Body-coupled portable transmitter

• US 3,902,118 A
• Filed: 04/04/1974
• Issued: 08/26/1975
• Est. Priority Date: 04/04/1974
• Status: Expired due to Term

• Current Assignee: Kurt Ikrath, William Kennebeck
• Original Assignee: Kurt Ikrath, William Kennebeck
• Inventors: Ikrath, Kurt, Kennebeck, William
• Primary Examiner(s): Libman, George H.
• Application Number:
  US05/457,869
• Time in Patent Office: 509 Days
• Field of Search: 325/118,178,179 343/718,895,720,842,866,867,868,908
• US Class Current: 455/100
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H04B 1/0343 to be carried on the body

Abstract

A body-coupled portable radio transmitter to be worn camouflaged, at about waist level, in the manner of a shoulder bag, under a covering outer garment, and depending from a resilient flexible open coil for coupling RF output of the transmitter to the body to be radiated by the body, the coil diameter being small enough for the coil to be worn under the garment and there being a sufficient number of turns in the coil to be tunable in place on the wearer, the combination with the transmitter being operable at average output power on the order of 1 watt, which is low enough not to be hazardous to the health of the wearer while having good signal-to-noise ratio, in a frequency band high enough for good radiation efficiency, i.e. above 3MHz, but not so high as to introduce health hazards to the wearer, i.e. below 40MHz, and operable with radiation efficiency greater than that of the same transmitter equipped with a whip antenna operated at the same average power and frequency when positioned next to the same person where the whip antenna does not extend above the head of the wearer so as not to be visible.

Claims

1. In combination, a compact portable radio transmitter operable in at least a segment of the frequency range between 3 MHz and 40 MHz and at average power output of about 1 watt when operated continuously for a long period of time, a stretchable resilient open coil coupled to the output of the transmitter and physically attached to the ends of the coil, the coil having a mean coil diameter of about 6.5 cm and being of an unstretched length on the order of 90 cm whereby when a person wears the coil on one shoulder And it extends across the front and back of the person with the transmitter depending from the ends of the coil, the coil is stretched by the weight of the transmitter and conforms to the front and back of the person and the transmitter is at about the waist level at his other side, and capacitor means coupled to the coil for tuning the coil when the coil and transmitter are worn by the person and the transmitter is in operation in a selected segment of the frequency range.

2. A method by which a person on foot can carry and safely operate a compact portable transmitter that is equipped with a whip antenna, so that it is camouflaged and has higher radiation efficiency comprising the steps of detaching the whip antenna from the transmitter terminals, coupling to the transmitter terminals a stretchable resilient coil to support the transmitter from one shoulder to the opposite side of the waist of a wearer, operating the transmitter at maximum average output power of 1 watt when operated continuously for a long period of time, setting the transmitter to a frequency between 3MHz and 40MHz and tuning the coil in place on the person for maximum RF current through the coil at the selected frequency and 1 watt average power.

3. A method of communication comprising pendantly supporting a compact portable radio transmitter from the ends of a loop of stretchable resilient flexible open coil, suspending the loop of coil from one shoulder of a person to extend across the front and back of the person to support the transmitter pendantly from its ends at the opposite side of the waist of the person, coupling the RF output of the transmitter to the coil, adjusting the transmitter for maximum average output power of one watt in a frequency band between the limits of 3 MHz and 40 MHz, and tuning the coil in place on the person for maximum RF current through the coil when the transmitter is operated at one watt average power and in said frequency band.