Hi Ray,
Thanks or your response. I have found that on 20 meters my K3 displays a high current warning above 80 watts displayed on the K3. Other bands I can transmit at 100 watts and no high current warning. I believe that is because the watt meter I have been using is not accurate and the K3 may be putting out in excess at this power level displayed on the K3 meter and therefore the high current warning. That is why I was asking which watt meter, the Palstar or the KPA-500 would be more accurate. I understand that 80 watts or 110 watts on the receiving end is not noticeable but I need to know why the high current warning at 80 watts on the K3? Is it the watt meter I am using to calibrate the K3? Thanks, Jim Douglas K2ZF -----Original Message----- From: Ray Sills <[email protected]> To: k2zf50 <[email protected]> Sent: Sun, Sep 18, 2011 5:22 am Subject: Re: [Elecraft] KPA-500 watt meter vs. Palstar HI Jim: Well, as always, measuring equipment has to be calibrated, and as you've noticed, indicated readings can vary over the range of operation. Most measuring gear for ham use has about a 10% or so tolerance, plus and minus, so you can't get truly accurate readings. To get to precision levels, (1% or so), you need very high quality instruments (meaning expensive), or at least a way of correlating the indicated readings to a know level of accuracy. For many hams Bird wattmeters are the reference measurement, but even they are not highly accurate, and it's often the case that the accuracy varies over the range of operation. The fact that the Elecraft unit has a digital display does not mean it's more accurate. It may be more "precise" (able to finely resolve a measurement), but that does not mean it's more accurate. A digital clock that displays seconds is more precise than an analog clock that has only a minute hand and hour hand, but the digital clock might have a bad time base and drift enough to gain or lose time in a day. The analog clock might be rock solid, and very accurate.. just not as precise. So, with regard to your measurements... take your pick. If you want to be a scientist, you can build a dummy load in a can, fill it with de-ionized (pure) water, and measure the temperature change over time of the water to determine how many watts are being dissipated. Then, make a comparison to what the meter says and construct a calibration chart. For me, that would be a lot of work. I'd be happy with approximate readings... if the 100 watt reading is actually 85 watts or 110 watts, it would not bother me. You'd hardly notice the difference at the receiving end, maybe not at all. 73 de Ray K2ULR FN20kf Warrington, PA On Sep 18, 2011, at 8:58 AM, [email protected] wrote: > > Hi, > > > > My KPA-500 watt meter and my Palstar watt meter read about the same > at the higher power readings. But at the 100 watt and lower ranges > there is a significant difference. My question is which is the more > correct reading at the lower ranges, the Elecraft or Palstar. If I > want to calibrate my K3 which one would be more accurate? Being > that the Elecraft is a digital display would that one be more > accurate? > > > Thanks, > Jim Douglas K2ZF > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
