Re: [Elecraft] variac question
It sounds like a polarity problem. The line cord feeding the variac may be reversed, or the switch may be in the neutral instead of the 120V line (or if it's a double-pole switch, one pole may have failed On.) Easy way to tell: check voltage from neutral to ground with the switch on. If it's zero when the switch is on and 120V with the switch off, the switch probably is in the neutral. If it's 120V both ways, the line cord or outlet is wired wrong. You definitely should fix it, but don't rely on the switch for safety. They can (and do) fail. Always unplug to be safe! --- This email has been checked for viruses by Avast antivirus software. http://www.avast.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] 240V Line
What Jim says here is correct. The old exception that allowed returning 120V loads to the bare or green grounding wire of a 240V circuit was very limited, allowed only for a few large appliances (dryers, stoves/ovens, and water heaters IIRC) which would be disconnected only for maintenance or replacement. The exception never applied to ham equipment. There are at least three possible Bad Things that can happen when you use a ground to carry operating current: (1) Some of the 120V load current returns by way of the coax, keying line, ALC line, the rig and its power supply, the antenna grounding system, etc.--anything connected to the amplifier chassis. This current often causes a stubborn hum in your transmitted signal (and other ill effects). (2) If the circuit has GFCI protection, the 120V load current is likely to trip the GFCI. (3) If the ground wire opens for any reason, the 120V load current has nowhere to go except the unintended paths, in particular through you if you are touching anything connected to the amplifier. This danger is the primary reason the NEC no longer allows combining neutral and ground conductors anywhere beyond the power service equipment (master disconnect enclosure). So if you have an older amplifier wired with 120V loads to chassis, it's wise to spend the time and money to make it safer and better by keeping the 120V load currents out of the chassis ground connections. --Tim (KR0u) On 12/24/2014 2:50 PM, Jim Brown wrote: You may be confusing a 120/240 outlet that has a four circuit plug (phase, phase, neutral, and Green) and can serve both 120V and 240V loads, with a 240V outlet that has a three circuit plug and serves only 240V loads. There is no neutral in a 240V outlet, and as noted above, it is illegal to connect a 120V load between one phase and the Green wire (Equipment Ground). That 120/240 circuit can feed both 120V and 240V outlets. A neutral IS required to feed those 120V outlets. --- This email has been checked for viruses by Avast antivirus software. http://www.avast.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] Astatic D104 mics
The basic D-104 (without amplifier) is a crystal microphone, designed for very high impedance (100K ohm), and delivering fairly high output voltage. It worked well with the vacuum tube amplifiers used when the D-104 was new. The K3 (and other modern rigs) have much lower input impedance and will load down the crystal mic element considerably. There were several amplified versions, the power mikes of the CB craze. These have low output impedance (a few K ohms, varies with the output level pot setting) combined with high output voltage. Their output level can over-drive radios designed for dynamic microphones unless the gain setting is kept very low, or an attenuator is placed in the output. Links: Adapting D-104 to modern radios (using an op-amp buffer) http://www.w6ier.org/images/9908034%5B1%5DAdapting%20the%20Astatic%20D104%20Mic.pdf Schematics for amplified Astatic mics http://www.barovelli.com/projects/radio/radioastatic.htm __ 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
Re: [Elecraft] [OT] Lead-acid battery question
665 CA would be cranking amps (normal temperature), vs. the lower CCA rating which is cold cranking amps. Unlike marine or RV batteries, a starting battery have low ampere hours for its size: it's optimized for high current loading, not for run-time. I agree with those who suggest a good quality float charger to continually maintain the battery at full charge. Be sure it has a true float mode (not just an automatic charge cut-off), and avoid bargain priced chargers (they often have poor voltage regulation). I wouldn't be surprised if your generator controller has one; perhaps it has failed. I hope you get the problem fixed! --Tim (KR0U) __ 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
Re: [Elecraft] USB Cable Power Requirements
It is a low power USB device, because it does not power anything in the rig. The only connections are TX data, RX data and common (ground)--see page 5 of the KX3 manual. It won't strain either of those USB hubs. --Tim (KR0U) I bought a Mac with only four USB ports and am going to purchase a powered hub. One of the hubs offers seven ports, but only 2 A for all the ports. The four-port version offers a full 500 mA per port. __ 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
Re: [Elecraft] KX3 in Sweepstakes
Mine performed very well: 305 QSOs and 72 sections for 10 hours of operating time, using my HF6V vertical antenna. The great dynamic range and no-ring filtering makes a receiver that's easy on the ears: it is much less fatiguing than my old rig. When the clock struck 0300Z, I said What? Time's up already? This rig makes the operating fun--thank you Wayne, and everyone at Elecraft! __ 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
Re: [Elecraft] Battery Charging
Using 400Hz power is risky, because the current in the RFI bypass capacitors will much higher than normal. The leakage current through the capacitors to the output and other accessible parts will be high, possibly high enough to be a shock hazard. Running a 50-60Hz product from 400Hz power may also cause early failure of those capacitors. Follow the charger's marked input frequency rating, which almost always will be 50-60Hz. A small variation for the tolerance of a motor-generator is acceptable, but 667% of the maximum rated frequency is no small variation! --Tim (KR0U) __ 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
Re: [Elecraft] [KX3] Antenna Tuner Or Not
I think you'll appreciate the internal tuner for portable operation. For me, having an internal tuner is a big incentive. Being in the rig's package, it takes up less packing space and has no extra cables to hook up. Connect the KX3 to an antenna and paddle or microphone, and it's on the air. Speaking of internal accessories, I hope the internal NiMH battery charger board will come out soon. When that's available, I can recharge through the truck's cigarette lighter socket instead of bringing along external chargers (two of them, since each will charge only four cells at a time). Enjoy your KX3! --Tim (KR0U) __ 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
