KPA500 transformer taps
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KPA500 transformer taps
 
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With no load, my AC line voltage is 121 and my power supply voltage is 73. With full load, the readings are 111 and 53, respectively. That is with the yellow transformer tap in place. Should I switch to another tap? 73 Ray W2RS ______________________________________________________________ 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 Message delivered to [hidden email] |
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I'd be first concerned with the 10V drop in line voltage. Do you know where that's occurring?
73, Josh W6XU Sent from my mobile device > On Jun 1, 2017, at 8:11 AM, Ray W2RS via Elecraft <[hidden email]> wrote: > > > With no load, my AC line voltage is 121 and my power supply voltage is 73. With full load, the readings are 111 and 53, respectively. That is with the yellow transformer tap in place. Should I switch to another tap? > > > ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by Elecraft mailing list
On 6/1/2017 8:11 AM, Ray W2RS via Elecraft wrote:
> > With no load, my AC line voltage is 121 and my power supply voltage > is 73. With full load, the readings are 111 and 53, respectively. > That is with the yellow transformer tap in place. Should I switch to > another tap? As Josh said earlier, be very concerned about the10 volt drop in the AC voltage measured at the load. Depending on the "amp-feet" of the circuity feeding the load, the drop for a 1 KW AC load should be no more than the industry standard of 2 volts. If you have the opportunity, put the amplifier on a dummy load and measure (CAREFULLY) the AC voltage at the entrance panel, the socket if it's a duplex one, and the load taps. This will tell you where the drop is occurring. I can't emphasize it more - BE CAREFUL. As an EE you know that. (Among other things my company designs comm station AC and DC power installations - if you need help, just ask.) Ray - contact me directly. Our paths have crossed way back when...... 73 de K2ASP - Phil Kane (since 1952) Elecraft K2/100 s/n 5402 VP - General Counsel & Engineering Manager CSI Telecommunications, Inc. - Consulting Engineers San Francisco, CA - Beaverton, OR ______________________________________________________________ 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 Message delivered to [hidden email] |
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On Thu,6/1/2017 9:41 AM, Phil Kane wrote:
> As Josh said earlier, be very concerned about the10 volt drop in the AC > voltage measured at the load. All great advice. Also, try to trace the wiring that feeds the outlet that the amp is plugged into. Possible causes of the high voltage drop are 1) conductors that are too small (AWG #14 is the smallest permitted for a 15A circuit, #12 for a 20A circuit); 2) bad splices; 3) miswiring of outlets or splices (reversals of hot and neutral, or hot and ground, or neutral and ground); 4) degraded outlets; 5) miswiring of the KPA500 power cable (like #3). For a circuit carrying this much current from an electronic load, wiring should be a direct run of #12 (hot, neutral, and ground) from the power panel to the outlet. While #12 is not legally required for a 15A circuit, the larger conductors reduce IR drop. AND -- load current to electronic loads is NOT a sine wave, but instead consists of pulses at positive and negative peaks of the waveform to recharge filter caps in the power supply. This causes IR drop to be greater than predicted by application of Ohm's Law to a sine wave. SO -- it's good engineering practice to oversize conductors on circuits for electronic loads. Two wire sizes is a good rule of thumb. 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 Message delivered to [hidden email] |
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In reply to this post by Phil Kane-2
Ray,
As Phil has indicated, the 10 volt drop in the AC mains may be the only problem and should be investigated. Tracking it down to the trouble spot as Phil has detailed is the 'only way to go'. What I would look for is loose connections (screws) at the breaker box and at each receptacle that is connected to that circuit. If you are capable, remove each receptacle in the circuit and check it. If it is wired with the push-in 'backstab' connectors, remove the wires and connect them securely under the screws. There are two types of "backstab" connectors. One type uses the screw to tighten a clamp around the wire. Those are normally OK, but you may want to make certain the screws are tight. The other type does not depend on the screws, but just have prongs in the wire insertion holes to secure the wire. If you have that type, remove the wire (twist while pulling and it will come out) and secure the wire under the screwhead. With that much AC voltage drop under load, you have a condition where the failing junction has significant resistance and could cause overheating and possibly a fire. 73, Don W3FPR On 6/1/2017 12:41 PM, Phil Kane wrote: > On 6/1/2017 8:11 AM, Ray W2RS via Elecraft wrote: >> >> With no load, my AC line voltage is 121 and my power supply voltage >> is 73. With full load, the readings are 111 and 53, respectively. >> That is with the yellow transformer tap in place. Should I switch to >> another tap? > As Josh said earlier, be very concerned about the10 volt drop in the AC > voltage measured at the load. Depending on the "amp-feet" of the > circuity feeding the load, the drop for a 1 KW AC load should be no more > than the industry standard of 2 volts. > > If you have the opportunity, put the amplifier on a dummy load and > measure (CAREFULLY) the AC voltage at the entrance panel, the socket if > it's a duplex one, and the load taps. This will tell you where the drop > is occurring. I can't emphasize it more - BE CAREFUL. As an EE you > know that. > 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 Message delivered to [hidden email] |
New radio , new display
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All the messages pro and con for a new display on the K3 etc,
Here is a new one for ya in the QRP class http://www.dxzone.com/rs-918ssb-hf-sdr-transceiver/ Dont know if its more than a crystal set, dont know if it even works looks like copies of a several radios, priced where you can buy it and love the display if nothing else, Not going to buy one, no interest, just thought it may be what those who dont care about performance and only looks may be looking for. Merv K9FD/KH6 ______________________________________________________________ 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 Message delivered to [hidden email] |
OT Re: New radio , new display -- mcHF
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Also, last known to be infringing on the rights of the original developer.
http://www.m0nka.co.uk/?p=5258 <http://www.m0nka.co.uk/?p=5258> > Here is a new one for ya in the QRP class > > http://www.dxzone.com/rs-918ssb-hf-sdr-transceiver/ 73, Bryan - k0emt ______________________________________________________________ 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 Message delivered to [hidden email] |
Re: OT Re: New radio , new display -- mcHF
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I also heard that the boards were old versions and not the latest ver.
Having lived near Shenzhen and worked with many Chinese companies, this is normal. nuff said. 73 Merv > Also, last known to be infringing on the rights of the original developer. > http://www.m0nka.co.uk/?p=5258 <http://www.m0nka.co.uk/?p=5258> > >> Here is a new one for ya in the QRP class >> >> http://www.dxzone.com/rs-918ssb-hf-sdr-transceiver/ > 73, > > Bryan - k0emt > ______________________________________________________________ > 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 > Message delivered to [hidden email] > ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by Elecraft mailing list
Interesting. At first glance it appears to have some disadvantages
compared to the Elecraft KX3. Regarding portable use: - 450 mA in RX mode (more than 2.5X that of the KX3) - no 6 meters - no 2 or 4 meter option - no built-in ATU - no indication of a built-in battery pack or charger - no CW/data message buffers - no mention of a KX3-comparable set of frequency memory features - no CW/PSK/FSK decode/encode - no paddle-based internal PSK31/63 or FSK transmit - no APF (a killer KX3/KX2 feature for digging out weak CW signals) - no attached keyer paddle option Missing KX3 features, or performance questions: - 160 meter TX - AM transmit - direct frequency entry - programmable function switches - voice-mode DVR - dual watch - no indication of blocking dynamic range at any spacing - no mention of roofing filters - no statement regarding transmit phase noise The 0.5 ppm spec for the optional TCXO is +/- 15 Hz on 10 meters. The currently shipping KX3 with extended temperature compensation (no $) is more like +/- 0.1 ppm. RX and TX performance are unknown (you probably get what you pay for in terms of ADC and DAC). One red flag is the serial data connector, located directly adjacent to the BNC antenna jack. This would simply not work if you were using a wire antenna attached directly to the radio, as is possible with the KX3 and KX2. The spectral display is a nice feature, but it appears to be about 0.5" x 1.5", which is less than a tenth the size of the PX3's spectral display. This is virtually unusable, either in the field or at the home QTH. The PX3 has many direct controls, waterfall AND spectrum display. 73, matt W6NIA On 6/1/2017 5:19 PM, Merv Schweigert via Elecraft wrote: > All the messages pro and con for a new display on the K3 etc, > > Here is a new one for ya in the QRP class > > http://www.dxzone.com/rs-918ssb-hf-sdr-transceiver/ > > Dont know if its more than a crystal set, dont know if it even works > looks like copies of a several radios, priced where you can buy it and > love the display if nothing else, > Not going to buy one, no interest, just thought it may be what those > who dont care about performance and only looks may be looking for. > > Merv K9FD/KH6 > ______________________________________________________________ > 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 > Message delivered to [hidden email] -- "A delay is better than a disaster." -- unknown Matt Zilmer, W6NIA [Shiraz] ______________________________________________________________ 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 Message delivered to [hidden email] |
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