Radio Shack 'HTX-400'
 

Extended range of 420 to 450 MHZ

To set the
transceiver to its extended range , turn off the transceiver, than hold down SC and turn on the
transceiver again. To return to standard turn off the transceiver than hold down SC and turn it on again.
All these instructions are contained in the manual that comes with the transceiver.

         by     Frank
 

HTX-400 1750 Tone Burst Mod
This mod will allow you to temporarily put your HTX-400 into a mode with limited bandwidth but with the ability to generate the 1750 tone burst required for some European repeaters. I also list instructions that will bring back your memories and bandwidth to normal so dont worry about that (at least it works for me! user beware!)
  1. Turn on radio while holding down the DOWN key and the MR key
    If you are lucky, the display will read MA-440
    If it does not, repeat step 1
    Once successful with this step, tuning and tx will be limited to 435.075 to 440.000
    Once successful do not turn the radio off again, it will go back to normal mode.

     
  2. While holding down the FUNC key, press the DOWN key until the screen reads MEL-5 Or any other melody selection as if you were selecting a ringer tone. scroll thru the ringer tones and stop when the screen reads 1750

     
  3. Press the PTT and you should be back to your selected frequency. Now when you press and hold the PTT and hit the BEEP button (labeled with an asterick), you will generate the 1750 tone burst on your tx audio. You could also select other ringer melodies under the MEL- menu in step 2 and generate those tones as well on your audio.

     
  4. To return the radio (and your memories to normal), just turn the rig off and then on again as you normally would and tx range and memories will be back to normal.
MARS/CP mods for the HTX-400
The only modification i know of on this radio is while turning it on you keep the SC botton pressed it will allow MARS/CP freq's.

To revert to normal do the same thing it will show your freq range for the current mode you are in as long as you keep the SC down.

 

ATTENTION
The KB2LJJ takes no responsibility for any damage during the modification or for any wrong information made on this modification.