Re: Drake W4 wattmeter woes and some success
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Thanks for? telling up the repair.
People put too much into the wattmeter numbers.? I just think that if any of the broad range wattmeters are with in about 10% that is good enough.? If I am thinking right just 1 db is about 25 % and that is hardly noticeable? on the receiving end.? I have several wattmeters and the? Drakes mostly match a Struthers I have.? I have 3 Heathkits and I just used the Struthers and set them to match it at 14 MHz and let it go at that.
When measuring the power of a transmitter I just note if it is within 10 % of what it is rated for.? If there is any? big change the next time I check it with the? same meter then I may start look for what the problem is, meter, dummy load , or transmitter.
Part of my job was to calibrate all kinds of instruments in a large plant.? We had two calibrators for each type of instrument? we calibrated and set everything to those calibrators? which were sent out every year for calibration.
Ralph ku4pt
On Sunday, January 21, 2024 at 11:37:58 AM EST, mike bryce <prosolar@...> wrote:
³Ò²¹²Ô²µ¡ An update on the W4 wattmeter. The one with the low readings and the inability to set the meter calibration has been fixed! The problem? Capacitor C5 showed about 3k¦¸ of resistance! Replaced C5 and C4 (why not?) and I could calibrated the meter. Now¡ according to Drake they want you to use 14mhz and apply so many volts RMS across the 50¦¸ dummy load with one value at 100W and the second at 1000W. I can¡¯t generated 1000W on 14mhz, so I set the 200W scale to 100 W, then set the 2000W scale to 100W. I know an analog? meter is not as accurate on the lower end of its scale, but that¡¯s the best I can do. Mike, wb8vge
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