Echo link reminds me of the days I was active in packet radio.  I had a node
set up on a common frequency and I noticed from my log, over a period of
time, that guys running handy talkies from third floor apartments, were
connecting to me and out to other nodes.  I had tall towers and big antennas
and they ran 1 watt to inside antennas.  I talk on echo link once and awhile
because our repeater club has an active node but I don't get all that turned
on by it for some reason.  I think I would, however, if I lived in a small
apartment and I have used and built many small inside antennas, ran wires,
and all sorts of inside antennas and never found it as enjoyable as having a
good wire or vertical antenna up even just a few feet.  Shoot, I wired a 100
watt light bulb on to a few feet of coax back in the sixties, tuned up and a
friend 50 miles away was talking to other friends on 75 meters.  I
transmitted, he heard me, and I had a conversation with him with the light
bulb laying on the table and the coax on the floor in a basement ham shack.
I've worked all 50 states on 40 meters running 2 watts output and a ground
mounted trapped vertical, too, but it was work.  I know a guy who worked a
ZL on 75 meter sideband running 1 watt but it took him weeks of trying
before the ZL ever copied him.  It just all comes down to what a person can
do and enjoys doing I suppose.

Phil.
K0NX