From: "Bill Jones" <kd7s@...>
To: <rod@...>
Subject: Rock Mite on steroids
Date: Friday, August 16, 2002 10:39 PM

Hi Rod,
...
The Rock Mite On Steroids

Because I have a very modest antenna system (a roof-mounted 4BTV vertical) I
increased the output power of my Rock Mite.  First, I replaced Q6, the
2N2222A final transistor with a 2N3053 from Radio Shack.  The 2N3053 lists
for .99 cents in my 2001 catalog.  Next, I dropped the value of R18 from 10
ohms down to 6.8 ohms (thanks NorCal for the great resistor assortment).
These two changes alone gives me 1.25 watts output with a 13.4 volt power
supply.  Running the rig on an 8-pack of alkaline batteries I still get a
solid one watt to the antenna.  The 2N3053 runs warm but not hot, even
without a heatsink.  There appears to be a fairly large voltage drop across
L1, the 10 uH molded r.f. choke feeding the collector of Q6.  As time
permits I plan replace L1 with 6 or 7 turns of #24 wire on an FT37-43 core
(thanks Norcal for the great toroid assortment) to reduce the voltage drop.

My first QSO with my modified Rock Mite was with none other than Pete
Hoover, W6ZH near Los Angeles.  Pete is only a couple hundred miles away but
signals were great both ways.

=================
Bill Jones - KD7S <><
Sanger, California
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