15. Connecting as a bandpass-cavity to the "Rx" or "Tx" connector. (See "topvuw.gif").

    Firts cavity (TX/RX side).
If the just adjusted cavity is the first one at the RX or TX-side of the 8-cavity filter, it will be a bandpass cavity. So no notch-L or -C will then be connected on that first cavity.

First, with the 1/2 wave cables still connected, tune the cavity with the tuning-rod as accurate as possible, to minimal VSWR at the pass-frequency.  The fine-tuning bolt should stay abt. 3 turns in, to allow easy finetuning afterwards, when the filter is completed.

Remove the testcables.

Shorten the "cold" sides of the links down to topplate "A".

Bend and shorten the the hot side of one link to the BNC connector in the side of the cavity.

Solder it, while a dummy-plug is in the recepticle for holding the centre-pin inposition. Use only best quality recepticle, with PTFE insulation! Or better, use an N-type recepticle.

When this cavity is the firs one, shorten the "hot" side of the other link low to the topplate. When it is not the first one, the hot side of the link is trimmed later, when the notch-L or C is connected. See drawing.

Solder a 1/4 wave (notch-frequency) 50 ohms PTFE cable onto the outgoing link. It will later be connected to the next cavity.



<< VV