Below are two builds by Johan, PD0LEW.  The one on the right hand side is actually a Magnetic Loop Controller, but on this picture it is showing a display identical to the 20x4 LCD version of the meter:

Here is a Display Mode showing Forward andReverse Power in separate bargraphs:

Actual output power, of course, is FWD - REF.

Here is a Modulation Scope showing an SSB signal.  Maximum full-screen sweep rate is a tad bit slow, at 300ms.  By overclocking the Microcontroller at 144 MHz it is possible to speed this up to 200ms(1500 samples per second):

This mode is a bit silly (only accessible through Config Menu). Since the two topmost graphs are dual graphs, this is effectively 8 bargraphs being displayed atonce:

• 100ms Peak Power, useful for SSB
• 100ms Average Power, closely emulates an analog needle meter, useful for all modes
• 1s Average Power, not sure how useful this one is for anything :)
• Instantaneous Power
• Power in dBm
• Three bargraphs, including separate bargraphs for forward and reflected power
• Modulation Scope

While the TFT version of the Configuration Menu looks a bit nicer than the LCD version it provides the same functions as before.  Below are pictures of the top level menu functions.  For a description of the lower level menu items, see the web pages on the original Power and SWR Meter Project.

Use the on-screen touch buttons tonavigate:

Schematic of the TFT and Touch Panel version:

(Click on schematic to enlarge)

The graphics screen  module is an ILI9341 240x320 SPI with anXPT2046 touch controller, available at pjrc.com or on eBay by using the searchcriteria:

Schematic of the 20x4 LCD alternative:

Signals identified but unconnected, are for potential future expansion of the project.

The meter is powered through the USB port.

A slightly updated Detector Circuit and Tandem Match Coupler:

(Click on schematic to enlarge)

The circuit above is the same as with the original Power and SWR meter project, however a 22pF variable capacitor has now been added on the forward output to minimize  coupling between forward and reverse outputs.  An even higher capacitance may improve the isolation further, but this will then also start to reduce the sensitivity of the SWR reading.  In other words, 22pF looks like a good maximum value when using the same cores as I do, and 30 turns on the secondaries. (Please disregard the RF sample output.  This was being used for a different purpose :)

With 30 turns on the secondaries and the capacitor at 22 pF I get lowest SWR at 1.03 at 28 MHz when transmitting into a good dummy load.  1.13 at 50 MHz.  Two 50 ohm dummy loads in parallel should give an SWR of 2.0.  I get just over 1.85 at both 28 and 50 MHz, good enough. 

However - If you are using the meter for power levels of 600W or less, then I would recommend that you change the transformers to 20 turns.  This will give a much better isolation at the higher end of the band and may even make the meter perform well at 50 MHz.  In this case, the capacitor will also help even further, but I suspect  about 5 - 10pF would be a good setting.

Here is one recent build of the coupler circuit, capacitor has not been added:

(Click on picture to enlarge)

An improved layout, including gerber files, by Johan PD0LEW, based on the above, is now available at his group page: Radio Stuff.

Here is another recent prototype, this time with some additional bells and whistles, like LiPo battery management and other stuff.  Not fully mature, so no details to be published :)

(Click on picture to enlarge)