Jason,
The circuit looks very useful. The layout of the LEDs is not
very typical, which makes it a bit unnatural to use. That is
easy to change. Can you provide some inside photographs
to show how you did the circuit layout?

I am not sure why people even use SWR as a measurement for
reflected power. Perhaps it provides a nice mathematic
simplification, but it is a very quirky and unnatural scale
for human operators: 1) it does not go to zero, 2) it is
hard to read/write/and even say, 3) without a forward
reading, a SWR of 1:1 could simply indicate no forward
power, and the useful range ends at 3. What is needed
is a scale that based on a 2-dimentional vector. For
example, magnitude and angle of a vector that is formed
from an X-axis of forward power and a y-axis of reflected
power. The difficulty is mostly converting this to
a graphical representation. An array of 100 LEDs is
not very practical (10 x 10), but perhaps a tiny LCD
is. A small LCD and microprocessor could be cheaper
and easier to read than cross needles.

Andy
WA3LTJ





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
: