[Lowfer] DK7FC

[pbunn]

I am planning to start construction on a 74 KHz loading coil for my 55 foot vertical antenna. The antenna has a capacitance of about 290 pF at 500 KHz and I assume that will be the same or close at 74 KHz.

My calculations show that the coil needs to be about 15 mH or so. I have a variometer that is about 400 - 900uH that I will use for tuning.

The coil form is a section of 20" thin wall PVC duct and it looks like about 240-250 turns gets me in that ballpark. I plan to use #12 stranded THHN - about 1350 feet.


Does this seem to be "in the ballpark" before I start the winding.

I'd appreciate any comments. Thanks.


Pat Bunn

WG2XLP
WG2XCT
N4LTA