The Radio Girls of Roselawn, Margaret Penrose, 1922, page 24:

    "It has been rather windy. I suppose it must be rough out in the ocean. Oh, Amy!" Jess suddenly exclaimed, "if I get my radio rigged why can't we communicate with the Marigold when it is at sea?"
    "I don't know just why you can't. But I guess the wireless rigging on the yacht isn't like this radio thing you are going to set up. They use some sort of telegraph alphabet."
    "I know," declared Jessie with conviction. "I'll tell Darry to put in a regular sending set--like the one I hope to have, if father will let me. And we can have our two sets tuned so that we can hear each other speak."
    "My goodness! You don't mean it is as easy as all that?" cried Amy.
    "Didn't you read that magazine article?" demanded her chum. "And didn't the man say that, pretty soon, we could carry receiving and sending sets in our pockets--maybe--and stop right on the street and send or receive any news we wanted to?"
    "No, I sha'n't," declared Amy. "Pockets spoil the set of even a sports skirt. Where you going now?"
Pages 55-56:

    "I guess, after all, Mrs. Grimsby has it partly right. Human beings cannot easily command the elements which Nature controls."
     "Seems to me we are disproving that right now in this radio business," cried Jessie. "And it is going to be wonderful--just wonderful--before long. They say moving pictures will be transmitted by radio; and there will be machines so that people can speak directly back and forth, and you'll have a picture before you of the person you are speaking to."
    She began to laugh again. "You know what Amy says? She says she always powders her nose before she goes to the telephone. You never know who you may have to speak to! So she is ready for the new invention."
    "Just the same, I am rather timid about the lightning, Jessie," her mother said.
Pages 58-59:

    "I tell you what," said Amy as, with their paddles, the girls wended their way down to the little boathouse and landing. "Won't it be great if they ever get pocket radios?"
    "Pocket radios!" exclaimed Jessie.
    "I mean what the man said in the magazine article we read in the first place. Don't you remember? About carrying some kind of a condensed receiving set in one's pocket--a receiving and a broadcasting set, too."
    "Oh! But that is a dream."
    "I don't know," rejoined Amy, who had become a thorough radio convert by this time. "It is not so far in advance, perhaps. I see one man has invented an umbrella aerial-receiving thing--what-you-may-call-it."
    "An umbrella!" gasped Jessie.
    "Honest. He opens it and points the ferrule in the direction of the broadcasting station he is tuned to. Then he connects the little radio set, clamps on his head harness, and listens in."
    "It sounds almost impossible."
    "Of course, he doesn't get the sounds very loud. But he hears. He can go off in his automobile and take it all with him. Or out in a boat--Say, it would be great sport to have one in our canoe."