KB2LJJ                                                           
                                   Radio Mods Database and Manuals
 








 
IC-T90 coverage

To mod the T90 for full coverage TX from 45MHz to 240 and 300 to 584MHz, remove batt and peal plastic cover of and remove all diodes (the ones with the cups drawn around then poof there you have it clandestine tx with dcs ctcs.

I would suggest opening the case (6 screws) but that isnt needed. my radio had a bank of 7 connectors with 3 diodes.

The plastic sign says something like it is illigal to modify or unblock the cell band.
If you have removed it, you see the very small diodes.
After the mod, you DON'T HAVE TO RESET the transceiver. It works great. It's very nice to transmit in the VHF low band 70-88 Mhz, because I don't kwow any HAM radio's with this TX capacity.

 

     Extended mod Tx and Rx for the IC-T90A
 
  • Remove three diodes circled. Two have two leads the other has three leads.


     
  • After removing the diodes it will look like this.


     
  • Reset the radio.

After resetting the coverage and power output will more of less be as follows: 

45.300 mhz	3.8 watts
to
75.100 mhz	1.5 watts	Power output as specified in the ham band.
to
89.000 mhz	Output tapers down until pll unlocks.


90.700 mhz	Pll locks very low output.
to
92.500 mhz	0.8 watts
to
110.000 mhz	0.8 watts


117.800 mhz	1.0 watts
to
179.900 mhz	2.0 watts	Power output as specified in the ham band.
to
238.000 mhz	Output tapers down until pll unlocks.  Output in the 220 band is very low.


300.000 mhz	0.5 watts
to
540.000 mhz	0.5 watts	Power output as specified in the ham band.
to
580.000 mhz	Output tapers down until pll unlocks.

Mod does not open the blocked cell area.

The above was verified on a Cushman CE50 service monitor. Even though the power output is low out of band, and near the edges of the pll lock range the frequency accuracy suffers, it is still useful for testing purposes. Transmit is FM only.