehicles and this rang a large bell with me: all military vehicles, land sea and air, require a separate dc return other than the chassis for the battery negative terminal. Filter caps for emc are returned to the chassis of the equipment which is strongly bonded to the chassis of the vehicle and dc return is a separate wire to the battery supply negative. Transmitter/receiver coax terminals make it tricky. David G3UNA The best fix for this > problem is to not have common chassis grounds on low voltage > sensitive signal leads, a good design isolates the sensitive > signal leads with isolation transformers. This problem is a > whole lot like the problem we create in vehicles when we run > the negative radio lead to the battery negative post. People > designing gear have to learn to not create a harmful path. I > can't imagine having an audio interface device that connects > audio and signal lead grounds all together at low > frequencies or dc! > > The voltage induced this way is typically hundreds of times > higher in magnitude than voltage induced by flux leakage > from power transformers. Worse yet, it is an extremely low > impedance source making it very difficult to "bypass". > > 73 Tom > > 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 |
|
|
On Wed, 31 Mar 2010 18:33:40 +0100, David Cutter wrote:
>all >military vehicles, land sea and air, require a separate dc return other than >the chassis for the battery negative terminal. Filter caps for emc are >returned to the chassis of the equipment which is strongly bonded to the >chassis of the vehicle and dc return is a separate wire to the battery >supply negative. That's nice. Unfortunately, vehicles sold to the public often do NOT have anything approaching bonded chassis. After buying a Toyota Sequoia several years ago during a Chicago winter, I took it into the heated loading dock at K9IKZ's business to scope out the installation of an HF rig. First thing we checked was body bonding. It wasn't pretty -- for all practical purposes, ALMOST NONE of the body parts showed anything approaching a low DC resistance between them. We found bolts inches apart with 30 ohms between them, and almost ten ohms between the battery negative terminal and the chassis! Tom -- it's really good to see you here. Your experience and engineering chops are greatly appreciated. 73, Jim K9YC ______________________________________________________________ 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 |
|
|
In reply to this post by W8JI
> There actually is a much more common and much more severe > issue that gets almost totally ignored, dc current paths > from external power supplies. Tom is absolutely correct. However, a much easier "fix" is to use a separate power supply for the low voltage accessories and ground (bond) any power supply chassis ONLY to the station common RF/safety ground. By connecting the DC return from the high current device directly to the power supply and only to the power supply as well as keeping the heavy "bonding" paths to the common safety/RF ground, the impedance of the alternate paths through low voltage accessories is generally high enough to prevent the return current diversion. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Tom W8JI > Sent: Wednesday, March 31, 2010 6:09 AM > To: Jim Brown; [hidden email] > Subject: Re: [Elecraft] DX Doubler/K3 issue > > > > There are two common causes of this problem. One is the potential > > difference between the two radios. Bonding and using > > the same outlet will fix that. > > > > The second common cause is a magnetic field that couples > > into > > the loop between the two radios and the DXDoubler. That > > field is > > most often is established by a big power transformer very > > close > > to the rig (either the linear supply for the rig(s) or the > > power > > transformer for the power amp. The field is coupled to the > > audio > > two ways. First as the induced voltage, and second as > > current > > flowing into a pin 1 problem at either (or both) end(s). > > There actually is a much more common and much more severe > issue that gets almost totally ignored, dc current paths > from external power supplies. > > The high supply current radios draw causes a ground loop > when we use low voltage supplies that have the negative > supply voltage grounded at the power supply or any other > point in the system other than at the radio. When the radio > has any sort of amplitude varying RF output, the rapidly > varying dc input current creates a pretty good voltage drop > across the negative supply lead. Since that lead is grounded > at more than one point, it drives the supply negative to a > different potential at different points in the system, and > the rig's chassis and other chassis "wiggle around" at > different potentials at the RF envelope's modulation rate as > PA current varies from quiescent to 20 amps or more peak > current on envelope peaks. > > The effect is almost indistinguishable from rectification of > the RF envelope. As a matter of fact many blame this problem > on RFI because it sounds like RFI even though it is "AFI". > > While bonding all the chassis helps a great deal, the real > issue is a design shortfall in the negative rail wiring of > the power supply and our equipment. The best fix for this > problem is to not have common chassis grounds on low voltage > sensitive signal leads, a good design isolates the sensitive > signal leads with isolation transformers. This problem is a > whole lot like the problem we create in vehicles when we run > the negative radio lead to the battery negative post. People > designing gear have to learn to not create a harmful path. I > can't imagine having an audio interface device that connects > audio and signal lead grounds all together at low > frequencies or dc! > > The voltage induced this way is typically hundreds of times > higher in magnitude than voltage induced by flux leakage > from power transformers. Worse yet, it is an extremely low > impedance source making it very difficult to "bypass". > > 73 Tom > > ______________________________________________________________ > 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 |
«
Return to [K3]
|
1 view|%1 views
| Free forum by Nabble | Edit this page |