





| This coil was plucked from an old base loaded vertical. The Vertical was about 26 ft high +/-. You can see on the left side a green wire with a tap on the coil. The coil was adjusted to resonate on one band...one frequency at a time. I think the vertical probably covered 80 through 10 meters. I measured the inductance as 36.9 microhenries with my Autek RF1 Analyst. |
| This is a powered iron core slug (2 inches in diameter) consisting of 5 T-200-2 toroidal cores stacked and held together with electrical tape. Up here in Canada; these cores cost us about $10.00 each..so this is a rather expensive slug!! This slug will be wrapped in paper and inserted in the 36.9 microhenry air core coil. The resulting increase in inductance will be noted. The results will be applied towards my work with permeability tuned antennas. |
| Slug is inserted in the COIL over half way and the inductance is measured on the RF Analyst as 61.4 microhenries. An increase of 24.5 uh. A very useful increase. |
| Test frequency is 2.077 MHZ during this test. The Analyst will go down to 1.7 mhz or so and up over 32 mhz. There can be a 5% to 10% errror..but for general work this is acceptable. The error percentage is repeatable..which means you can factor that into your measurements if you find out the error % of your meter. |
| MAXIMUM INDUCTANCE WAS 77 UH WITH THE SLUG FULLY INSERTED INTO THE COIL. THE ORIGINAL INDUCTANCE WAS 36.9. THE INDUCTANCE WAS DOUBLED AND THEN SOME. If this inductor was used to tune the antenna on 80 meters; fully inserted coil slug could then perhaps get the antenna to tune on 160 meters..or pretty close perhaps. A remote slow turning motor and a threaded rod so that the core could be inserted gradually would allow the tuning of a vertical antenna; similar to the way the popular SCREWDRIVER MOBILE ANTENNAS ARE TUNED. |
| NOTE: I placed the big slug (consisting of 5 stacked T200-2 torroidal forms) into a roll of paper. You can see the paper and the core inside the coil in this picture. |
