LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #5   Report Post  
Old January 20th 04, 04:25 AM
H. Adam Stevens
 
Posts: n/a
Default

No
It means there is less loss resistance.
The radiation resistance on 80 and 40 of all these short antennas is tiny, a
very few ohms.
At resonance the measured resistance is the sum of radiation and loss
resistance.
Matching the impedance at resonance results in the greatest measured field
strength, at least in my front pasture;
So making the antenna resonant, then matching the impedance, is my preferred
approach.
Using reactances to do that is the same as the bazooka antenna: storing
energy in tank circuits; A lossy enterprise.
Funny thing about this stuff, I built my first crystal set in 1956, my first
transmitter in 1961 and I'm not bored yet.
73
H.
NQ5H

"Craig Buck" wrote in message
news:ZT1Pb.4811$ZJ1.4783@lakeread01...
Doesn't; the Screwdriver's low feedpoint impendence mean it will be less
efficient not more?
--
Radio K4ia
Craig "Buck"
Fredericksburg, VA USA
FISTS 6702 cc 788 Diamond 64
"H. Adam Stevens, NQ5H" wrote in message
...
QST
It's been a while since I posted all that bazooka data that made me

stick
to
dipoles, so here goes:
I've been using Hustlers mobile for almost 40 years and find them

adequate;
The mast I bought in 1970 only recently failed.
I'm reworking my HF mobile installation around a TS-480HX and decided to
graduate to a screwdriver. I bought a Tarheel 200.
I prefer to operate a mobile antenna at it's resonant frequency and

match
to
the impedance of the transmission line with a transformer.
So here I present the resonant feedpoint impedances of a Hustler (small
resonators), the Tarheel 200 screwdriver and a 103" whip on a bug

catcher
on
a 54" Hustler base. All antennas on the same ball mount. Measurements by
MFJ. "Resonant" implies X=0.

band Hustler Screwdriver 103"/BugCatcher/54"
80 21 ohms 9 ohms 23 ohms
40 25 11 na
20 30 30
10 40 32

I really thought the huge bug catcher would do better.
The screwdriver shows encouraging results for signal improvement over

the
others on 80 and 40.
Seems the diameter of that bottom conductor on the screwdriver makes a

big
difference at the lower frequencies.
Since the TS-480HX has two antenna jacks, I think an additional small
screwdriver is in order; One for 80-20; One for 20-6.
73
H.
NQ5H








 
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
Inverted ground plane antenna: compared with normal GP and low dipole. Serge Stroobandt, ON4BAA Antenna 8 February 24th 11 10:22 PM
Mobile Ant L match ? Henry Kolesnik Antenna 14 January 20th 04 04:08 AM
Poor quality low + High TV channels? How much dB in Preamp? lbbs Antenna 16 December 13th 03 03:01 PM
QST Article: An Easy to Build, Dual-Band Collinear Antenna Serge Stroobandt, ON4BAA Antenna 12 October 16th 03 07:44 PM


All times are GMT +1. The time now is 01:47 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017