[BC] Part 15 LPAM Questions?

[Richard Fry]

>if you look here:  www.w8ji.com , you'll see that at 1500,
>a 10 foot radiator is about 5.5 electrical degrees, and has
>a characteristic resistance of about .22 ohms (with a couple
>thousand + ohms of cap reactance). So, our numbers
>are off by about 1/2.
____________________

I'll have to quibble about that radiation resistance, sorry.  Here are 
values I calculated in a spreadsheet using the formulas in Carl E.Smith's 
1946 I.R.E. paper titled "Performance of Short Antennas."

Frequency (MHz) 1.5
Wavelength: 656 feet
Diameter of antenna in inches: 0.5
Antenna diameter in degrees: 0.022865854
Height of antenna in feet 9.84
Antenna height in degrees: 5.4

Rr = 0.093461538 ohms
Xc = 2,833.77 ohms

Using a larger or smaller OD radiator of that length changes its input 
reactance, but not its radiation resistance.

So I think the radiation resistance for this configuration is bit smaller 
than in your earlier post, not ~ twice as great.

RF