HopeRF issues

[manuka]

A brief glance indicates your figures are in line, but check my pix below. Due to the antenna VR ( ~ 0.93 for TV ribbon) the actual wavelength is lower than a free space prediction. Start longer & trim to suit of course! My own 162MHz AIS deisgns didn't seem too critical however. Hint - if you do a lot of antenna work save yourself some keystrokes by using ALT 0188 for ¼ , 0189 for ½ & 0190 for ¾.

Slim JIMs have a gain of ~6dB (& thus comparable to a "Cotanga" Yagi), but they're omnidirectional & hence better suit "all bearings" horizontal signal paths. Forget them for satellites, aircraft or valley to mountain top links! As each 6dB gain doubles range, with one at each end you should obtain double x double = x4 the bare isotropic range. Stan.

 

[D n T]

slim jim meets cotanga

I reckon you could make a slim jim out of the immortal cotanga.
Just need to add a piece of 12mm ( half inch) plasic pipe in the middle for support, magic: Cotangatoo

 

[manuka]

Sure- almost any closely paralleled conductors can be used, & the whole lot can be slipped inside a palstic pipe. One of the more imaginative I've run across was made from model railway track!