LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #1   Report Post  
Old February 4th 05, 06:46 PM
Spam Fighter
 
Posts: n/a
Default whip antenna calculations

I am looking for a .xls spreadsheet (or something that works under LINUX),
to calculate the equations for matching common maritime mobile HF whip
antennas:

8 ft
10 ft
15 ft
23 ft
40 ft (backstay, approx 5/8 on 20 Meters)

I want to calculate the matching parameters including voltages generated
in the tuner for the 1.8 3.5 7 10.1 14 21 28 MHz ham bands and the 2 4 6 8
12 16 and 22 MHz marine bands.

The ARRL ANTENNA HANDBOOK, 18th edition, chapter 18, has some equations
and a table of calculated values for a 8 ft whip on ham bands. I wish to
duplicate the calculations and figure out the voltage maximums for
component values for, say, 100 W key down power.

Take for example the 1st row of the table:

BASE LOADED 8ft whip
F=1.8 MHz
Loading L = 345 uH
Rc Q=50 = 77 ohms
Rc Q=300 = 13 ohms
Rr =0.1 ohms
Feed R = 23 ohms
Matching L = 3 uH

Now at 1.8 MHz
XL of 345 uH = +j3902 ohms

Do I calculate the current from P=I*I*R so for
Rr = 0.1 ohms, I = sqrt(100/Rr) = 31.6 A
so V XL is I*R = 31.6*3902 = over 123 KV? (seems excessive)

or do I use the R values of 77, 13, or 23 ohms? (4.4 KV, 57 KV, 8.1 KV )?

Do I multiple all RMS voltages by sqrt(2) to convert RMS to PEAK?

Greg
VE0ACR
gblair _at_ sympatico _dot_ ca
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Mobile Ant L match ? Henry Kolesnik Antenna 14 January 20th 04 04:08 AM
Question for better antenna mavens than I Tony Meloche Shortwave 7 October 28th 03 09:16 AM
QST Article: An Easy to Build, Dual-Band Collinear Antenna Serge Stroobandt, ON4BAA Antenna 12 October 16th 03 07:44 PM
Outdoor Scanner antenna and eventually a reference to SW reception Soliloquy Shortwave 2 September 29th 03 04:04 PM
Sony Portable versus Tabletops mike Shortwave 10 August 30th 03 11:46 PM


All times are GMT +1. The time now is 03:05 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017