This information is intended for educational (and/or entertainment) purposes only!
"How easy is it to unlock the Alpha channels?"
Well it is very easy, dare I say "too easy"!!
This lovely Cybernet chassis radio has the PTBM092COX PCB,
used in several mobiles like the GE 3-5804D, Midland 77-830, 77-882, Ham-International Puma, & Colt 870.
It is somewhat similar to the PTBM094COX used in the "Ham-International Viking", & Formac 88;
of course we didn't get the PTZZ033AOX FM board or PTOS008AOX for bands here in the states.
One nice thing about these vintage radios, they utilized 02A PLL!!!
(US) AM only, Cybernet radios with PLL02A
& 2 crystals, 10.240 MHz + 10.695 MHz use N-Codes
in the range of 330 to 286 for the "mid block" or standard FCC 40 channels
If we change the least significant programming bit (Pin 15, p0) we can access the "skipped channels"!
I'll spell it out for my brethren who may have a difficult time..
Shout out to "Night Ranger" for the N-Code truth table, thank you very much!!
All the best!
"How easy is it to unlock the Alpha channels?"
Well it is very easy, dare I say "too easy"!!
This lovely Cybernet chassis radio has the PTBM092COX PCB,
used in several mobiles like the GE 3-5804D, Midland 77-830, 77-882, Ham-International Puma, & Colt 870.
It is somewhat similar to the PTBM094COX used in the "Ham-International Viking", & Formac 88;
of course we didn't get the PTZZ033AOX FM board or PTOS008AOX for bands here in the states.
One nice thing about these vintage radios, they utilized 02A PLL!!!
(US) AM only, Cybernet radios with PLL02A
& 2 crystals, 10.240 MHz + 10.695 MHz use N-Codes
in the range of 330 to 286 for the "mid block" or standard FCC 40 channels
If we change the least significant programming bit (Pin 15, p0) we can access the "skipped channels"!
and so here is the "cheat sheet"N-Code = 331
26.955 101001011
N-Code = 330 (Channel 1)
26.965 101001010
If we change the state of pin 15 to High while on Ch. 1, we move "downstairs", 10 KHz below Ch. 1
Ch. 3 = 328 26.985 101001000
Ch.3A=327 26.995 101000111 <- Ch. 3A
Ch. 4 = 326 27.005 101000110
Ch. 5 = 325 27.015 101000101
Ch. 6 = 324 27.025 101000100
Ch. 7 = 323 27.035 101000011
Ch.7A =322 27.045 101000010 <- Ch. 7A
Ch. 8 = 321 27.055 101000001
Ch. 9 = 320 27.065 101000000
Ch. 10= 319 27.075 100111111
Ch. 11= 318 27.085 100111110
Ch.11A=317 27.095 100111101 <- Ch. 11A
Ch. 12= 316 27.105 100111100
Ch. 13= 315 27.115 100111011
Ch. 14= 314 27.125 100111010
Ch. 15= 313 27.135 100111001
Ch.15A=312 27.145 100111000 <- Ch. 15A
Ch. 16= 311 27.155 100110111
Ch. 17= 310 27.165 100110110
Ch. 18= 309 27.175 100110101
Ch. 19= 308 27.185 100110100
Ch.19A=307 27.195 100110011 <- Ch. 19A
Ch. 20 = 306 27.205 100110010
Changing the state of Pin 15 allows you to access the skipped frequencies.
You can see that for some channels we must make Pin 15 Low,
and for others we will need to make Pin 15 High.
Using a 3 position (center n/c) switch and a 4K7 resistor we can do this, easily!
Cut the trace leading to Pin 15, solder the resistor across the cut, center pole of switch goes to pin 15,
One side goes to GND (Pin 16 of 02A) and the other to 5.4 Volts + (Pin 1 of 02A)
I'll spell it out for my brethren who may have a difficult time..
Ham International posted a "how to" that includes an inverting circuit for push button operation.To access Ch. 3A put radio on Ch. 4 & Pin 15 = High
To access Ch. 7A put radio on Ch. 7 & Pin 15 = Low
To access Ch. 11A put radio on Ch. 12 & Pin 15 = High
To access Ch. 15A put radio on Ch. 15 & Pin 15 = Low
To access Ch. 19A put radio on Ch. 20 & Pin 15 = High
Shout out to "Night Ranger" for the N-Code truth table, thank you very much!!
All the best!
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