[aprssig] Battery & Charger for APRS Station

[John Habbinga]

> One thing I'd be weary of is that you likely have no isolation of the
> charger from the TNC/transmitter.  Be sure it's providing a clean DC
> Voltage and not introducing any unwanted things like hum into the TX
> Audio.  It might be fine during receive but TX could get into the
> charger
> And give you problems.  Look at signals on a scope to see any unwanted
> audio
> Or ripples.

I have never heard any transmit hums and I haven't heard any hums or
hash in either VHF or HF radios that I've attached to the battery with
the charger connected.  This page
http://www.ctek.com/EN-US/Academy/Ripple.aspx has some interesting
graphs that might relate.