功率计&频率计制作

文章摘要：so that it's hard to come in and make modifications. Here a view of the back side of the switches and the rotary encodernote the RF filter on the DC voltage input. The backside powersupply input, and powersupply selector switchThe DC voltmeter switch is connected so that it's only possible t

功率计&频率计制作,标签：电子小制作,http://www.88dzw.com
so that it's hard to come in and make modifications.

Here a view of the back side of the switches and the rotary encoder
note the RF filter on the DC voltage input.

The backside powersupply input, and powersupply selector switch
The DC voltmeter switch is connected so that it's only possible to measure the battery voltage when it's running on battery.

Here is how I have connected the two switches, the charge resistor and diode needs to be adjusted to fit the used battery.
If no battery supply is needed, only one switch is then mounted.

Also the powersupply cords can transfer unwanted RF noice, so here is also added a RF bLOCking filter
Note the diode and little-fuse for reverse polarity protection.

The NEW version of the PCB Now the input coil has been removed
The AD8307 is SMD SO-8, the extra input board is for a later project (SWR bridge), more about this next year.
The TX serial out PIN is for several future projects, that uses a PC to draw curves and more.

The bottom PCB side is mostly shilding PCB size is 79mm wide and 37mm height

Here is all the measurements curves
Software information users guide and download
PC logger software for windows
Complete part list
Assembly and solder instructions
Digital Wattmeter construction-competition
Serial output format and hardware sorry this page only in Danish
Front plate and box design Here is my sugestion about how to do it
Comments, Ideas, News from all of us to all of you
Output to freq counter and DFD4 counter modifications
F6GOG Wattmeter page A must see page !!

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How To Measure High Power

The digital-powermeter input range is 1nW to 1W.
To measure more power an attenuator can be mounted in front of it, but they are expensive !
A good and cheap solution is to use a -40 dB tab.
The Wattmeter readout can be set to show correct values, using five standard attenuators,
Attenuator settings: none, -10, -20, -30, -40 and -50dB, by this it is now possible to measure from 1nW up to 100 kW

Here is my simple homemade -40dB tap, using 3 BNC connectors a small cheap box and a few resistors.
The four first resistors is 620 Ohm each the bottom resistors is two 100 Ohm in parallel.

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