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Old August 23rd 03, 04:34 PM
Dave Shrader
 
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Ken Bessler wrote:

[SNIP]

EZNEC not only shows a differant resonance point (3.2:1 @ 9.5 mhz
with Z=19.81 - j 24.27 ohms) but shows a tighter bandwidth.


Ken, 19.81 - j24.27 IS NOT Resonant!!!

Resonant would be: 19.81 + j0 !!!! Get rid of the reactance!!

DD, W1MCE

I can not, however, deny that the antenna works. Again last night
I listened in on the 40 meter 3905 century club net and I was hearing
stations all over. I later moved to WWV @ 5 mhz and heard WWVH
just as strong as WWV (60 miles away).

Now if I could just figure out how to model the 6 turn choke at the
feedpoint...... I'd be happy to e-mail anyone my antenna file if they
would like to modify it. The wires are done and I think I got the feed-
line right but I'm not sure. Then there is the choke - 6 turns of rg8x
@ 2-5/8" dia at the feedpoint with 11 feet of rg8x going from there
to my Z11 tuner.

Any help?

Ken KG0WX



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Old August 23rd 03, 05:05 PM
Ken Bessler
 
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"Dave Shrader" wrote in message
newsQL1b.235607$YN5.159155@sccrnsc01...
Ken Bessler wrote:

[SNIP]

EZNEC not only shows a differant resonance point (3.2:1 @ 9.5 mhz
with Z=19.81 - j 24.27 ohms) but shows a tighter bandwidth.


Ken, 19.81 - j24.27 IS NOT Resonant!!!

Resonant would be: 19.81 + j0 !!!! Get rid of the reactance!!

DD, W1MCE


I need to buy a MFJ 269..... this is getting serious!

:-)

Ken KG0WX


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Old August 23rd 03, 08:03 PM
Dave Shrader
 
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No need to buy one. In most ham clubs you can find some sucker who owns
one. I own a MFJ 259B for example. :-)

If you live in the Concord NH area you can borrow mine.

Seriously, many people miss use the term 'resonant' when they mean
lowest VSWR. For years I used a non-resonant antenna and a high quality
tuner for 80/75, 40 and 30 meters. True resonance is not a requirement
for an effective antenna. If you can load it, it will radiate.

Deacon Dave, W1MCE
+ + +

Ken Bessler wrote:

"Dave Shrader" wrote in message
newsQL1b.235607$YN5.159155@sccrnsc01...

Ken Bessler wrote:

[SNIP]

EZNEC not only shows a differant resonance point (3.2:1 @ 9.5 mhz
with Z=19.81 - j 24.27 ohms) but shows a tighter bandwidth.


Ken, 19.81 - j24.27 IS NOT Resonant!!!

Resonant would be: 19.81 + j0 !!!! Get rid of the reactance!!

DD, W1MCE



I need to buy a MFJ 269..... this is getting serious!

:-)

Ken KG0WX



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Old August 24th 03, 04:53 AM
Roger Halstead
 
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On Thu, 21 Aug 2003 17:14:33 -0600, "Ken Bessler"
wrote:

What effect would a brick wall have on a HF antenna?
I'm talking 1-2" distance from the bricks, folks. The


Remember too that many brick walls use steel reinforcement, or lots of
steel strips to hold them to the frame structure unless we are talking
a "real" brick wall which is seldom found in the US in buildings much
less than a century old.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)
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Old August 25th 03, 06:36 PM
Roy Lewallen
 
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" I can not, however, deny that the antenna works."

"Works" is a binary quantity, with only two values. If we divide
antennas up into only the two categories of "works" and "doesn't work",
I could simplify the EZNEC output a tremendous amount. It would go
through all its calculations, then either turn the screen red or green,
and that's all the information you'd need. Sounds like your antenna
already "works", so what's left to do?

Seriously, if all you want to do is listen to signals, nearly any
antenna will "work". At HF, it can be very small and very, very
inefficient, and you'll still hear just as many signals as somebody with
a big, efficient antenna. I can hear plenty of DX with my tiny Sony
radio and its 18" or so whip. So if listening is your goal, any more
fussing around you do with the antenna is a waste of time.

But getting them to hear you is another matter entirely. If that's your
goal, then effort spent in understanding your antenna is worthwhile,
because it will lead the way to improving it.

If you want EZNEC to tell you what the antenna will do, you've got to
describe the antenna accurately to EZNEC. In another posting I just
made, I suggested three approaches you can take to deal with the
feedpoint choke. Hopefully one of them will give you enough information
to answer your questions about the antenna.

Roy Lewallen, W7EL

Ken Bessler wrote:

I've run the antenna through EZNEC. I didn't include the feedline
coil because I did'nt know how to model it. I'm still learning how
to use the program.

EZNEC not only shows a differant resonance point (3.2:1 @ 9.5 mhz
with Z=19.81 - j 24.27 ohms) but shows a tighter bandwidth.

I can not, however, deny that the antenna works. Again last night
I listened in on the 40 meter 3905 century club net and I was hearing
stations all over. I later moved to WWV @ 5 mhz and heard WWVH
just as strong as WWV (60 miles away).

Now if I could just figure out how to model the 6 turn choke at the
feedpoint...... I'd be happy to e-mail anyone my antenna file if they
would like to modify it. The wires are done and I think I got the feed-
line right but I'm not sure. Then there is the choke - 6 turns of rg8x
@ 2-5/8" dia at the feedpoint with 11 feet of rg8x going from there
to my Z11 tuner.

Any help?

Ken KG0WX



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