GB2038561A

GB2038561A - Variable high frequency frame antenna

Info

Publication number: GB2038561A
Application number: GB7848062A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-12-12
Filing date: 1978-12-12
Publication date: 1980-07-23
Also published as: GB2038561B

Abstract

The Variable High Frequency Frame Antenna is a device for the reception of wireless signals on all frequencies from 3500 to 28000 K.Hertz and for transmission of wireless signals on the 80, 40, 20, 15 and 10 metre Amateur Bands. It consists of a frame twentyone inches square having wound thereon four turns of 16 SWG wire. The frame is tuned to the desired frequency by means of two 250 pfd variable capacitors C1, C2, coupled up to two seven turn inductances L1, L2, which in turn are link coupled to the frame antenna via a link coil L3 having four turns. Reception and transmission of signals is achieved in the range 3500 to 28000 K.Hertz without the necessity of changing-tuning inductances or capacitors. The frame can be rotated and, therefore, acts as a beam when used for transmission purposes. <IMAGE>

Description

SPECIFICATION Variable high frequency frame antenna SUBJECT The Variable High Frequency Frame Antenna has Beam and Directional properties and is designed specifically for transmission and reception of the 80, 40, 20, 1 5 and 10 metre Amateur Bands but which is also ideally suited for reception of wireless signals on all frequencies from 3500 to 28000 K.Hertz.

FRAME AND WIRING OF FRAME The frame consists of two wooden pieces 2+" x 21" X 3/,,"; three lengths of dowelling one having a diameter of 41' (three quarter inch) and being 26q" in length and two having a diameter of +" (half inch) and each being 202" in length. The frame could also be made in plastic or similar lightweight material to the same dimensions. The wire used on the frame is 1 6 SWG copper or similar guage in other wire types, and one turn round the frame is 7 (seven) feet. There are four turns around the frame giving a total length of 28 (twentyeight) feet.It is essential that the spacing between each turn is +" (half inch) and that the wiring does not touch at any point. Each end of the wire on the frame terminates into a separate terminal block, the blocks being fixed to the frame.

CONTROL BOX The control box which has the following dimensions, 51" x 4" > < 2+",canbe made from wood, plastic or similar material having insulation properties. To tune the frame two 250 pfd variable capacitors (Fig. 1 - Cl and C2) are used together with two inductances (Fig. 1 - L1 and L2) each having 7 (seven) turns of 1 6 SWG insulated wire close wound on a 12 outside diameter coil form, with a space of 21' (half inch) between each inductance and into this 21' (half inch) space is wound a link coil (Fig. 1 - L3) of 1 6 SWG insulated wire having four turns.

WIRING OF CONTROL BOX The wiring of the controls is as follows: One end of each 7 (seven) turn inductance is fixed to a separate terminal block on the rear of the control box, and the other end of each 7 (seven) turn inductance is fixed to the fixed vanes of each 250 pfd variable capacitor mounted in the control box. The moving vanes of the two 250 pfd variable capacitors are joined together by wire, the wire then being connected to the centre pin of a co-axial socket (Belling Lee type) which is mounted on the rear of the control box. One end of the four turn link coil is affixed to the moving vanes connection of the 250 pfd variable capacitors, and the other end of the four turn link coil is affixed to the earth side of the coaxial socket.The frame is then mounted into the control box through a b" (three quarter inch) diameter hole in the centre of the lid so that it can be rotated. It is then connected to the control box by means of two 6" (six inch) lengths of ordinary flex via the terminal blocks on the frame and on the rear of the control box.

OPERATION OF VARIABLE HIGH FRE QUENCY FRAME ANTENNA RECEPTION: The antenna is connected to the short wave receiver by means of a short length of co-axial cable terminating in a coaxial plug. The antenna can also be connected to the short wave receiver by means of a short length of domestic light flex and terminating in two plugs in those cases where the short wave receiver is not fitted with a co-axial socket. In either case the length of connecting cable should be kept as short as possible. The short wave receiver should then be tuned to the desired band, e.g., 80 metres and the two tuning knobs on the control box of the antenna rotated to peak reception; the dial reading of both knobs should be identical thus indication electrical balance of the antenna.

On the 80 metre band the antenna exhibits very strong directional characteristics, and local electrical interference can be nulled out by rotating the antenna. On 40 metres there is also a directional effect, but local electrical interference cannot be nulled out. On the remaining bands, i.e., 20, 1 5 and 10 metres there is no directional effect when used as a reception antenna.

TRANSMISSION: The antenna must be connected to the transmitter via an Antenna Turi- ing Unit in the conventional manner for amateur transmission. The tuning of the frame antenna is identical to that for reception. The fact that the antenna rotates means that when used as an antenna for transmission the radiated signal can be directed in the desired direction thus acting as a Beam.

1. The Variable High Frequency Frame Antenna is the first practical device for the transmission of amateur radio signals on the 80, 40, 20, 1 5 and 10 metre amateur bands without having to change tuning inductance or capacitors, and is also the first frame antenna to provide satisfactory reception of all high frequency signals from 3500 to 28000 K. Hertz.

The invention has been developed to cater for Radio Amateurs and Short Wave Listeners world wide.

It is claimed that the combination of length of frame and construction of frame together with the two inductances and two capacitors as described in the Specification and the circuit data (Fig. 1) are an inventive step

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Variable high frequency frame antenna SUBJECT The Variable High Frequency Frame Antenna has Beam and Directional properties and is designed specifically for transmission and reception of the 80, 40, 20, 1 5 and 10 metre Amateur Bands but which is also ideally suited for reception of wireless signals on all frequencies from 3500 to 28000 K.Hertz. FRAME AND WIRING OF FRAME The frame consists of two wooden pieces 2+" x 21" X 3/,,"; three lengths of dowelling one having a diameter of 41' (three quarter inch) and being 26q" in length and two having a diameter of +" (half inch) and each being 202" in length. The frame could also be made in plastic or similar lightweight material to the same dimensions. The wire used on the frame is 1 6 SWG copper or similar guage in other wire types, and one turn round the frame is 7 (seven) feet. There are four turns around the frame giving a total length of 28 (twentyeight) feet.It is essential that the spacing between each turn is +" (half inch) and that the wiring does not touch at any point. Each end of the wire on the frame terminates into a separate terminal block, the blocks being fixed to the frame. CONTROL BOX The control box which has the following dimensions, 51" x 4" > < 2+",canbe made from wood, plastic or similar material having insulation properties. To tune the frame two 250 pfd variable capacitors (Fig. 1 - Cl and C2) are used together with two inductances (Fig. 1 - L1 and L2) each having 7 (seven) turns of 1 6 SWG insulated wire close wound on a 12 outside diameter coil form, with a space of 21' (half inch) between each inductance and into this 21' (half inch) space is wound a link coil (Fig. 1 - L3) of 1 6 SWG insulated wire having four turns. WIRING OF CONTROL BOX The wiring of the controls is as follows: One end of each 7 (seven) turn inductance is fixed to a separate terminal block on the rear of the control box, and the other end of each 7 (seven) turn inductance is fixed to the fixed vanes of each 250 pfd variable capacitor mounted in the control box. The moving vanes of the two 250 pfd variable capacitors are joined together by wire, the wire then being connected to the centre pin of a co-axial socket (Belling Lee type) which is mounted on the rear of the control box. One end of the four turn link coil is affixed to the moving vanes connection of the 250 pfd variable capacitors, and the other end of the four turn link coil is affixed to the earth side of the coaxial socket.The frame is then mounted into the control box through a b" (three quarter inch) diameter hole in the centre of the lid so that it can be rotated. It is then connected to the control box by means of two 6" (six inch) lengths of ordinary flex via the terminal blocks on the frame and on the rear of the control box. OPERATION OF VARIABLE HIGH FRE QUENCY FRAME ANTENNA RECEPTION: The antenna is connected to the short wave receiver by means of a short length of co-axial cable terminating in a coaxial plug. The antenna can also be connected to the short wave receiver by means of a short length of domestic light flex and terminating in two plugs in those cases where the short wave receiver is not fitted with a co-axial socket. In either case the length of connecting cable should be kept as short as possible. The short wave receiver should then be tuned to the desired band, e.g., 80 metres and the two tuning knobs on the control box of the antenna rotated to peak reception; the dial reading of both knobs should be identical thus indication electrical balance of the antenna. On the 80 metre band the antenna exhibits very strong directional characteristics, and local electrical interference can be nulled out by rotating the antenna. On 40 metres there is also a directional effect, but local electrical interference cannot be nulled out. On the remaining bands, i.e., 20, 1 5 and 10 metres there is no directional effect when used as a reception antenna. TRANSMISSION: The antenna must be connected to the transmitter via an Antenna Turi- ing Unit in the conventional manner for amateur transmission. The tuning of the frame antenna is identical to that for reception. The fact that the antenna rotates means that when used as an antenna for transmission the radiated signal can be directed in the desired direction thus acting as a Beam. CLAIMS 1. The Variable High Frequency Frame Antenna is the first practical device for the transmission of amateur radio signals on the 80, 40, 20, 1 5 and 10 metre amateur bands without having to change tuning inductance or capacitors, and is also the first frame antenna to provide satisfactory reception of all high frequency signals from 3500 to 28000 K. Hertz. The invention has been developed to cater for Radio Amateurs and Short Wave Listeners world wide. It is claimed that the combination of length of frame and construction of frame together with the two inductances and two capacitors as described in the Specification and the circuit data (Fig. 1) are an inventive step never before- achieved in the field of frame typaantennas for transmission and reception of ht L. frequency radio signals. TEiere exists in--the United Kingdom and t51roughout the World many thousands of radio amateurs and short wave listeners who do not have the required space- outside in which to erect a conventional antenna for transm-is- sion and reception, and who would benefit from the use of the Variable High Frequency Frame Antenna. At the present time there is no- Variable High Frequency Frame Antenna on the market to cater for this need in the United Kingdom or anywhere else. The.. radio. amateur population in the. World is around 500,000. Of this number there are around 30O,00.0 in the United States and 20,000 in the United Kingdom. No one can estimate the totai number of short wave listeners. CLAIMS (13 Jul 1979)

1. A Wireless Variable High Frequency arrangement having a frame antenna., characterised by the. fact that the length of wire on the frame, the coupling inductances between the frame and the tuning capacitors permit of receiving and transmitting Amateur Radio wir- eless signals in the range of 3500 to. 28000 K Hz. without the necessity to change inductances or the tuning. capacitors to resonate the antenna at any frequency within the range of 3500 to 28000KHz.

2. A Wireless Variable High Frequency arrangement according to claim 1 that is ideally suited to the reception of wireless broadcast programmes for domestic entertainment purposes in the range of 350Q to 28000 KHz as the frame antenna can be tuned to any given broadcast band within that range af frequencies.

3. A Wireless Variable High Frequency receiving and transmitting arrangement accord- ing to claim 1 which, when correctly tuned, is capable of nulling out interference from- domestic appliances, motors, etc-. in the 3500 K Hz Amateur band of radio frequencies, where this type of interference is common.

4. A Wireless Variable High Frequency arrangement according to claim 1 which exhibits directional receiving and transmitting char acteristics. in the range of frequencies from 3500 to 7500 K Hz.