[Antennas] Studies of propagation and signal strength of aviation antennas

[Dave Holford]

It has been a long time, but I have operated with trailing wires, fixed 
wires and sections of the airframe on HF. My recollection is that the 
trailing wire, when extended out to its full 200 ft length was the best when 
the navigator wanted an antenna for LORAN-A; which operated on 1750, 1850, 
1900 and 1950 kHz (those were the days when sections of the 160m band were 
prohibited to avoid interference with LORAN). Otherwise the only real 
difference I recall between fixed wire and trailing wire was that 200ft of 
trailing wire could pick up one heck of a static charge, especially in snow. 
It was amazing how far those purple arcs could jump sometimes.

One aircraft used the top half of the vertical stabilizer - fin and rudder - 
as an HF antenna. There was an insulating band between it and the rest of 
the airframe and it was fed with a remote antenna tuner. In my recollection 
it was almost always superior to the fixed wire.  Since that aircraft did 
not have a trailing wire I cannot make that comparison.

Operations were conducted in CW, AM and SSB; with some specialized data 
systems, over the range 2 to 28MHz; but mostly beteen 3 and 18MHz.

Incidentally there is still a lot of HF aviation traffic. Most, if not all, 
operations beyond VHF range still involve some HF comm, even if only for a 
communications and SELCAL check as a standby for loss of SATCOM. Also there 
is a lot of HF Data Link in both civil and military aviation use.


73
Dave
VE3HLU