In article , starman
wrote:

RHF wrote:

starman wrote in message
...

What you have is a sloping inverted-L antenna. A real longwire is much
longer than 80-ft for most of the HF spectrum.

TailGator & StarMan,

FWIW: More 'properly' called a "Random" Wire Antenna
- - - Vice a [Longwire] Antenna

Are all inverted-L's, random wires?

Depends on how you connect it to the radio. With just a single vertical
lead-in then yes but use a coax grounded in some way then no. Another
thing to consider is that the vertical portion should be a significant
portion of the antenna to qualify as an inverted L. An antenna that is
15 feet high and 150 feet long the vertical portion is only 10% of the
total pickup area. I would consider that to be a horizontal random/long
wire.

--
Telamon
Ventura, California

"Telamon" wrote in message
...

Depends on how you connect it to the radio. With just a single vertical
lead-in then yes but use a coax grounded in some way then no.

Feedline type has nothing to do with it. The classic inverted L was
connected with a single wire feedline. Coax feed is often used now but not
always. I, and many others, have run inverted Ls (transmitting) right off
the back of the radio.

Another
thing to consider is that the vertical portion should be a significant
portion of the antenna to qualify as an inverted L. An antenna that is
15 feet high and 150 feet long the vertical portion is only 10% of the
total pickup area. I would consider that to be a horizontal random/long
wire.

There is a bit of truth to that. It is generally excepted that an inverted
L is most efficient when the verticle portion is as long as possible.
--
Telamon
Ventura, California

In article ,
"CW" wrote:

"Telamon" wrote in
message
...

Depends on how you connect it to the radio. With just a single
vertical lead-in then yes but use a coax grounded in some way then
no.

Feedline type has nothing to do with it. The classic inverted L was
connected with a single wire feedline. Coax feed is often used now
but not always. I, and many others, have run inverted Ls
(transmitting) right off the back of the radio.

If a coax cable is the vertical section then there is no vertical part
to the antenna so the answer is no. If it is a single wire then the
lead-in is part of the antenna and will radiate similar to the
horizontal section.

Another thing to consider is that the vertical portion should be a
significant portion of the antenna to qualify as an inverted L. An
antenna that is 15 feet high and 150 feet long the vertical portion
is only 10% of the total pickup area. I would consider that to be a
horizontal random/long wire.

There is a bit of truth to that. It is generally excepted that an
inverted L is most efficient when the verticle portion is as long as
possible.

I went looking for a definition and could not find one specifically. The
closest I could find resembled a Marconi type where the vertical and
horizontal sections were 1/8 wavelength each or 50%.

--
Telamon
Ventura, California

In article ,
Telamon wrote:
In article , starman
[snip]

Are all inverted-L's, random wires?

Depends on how you connect it to the radio. With just a single vertical
lead-in then yes but use a coax grounded in some way then no. Another
thing to consider is that the vertical portion should be a significant
portion of the antenna to qualify as an inverted L. An antenna that is
15 feet high and 150 feet long the vertical portion is only 10% of the
total pickup area. I would consider that to be a horizontal random/long
wire.

--
Telamon
Ventura, California

Nothing about antenna theory seems to ever be simple. The antenna you
describe, above about 15MHz, will have a horizontal pattern quite
different from a 150 foot horizontal wire. The horizontal wire will have
a horizontal pattern like the petals of a warped daisy flower, with many
lobes separated by deep nulls, some more than 40dB 'deep'. That
vertical section of the above-described inverted-L will do quite a bit to
fill in those nulls.

Also, the inverted-L is simple to ground. Electromagnetic theory does not
require such a ground, but your friendly local Electrical Code does.

Not saying you're wrong, Telamon; below 10 MHz, you're basically right.
Just saying that we SW & scanner types work with wavelengths from about
one mile down to about a foot, and it's hard to find rules or principles
that apply uniformly across the whole range.
--

R F Wieland Newark, DE 19711-5323 USA 39.68N 75.74W
Icom R75 Heathkit GR-81 Inverted-L in the attic
Reply to wieland at me dot udel dot edu

RFW,

What would be your evaluation of these three
SWL (Receive Only) Inverted "L" Antennas:

* 49M Band Half Wavelength Inverted "L" Antenna
Vertical 27.6 Feet and Horizontal 55.1 Feet with a Total of 82.7 Feet
- - - V = 1/6WL & H = 1/3WL

* 49M Band Three Quarter (3/4) Wavelength Inverted "L" Antenna
Vertical 41.4 Feet and Horizontal 82.7 Feet with a Total of 124.1 Feet
- - - V = 1/4WL & H = 1/2WL

* 49M Band Full Wavelength Inverted "L" Antenna
Vertical 55.1 Feet and Horizontal 110.3 Feet with a Total of 165.4 Feet
- - - V = 1/3WL & H = 2/3WL


iwtk ~ RHF
..
..
= = =
= = = (Robert F Wieland) wrote in message ...
In article ,
Telamon wrote:
In article , starman
[snip]

Are all inverted-L's, random wires?

Depends on how you connect it to the radio. With just a single vertical
lead-in then yes but use a coax grounded in some way then no. Another
thing to consider is that the vertical portion should be a significant
portion of the antenna to qualify as an inverted L. An antenna that is
15 feet high and 150 feet long the vertical portion is only 10% of the
total pickup area. I would consider that to be a horizontal random/long
wire.

--
Telamon
Ventura, California

Nothing about antenna theory seems to ever be simple. The antenna you
describe, above about 15MHz, will have a horizontal pattern quite
different from a 150 foot horizontal wire. The horizontal wire will have
a horizontal pattern like the petals of a warped daisy flower, with many
lobes separated by deep nulls, some more than 40dB 'deep'. That
vertical section of the above-described inverted-L will do quite a bit to
fill in those nulls.

Also, the inverted-L is simple to ground. Electromagnetic theory does not
require such a ground, but your friendly local Electrical Code does.

Not saying you're wrong, Telamon; below 10 MHz, you're basically right.
Just saying that we SW & scanner types work with wavelengths from about
one mile down to about a foot, and it's hard to find rules or principles
that apply uniformly across the whole range.