[TowerTalk] Matching a Delta Loop

[Bill Coleman]

On Oct 18, 2006, at 4:03 PM, Phil Clements wrote:

> I hastily threw together a 30 meter Delta Loop this summer in order  
> to get
> KH8SI in the log for a new one on CW. Using the formula, the  
> resonant point
> came out 10.105 mhz (great, first try!) but the feed-point  
> impedance is 79
> ohms.

Before I put the tower up, I had a 10/15m delta loop in the attic.  
Worked pretty well. I made gamma matches to feed mine. I ended up  
with a gamma wire the same diameter as the elements, about 4% of the  
loop length, and spaced about 3 inches. You'd probably need about  
75-100 pF variable cap to cancel out the inductance.

It only took about 10 minutes with a borrowed antenna analyzer to  
find the right matching point. (Which sold me on buying an antenna  
analyzer -- now I own two)

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901