N2FFL's MOBILE STATION
I picked one of these up in December of 2001 and am quite pleased with it. My only complaint is that the radio does not come with a DTMF microphone. I wanted to be able to access the IRLP on the local 6 meter repeater so a DTMF microphone was a must, I purchased one when I picked up the radio. The radio's compact size is perfect for my needs, it goes from the house to the car and to my job with little effort.
For more info on this radio visit the Icom website.
When operating FM on your local repeater these radios sound best with the mic gain set at 2 or 3 and the speech compression turned off.
Click on a picture for a larger view.
The 706 ready to go mobile...
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In the mobile waiting for some 6 meter DX action...
Left photo: The mounting plate secured in place prior to the placement of the radio.
Center and right photos: The radio secured to the mounting plate by a small bungee cord.
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My homebrew mounting plate...
Left photo: Top of the plate, viewed from the front. The rear of the radio rests against the two "pegs" at the rear of the plate. The pegs are just two, three inch long 1/4" bolts that have had the heads cut off of them. The bolts are covered with rubber hose for cushioning. The radio is held in place by a small bungee cord hooked to the two "ears" towards the front of the plate.
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Right photo: The bottom of the plate, viewed from the rear. The metal bar seen across the middle of the plate has holes drilled in both ends. To each end of the bar a small bungee cord is attached. The opposite end of each bungee cord is attached to a metal rod which I found located on the underside of the front seat. One of the bungee cords can be seen in the lower left corner of the photo. The plate itself is a 6 1/2" X 12" piece of fairly thick sheet metal. The mounting plate took about two hours to build, it was constructed from bits and pieces of junk I had lying around. This arrangement works well, the radio is held firmly in place and can easily be installed when I get into the car and removed when I get out.
Antennas...
I was using three mag mount antennas. The 2 m / 70 cm is a Diamond Dual Band. The 6 meter is a 1/4 wave (constructed from two Radio Shack CB antennas that were collecting dust) and a Wilson 1000 on the trunk lid tuned for 10 meters.
After a couple of months I got the itch to expand my mobile HF capabilities. One of my requirements was that the antenna be magnetically attached to the car. The following is what I devised....
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My first homebrew antenna, a 20 meter monobander. This was originally a 10 meter antenna that I purchased about 18 years ago. It 's a hollow fiberglass tube that had a coil inside with a whip attached to the top. The original coil was removed and a new coil was wound on the outside of the tube. After the coil was pruned to the proper length the I applied several coats of clear acrylic enamel and then covered it with heat shrink tubing. The entire antenna is about 6 feet long and works well. This antenna is lightweight and only a single 5 inch diameter mag mount was needed to hold it in place. |
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After a short time I got tired of being stuck on one band so I constructed a multi band antenna for 40 through 10 meters. I purchased a Wilson 5 foot fiberglass CB antenna and removed the heat shrink tubing and coil from it. I then wound 95 feet of 18 guage enameled onto the shaft. The antenna originally had a short "whip" (3") attached to the top for tuning purposes, this was replaced by a 12 inch whip. A "wander lead" (twice as long as the antenna) was then attached to the base. Through experimentation the various tap points for the different bands were found. I then soldered and epoxied Radio Shack binding posts to the tap points along the length of the coil. To the free end of the "wander lead" a banana plug was attached. The whole thing was then covered with several layers of clear acrylic enamel and several layers of heat shrink tubing. What I didn't take into consideration was the loading effect of the heat shrink tubing which lowered the the resonant frequency of the antenna somewhat. I adjusted the whip at the top to compensate for this. The antenna works great on 20 through 10 meters, the 40 meter operation leaves a little to be desired, the resonant frequency is lower than I'd like it to be and at it's lowest the SWR is 1.8 to 1. |
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Close up view of the top section of the antenna showing the 20 through 10 meter taps. The "wander lead" is plugged into the 18 MHz tap in this photo. Everything needed to construct the antenna was purchased new at a total cost of only about $40. This antenna is quite a bit heavier than the the 20 meter monoband so a much more robust mount had to be devised. Another homebrew antenna of similar design can be found here. |
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A more robust mount. The 3 magnet assemblies were purchased from H&Y Electronics for $8.95 each. They are the 5 inch mounts (they are actually 6 inches in diameter). I disassembled each one, removed the coax cables and connected the center studs to the frame of each magnet for grounding purposes. Each one comes with a rubber "boot" on the bottom to protect the car's finish. After a few days on the car and a couple of rainstorms I noticed water had found it's way up into the magnets. A little RTV sealant applied to each solved this problem. |
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Mount viewed from the rear. The cross brace was not part of the original design but after driving on some rough roads, which there seem to be a lot of around here, I noticed the antenna would sometimes move from side to side quite a bit. While the antenna assembly did not tip over I wanted to make sure that it wouldn't in the future. The cross brace and small magnets added a great deal of stability to the mount. All of the hardware for the cross brace, including the magnets were purchased from Home Depot. The magnets are 2 1/2 inches in diameter. |
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My 75 meter monobander. This one
I didn't build, it was purchased at a hamfest for $18. This antenna is
similar in design to a Hamstick, it was "made" by Workman
Electronics. They also make other antennas for ham radio use none of
which are shown on their web site (at the time of this writing). The
antenna is 8 feet long. I found it easy to tune up and it appears to work
fairly well.
The shorter antenna on the left is my 6 meter 1/4 wave. |
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My collection of mobile HF antennas. The 20 meter is on the left, the multiband is in the center and the 75 meter is on the right. |
IC-706 RESOURCES ON THE WEB...
Some of these pages contain mods which if improperly done could damage your radio. Some of the info is for earlier versions and may not apply to the newer versions.
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ICOM706 Modifications - From N2KBK |
706 Tune Control - From the BetterRF co. |
How I modified my IC-706 MII G - From QRZ.com |
OH6KTR Icom IC-706 Resources - Mods, programs. |
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TR-Log to Icom Control Cable - "Contestpedition" Cable for TR-Log and the IC-706 |
ICBSCIV - Icom Automatic Band Select and Serial Interface |
IC706 Amp T/R interface - External Amplifier Keying for the IC-706. |
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ICOM Radio Software - From AMateur Radio Enthusiast's Group |
IRC Download page - A radio control program for Icom radios. |
ADM - 706 - Microphone adaptor from Heil Sound. |
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Microphone Wiring Info - For the 706 & others. |
TacPack™ for the IC-706/MKII/G - Carrying case for the 706. |
MARS mod - For the IC706MKIIG |
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