American Radio Library added an old RCA research publication from 1936, exploring the possibilities of TV.

At that time the BBC was already broadcasting a regular TV schedule using CRT systems. American stations had been experimenting with both mechanical and electronic systems, and several stations (including the usual NYC suspects and also KMBC in Kansas City) were running very short regular schedules.

One article shows highly detailed field strength readings through a city, and inside a typical suburban NY two-story house. Not pictured but probably like this:

A portable transmitter was placed to the northeast as indicated by the line, and the field strength of the ether waves was measured in FINE detail.

50 MC is roughly where Channel 2 was later assigned, and 70 MC is roughly Channel 4. These two freqs are similar in most ways, but the objects in the house didn’t see them as similar! At 50 MC the fireplace, the kitchen stove, and several outlets and switches were resonating and re-radiating. At 70 MC nothing much was resonating; the pattern was mainly about the walls and partitions. The article didn’t specify how the house was built; if it had plaster walls with chickenwire lath, it’s easy to see how the walls would be blocking a higher frequency.