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Re: [AT_Sprint] Re: ATS 4 mods/power out

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  • Thomas Kuehl
    Leroy, The W7EL Wattmeter appeared in the February, 1990, QST. The article was tittled, A Simple and Accurate QRP Directional Wattmeter. Roy Lewallen, W7EL,
    Message 1 of 5 , Dec 31, 2010
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      Leroy,

      The W7EL Wattmeter appeared in the February, 1990, QST. The article was tittled, "A Simple and Accurate QRP Directional Wattmeter." Roy Lewallen, W7EL, is a highly regarded RF Engineer and is probably best known for his EZNEC antenna software and his revealing work about how baluns work. I think the popular WM-1  and WM-2 QRP wattmeters bare similarity to his QRP wattmeter design. The article should be available through the ARRL on-line QST archives.

      Happy New Year to all the ATS gang!

      Thomas - AC7A (in an unusually cold Tucson)

      --- On Fri, 12/31/10, leroy <lmarion@...> wrote:

      From: leroy <lmarion@...>
      Subject: [AT_Sprint] Re: ATS 4 mods/power out
      To: AT_Sprint@yahoogroups.com
      Date: Friday, December 31, 2010, 5:49 PM

       

      I am using my OHR qrp power meter. It was amazingly close when
      I checked it in the lab against NIST standards. Most kit/homebrew
      power meters I checked were good to excellent. Most commercial meters
      were poor to little more than a general indication. Consistently bad
      was the ubiquitous B**d wattmeter. Never saw one in the claimed 5%,
      most not even 10%. (I was a NIST PMEL tech)
      I will check into a W7EL power meter, it is probably very good.

      Leroy AB7CE


      --- In AT_Sprint@yahoogroups.com, Thomas Kuehl <qrp_op@...> wrote:
      >
      > Hi Leroy,
      >
      > I am working on building the W7EL QRP watt-meter so that I can accurately measure my ATS-4 output power. For now, without an accurate meter, I can tell I am getting about 5W on 80m, and between 4 and 5W on 40-20m, but the power on 15m is less; maybe 2.5 to 3W (12V supply). That is derived by comparing the output levels to my K2's ATU forward power reading. I'll be able to get a more accurate measure with the watt-meter once it is completed.
      >
      > I've tried adjusting turns and spacing on the 15m coils and I've arrived at the maximum output. I think it is common for the output to be lower on the higher bands.
      >
      > '73, Thomas - AC7A (Tucson)
      >
      > --- On Fri, 12/31/10, leroy <lmarion@...> wrote:
      >
      > From: leroy <lmarion@...>
      > Subject: [AT_Sprint] ATS 4 mods/power out
      > To: AT_Sprint@yahoogroups.com
      > Date: Friday, December 31, 2010, 10:13 AM
      >
      >
      > After trying the power out alignment by sqeezing/spreading the windings, here is where I am at with 12V supplied:
      >
      >
      >
      > 80mtr 4.5
      >
      > 40mtr 3.5
      >
      > 30mtr 4.2
      >
      > 20mtr 3.2
      >
      > 15mtr 2.5
      >
      >
      >
      > I realize this is not that bad. But if I can get the advertised 4.5 on all bands that would be desireable. Any advice?
      >
      >
      >
      > Thanks, Leroy AB7CE in Montana where its currently -21 degrees and a good day to work at the bench!
      >


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