Hi Steve,
5300 pF is way large. It indicates *something *else is going on.
"Something" needs to be determined.
One thing for sure, after nearly a decade of correspondence with this as a
frequent subject, there is no one single "silver bullet" to fix this in all
cases. It is complicated and with
Remember, Steve, for a given frequency more capacitance equals less
capacitive reactance [Xc = 1/(2*pi*f*c)]. At 1825 KHz, 5300 pf is only
16.5 ohms reactance. That means you are only offsetting a small amount
of inductive reactance. Where you should be more concerned is when the
series
FWIW, for 160 I used my old 97-foot Rohn 25 tower, with 2 tribanders and
a 40M 2-el on it, shunt fed at about 50 feet. I had a pair of 300 uf
variable caps at the bottom, one in series with the feed and the other
in parallel. It proved to be easy to tune to low SWR once I discovered
that the
On 12/21/2023 12:54 PM, Paul Dulaff via Topband wrote:
Ran a basic EZNEC model with no tower present for your 80 ft X 45 ft
inverted L at 1.825 Mhz. The base impedance for this is 28.5 - j 130
ohms. The get rid of the reactance I extended the top wire an
additional 20 ft so 80 X 65 ft and
Steve
Ran a basic EZNEC model with no tower present for your 80 ft X 45 ft
inverted L at 1.825 Mhz. The base impedance for this is 28.5 - j 130
ohms. The get rid of the reactance I extended the top wire an
additional 20 ft so 80 X 65 ft and base impedance is 37.2 + j0. The
tower is
Steve,
For comparison my inverted-L is similar to yours with a 94 ft vertical
section and 43 ft horizontal (ish). It is on a tall tree, not a tower.
Like you, I use an L-network to match it and get a feed impedance on 1826.5
KHz of 50+j0. I have a 1600pF capacitor in parallel but no inductor as I
Without getting into the measurements - I think you need to detune the
tower if that is going to work at all. Probably put a trap in the bottom
20 feet.
Tree N6TR
On Thu, Dec 21, 2023 at 6:27 AM Noel Lopez via Topband <
topband@contesting.com> wrote:
> Here is my 2 cents worth. First of all,
Here is my 2 cents worth. First of all, I am not an antenna expert nor do I
know how to use antenna modeling software.These are my thoughts based on my
experience and what I remember reading. My low band system is an inverted L
under a SteppIr yagi that can be retracted. This avoids the
I have an Inverted-L question that hopefully someone can answer for me.
I installed the 160m wire to the 80 ft level on a 100 ft Rohn 45 tower
with top mounted yagis.
The horizontal (sort of) portion is approx 45ft long.
The wire starts at 80 ft down approx 5 ft from tower and when it gets to
Art, from what I’ve read, I understand that the non-vertical part of the
Inverted L does not have to be completely horizontal - it can slope with little
detriment to it’s radiation pattern. I have two - one for 80 and one for 160.
Both of ‘em slope away from the top support.
Jim / W6JHB
On
The most important part of an inverted L is the counterpoise, be it raised
radials, buried or on-ground radials or an FCP. Be sure you can do a
counterpoise well. Otherwise the counterpoise can be a huge RF loss, easily
negating anything done well with the L wire itself.
Next the vertical part of
I have been looking at locations on my property to install an Inverted L
for 160.
How important is it for the top part to be led away at a right angle?
I was considering running it vertically 80ft, then about 25 feet at a 45
degree up angle and 25 feet at a 45 degree down angle, over the top of
On Thu, Dec 27, 2012 at 10:12 AM, Ashton Lee ashton.r@hotmail.com
wrote:
Several of us here in Western Colorado run slopers off the tower, which I
believe is essentially loading the tower with an elevated lead. It works
for us.
Sloper is really not the same thing as a parallel vertical
- Original Message -
From: Tom W8JI w...@w8ji.com
To: Herb Krumich wa2...@yahoo.com; topband@contesting.com
Sent: Wednesday, December 26, 2012 3:08 PM
Subject: Re: Topband: Inverted L question
I am right now using an inverted L which is spaced about 4 feet away from
my tower
On Wed, Dec 26, 2012 at 3:08 PM, Tom W8JI w...@w8ji.com wrote:
At any distance less than 1/4 wave or so, which is around 130 feet, the
inverted L is coupled very tightly to the tower. At wider spacings, like
50-100 feet, the tower and things on the tower **sometimes** won't have
much
Snip: I am right now using an inverted L which is spaced about 4 feet away
from my tower. The vertical leg is about 85 feet.
I remember a number of years ago talking with Jeff Briggs (K1ZM) about
ideas for my first inverted-L while we were both waiting for flights out of
the Dayton Hamvention.
Mike, You would be much better off by feeding the tower with a shunt or
cage feed. As K2AV so accurately pointed out...an inverted L
supported by a metal tower is not the answer for an efficient system on
160. With the amount of radials you have at the base you could do much
better by
- Original Message -
From: Lloyd Korb k8...@roadrunner.com
To: topband@contesting.com
Sent: Sunday, April 29, 2012 7:51 AM
Subject: Topband: Inverted L Question - Reply
What is interesting to me is the fact that at times the L seems to have a
different polarity than the 6BTV. I can
: Lloyd Korbk8...@roadrunner.com
To:topband@contesting.com
Sent: Sunday, April 29, 2012 7:51 AM
Subject: Topband: Inverted L Question - Reply
What is interesting to me is the fact that at times the L seems to have a
different polarity than the 6BTV. I can switch back and forth between
First year on Top Band and I have a question regarding my inverted L. I now
have it 55 foot vertical with the remainder horizontal with elevated
radials. It works well, but the neighbors will not be happy in the spring
when they come back to their summer cottages! Hihi. I am going to move it
to
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