anyone here tried a homebrew wattmeter using an AD8307 log amp?? need
to chat w/ you...

gary
ka9rao

Yes. My meter is used for low level RF measurement. Primarily I have
been using it for LO measurement and crystal filter construction. It
waspretty simple to build ugly style. The June 2001 article by Bob
Larkin is a good article to read. Calibration will be a concern. I also
created a spreadsheet using the slope formulas provided in excel. I
guarentee you will fine it useful.

AADE has a kit.

K5UOS

On Oct 14, 8:03 am, Gary wrote:
anyone here tried a homebrew wattmeter using an AD8307 log amp?? need
to chat w/ you...

gary
ka9rao

In article , Gary
wrote:

anyone here tried a homebrew wattmeter using an AD8307 log amp?? need
to chat w/ you...

gary
ka9rao

Built one using an 8307, A/D, and Stamp II. As the other poster
mentioned, depending on what you want to do with it, calibration can be
an issue, for both frequency and amplitude. "Dead bug" style
construction works well with this part, providing a solid ground plane.

Oh, and look on eBay for HP 436 and 437 wattmeters. That part is
cheap. The expensive part is the probe -- 8481, 8482. But even
without the probe, the 436 and 437 have reference sources that put out
1mW into 50 ohms at 50 MHz with better than 1% accuracy.


omit the usual to e-mail me.

--
Namaste--

Gary wrote:
anyone here tried a homebrew wattmeter using an AD8307 log amp?? need
to chat w/ you...

gary
ka9rao

Hi; my first post so hope it works.

Yes, I built mine largely on the Kopski circuit. Manhattan
construction.

I made a separate measuring head in a small diecast box with a cable
which plugs-in to the meter unit via a microphone plug/socket.

I also made another head in an identical little box; it contains a
return-loss bridge with an AD8307 as the detector. Works fine up to
650 MHz. It allows quick & accurate return-loss measurements; I call
it my poor man's scalar network analyser.

Kerry VK2TIL.