Topband: Source of terminator resistors for EWE's?

Tom Rauch
Thu, 31 Oct 2002 13:35:25 -0500

With a EWE antenna or any other small-area antenna of that family 
like Flags, Pennants, or small verticals almost any style resistor 
except wire-wound will work. If it is near a transmitting antenna, 
then the resistor's power rating must be increased...but even a metal 
film would be fine and actually more desirable than carbon types. 

Composition or high surge-energy rated resistors are advisable in 
Beverages and other large area antennas, because even lightning 
strikes a few miles away can open metal film or carbon film or change 
the value of film-type carbon resistors. They won't always show 
external damage when ruined by lightning.

At 30MHz and lower, almost any resistor except wire wound is fine 

> Most of these I have found at hamfests, others at Meshna last year in
> Dayton. Check also other surplus houses like Hosfelt Electronics or
> All-Electronics.

Most carbon resistors manufactured since the 70's are carbon film, 
and that includes large brown cased resistors commonly mistaken for 
compositions. This is especially problematic with resistors used in  
parasitic suppressors, surge suppression, and long wire antenna 

There isn't any identifying mark or style that allows us to just look 
at the outside of most carbon resistors and tell what type they are. 
Always be sure to break a resistor open, and look at the core. If it 
has a light-colored core or if it is not a solid core of carbon (you 
can scrape carbon with a knife and watch it crumble or flake off into 
grains) it is a carbon film.

Most of the resistors I find surplus are carbon film, and are 
physically identical to the much less common carbon comps. The only 
harm from using the wrong type is in life in surge applications, or 
in use at 30MHz and higher (like in VHF and higher combiners, 
amplifier parasitic suppressors, and dummy loads).73, Tom W8JI