Realistic trc 457 458 extra channels

[Thomas Lee]

Hello, new to this. But decided to do all the work on my radios myself. Here's my issue both radios have the d858 chip I did the extra channel mods and both radios do not have 26.895 am I missing something? Thanks 73's

 

[midnight special]

just like the "A" channels on the standard 40 when you go up or down it will skip,,,, here is a chart with the A/rc channels marked,,,, http://www.techlib.com/reference/CB.htm that is a reason some put +10kc mods in the radio,,

 

[TM86]

Hello, new to this. But decided to do all the work on my radios myself. Here's my issue both radios have the d858 chip I did the extra channel mods and both radios do not have 26.895 am I missing something? Thanks 73's

Without looking, 'cause I'm lazy, do you have a truth chart? IIRC, 26.895 would be an N-code of 84. You'll need to figure out which pins you need to feed +5V or GND to get that 84. That's why a truth chart is critical. Normally for the Uniden SSB chassis the upd858 N-codes are 91 for channel 1 up to 135 for channel 40.

Also, if 26.895 falls into a spot where the "A" channels would normally be on an unmodified radio, you'll need to add a 10kc up or down switch to get there. To illustrate the idea a little better, in an unmodified radio channel 11 is at 27.085 (N-code 103) and channel 12 is at 27.105 (N-code 105). The "A" channel, in this case "11A", 27.095 (N-code 104) is skipped. This is by design as 27.105 is actually a frequency assigned for radio controlled model cars and/or airplanes. As long as the channel selector is involved in setting the operating frequency that gap will be there. Again, a truth chart would show this.

One last thing, check your soldering. If you've got the switches and the channel selector set right for 26.895 and the radio is somewhere else, might be a small solder bridge or cold solder joint somewhere.

Keep in mind that this all guesswork on my part. I don't know which mods you did, so I figured it was something like this: http://robconet.com/cb/pllfreqmods.htm

 

[tramd]

If done correctly you can use 4 switches or a rotary switch and have no channel skips including the "A"s for 399 channels. But since the radio doesn't do 10 meters well without some more work, 3 switches or the rotary one will get you 299 with no skipped channels.

 

[Thomas Lee]

Without looking, 'cause I'm lazy, do you have a truth chart? IIRC, 26.895 would be an N-code of 84. You'll need to figure out which pins you need to feed +5V or GND to get that 84. That's why a truth chart is critical. Normally for the Uniden SSB chassis the upd858 N-codes are 91 for channel 1 up to 135 for channel 40.

Also, if 26.895 falls into a spot where the "A" channels would normally be on an unmodified radio, you'll need to add a 10kc up or down switch to get there. To illustrate the idea a little better, in an unmodified radio channel 11 is at 27.085 (N-code 103) and channel 12 is at 27.105 (N-code 105). The "A" channel, in this case "11A", 27.095 (N-code 104) is skipped. This is by design as 27.105 is actually a frequency assigned for radio controlled model cars and/or airplanes. As long as the channel selector is involved in setting the operating frequency that gap will be there. Again, a truth chart would show this.

One last thing, check your soldering. If you've got the switches and the channel selector set right for 26.895 and the radio is somewhere else, might be a small solder bridge or cold solder joint somewhere.

Keep in mind that this all guesswork on my part. I don't know which mods you did, so I figured it was something like this: http://robconet.com/cb/pllfreqmods.htm

I did a different mod with the 2 switches says the channel should be the maybe just try the one switch mod. Thanks for the info!

 

[Sheplin]

Without looking, 'cause I'm lazy, do you have a truth chart? IIRC, 26.895 would be an N-code of 84. You'll need to figure out which pins you need to feed +5V or GND to get that 84. That's why a truth chart is critical. Normally for the Uniden SSB chassis the upd858 N-codes are 91 for channel 1 up to 135 for channel 40.

Also, if 26.895 falls into a spot where the "A" channels would normally be on an unmodified radio, you'll need to add a 10kc up or down switch to get there. To illustrate the idea a little better, in an unmodified radio channel 11 is at 27.085 (N-code 103) and channel 12 is at 27.105 (N-code 105). The "A" channel, in this case "11A", 27.095 (N-code 104) is skipped. This is by design as 27.105 is actually a frequency assigned for radio controlled model cars and/or airplanes. As long as the channel selector is involved in setting the operating frequency that gap will be there. Again, a truth chart would show this.

One last thing, check your soldering. If you've got the switches and the channel selector set right for 26.895 and the radio is somewhere else, might be a small solder bridge or cold solder joint somewhere.

Keep in mind that this all guesswork on my part. I don't know which mods you did, so I figured it was something like this: http://robconet.com/cb/pllfreqmods.htm

Very informative article. I had both a TRC 458 and then a 457. Wish I still had one. I would like to buy another one. I just found this website and plan on saving it as well as the link you provided. I still do have my D104 with the black base and bottom key, Looks and works great with either radio. It's still wired for those radios. Thanx, Glenn D