Re: [amsat-bb] Parallelling UP/DOWN Connections

[Paul Yeager <w4ski@xxxxxxxx>]

Bill:

Good question.... I've thought of doing the same thing myself.  Your 
question prompted me to think on it a bit.

I see a potential problem, but it's easily solved by using DPST pushbuttons.

Let's suppose that the up/down buttons work by grounding an input to the 
radio.  To use a single SPST button, we'd have to tie the mic commons 
together, and then tie the up inputs together, and the down inputs 
together.  This might create a problem if the voltages supplied to the 
inputs (internal pullups) were not the same.  We've tied the mic commons 
together, so we will have a current flow through the tied-together up/down 
inputs if they are not pulled up to the same voltage.  At best, we're 
wasting energy.  At worst, som magic smoke leaks out.

As mentioned above, simple solution is to use DPST pushbuttons, so that we 
don't have to tie the radios together.

See ya someday on AO-40!

Paul W4SKI
I see a potential problem, but it's easily solved by using DPST pushbuttons.
At 03:48 PM 7/31/03 -0400, Bill Acito W1PA wrote:
>Can anyone think of a reason why I couldn't take two "like" mobile radios,
>parallel the up and down connections of their mic jacks, and use the up and
>down keys on the mic to move the radios memories in unison?
>
>Bill
>W1PA
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