Mobile amateur radio

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Welcome to
Mobile Amateur Radio Station
KØMDJ

(Kay Zero Em Dee Jay)
Licensed by the
Federal Communications Commission
to owner and operator
Mark D. Johns

Life Member

Updated 26 Oct. 2003

Because I have a long commute to work, my mobile station is where I do most of my operating. Therefore, I've invested most of my ham radio resources in building a "muscular" mobile station in my car.

The vehicle is a 1998 Toyota Camry. The design aim was to create an operating console that would allow safe and easy operation on as many amateur bands as possible. A Heil© HS-706 headset with boom mic allows hands-free HF operation (part of the headset can be seen near the bottom of the photo at left). A foot switch under the driver's left foot provides PTT control.

Life Member

The Icom IC-706MkIIG HF/VHF/UHF transceiver is used almost exclusively for HF. The main unit is mounted under the front seat. The control head is attached to a custom made bracket that extends above the car's factory AM/FM/cassette audio system, which remains fully functional.

The Icom IC-2350H dualband FM transceiver is semi-permanently mounted in the dash, in the space that would have been used for the CD player, if the car had been so equipped. An outboard speaker for VHF/UHF is mounted on the extreme left corner of dash, out of the driver's line of vision.

The HF antenna is a Hi-Q Stealth II.-2.5/40 mounted on a trailer hitch receiver. The antenna covers all bands, 6 through 40 meters, and is motorized for remote tuning. This antenna offers several advantages over traditional screwdriver type antennas. First, because there is no attempt to cover the 80 and 160 meter bands, it is much smaller in size. Second, the tuning mechanism is entirely inside the coil within a sealed Lexan™ tube, which means that the antenna does not change in length and has no moving parts exposed to the elements.

Also part of the antenna system is the Am-Com Automatic Screwdriver Antenna Controller which automatically tunes the antenna to resonance simply by touching the "Tune" button on the radio. This allows my full attention to be directed to driving, rather than watching meters or tuning indicators. It also means that changing bands can be done much more quickly than with manual tuning.

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The final piece of the "muscular mobile" setup is a 500 watt SGC "Smart Power Cube" solid state linear amplifier which boosts the power output to a level five times greater than that provided by the radio "barefoot." The Power Cube automatically senses the radio frequency of the signal and tunes itself accordingly. It is shown here strapped to its palate in the trunk of the car, beneath the antenna tuner.
Because the amplifier draws nearly 80 amps of current at 13.8 VDC, the car has been equipped with a second battery, located in the trunk next to the amp. The battery is charged from the car's electrical system through a length of #4 gauge wire run from the engine compartment. A heavy duty solenoid isolates this battery from the car when the ignition is turned off.

Back to Mark's Amateur Radio page	Welcome to Mobile Amateur Radio Station KØMDJ (Kay Zero Em Dee Jay) Licensed by the Federal Communications Commission to owner and operator Mark D. Johns
Life Member
Updated 26 Oct. 2003		Because I have a long commute to work, my mobile station is where I do most of my operating. Therefore, I've invested most of my ham radio resources in building a "muscular" mobile station in my car. The vehicle is a 1998 Toyota Camry. The design aim was to create an operating console that would allow safe and easy operation on as many amateur bands as possible. A Heil© HS-706 headset with boom mic allows hands-free HF operation (part of the headset can be seen near the bottom of the photo at left). A foot switch under the driver's left foot provides PTT control.
Life Member

	The Icom IC-706MkIIG HF/VHF/UHF transceiver is used almost exclusively for HF. The main unit is mounted under the front seat. The control head is attached to a custom made bracket that extends above the car's factory AM/FM/cassette audio system, which remains fully functional. The Icom IC-2350H dualband FM transceiver is semi-permanently mounted in the dash, in the space that would have been used for the CD player, if the car had been so equipped. An outboard speaker for VHF/UHF is mounted on the extreme left corner of dash, out of the driver's line of vision.
		The HF antenna is a Hi-Q Stealth II.-2.5/40 mounted on a trailer hitch receiver. The antenna covers all bands, 6 through 40 meters, and is motorized for remote tuning. This antenna offers several advantages over traditional screwdriver type antennas. First, because there is no attempt to cover the 80 and 160 meter bands, it is much smaller in size. Second, the tuning mechanism is entirely inside the coil within a sealed Lexan™ tube, which means that the antenna does not change in length and has no moving parts exposed to the elements. Also part of the antenna system is the Am-Com Automatic Screwdriver Antenna Controller which automatically tunes the antenna to resonance simply by touching the "Tune" button on the radio. This allows my full attention to be directed to driving, rather than watching meters or tuning indicators. It also means that changing bands can be done much more quickly than with manual tuning.
Page created with Dreamweaver MX	The final piece of the "muscular mobile" setup is a 500 watt SGC "Smart Power Cube" solid state linear amplifier which boosts the power output to a level five times greater than that provided by the radio "barefoot." The Power Cube automatically senses the radio frequency of the signal and tunes itself accordingly. It is shown here strapped to its palate in the trunk of the car, beneath the antenna tuner. Because the amplifier draws nearly 80 amps of current at 13.8 VDC, the car has been equipped with a second battery, located in the trunk next to the amp. The battery is charged from the car's electrical system through a length of #4 gauge wire run from the engine compartment. A heavy duty solenoid isolates this battery from the car when the ignition is turned off.

KØMDJ