Has anybody ever created a remote base with a radio like the SM120 16 channel commercial radio? Would it be possible to use the URI to specify the channel I want to go to, for example, hooking a GPIO pin to the “channel -” button and hooking another to the “channel +” button? So if I am on channel 1 and want to go to 7, the GPIO for “chan +” would have to pulse 6 times. That wouldn’t be very reliable probably because there is no confirmation that you are actually on the right channel, but this is how I would do it:
When a channel change is requested, pulse 16 or more times on the “chan -” button to make sure it is on channel 1. Then count the + button up to the channel number you want to go to. That idea, however wouldn’t work on the SM120 because going below channel 1 brings you back to 16.
Another idea I have is put one channel on a frequency reference (maybe those 150mhz re-broadcasts of radio stations?) and then find the channel you want based on that reference.
Another idea yet would be to use a few more GPIO pins to see which elements of the 7-segment displays are lit up and then make an estimate on which channel you currently are on.
I did this years ago. I don’t have my configuration files and more, but that I did was use 2 gpio outputs and created macros for them. First it would pulse the first output to hit the home button so it would default to channel one and then pause and use the 2nd output to pulse the number of channels I wanted. I never had any troubles with it. I think I used either a maxtrac or a gm300, but I can’t remember at this time which one for sure.
If you have a Parallel port you could use the I/O pins there to do BCD assuming the SM120 can do it (which it looks like it can). It only requires 4 lines to
get 16 channels. To select a particular channel just set the line to the Binary equivalent.
···
Line
Line
Line
Line
Channel
4
3
2
1
1
0
0
0
0
2
0
0
0
1
3
0
0
1
0
4
0
0
1
1
5
0
1
0
0
6
0
1
0
1
7
0
1
1
0
8
0
1
1
1
9
1
0
0
0
10
1
0
0
1
11
1
0
1
0
12
1
0
1
1
13
1
1
0
0
14
1
1
0
1
15
1
1
1
0
16
1
1
1
1
I do this with a commercial repeater controller and Kenwood TK-7180/8180 radios and it works great.
Has anybody ever created a remote base with a radio like the SM120 16 channel commercial radio? Would it be possible to use the URI to specify the channel I want to go to, for example, hooking a GPIO pin to the “channel -” button and hooking
another to the “channel +” button? So if I am on channel 1 and want to go to 7, the GPIO for “chan +” would have to pulse 6 times. That wouldn’t be very reliable probably because there is no confirmation that you are actually on the right channel, but this
is how I would do it:
When a channel change is requested, pulse 16 or more times on the “chan -” button to make sure it is on channel 1. Then count the + button up to the channel number you want to go to. That idea, however wouldn’t work on the SM120 because
going below channel 1 brings you back to 16.
Another idea I have is put one channel on a frequency reference (maybe those 150mhz re-broadcasts of radio stations?) and then find the channel you want based on that reference.
Another idea yet would be to use a few more GPIO pins to see which elements of the 7-segment displays are lit up and then make an estimate on which channel you currently are on.
Ok I’ve done it on the GM300 using a pacific research controller. The GM300 use BCD binary coded decimal. Basically pulling certain pins low will cause the radio to jump to the requested channel. It worked very slick. I know this isn’t specific to app_rpt but it should be doable. I also am not sure on the SM120 if it does BCD. I will say it worked really slick. When the controller heard a certain DTMF it would pull what ever combination pins low and go to that channel. I’m pretty sure this can be done with app_rpt it seems you can do just about anything you can dream up.
I did this years ago. I don’t have my configuration files and more, but that I did was use 2 gpio outputs and created macros for them. First it would pulse the first output to hit the home button so it would default to channel one and then pause and use the 2nd output to pulse the number of channels I wanted. I never had any troubles with it. I think I used either a maxtrac or a gm300, but I can’t remember at this time which one for sure.
Has anybody ever created a remote base with a radio like the SM120 16 channel commercial radio? Would it be possible to use the URI to specify the channel I want to go to, for example, hooking a GPIO pin to the “channel -” button and hooking another to the “channel +” button? So if I am on channel 1 and want to go to 7, the GPIO for “chan +” would have to pulse 6 times. That wouldn’t be very reliable probably because there is no confirmation that you are actually on the right channel, but this is how I would do it:
When a channel change is requested, pulse 16 or more times on the “chan -” button to make sure it is on channel 1. Then count the + button up to the channel number you want to go to. That idea, however wouldn’t work on the SM120 because going below channel 1 brings you back to 16.
Another idea I have is put one channel on a frequency reference (maybe those 150mhz re-broadcasts of radio stations?) and then find the channel you want based on that reference.
Another idea yet would be to use a few more GPIO pins to see which elements of the 7-segment displays are lit up and then make an estimate on which channel you currently are on.
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In the app_rpt.c source there is mention of cop 31, Channel Selector for Parallel Programmed Xcvr and ppp16. Have asked several times on the list about this but never got a response. Any gurus out there have any info?
BCD channel steering would certainly be a better solution than pulsing the up down selector.
Ed W8VT
···
On 6/10/2015 9:53 AM, Skyler F wrote:
Has anybody ever created a remote base with a radio like the SM120 16 channel commercial radio? Would it be possible to use the URI to specify the channel I want to go to, for example, hooking a GPIO pin to the "channel -" button and hooking another to the "channel +" button? So if I am on channel 1 and want to go to 7, the GPIO for "chan +" would have to pulse 6 times. That wouldn't be very reliable probably because there is no confirmation that you are actually on the right channel, but this is how I would do it:
When a channel change is requested, pulse 16 or more times on the "chan -" button to make sure it is on channel 1. Then count the + button up to the channel number you want to go to. That idea, however wouldn't work on the SM120 because going below channel 1 brings you back to 16.
Another idea I have is put one channel on a frequency reference (maybe those 150mhz re-broadcasts of radio stations?) and then find the channel you want based on that reference.
Another idea yet would be to use a few more GPIO pins to see which elements of the 7-segment displays are lit up and then make an estimate on which channel you currently are on.
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You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.
I've got some software for little motorola HC908 microcontrollers that
interfaces with the standard MaxTrac type radios. The software reads the
channel by intercepting the serial data going to the front panel LED
display. Then, it can change channels by pulsing the up/down channel
buttons. I originally wrote this code after learning I could not do
channel steering on pre-GM300 family radios, using the 16 pin accy
plug....I learned this little problem -after- buying a box full of radios.
Oops.
It's on my list to rewrite this code for RPi2 GPIO, unless someone else
beats me to it, first!
73, David KB4FXC
···
On Wed, 10 Jun 2015, Skyler F wrote:
Has anybody ever created a remote base with a radio like the SM120 16
channel commercial radio? Would it be possible to use the URI to specify
the channel I want to go to, for example, hooking a GPIO pin to the
"channel -" button and hooking another to the "channel +" button? So if I
am on channel 1 and want to go to 7, the GPIO for "chan +" would have to
pulse 6 times. That wouldn't be very reliable probably because there is no
confirmation that you are actually on the right channel, but this is how I
would do it:
When a channel change is requested, pulse 16 or more times on the "chan -"
button to make sure it is on channel 1. Then count the + button up to the
channel number you want to go to. That idea, however wouldn't work on the
SM120 because going below channel 1 brings you back to 16.
Another idea I have is put one channel on a frequency reference (maybe
those 150mhz re-broadcasts of radio stations?) and then find the channel
you want based on that reference.
Another idea yet would be to use a few more GPIO pins to see which elements
of the 7-segment displays are lit up and then make an estimate on which
channel you currently are on.