Peter,
I am talking about the RF signal. The Sony antenna uses an RCA plug, so I connected the phone wire to an RCA jack on a wall plate for the antenna, and to a chassis-mount F connector at the receiver end. And, surprise! the first time I tried it, I just twisted together the three different phone leads. In parallel. Just like it was a phone line!

I would never have done this. My buddy does not know that it should not work, so he did. Lucky him.

I just attached the wires. No baluns, no matching, no nuttin. Just maintained hot and ground, and for all I know even that might not be necessary.

After that it only got as hairy as regular RF stuff -- amplified it, split it out to the four receivers, and used F to RCA adaptors to go into the receivers.

I was a little skeptical about feeding several receivers from a splitter. Back when Sony had that stupid "egg" RF remote, I happened to put the DSS remote's antenna near the antenna for the A/V receiver, and neither remote worked. Seems something in each component leaked something out on the antenna that interfered with the other component. Once the antennas were four feet apart, all was well.