Topband: Inverted L redux

donovanf at donovanf at
Mon Sep 2 16:23:55 EDT 2019

Hi Pete, 

Unless you're planning more than 30 radials eventually, there's no reason 
to install radials longer than the 50-60 feet you're already using. 

This is one of several classic references on the topic. See 
see Figure 3 and the 160 meter column in Table X: 


----- Original Message -----

From: "N4ZR" <n4zr at> 
To: "topband reflector" <Topband at> 
Sent: Monday, September 2, 2019 7:08:16 PM 
Subject: Topband: Inverted L redux 

More as an experiment and a thought-provoker than anything else, I've 
started adding 50-60-foot, on-the-ground radials to my 135-foot inverted 
L. In the latest incarnation I'm up to 4 radials. On my ancient 
MFJ-259B the lowest SWR is 1.3:1 at 1825 KHz, with an R of 77. X=0 (the 
259B doesn't give the sign of j) from 1808 to1894, which I assume is 
roughly centered on the actual cross-over point. 

With my rudimentary knowledge of such things, I'm guessing that there 
remains something on the order of 50 ohms of ground resistance to be 
reduced for efficiency, through addition of radials. Question is, 
would I profit most by adding another 4 50-60 foot radials, or 2 radials 
each 100-120 feet? 

Comments appreciated. 


73, Pete N4ZR 
Check out the Reverse Beacon Network 
at <>, now 
spotting RTTY activity worldwide. 
For spots, please use your favorite 
"retail" DX cluster. 

Searchable Archives: - Topband Reflector 

More information about the Topband mailing list