CVARS WA7UHD

CVARS
The Chehalis Valley
Amateur Radio Society
WA7UHD

ARRL special service club




Electronics Workshop - October 25, 2018

Time & Location:

Topics:
  1. Dummy Load with Wattmeter
  2. Looking at filters with a vector network analyzer:
    1. Comet CF-416 2-meter/70-centimeter Duplexer
    2. 10/15/20 meter Triplexer and Bandpass filters

Notes:
With Ohm's law: Voltage = Current x Resistance
and power law: Power = Voltage x Current
voltage across 50 ohms at 150 watts = square root of (power x resistance) = 86.6 volts rms = 122.4 volts peak.


Reference:
Dummy Load with Wattmeter:
  1. "Build an Inexpensive 150 W Dummy Load with Wattmeter," by Jack Purdum and Al Peter, November 2018 QST, pages 32 through 35.
  2. Assembly Manual and Arduino source code:
    www.arrl.org/files/file/QST%20Binaries/November2018/QST-1118-PurdumPeter-Source-code.zip

Filter Basics:
  1. "Filter Basics, Stop, Block, and Roll(off)," by Ward Silver, July/August 2018 Nuts and Volts, pages 16 through 21.
  2. "Filter Design Software, Once you start, it's hard to stop!," by Ward Silver, September/October 2018 Nuts and Volts, pages 12 through 17.

Vector Network Analyzer:
  1. Array Solutions vector network analyzer VNA UHF:
    https://www.arraysolutions.com/antenna-analyzers and
    http://www.w5big.com/vnauhf.htm
  2. Software, which can be run in demo mode without the VNA UHF:
    www.w5big.com/VNAuhf_636.zip

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