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Old May 10th 05, 05:43 AM
John Smith
 
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Here is the schematic...
http://blake.prohosting.com/mailguy2/final.jpg
I am afraid this is may only good for QRP-one watt or less power...
Here is the link, this should be viewed as a starting design, far from
finished--I would be interested if some QRP'ers would play with it and let
me know of their experiences.

It was pointed out, that this was over-stressing components capabilites (Roy
even made comment)--the FET will just not take the demands put on it at 10
watts (I ran the ten watts through a resistive splitter and sent ~5 watts
too it--with a new FET, it lasted long enough for proof of concept tests...
then FET blew again)

I have fets of 200+ volts (mpf-102 is 25v)--just gotta find 'em... will
stick one of these in when I have time again...

I ended up with total turns of 30 on the toroid (center tapped.)

Warmest regards,
John
--
When Viagra fails to work--you are DOOMED!!!

"John Smith" wrote in message
...
| Here are some pics of the prototype I "junkboxed" together--sorry the
| quality is so bad...
| http://blake.prohosting.com/mailguy2/
| or:
| http://blake.prohosting.com/mailguy2/index.html
| click on the thumbnails for larger pic(s).
|
| The toroid has the winding grounded at center, there are 20 turns
total--10
| turns per side (way too many!!! I would suggest somewhere between 1-5
turns
| for 10 watts or greater!!!)
|
| And, for Richard, BOTH leds share a common current source through the
FET...
|
| Later, when I have time, will sketch the schematic and post it here...
|
| PARTS LIST:
| 1) One aluminum panel to mount SO-239s'
| 2) Two SO-239's
| 3) Two hyper-brite LEDs (I would suggest LESS efficient leds--unless for
| QRP--these were just handy)
| 4) One 1K resistor
| 5) One MPF-102 Fet
| 6) Hookup wire
|
| If this isn't the most parts-efficient swr indicator in existance, one
which
| is suitable for QRP thru QRO--then I'll eat this post!!! (well, granted,
| Cecils' "Two Lamp SWR Indicator" beats it--but then, this works on
coax!!!)
|
| Build one! It works!!!
|
| Anyone know a QRP newsgroup where I can share this design with?
|
| Warmest regards,
| John
|
|
| --
| When Viagra fails to work--you are DOOMED!!!
|
| "John Smith" wrote in message
| ...
|| This is a SWR bridge I built using leds and a homemade "directional
|| coupler."
||
|| ALL critiques on it, and ideas for improvements are welcomed!!!
||
|| Please excuse my rough drawing, I am NOT a draftsperson!
||
|| Hopefully, the attachment of the .jpg was successful....
||
|| Warmest regards,
|| John
||
||
|
|