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Thursday, January 1, 2015

Larry's Mighty Mite



Larry's rig looks like it is almost ready to go for Straight Key Night!   FB.   I was glad to heat that the crystal survived the rough treatment dished out by the US Postal Service these days.  Apparently all envelopes are sent through a steam roller!  Who knew?

Hi Bill and Pete,

As usual life has intervened in my plans, but after a delay for professional and personal reasons I can now report success in yet another additional the the CLA.  I was able to successfully transmit into a dummy load yesterday with my new transmitter.  It is not the prettiest device I have ever built but it is functional.  I tried the home made mepad construction and it works fairly well.  I did discover a few things while building and testing this unit.  First, I need a new soldering iron with a little better temperature control.  Second, before using this transmitter on the air (currently on a dummy load), it needs a low pass filter.  I can see several harmonics imposed on the generated signal.

The first picture show how everything is mounted to piece of scrap wood for stability.  I even screwed down the old key for stability during testing.  The alligator clips are for the dummy load connection (the dummy load is also home built from 20, 1K ohm resistors which is located just on the right edge of the picture).  

Even without an antenna I was able to receive the transmitted signal on my IC-7200 in the shack.  

The signal on the scope is messy but the tome received on the IC-7200 sounds good.

Next steps are the additional of a Low Pass Filter and better matching to the dummy load (currently I'm only at about 49 Ohms).

Thanks again for the encouragement.  I plan to do a little more tweaking on this unit and will keep you updated on any progress.

Have a great holiday and a Happy New Year,
73
Larry
AE7TM

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