Subject: Here is HTX-242 Mod 136-174 RX/TX NOTICE: use at your own risk Posted by Jeff Parrish (KB9GXK) on September 11, 1998 at 00:16:12: I didn't try it quite yet, but here's what I found to expand the RX/TX to 136-174MHz ------------------------------------------------------- Special NOTICE: This is for the HAMS who say radio shack radio's are "can't be modified, because the FCC was real strict with Radio Shack", or buy a real radio so that you can modify it. That is a bunch of bull. Mod: Expands TX from 143-149mhz to 136-174mhz Tools Required: Phillips Screwdriver, Mini screwdriver, Soldering Iron (Fine tip) , NeedleNose Pliers Process: 1. Remove Screws on bottom and top 2. Take the Bottom and Top off the Radio 3. Unplug Speaker from top of the radio and remove the dials from the face plate 4. Unscrew the screws on the top and bottom of the face plate. 5. CAREFULLY: remove the face plate from the radio 6. Remove the bolts and washers (little rings) from the dials (countersunk into the dials). 7. CAREFULLY: remove the LCD and plastic around it by pulling gentle and wiggling it a little being careful not to bend the LCD pins. 8. Remove the screws holding down the PCB from the cases 9. CAREFULLY: (Plug in type PCB) remove the PCB from the radio and place the VFO tuning dial face down and to your left. 10. There will be two blue jumper mounts on the PCB. Remove the 1 closest to the 2 black raised chips that are closest to the VFO tuning dial (this jumper should be near the middle of the board) The other jumper makes the transmitter do 143-144 (military) and it is near the side. 11. Put all the parts back together and blamo you have 136-174mhz RX/TX Notes: If you do it right you won't even loose your memories. This mod took me about 30 minutes to complete and my radio is working fine. However I'm sure this voids the warranty and the service contracts so you may not want to do it for that reason alone. I checked the radio out (with a frequency counter) on several frequencies and it is performing well. This mod requires a little skill but most people that are hams could do this mod. This mod was given to me by a fellow North Carolinian KC4VYY , and I just put it in a simpler form. I wanted to thank him. Date: Thu, 28 Jan 1999 22:15:45 -0800 From: Hugh Henderson To: editor@qrz.com Subject: HTX-242 Mod Hello: The instructions for the mod to open up the HTX-242 that you have on your site are not very clear. I am attaching 2 scanned images that show which SMD (surface mount devices) that can be removed to open up the Tx. This mod is not for the faint of heart. Any damage you cause to your radio by doing it, is your responsibility. You should also note that doing this mod most likely voids the warranty. Operating on frequencies outside of the amateur band may be considered illegal. Modifier beware. To open up the Tx for 143 - 144 Mhz, remove the small blue SMD shown on the right of the picture. To open up the Tx for 136-174 Mhz, remove the small blue SMD shown on the left of the image. Do NOT remove both of these devices (one or the other, not both). 73's Hugh - VY1HH | This e-mail is to confirm that the listed modification to open up transmit | on htx-242 is good and functional. I did the 136-174 MC mod. on my radio. | The surface mount device in question is listed as r-605 in the Radio Shack | service manuel. One does not have to remove the SMD, just take a sharp | knife and cut one side of the surface mount device and gently lift it up off | of the trace. The solder used on the board is very soft and cuts very | easily. During testing after re-assembly, I tested the unit and it preform | as describe but i did notice at about 170 MC, there was a slight audible | oscillation, but still operational. | I hope this helps. 73 | Pat Duncan | N5WVC --------------------------------------------------------------------------- From: To: Sent: Saturday, July 22, 2000 7:41 PM Subject: New Htx-242 Mod | Dear Sirs: | KC8OXJ my callsign, | I have diiscovered a new mod for the radio shack 2-meter, I was working on | my HTX-242 one of my many 2-meters and I discovered that if you change | the capacitor | C-129 from 20 pf to 10 pf it improves the recievieve incredibly, it doesn't | change output power and actually greatley improves SWR and Reflected Power. I | replcaled it with a 10 pf 600 volt rolled aluminum cap in place of the | surface mount exactly in between the co-ax cable. I don't know but I have | been doing electronics for 23 years and I think I have discovered a real mod | for the recieve since it is only a single IF reciever, The machine I modified | actually outperformes my ICOM with double IF'S. | KC8OXJ | | Terance DeJuliannie | 259 North Pine Street | Gwinn, Mi, | 49841