How does "Doty" Inverted-L do on MW?

Fizz Wix

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Oct 11, 2002, 2:40:51 PM10/11/02

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I've been reading the antenna discussions on the Google archives, and I'm
almost persuaded I could manage to construct the inverted-L, low-noise
antenna described by John Doty here:

http://www.anarc.org/naswa/badx/antennas/low-noise_antenna.html

Mr primary concern is of course SW, on which the installation seems to be
almost unbeatable. My only reservation is its performance on MW, about
which I can find nothing in the archives. Since so many of you claim great
success with the design, I was sure someone -- perhaps even The Master
himself -- could let me know how it does on MW.

I understand, of course, it's not going to beat a K9AY or Kiwa Loop, but I'm
less concerned about nulling and directionality than I am about simple
decent (i.e., strong and quiet) reception. I am also considering the
Alpha-Delta DX-Ultra (I had the SWL Sloper in the past and was pleased with
it), which is cut for MW, among other bands, so direct comparisons would be
particularly helpful.

My installation of the inverted-L would be on a rural lot (farm country,
neighbors a long way away) with about 150-175 feet of wire. It will run
approximately north to south, at a height of about 50 feet at the north end
and 25 to 30 feet at the south end, where it will meet the feedline (which
will be grounded, buried, possibly isolated, grounded again, and static
protected in turn before entering the house).

Also, given that amount of slope, should I notice any directionality on MW?
In what directions?

Thanks a lot.

Fizz

RHF

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Oct 12, 2002, 8:48:52 AM10/12/02

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FW,

Here are some Links related to the Inverted "L" Antenna.

1. Directivity of the 'Inverted" "L" Antenna',
with Speculation as to Why it Occurs and "How To Enhance It".
http://uweb.superlink.net/bhtongue/12ILAnt/12ILAnt.html

2. The Inverted "L" Antenna for the BCB
Written by Don Adamson
http://members.aol.com/djadamson7/articles/antenna1.html
In the 1922 book "Radio for Everybody," Lescarboura recommended an
antenna using No. 14 or 16 copper wire at least 30 feet above the
ground with a length of about 75 feet for Broadcast Band reception:

3. The All Band Inverted "L" Antenna
http://www.antennex.com/preview/archive3/ltv.htm
The 1/2 WaveLength (WL) Inverted-L Antenna differs from standard 1/4
WL Inverted "L" Antenna in 2 ways:
* First, it is longer, of course.
* Second, it is normally fed at the center.
Hence, it can be viewed as an Inverted Vee that is Tilted over by 45
Degrees.
Alternatively, it can be viewed as a One Leg-Ground-Plane 1/4 WL
Vertical Upside Down.

4. Dr. Ace's Inverted "L" Antenna Info
http://www.bloomington.in.us/~wh2t/invertedl.html
* Feed 1/4 WL of wire at one end with a piece of either 50 or 75 ohm
coax.
* Connect the center Coax wire to one end of the 1/4 WL antenna wire
and run the wire up the tower as high as possible then bend the wire
and run it horizontily to a tree or whatever support is handy . Be
sure to insulate the wire from the support .
* To determine the approximate length in feet of a 1/4 WL Inverted "L"
Antenna. Use the Formula 234/Freq in Mhz = Length in Feet.
* For the BCB a 1/4 Wave Antenna resonant at One Mega Hertz (1Mhz)
would be about 234 Feet Long.
Note: Top End BCB=1700~137Ft & Bottom End BCB=540~433Ft.

~ RHF

= = = "Fizz Wix" <la...@pcpartner.net> wrote in message news:<ao7601$h2u$1...@ins22.netins.net>...

Fizz Wix

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Oct 13, 2002, 11:12:33 PM10/13/02

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Thanks, RHF. Very interesting reading there, some of which I'd seen before.

Doesn't look like I'm going to get any other responses to this query. Where
are all the geniuses on this board (other than you, of course) when you need
them?

Fizz

"RHF" <rhf-...@usa.com> wrote in message
news:3ef6beca.02101...@posting.google.com...

RHF

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Oct 14, 2002, 3:11:15 PM10/14/02

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FW,

Give it a chance, "John Doty" still Reads and Posts to this NewsGroup.

I am no expert, just like the challenge to look up and read on an
interesting topic; find some applicable links; and provide a reply for
the reader to go learn for themselves.

Simply - Don't Tell the Reader "What To Do":
Let the Reader "Learn and Decide for Themselves".

Seams to me that you have enough Space and Height to "CUT" and Install
an Inverted "L" Antenna that would work well on the AM/MW/BCB and also
perform well on SW too.

~ RHF

= = = "Fizz Wix" <la...@pcpartner.net> wrote in message news:<aodcnj$l6m$1...@ins22.netins.net>...

John Doty

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Oct 16, 2002, 12:24:52 AM10/16/02

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In article <ao7601$h2u$1...@ins22.netins.net>, "Fizz Wix"
<la...@pcpartner.net> wrote:

> I understand, of course, it's not going to beat a K9AY or Kiwa Loop, but
> I'm less concerned about nulling and directionality than I am about
> simple decent (i.e., strong and quiet) reception.

If that's what you want, it should be fine.

>
> My installation of the inverted-L would be on a rural lot (farm country,
> neighbors a long way away) with about 150-175 feet of wire. It will run
> approximately north to south, at a height of about 50 feet at the north
> end and 25 to 30 feet at the south end, where it will meet the feedline
> (which will be grounded, buried, possibly isolated, grounded again, and
> static protected in turn before entering the house).
>
> Also, given that amount of slope, should I notice any directionality on
> MW? In what directions?

At MW, you may have a bit of a null to the north, with depth dependent on
frequency.

--
| John Doty "You can't confuse me, that's my job."
| Home: j...@w-d.org
| Work: j...@space.mit.edu

Fizz Wix

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Oct 16, 2002, 3:35:28 PM10/16/02

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Hey John, thanks. I feel like I know you intimately, having read dozens of
your past posts in the archives. Thanks for taking time to consider my
little problem. You confirmed what I suspected about the northern null, but
it's either ask you guys or spend a year studying antenna theory and risk
still not knowing the answer.

Fizz

"John Doty" <j...@w-d.org> wrote in message
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