Tuning aid for QRP field gear

FT-817 is an ultimate QRP field radio. There are plenty of new field rigs, but the old 817 is still one of the best choice. Of course it has few minor bugs as all the other fellas have. Its internal SWR meter is one of them. It is more like an SWR indicator instead of SWR meter. The bulit in bridge is not so accurate, therefore it is not possible to tell the difference between SWR 1.1 and 1.8 simply watching bars on the screen. In both cases it says no bars at all...
The tuner I built last time has an internal tuning indicator. It is so easy. Two ge diodes, a cap, and a small meter. There is also a led for dark environment. Sensitivity can be set by twisting a 10k pot. This tuner works really good. I've tested it with a 5m long vertical and few CPs against a doublet with ZM-2 tuner. 
Mine was significantly better. The station was able to hear me loud and clear enough for reliable communication, while doublet and ZM-2 was weak, and signals were hard to copy. There were stations unable to copy the other setup, while giving fine reports to mine. 
While trying the doublet mounted next to my rig I noticed the needle was dancing on my tuner's meter. I tried the led indicator and I was able to see the light and observe the changes of the signals on that as well. I decided to build a stand alone field strength indicator for QRP field days. 
Here it is:

The circuit is easy. It looks exactly the same as the one you can find here https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiRPO1C5HFqyEIOg818nPQvyP6Wsjo2fKdbagdgny89TvIJCAZHERdmFGFoI-_flwrRaVIkcYgMJuS_JsAdb0YuYkkrFyvFnqz29Yy3e_sEIz8evcPfxIrg0XbKKOzpxh3cniK1rRo639o/s1600/tuning+aid.GIF

 Thanks to PD7MAA!

There are two banana plugs for the antenna and GND cables. BNC for my small telescopic whip is mounted on the front. This way it stands on the desk if needed. The small patch cable with the croc at the end goes right to the gnd terminal of the FT-817. Sensitivity can be set just by twisting the pot on the middle. Few watts are enough to light the led up from few feet away from the antenna. 
After tuning the antenna to 'no bars' on the radio, just set the pot to low light on the led. Tune it until the led will give the brightest light.

Price is so low... every parts are recycled, except the plastic box. (aprox 30 cent:))

Update: 
My friends asked me to lend it to them for a test, therefore I made some stickers to the face of the box. Does not look professional, but helps to find out what is for what purpose on this over-complicated front end:)
Also I made a pic of the inside. As you can see it is not a sort of rocket science:)