Jason:

Ok for the QRP to barefoot operator, but what about someone that at least
occasionally uses an amplifier?

I've got a couple of swr/wattmeters (two meters) that provide everything I
need, though they are a bit difficult to read at QRP levels. Autek WM-1
is one of them and currently available, and the other is a SignalCrafter
30 (may not be full name and model, but also not available any more).
Both have ranges for 20w, 200w and 2000w full scale, and show average or
peak readings. They tend to match one another pretty well, especially
considering the WM-1 is less than a year old and the other is probably 20
years old....

Will your meter be able to perform as well? I've found that most LED
based metering circuits are horribly inaccurate compared to a needle based
meter....

On the other hand, I'd love to see a new meter available, particularly one
that would work from qrp levels all the way up to legal limits.... while
providing both SWR and Power metering. I really really dislike dual
needle interpreted displays.

Thanks
--Rick AH7H



Jason Hsu wrote:

Last semester, I designed and built the QROP Meter for my
graduate school independent study project. Thanks to those of you who
helped me with certain thorny issues, such as transformers and DC
amplification. Go to my web page at http://www.jasonhsu.com/ee.html
to learn how to build the instrument.

What makes my SWR/wattmeter different from the numerous versions
available from MFJ and the numerous homebrew designs out there?

1. Works from 200mW to 100W! You get the best of both worlds! MFJ
SWR/wattmeters don't work at QRP, and QRP SWR/wattmeters can't handle
100W. Tuning up at 1W instead of 100W reduces the QRM you cause by
20dB, or over 3 S units! You can also safely change the tuner's
inductance taps WHILE transmitting at 1W.
2. GOOD resolution at SWR values above 3 and even above 5! This can
be very handy at 160m and 80/75m.
3. 10-LED display for the SWR meter and another 10-LED display for
the wattmeter: No more squinting at cross-needle meters!
4. More accuracy at low power levels: Most SWR meters understate SWR
at low power levels due to the infamous diode drop loss. My design
compensates for this and allows accurate SWR measurements at QRP power
levels.

Let me know what you think, and feel free to contact me if you have
any questions or suggestions. If you decide to build the QROP Meter,
let me know how it goes.

Jason Hsu, AG4DG