Tunable Yagi and other antennas
A tunable antenna is formed on a boom. First and a second opposed non-conductive support pole extend from a first end of the boom. Third and a fourth opposed non-conductive support pole extending from a second end of the boom. Each pole has a wire guide at its end. First and second spools are mounted near the first end of the boom. Third and fourth spools are mounted near the second end of the boom. First and second wires are spooled on the first and second spools. A third wire is spooled on the third spool and mechanically coupled to the first wire by a non-conductive cord, the first and third wires running through the first and third pole guides. A fourth wire is spooled on the fourth spool and mechanically coupled to the second wire by non-conductive cord, the second and fourth wires running through the second and fourth pole guides.
1. A tunable antenna, comprising:
a boom;
a first and a second opposed non-conductive support pole extending from a first end of the boom each having a wire guide at a distal end thereof;
a third and a fourth opposed non-conductive support pole extending from a second end of the boom each having a wire guide at a distal end thereof;
first and second spools rotatably mounted proximate to the first end of the boom;
third and fourth spools rotatably mounted proximate to the second end of the boom;
a first wire spooled on the first spool in a first direction;
a second wire spooled on the second spool in a first direction;
a third wire spooled on the third spool in a direction opposite the first direction and mechanically coupled to the first wire by a length of non-conductive cord, the first and third wires running through the guides on the first and third poles; and
a fourth wire spooled on the fourth spool in a direction opposite the first direction and mechanically coupled to the second wire by a length of non-conductive cord, the second and fourth wires running through the guides on the second and fourth poles.
2. The tunable antenna of claim 1 wherein;
the first and second support poles are spring biased against stops limiting a maximum angle that the first and second support poles can extend from the boom; and
the third and fourth support poles are spring biased against stops limiting a maximum angle that the third and fourth support poles can extend from the boom.
3. The tunable antenna of claim 1 wherein;
the first and second spools are ganged; and
the third and fourth spools are ganged.
4. The tunable antenna of claim 1 wherein;
the first and second spools are releaseably ganged; and
the third and fourth spools are releaseably ganged.
5. The tunable antenna of claim 1 wherein the guides comprise pulleys.
6. The tunable antenna of claim 1 further comprising:
a first rotating mechanism remote from the first and second spools and coupled to the first and second spools;
a second rotating mechanism remote from the third and fourth spools and coupled to the third and fourth spools.
7. The tunable antenna of claim 6 wherein the first and second rotating mechanisms are hand actuated.
8. The tunable antenna of claim 6 wherein the first and second rotating mechanisms are motor actuated.
9. The tunable antenna of claim 1 wherein the first and second spools are releaseably ganged.
10. A tunable antenna element comprising:
a support pole;
first and second spools rotatably mounted proximate to a first end of the support pole;
an upper cross member formed from a flexible material and mounted at a second end of the support pole;
spaced apart first and second guides mounted on the cross member, at least one of the first and second guides mounted at a position away from the support pole to form a tension member;
a wire wound on the first spool in a first direction; and
a non-conductive cord wound on the second spool in a second direction opposite the first direction and attached to an end of the wire, the attached wire and non-conductive cord passing through the first and second guides.
11. The tunable antenna of claim 10 wherein the first and second spools are ganged.
12. The tunable antenna of claim 10 wherein the first and second guides comprise pulleys.
13. The tunable antenna of claim 10 further comprising a rotating mechanism remote from the first and second spools and coupled to the first and second spools.
14. The tunable antenna of claim 13 wherein the rotating mechanism is hand actuated.
15. The tunable antenna of claim 13 wherein the rotating mechanism is motor actuated.
16. The tunable antenna of claim 10 wherein both of the first and second guides are mounted on opposite sides of the support pole at positions away from the support pole to form tension members.
17. The tunable antenna of claim 10 , further comprising:
a lower cross member mounted proximate to a first end of the support pole, the first and second spools rotatably mounted on the lower cross member; and
a guide pulley mounted on the lower cross member through which the non-conductive cord from the second spool passes.