PLL01A channel mod?

[Harley3315]

I had this info somewhere but can't for the life of me find it again I need to get down to 26.815 as its the local channel around here anyone have this? Also on a pll03a couldn't it just be swapped out for an 02a making the radio then modifiable?

 

[brandon7861]

The PLL01A has a normal binary divider and can be modified by changing the binary. The PLL03A was the first PLL with a ROM and the N values cannot be changed. I think you will need a crystal swap for that one.

Looking at the block diagram for a hygain 681 (since that radio uses the PLL01A) and hoping it is relevant, looks like in that radio, the input binary would need to be 10111001 for N=185 to get 26.815. By the same logic, ch1 should be 11001000 for N=200 for verification first.

Reasoning: 26.815-5.945=20.87 and 20.87-(9.51*2)=1.85MHz into the PLL.

 

[Harley3315]

The PLL01A has a normal binary divider and can be modified by changing the binary. The PLL03A was the first PLL with a ROM and the N values cannot be changed. I think you will need a crystal swap for that one.

Looking at the block diagram for a hygain 681 (since that radio uses the PLL01A) and hoping it is relevant, looks like in that radio, the input binary would need to be 10111001 for N=185 to get 26.815. By the same logic, ch1 should be 11001000 for N=200 for verification first.

Reasoning: 26.815-5.945=20.87 and 20.87-(9.51*2)=1.85MHz into the PLL.

Guess I was looking for a bit more simple answer like what pins need cut bridged with a 3.3k and to ground or pin 7 I think it is ? On the 01A

 

[nomadradio]

There's more to it than just the PLL chip's specs alone. What model radio is this? The Sams CB books would mostly provide a guide to the particular divider arithmetic for a specific model. That's always been my starting point for a channel mod.

73

 

[Harley3315]

There's more to it than just the PLL chip's specs alone. What model radio is this? The Sams CB books would mostly provide a guide to the particular divider arithmetic for a specific model. That's always been my starting point for a channel mod.

73

I actually have 2 one is an early midland board and the second is a kraco if I remember correctly I'll look in the am and post the right models for sure I think they are pretty much the same board and lay out pre 13-882c cause those have the 02A.