Andy
A correction: I should have said ‘in
series with’ and not ‘across’. So that my post should
read:
“For a second zero on the HF side
try an inductor ‘in series with’ the ‘zero’
capacitor. The trouble is that it will have to have the same reactance as
this 1.5p capacitor and that may not be easily realisable in practice.
The inductor could also go between resonators 1 and 3 or 3 and 5 I think.
If the inductor value is too high you can use a small ‘link’ coil
on each of the resonators to be inductively coupled and connect these by a pair
of twisted wires. Getting the coupling right can be fiddly. You can get
another LF zero rather than the wanted HF zero, I think, if you get the phasing
wrong.” .
I hope this helps but as I said it is some
time since I taught this stuff! Good luck.
Mike – G3LHZ
