Re: Power Meter

Nick Kennedy
 

I also used that circuit by Bob Kopski K3NHI for my calibration.

Note that some years after the article appeared in QEX, the author
discovered that currently manufactured AD8307 chips no longer responded the
same way when a square wave was applied, at least not over the full range
of inputs. It turns out the relationship still applied at -10 dBm but might
deviate at -20 dBm, so he released a revised schematic of his calibrator
that outputs the equivalent of -10 dBm.

I just browsed our Files section for the paper describing the issue and the
revised schematic, but didn't find them. So, I've uploaded them to my
WA5BDU folder in the group's Files section. The discussion is in "AN AD8307
ADVISORY - K3NHI.rtf", and the new schematic is in "RF POWER CALIBRATOR II
- Kopski.pdf".

73-

Nick, WA5BDU

On Wed, May 9, 2018 at 9:21 AM David Collins <ad7jt@...> wrote:

Hi Alfredo and the group,

Check this out and save some $$$.

http://sp-hm.pl/attachment.php?aid=13774

We use this technique in the MSNA and it works very good.


73,
Dave Collins - AD7JT




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