This Instructable demonstrates how to modify a standard Icom IC-T7H hand-held dual-band radio transceiver to both receive and transmit on a wider range of frequencies.
2 Meter: 144.0-148.0 MHz
70 Centimeter: 420.0-450.0 MHz.
2 Meter: 118.0 - 174.0 MHz
70 Centimeter: 400.0 - 470.0 MHz.
Hopefully this will be the first of many ham radio related Instructables I will post.
This modification should only be made in preparation for emergency situations where communications out of regular ham bands are necessary, at no other time should an amateur radio operator transmit on frequencies outside of ham bands.
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Step 1: Step 1, Disassembly
There are 10 screws that need to be removed to gain access to the internal control circuitry.
Four above the battery compartment
Two at the top of the battery compartment
And two at the bottom of the battery compartment
Remove these screws and set them aside carefully so they don't get lost or knocked around and then proceed to step two.
Step 2: Opening the Tranciever and Identifying D15
After removing the ten screws the radio should separate fairly easily into 3 parts,
The top "controller unit"
The back-plane "logic unit"
And the battery compartment cover which is just a piece of metal.
Next take a second to locate D15, a 3 pin diode in the lower right of the back-plane logic unit.
After locating the diode and checking out the rest of the awesome circuitry head to step three.
Step 3: Remove D15 and Reassemble
At this point you need to remove D15
There are many ways to do this and I'm no pro myself but I suggest desoldering the single pin on the bottom side of D15 and then simply using a toothpick or small instrument to lever it out.
Be very careful not to damage any other components in the process and use low heat on your soldering iron if you use one.
After you have removed the Diode reassemble the radio using the screws removed earlier and rest easy knowing in an emergency your radio can now reach out to a much broader audience.
Modifications such as this simply make your radio a more versatile tool, but keep in mind, like any modifications to RF equipment it is likely the FCC would frown on this unless used for emergency purposes by a licensed ham operator.
Until next time,