The pictures on this page show the current mobile installation in my 2000 Toyota 4Runner. I have made several changes in the past 5 years which were the result of over 40,000 mobile contacts of which 75% were CW and 25% were SSB. Most of these pictures were taken in late 2007 and early 2008. The high resolution (1200x900) version of all the pictures may be downloaded in a single zipfile (1MB) by clicking here.
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Page content last updated May 6, 2009 (orig. content 2008)
Copyright © 2008-2009 Larry Benko, W0QE
The pictures in this area show the radio installation. The original installation was for an Icom 706mkIIG and the space where the ashtray was located seemed to be perfect. A quick trip to the Toyota dealer produced a sacrificial ashtray insert for about $20. The side picture shows a custom fit chunk of wood that is screwed into the ashtray which then provides a surface to mount the bracket for the radio face. Underneath the ashtray are 2 neoprene wedges that secure the open ashtray and the radio face never moves or vibrates loose even on 4WD backroads in the mountains. Removal is as easy as pulling out the 2 wedges and pushing down on the lid of the ashtray which takes about 30 seconds. The side view picture shows a piece of blue plastic which was needed for the Icom 7000 which has a face that is just slightly different in shape from the 706.
The radio mounts under the driver's seat and when the seat is pushed back is completely captured. The picture shows the radio with an external LDG Z11Pro tuner, used for 40m SSB and 17m, and a 2 Farad capacitor (in plastic wrap in case of a leak). The 2F capacitor allows for longer operating with the engine stopped and totally eliminates alternator noise from the radio. The resistance of the DC wire from the battery at .01 ohm and the the 2F capacitor form a low pass filter with a 3dB roll off frequency of 8Hz. Also the 2F capacitor smoothes out the current draw from the battery so that the wiring only needs to provide the average current and not the peak current resulting in the radio not resetting when running with the engine off.
Additionally for contests, when my wife drives (and I do appreciate it), I temporarily remove the glove box and mount an Icom 746Pro with a special bracket in that space. The 746Pro is really a better radio than the 706 or 7000 in a contest. This picture was taken in May 2007 before I purchased the IC7000 and shows the original IC706mkIIG in the ashtray mount. The keyer mounts to the top of the IC746Pro using a couple of existing screw holes. Note that the radio clears the air bag and even if the vehicle rolls over the radios remain captive.
The radio mounts under the driver's seat and when the seat is pushed back is completely captured. The picture shows the radio with an external LDG Z11Pro tuner, used for 40m SSB and 17m, and a 2 Farad capacitor (in plastic wrap in case of a leak). The 2F capacitor allows for longer operating with the engine stopped and totally eliminates alternator noise from the radio. The resistance of the DC wire from the battery at .01 ohm and the the 2F capacitor form a low pass filter with a 3dB roll off frequency of 8Hz. Also the 2F capacitor smoothes out the current draw from the battery so that the wiring only needs to provide the average current and not the peak current resulting in the radio not resetting when running with the engine off.
Additionally for contests, when my wife drives (and I do appreciate it), I temporarily remove the glove box and mount an Icom 746Pro with a special bracket in that space. The 746Pro is really a better radio than the 706 or 7000 in a contest. This picture was taken in May 2007 before I purchased the IC7000 and shows the original IC706mkIIG in the ashtray mount. The keyer mounts to the top of the IC746Pro using a couple of existing screw holes. Note that the radio clears the air bag and even if the vehicle rolls over the radios remain captive.
The 2 pictures below and the top right picture above show how the paddle is mounted in one of the cup holders (I use the cup holders behind the console for drinks) with the keyer on top of the paddle. The position is perfect as I can wedge my arm between the seat and the cosole and can send good CW even on bumpy roads. A piece of delrin locks the paddle in place and a 1/4 turn with a screwdriver allows instant removal. Making 1000 mobile contacts in a single day requires a good comfortable operating position.
The 3 pictures to the right and the group below show the antenna installation. Several different antennas have been used but I have settled on a home made multiband antenna based on a W9UCW design. This antenna is not as frequency agile as a large screwdriver antenna but can do band changes instantly. A mobile trip from Colorado to Virginia at the beginning of 2008 resulted in 6335 contacts from 163 counties and according to the log nearly 1500 band changes.
The antenna brackets are made from 1/4" 6061-T6 aluminum and mount directly to the roof rack with 6x1.0mm SS screws. Each side of roof rack mounts with five 6x1.0mm screws through the roof to a backing bar above the headliner inside the vehicle. All the threaded holes in both backing bars had the paint cleaned from the threads with a tap and SS screws with Penetrox on the threads were re-installed. The connection to vehicle ground is very good and short. Then the brackets were connected to the cross bar on the roof rack via some homemade delrin brackets for lateral support. This scheme worked fine when I was running Hamsticks but with the big antenna I added a 5/8" 2024 hardened aluminum cross bar to minimize sideways flex with the big antenna. This has worked well when travelling 75mph on I-25 in Wyoming heading north with a 70mph crosswind from the west.
The antenna base is a homemade piece of delrin machined at an angle (so the antenna is vertical) to a 1" diameter solid stud made of 6061-T6 aluminum. Notice the drain holes in the bracket and the stud is connected with a 5/8" grade 8 bolt and a small 1/4x20 screw to prevent rotation.
A mount with 4 springs (with internal continuity wires) connects to the 1" stud and is easily removed in a minute or less for garaging the vehicle. A 72" mast (plus springs) of 7/8" 6061-T6 connected to a 1.5" piece of 6061-T6 hex aluminum yields a 76" high mast with some flex to mount up to 6 resonators. The homemade hex adapter is tapped with standard 3/8-24 setscrews which are how the resonators mount. The antenna is guyed to the front of the roof rack with two 1/16" kevlar cords and some bungie cords that provide a very nice shock absorber mecahanism. I have had this antenna over many Colorado 4WD passes in terrible conditions and has never failed.
The antenna shown with 6 resonators covers 80m to the rear (12 KHz 2:1 SWR bandwidth), 40m to the front (80 KHz 2:1 SWR bandwidth), 30m, 20m, 15m, and 10m. A 1.5 uH inductor to ground wound on a T94-6 torroid matches the antenna to less than a 1.3:1 SWR on all bands. Additionally this particular resonator placement produces a spurious resonance near 18MHz. allowing 17m operation with a 2.5:1 SWR or can be reduced with the LDG tuner.
The antenna brackets are made from 1/4" 6061-T6 aluminum and mount directly to the roof rack with 6x1.0mm SS screws. Each side of roof rack mounts with five 6x1.0mm screws through the roof to a backing bar above the headliner inside the vehicle. All the threaded holes in both backing bars had the paint cleaned from the threads with a tap and SS screws with Penetrox on the threads were re-installed. The connection to vehicle ground is very good and short. Then the brackets were connected to the cross bar on the roof rack via some homemade delrin brackets for lateral support. This scheme worked fine when I was running Hamsticks but with the big antenna I added a 5/8" 2024 hardened aluminum cross bar to minimize sideways flex with the big antenna. This has worked well when travelling 75mph on I-25 in Wyoming heading north with a 70mph crosswind from the west.
The antenna base is a homemade piece of delrin machined at an angle (so the antenna is vertical) to a 1" diameter solid stud made of 6061-T6 aluminum. Notice the drain holes in the bracket and the stud is connected with a 5/8" grade 8 bolt and a small 1/4x20 screw to prevent rotation.
A mount with 4 springs (with internal continuity wires) connects to the 1" stud and is easily removed in a minute or less for garaging the vehicle. A 72" mast (plus springs) of 7/8" 6061-T6 connected to a 1.5" piece of 6061-T6 hex aluminum yields a 76" high mast with some flex to mount up to 6 resonators. The homemade hex adapter is tapped with standard 3/8-24 setscrews which are how the resonators mount. The antenna is guyed to the front of the roof rack with two 1/16" kevlar cords and some bungie cords that provide a very nice shock absorber mecahanism. I have had this antenna over many Colorado 4WD passes in terrible conditions and has never failed.
The antenna shown with 6 resonators covers 80m to the rear (12 KHz 2:1 SWR bandwidth), 40m to the front (80 KHz 2:1 SWR bandwidth), 30m, 20m, 15m, and 10m. A 1.5 uH inductor to ground wound on a T94-6 torroid matches the antenna to less than a 1.3:1 SWR on all bands. Additionally this particular resonator placement produces a spurious resonance near 18MHz. allowing 17m operation with a 2.5:1 SWR or can be reduced with the LDG tuner.
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2009 MARAC, 7QP, and NEQP Contest (May 2-3, 2009)
For the past several years I have done this contest weekend from somewhere in Kansas or Nebraska and usually run into lightning or tornadoes. I was even hit by lightning a few years ago in Dundy County, NE which needless to say ruined the weekend and the radios. While operating is an awful lot of fun so is changing something so I decided to operate from the 7th call area for the 7QP part of the weekend and decided to run the contests with a laptop computer meaning that I would use the IC-7000 rather than the IC-746Pro for the radio due to space. I started the weekend in northwest Colorado an drove through SW Wyoming, NE Utah, eastern and central Idaho, northern and eastern Utah, and finally back home through Colorado. I operated from 39 different counties during the contest(s), drove 1820 miles (including getting to and from the starting and ending locations), and made about 1500 contacts. The weather was rainy with some light snow and the scenery was gorgeous. For those who have never done mobile contesting there are challenges but it is extremely addictive.
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Click on any pic for higher resolution image
