LA4RT Jon Kåre Hellan wrote:
Once it's up, you can't rotate it.

I have a 10m rotatable EDZ about which I wrote a
magazine article entitled, "Who Needs A Beam?".
--
73, Cecil http://www.w5dxp.com

Cecil Moore writes:

LA4RT Jon KÃ¥re Hellan wrote:
Once it's up, you can't rotate it.

I have a 10m rotatable EDZ about which I wrote a
magazine article entitled, "Who Needs A Beam?".

*Blush*

"F8BOE" wrote in message
...
Jerry wrote:


"Bob D." wrote in message
m...
I'm contemplating a Yaesu TF-857D with the FC-40 antenna tuner as a base
rig. I'd like to cover as many HF bands as possible with a simple wire
antenna. I'm on a small lot with an 80' tower. So anything I put up is
going to slope!

I've never used an antenna tuner before. I believe the FC-40 is weather
proof and meant for remote use.

If I slope a random wire and end-feed it, should the tuner go up on the
tower or stay on the ground? (In other words, which end should I feed?)
How should I ground the FC-40?

Anything better than a random wire that is still simple and covers
all/most of the HF bands?

--
Bob D. ND9B

Try this one: www.k1jek.com This is a dipole that comes in lengths of
73'
and 140' respectively. The short one covers 80-10, the longer one,
160-10
Meters, and perhaps, 6 Meters. I've had the long one for a couple of
years, and with a tuner, I've had EXCELLENT results!
With that 80 foot tower, you'd get some nice contacts!

73

Jerry




Hmmmm

This one seems to be another multifolded resonnator non-radiator concept
from the $hitizen bandits. If you need such bull****, there's no need to
pay buck$ for it if you can homebrew it so easily.

If you cannot afford homebrewing, then go for a real antenna! Cushcraft
used
to make good multiband verticals such as the AP8A or the R7/7000-R8
series.

If you already have a "tuner" you can homebrew a 1/9 Un-Un à la ZX-Yagi
MTFT
(Miracle Tranformator For Totaly-dumb-people) and hook it to your 80'
pole... Guarated under 20$ including plastic box, silvered copper wire,
inox screwery and BNC socket. For low band action you can slide a ferrite
bar in it.

73 de F8BOE Olivier ...-.-

Sir, I've built more antennas since 1964 than you can count. Including
scewdrivers (www.qsl.net/k4kwh) In this case, the one I recommended (since
he didn't say specifically) was because I had some illness/death at home, I
wanted to cover 160 Meters in a small lot, and I couldn't devote the time to
building an antenna at the time. I beg to differ with the non-radiator
antenna comment. KNOW of which you speak.........like actually reading the
reviews of it on www.eham.net.
There ARE reasons for the choices we make! The Cobra WORKS, and next time,
yeah, I will probably make one as I now have the time I did not have prior
to my Father's illness and death!!!

"Jerry" wrote in
:

....
Try this one: www.k1jek.com This is a dipole that comes in lengths
of 73' and 140' respectively. The short one covers 80-10, the longer

Ah, the Cobra! An interesting antenna for exploration of the myth that
linear loading is essentially lossless, see my analysis of NEC models of a
Cobra design at http://www.vk1od.net/cobra/index.htm .

Owen

"Owen Duffy" wrote in message
...
"Jerry" wrote in
:

...
Try this one: www.k1jek.com This is a dipole that comes in lengths
of 73' and 140' respectively. The short one covers 80-10, the longer

Ah, the Cobra! An interesting antenna for exploration of the myth that
linear loading is essentially lossless, see my analysis of NEC models of a
Cobra design at http://www.vk1od.net/cobra/index.htm .

Owen

Says "Page not found"!


JWO

On Wed, 25 Apr 2007 22:45:33 -0400, "Jerry"
wrote:


"Owen Duffy" wrote in message
...
"Jerry" wrote in
:

...
Try this one: www.k1jek.com This is a dipole that comes in lengths
of 73' and 140' respectively. The short one covers 80-10, the longer

Ah, the Cobra! An interesting antenna for exploration of the myth that
linear loading is essentially lossless, see my analysis of NEC models of a
Cobra design at http://www.vk1od.net/cobra/index.htm .

Owen

Says "Page not found"!


JWO


Works okay for me. Nice paper ( I stole the NEC deck).

Danny, K6MHE

Danny Richardson wrote in
:

....
Works okay for me. Nice paper ( I stole the NEC deck).

Hi Danny,

You will see that the FR card has a symbolic variable for the frequency,
you will need to feed it a float value. (I used a PERL script to run a
series of models by tailoring the basic NEC deck, executing it, and
summarising the results.)

Differently to many of the commercial Cobras, my model used 2mm dia
copper and wider spacing. Most seem to use smaller, even very small
spacings where proximity effect becomes significant, smaller conductors,
and possibly steel cored copper clad conductors.

IMHO, the interesting aspect of the article is the loss mechanism of
linear loading, it makes sense once you see the current magnitudes and
phase and realise this thing at some frequencies carries large conductor
currents for low net current moment.

I have been exploring a 13m unloaded vertical with 2 radials for each of
80, 40, 30, & 20 metre bands, and there is a different but similar (!!!)
effect where at some frequencies the radials carry large individual
currents (larger in magnitude than the current in the vertical) with a
peak in loss at these frequencies, see
http://www.vk1od.net/multibandunload...al/13mEV-1.gif .

Owen

On Thu, 26 Apr 2007 03:34:29 GMT, Owen Duffy wrote:

Danny Richardson wrote in
:

...
Works okay for me. Nice paper ( I stole the NEC deck).

Hi Danny,

You will see that the FR card has a symbolic variable for the frequency,
you will need to feed it a float value. (I used a PERL script to run a
series of models by tailoring the basic NEC deck, executing it, and
summarising the results.)

[snip]

Owen

No problem Owen, I'll use MultiNec which very easily allows me to run
"test cases" using variables with no programming required on my part.
G.

Danny

Danny Richardson wrote in
:
....
No problem Owen, I'll use MultiNec which very easily allows me to run
"test cases" using variables with no programming required on my part.

Ok. There are other tools that allow symbolic variables, and of course NEC
allows specification of a range of frequencies on the FR card.

The main reason for using PERL to build, run and sumamrise is the summarise
stage. At that point I merge the NEC output with real transmission line
models, L-tuner models etc... and without wading through 5MB of NEC output
by hand. The system view is a bigger picture than the NEC output.

Owen

Jerry wrote:
"Owen Duffy" wrote:
http://www.vk1od.net/cobra/index.htm .

Says "Page not found"!

Worked for me.
--
73, Cecil http://www.w5dxp.com