Dipole Antenna Impedance Equation

Andy2

DTVUSA Jr. Member
#1
I'm looking for the complex feed point impedance of an ideal Hertzian dipole in free space as a function of frequency? Kind of an advanced question, hope someone can help.
 

rabbit73

DTVUSA Member
#3
If the dipole is used below its design frequency the real resistive part is less than 73 ohms and the reactance is negative. If the dipole is used above its design frequency the real resistive part is more than 73 ohms, and the reactance is positive. The change in reactance is more rapid with thin diameter elements because of higher Q.
 

Tower Guy

DTVUSA Member
#4
If the dipole is used below its design frequency the real resistive part is less than 73 ohms and the reactance is negative. If the dipole is used above its design frequency the real resistive part is more than 73 ohms, and the reactance is positive. The change in reactance is more rapid with thin diameter elements because of higher Q.
Is that why you have the number 73 in your alias?
 

Andy2

DTVUSA Jr. Member
#6
wonderful, thank you. I had asked this question elsewhere but not one could help out. Sad part is, I had seen that wiki article but didn't catch browsed right over that info.

Just in time to turn in my term paper tomorrow.
 

Piggie

Super Moderator
#7
Ha! LOL!
It's just a coincidence. I used 73 ohms (rounded) because you did.
It actually comes from ham radio and means best regards.

I wonder if Andy2 ever came back.
Dang site better than sending 88's to guys on the forum..... lol..

Maybe that is where 73 started? Best Regard, meaning good luck tuning your dipole?

Funny how I and probably others here just hooked a piece of 50 ohm coax to it or a vertical. Tuned out the reluctance and fired up the finals.

Now I did always build gamma for my loops. They didn't do too well hooked directly to a piece of RG8.
 
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