Hi Matt
Sounds good. Here is some advice regarding the measurement of traps. I have used this method successfully when I made a trapped dipole for 18 and 14 MHz.
When measuring a trap, we have to consider that a trap is a parallel-tuned circuit. It is therefore not advisable to measure traps directly with the FA-VA5. Any small amount of capacitance will falsify the measurement.?
I found the best way to measure traps is by using the FA-VA5 like we would use a Dip-meter. We can do this by setting the FA-VA5 to VSWR sweep mode with a narrow sweep width of say 1..2 MHz. You may need to refer to the manual (pages 15 to 17).
Then we connect a suitable one or two-winding coupling coil made from solid wire to the FA-VA5 BNC socket. Coil diameter is not critical and should suit the trap coil. The idea is to couple loosely to the trap and observe a small VSWR dip in the VSWR graph at coil resonance. In order to obtain best results, the weakest?coupling that still gives a visible VSWR dip will ensure highest accuracy. The marker function may come in very handy. Keep in mind that during marker adjustment, the FA-VA5 does not make new measurements !
This worked rather well here and I found very good agreement with a measurement made with my boat-anchor Agilent 8753 analyser.?
During trap measurement, the trap should be placed far away from any metal. You can support it with non-metallic supports.
If the above is not entirely clear, please let me know.
73
Dieter, VK3FFB
Dieter VK3FFB