Calling AudioGuru Need a little help on MFJ schematic Please

Hi,
I am stuck on four points on this schematic of an mfj-1708 RF sensing switch.
I want to duplicate this circuit and build one for protection of my sons receiver (in another room).
As my transmitted RF may be picked up on his RX antenna and damage his receiver.

I have uploaded a picture , as this speaks a thousand words.

The indicated questionable areas of the schematic ,dont stand out to me as obvious
and need people with better knowledge of how this thing gets switched to look at it.

I:e do i really need a control wire , or does the circuit switch RX to ground on detecting RF ?
Is the relay a DPDT signal relay type ?
There seems to be no Q1 the schematic indicates only Q2 Q3 (why not called Q1 Q2).
I can see that the relay switches rx to ground ,but at top right of schematic how does the relay get wired into the Q2 mosfet.

The RF it is sensing is directly from the keyed Transmitter's RF output coax cable; not off the air. Unless your son is sharing your antenna, I dont see how this will help him?

The control input is optional; if asserted by grounding that input, it does exactly the same thing as detecting RF from the transmitter.

The relay is DPDT, 12V dc coil, contact rating should be for several amps AC, depending on the RF output of your transmitter. Q2 is what switches the coil of the relay. I would have put a snubber diode across the relay coil.

Dont worry about the missing Q1.