Radials vs Counterpoise... what am I using?

Status
Not open for further replies.

prcguy

Member
Joined
Jun 30, 2006
Messages
8,100
Location
So Cal - Richardson, TX - Tewksbury, MA
A 1/4 wave monopole over perfect ground is supposed to be around 36 ohms but except for 10m, the OPs antenna is shortened by traps that also act as loading coils to shorten the antenna on lower bands. A short loaded 1/4 wave antenna over a good ground can be 15 ohms or less.

Most people have insufficient counterpoise under their trap antenna and it can show a really good 50 ohm match on a band where it should be less than 20 ohms.
prcguy

You should have several dozens of radials in place to get that impedance anywhere near 36 ohms. Two radials is nowhere near enough. Consider using at least 8 to 16 evenly spaced radials. That might get you just below 50 ohms. I suggest using (or borrowing) a noise bridge or an antenna analyzer to get the straight scoop on what impedance you're seeing.
 

AgentCOPP1

Member
Joined
Nov 16, 2011
Messages
295
You should have several dozens of radials in place to get that impedance anywhere near 36 ohms. Two radials is nowhere near enough. Consider using at least 8 to 16 evenly spaced radials. That might get you just below 50 ohms. I suggest using (or borrowing) a noise bridge or an antenna analyzer to get the straight scoop on what impedance you're seeing.
I never said I was using 2 radials, but nonetheless I probably didn't have enough. It's too dark right now but I'm going to take an updated picture with my 32 (?) radials soon.

SWR hasn't gone down too much unfortunately, and I'm beginning to wonder why. It's still around 1.7 and I'm not too sure how to get it down. The minimum SWR for 40 meters is 1.3 which is perfect but the bandwidth is still pretty low, but I guess it's a trade off.
 
Status
Not open for further replies.
Top