Rotorcraft pilot reported during liftoff; they passed close to a helicopter arriving at the adjacent parking spot. Departing pilot stated they did not communicate intentions on the airport frequency prior to lifting.

Narrative

While flying single pilot VFR and before entering the ZZZ1 Class Bravo airspace; I was issued a squawk code during the VIP TFR. After arriving at heliport ZZZ at XA:30; I held the code to the ground and after waiting approximately 15 more minutes before departing; I began attempting to contact ZZZ for a clearance to depart the heliport back into the TFR while still on my discreet code.During my first two attempts on com 1 in my assigned helicopter; I was unable to reach Tower Controller. This was most likely due to line of sight to the Tower. While this was happening; I could hear aircraft on frequency; but was not able to send and receive. I then switched to com 2 and had better results. At this time; I elected to hold on the ground for an inbound helicopter; which was about a mile from the heliport. ZZZ Controller was busy with float planes landing and departing from ZZZ2; therefore the frequency was quite busy. When I finally got my clearance to depart; I cleared my area and appeared safe to lift from spot Transit at ZZZ. At this point; I remained on ZZZ frequency to depart since I now had a Class Bravo clearance into the TFR southbound and did not notify ZZZ prior to lifting.While lifting into hover and climbing rearward to stay in sight of my parking line; at about 40 ft.; I noticed a helicopter to my left landing on Spot X; which is adjacent to the Transit parking spot. We passed each other while my aircraft was departing and the other aircraft was arriving. Both aircraft successfully departed and arrived respectively with out incident however relatively close to one another.After departing; the realization was that a call to ZZZ was not made after getting cleared into ZZZ1 Class B prior to lifting was not made; nor was the frequency monitored due to the inability to contact ZZZ Tower on com 1; and never reverting either radio to the appropriate frequency to monitor XXX.XX.