Power Saving 555 pulser/sampler/timer

This circuit was built back in my Packet Radio enthusiast days.
I was using Commodore 64's with Digicom-64 and homebrew "DEVCOM"
modems. I built up a weatherproof /\/\otorola outdoor cabinet containing
a C-64, homebrew 12 Volt DC power supply, Digicom software and modem,
complete with lead-acid deep cycle battery and a 37 watt solar panel to charge it
with. Trouble is, the system would only operate reliably when the sun was overhead
allowing the solar panel to deliver full wattage which would barely keep the system
running. After the panel lost sunlight, the system would only a few minutes
before running down.
This circuit was cobbled up to:
-Turn on the entire system every 10 minutes or so
-Keep the system on for 2 minutes or so;
-Keep the system powered on IF someone activated it
(digipeated thru it or connected to it and sent packets)
-Then, Shut the system down after a period of inactivity,
-OR, if no station used the digipeater/terminal, turn it off to
conserve battery power.
This circuit activates the relay every 10 minutes or so, and if a low is presented to the
PTT input, the timer is reset and the relay keeps activated.
If no low is presented to the PTT input, the relay will drop out after about a minute.
I used CMOS 555's for this circuit which lowered standby current consumption even further.

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