MFJ 1899T antenna tripod mount and balun
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SummaryThis little box serves two purposes; to make a sturdy tripod mount for my MFJ 1899T multiband vertical antenna, and to improve its performance by adding a 1:1 current balun and a banana jack for adding counterpoises. The balun will make sure the performance isn't affected by the length of the antenna cable. It was built to be used in a lightweight QRP radio setup based on a Yaesu FT-817ND. |
Parts
- Small metal chassis (approx 50*50*25mm)
- BNC-connector and four M3 screws
- Female SMA-connector
- FT114-43 ferrite core
- 0.5m RG-174 coaxial cable
- Female banana connector
- Zip-ties and heat shrink tubing
Construction
I started by winding ten turns of RG-174 on the ferrite core.
I then drilled and threaded (M3) three of the mounting holes for the BNC-connector. The remaining hole was not threaded, as I needed a nut on the inside of the box anyway.
The coaxial cable was then soldered to the BNC-connector, and the ferrite core was glued to the inside of the box.
This step includes threading (1/4"-20) the underside of the box for mounting on a tripod, and terminating the cable with a female SMA-connector. I made a neat cable of approx. 5 m length for my Yaesu FT-817ND as well. It is terminated with a BNC- (for the front panel connector) and an SMA-connector.
