I did some calculations on a more 'real-world' model of a MTV antenna,
assuming that the second tuned section has its own radial system (loss
resistance = R2)
+------+---------+
| | |
+-+ ----- +-+
L' | | ----- C | | L'
| | | | |
+-+ +-+ +-+
| | | R1 |
| +-+ +-+
| | | | R2
-----+ | +-+
Z = | |
------------+---------+
If we further assume that :
- both inductors are equal and have the double reactance as C
- the reactances of C and L are large compared to R1 and R2
The the result of the calculations is Z = 4 x R1 + R2
That means that only the 'R1' component is quadrupled, the 'loss
resistance' R2 of the second tuned section is just added !
I don't want to bore the whole LF-group with the maths, but I'm willing to
mail it direct to those interested (it's only about 5 lines of basic math).
73, Rik ON7YD
Rik Strobbe ON7YD
rik.strobbe@fys.kuleuven.ac.be
Villadreef 14 B-3128 Baal BELGIUM (JO20IX)
| 