A correspondent has asked about the tripod mounting arrangement I use for the Arrow dual band 70cm/2m Yagi.
Photos: © Copyright 2016 Andrew VK1AD
The SLIK F153 aluminum lightweight tripod is designed to support a camera, however when I spotted the tripod in a local camera store, I immediately visualised a lightweight VHF/UHF Yagi, suitable for SOTA operations mounted to the tripod head. The SLIK tripod sales promotion mentions the following features, which after using the tripod for the best part of three years are correct.
- 3-way pan head with long panhandle for sure camera control.
- Single bubble level (useful)
- Rack and pinion geared center column with handle for controlled elevation of the camera.
- Easy to attach quick release plate makes for easy mounting and dismounting of the camera.
- Maximum height 1315 mm
- Folded length 520 mm
If you substitute the words ‘Lightweight Yagi Antenna’ in place of ‘Camera’ the features stay true.
Mounting the Yagi – Lessons learned
The quick release top plate is supplied with a short 1/4 inch, 20 TPI (BSW) fold-down wing screw and has a recess to accommodate a rubber-pad insert designed to grip the base of the camera. The plate has a dovetail mount which mates with the tripod head mount.
For my first attempt to mount the Arrow, I drilled a 5 mm hole in aluminium boom (mid way) and tapped the hole with a 1/4 BSW 20 TPI thread tap. The thread cut was clean, no issues, however after mounting and dismounting the antenna in the field, say 5 or 6 times it didn’t take long for the 1/4 inch thread in the aluminium boom to strip. The cross-section of the boom isn’t designed for a 1/4 inch internal thread. 😦
To overcome this issue I replaced the 1/4 inch wing-head screw with 2 inch long 3/16 inch pan head screw. Next I drilled a 1/4 inch hole through the antenna boom and deburred the hole for a clean finish. With the 3/16 inch screw in the quick release plate, place the antenna boom over the screw and secure the quick release plate to the antenna boom with a nut and washer. Retain the plate rubber pad insert, you need the pad to create a friction surface to hold the antenna boom steady when rotating the antenna on its axis. You can select a screw size to suit your needs.
Quick release plate mounted to the antenna boom by a 2 inch 3/16 pan head screw
Ready to fit the antenna to the tripod head mount
Arrow dual band Yagi with the 2m and 70 cm elements fitted to the boom
Reference / Links
SLIK F153 Tripod (n.d) in SLIK CORPORATION http://www.slik.co.jp/slik_com/UFS-F153.html