(ex-W6OOQ)
Escondido, CA
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The latest K3QEP project, an 'experimental'
transmitter covering 160, 80 and 40 meters. The final
amplifier runs a 4-1000A tetrode which is modulated by a pair of 572B
zero-bias triodes. Separate power supplies are used for the final
plate, the final screen grid and the modulators. This
necessitates the use of self modulation for the tetrode screen grid by
inserting an audio choke in the screen supply. The Johnson Ranger at
left functions as the exciter. The current power level for the
transmitter is a 375-watt carrier with the 4-1000A operating far below
its ratings. |
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A closer view of the RF deck of the
transmitter with the 4-1000A easily visible through the viewing
port. The rack is a genuine Gates Radio unit, so the RF deck gets a
bit of the Gates flavor by proximity. The transmitter is well
metered and improved overload-protection measures are currently being
implemented. |
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The K3QEP Operating Position: At left is the Johnson Desk Kilowatt, excited by the Johnson Ranger above it. The Collins 75A4 is the primary receiver while the Collins R-388 serves as an all-band auxiliary. The Johnson Kilowatt Matchbox at right interfaces to a loop antenna fed with balanced line. The setup is completed with a Heath SB-614 station monitor and a decidedly retro-looking D-104 microphone. Behind the D-104 is a Hammarlund SP-600 receiver. |
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The
Heavy Metal Dept. at K3QEP: Large grey box at right
is a Gates
BC-1G ex-broadcast rig used on 160 meters. Racks
contain
other Home-Brew Transmitters and Amplifiers as well as a National
NC-303 receiver, mod monitor and scope. Audio chain is a
Gates
'Producer' Console driving a Gates Limiting
Amplifier. |
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The
Balanced-Line Tuner at K3QEP: Each coil is wound with 50 feet
of
quarter-inch copper tubing and the variable capacitor has a
1-inch plate spacing. Bob reports the inductors show no sign
of
heating and the capacitor does not arc-over when he drives his
full-size loop antenna on 160 meters with full legal-limit power
through this impedance-matching network. |
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Whatizzit??
A desk display made from the neutralizing capacitor and
final-tube mounts of a Gates BC-1F broadcast transmitter. |
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The
HF mobile antenna system on the K3QEP service van. The
weather-proof box contains a DC motor coupled to a heavy-duty gearbox
that can raise and lower the Hustler antenna is about 5 seconds.
K3QEP is frequently heard on 75 and 40 meters AM during the day as he
tends to his electronics businesses around Escondido. |
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The HF mobile antenna system showing the
Hustler antenna in the stowed position. |
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The Hustler antenna in the
raised position and listening on 7293. |
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Inside
picture of the motor/gear enclosure. The big gear box on the left was
orginally attached to a 110 volt AC/DC motor (Not reversible) which
could not be removed from the gear box without some trouble. The
solution was to connect a NEW motor at the rear of the old motor, the
latter having a one-quarter-inch through-shaft which facilitated the
coupling. As can be seen, all of this is mounted on a plywood board which is screwed to the fiberglass weatherproof enclosure, one of several purchased at the Mesa Hamfest a few years ago. The rest of the parts came from the extensive K3QEP junkbox and from local electronics/surplus stores in San Diego. |
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A
closeup the insulator and the machined aluminum block. The insulator is
a type used in electrical power installations and was found at the
local swap meet. All of the screws are stainless steel. |
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