At 01:03 PM 2006-10-18, Phil Clements K5PC 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.
>
>What is a good method of matching this antenna to 50 ohm coax? I don't want
>to use ferrites. I'm using a line-flattener in the shack now, but I robbed
>it from another project, and I need to return it.
>
>This antenna is a real "keeper;" I was able to bust the pile-up on 2nd call.
>The apex is a 50 feet on an 80 foot Rohn 25 tower.
A series-section matching arrangement would work well to match to 79
ohms at 10.125 MHz.
Connect 4.83 feet of 50 ohm line to the feedpoint (VF=0.66)
Then follow with 5.99 feet of 75 ohm line (VF=0.66)
Looking into the 75 ohm line it will be 50 ohms.
The bandwidth of the series-matching lines is much greater than the 30m band.
73, Terry N6RY
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