50 foot high inv. L here; total length 120 feet; 101 radials on
ground, but lengths vary from 10 feet to around 100 feet with most in
the 20, 30, 50 foot lengths. Also I have an aluminum sided garage
that I strapped into the ground system. Minimal reactance is at 1840
(I forget, but I think aroun
Multiple misunderstandings here. First, the earth is a big resistor, so
the only function of that ground rod is lightning protection, and it
ought to be at the shack, not at the antenna.
Second, the function of radials is NOT to couple to the resistive earth,
but the SHIELD the antenna's field
From: Steve Harrison
To: topband@contesting.com
Subject: Topband: Inv L Radiation Patterns?
Message-ID:
Content-Type: text/plain; charset=UTF-8; format=flowed
Has anybody plotted the radiation patterns for inverted Ls on 160?
I'm
particularly interested in those for relatively-low ante
A bit more field intensity extends in the direction opposite the
direction of the horizontal part of the inverted L element.
73
Rob
K5UJ
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
The modeling i’ve seen plus my own has been +\~ 1 to 2dB for 50 - 70 ft
vertical sections
-Charlie N1RR
401-742-7240 <(401)%20742-7240> 8AM - 9PM
*E-mail*: n...@n1rr.com
*Website*: www.n1rr.com
*Youtube channel*: NovemberOne RomeoRomeo
https://www.youtube.com/channel/UCPDzEf57Ad80cVKOiLZ
Has anybody plotted the radiation patterns for inverted Ls on 160? I'm
particularly interested in those for relatively-low antennas, say 40 ft
max, over fairly-poor ground such as desert sand with the water table
perhaps 120 feet down.
TNX,
Steve K0XP
On 1/2/2024 6:56 AM, VE6WZ_Steve wrote:
On 9/27/2021 4:37 PM, Joe Subich, W4TV wrote:
Place an engineer and mathematician on one goal line of a football
field with a comely cheerleader on the other goal line. If you tell
the engineer and mathematician the can go to her but can only go half
the distance at a time, the mathematician wil
> Reminds me of the Engineers' interpretation of the glass being half
> empty or half full - It's actually larger than it needs to be.
Or the difference between an engineer and mathematician ...
Place an engineer and mathematician on one goal line of a football
field with a comely cheerleader o
Gents:
I've heard Engineering described as the art of approximation.
Reminds me of the Engineers' interpretation of the glass being half
empty or half full - It's actually larger than it needs to be.
73 de
Gene Smar AD3F, PE
THAT'S what good engineering is all about! It's not about
My hunch is that your problem is the wire you are using. My inv. L
is strung with hard drawn 7 strand bare AWG 14 copper. Multi-strand
or solid soft drawn will probably break on you eventually.
73
Rob
K5UJ
_
Searchable Archives: http://www.contesting.com/_topband - Topband Refl
On 9/26/2021 12:05 AM, Jim Monahan wrote:
On my property, I have an endless number of trees so
I try to use the largest trees which will sway less to
minimize stress on the installation.
This correctly considers the options available to each of us afforded by
the details of our own real estate
The pulley system is probably the best way to go as
others have noted.
As an option, perhaps, I use springs selected from Home
Depot that are about 6 inches long. I put a loop
of dacron between each end of the spring just in case
of failure.
They are installed at each end of the supports between
Sorry for bandwith
Attention CSABA HA3LN, I am unable to reply to your e-mail.
Please give me another mail address.
73
--
Bob, I2WIJ
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
On 5/14/2020 9:26 AM, Tom | SP5XO wrote:
d,
wideband match. Since short vertical inv L over reasonable ground should
have roughly 20 OHm impedance that could work here as well.
The matching network that will maximize bandwidth
is an autotransformer wound on a 2.4 inch diameter
ferrite core.
Hello OMs Topbbanders
As I'm planning to put up inverted L antenna for next season i will face
the matching vs bandwidth struggle I know there is a cure for short
vertical section and low impedance (with reasonable radial system) and I
already tested some extended horizontal section and matching ca
Hi all,I have an Inv-L for 160, shaped like the AKI-Special,
with stranded wire AWG 12, held up by a support pole of 11m
then a fiber fishing rod abt 10m then hooked to a distant walnut treeat about 5
mt above ground.All this works and I measured an R of 11/12 ohm but I would
like
to make some
Unlike raised radials or a counterpoise...however,.
Its better if the radials, if only a few, under ground are not resonant as the
high impedance/ high voltage end can loose a lots of energy to ground.
It is quite well known that a 'fat' (large diameter) antenna is lower Q, is
wider
Can a radial(s) buried a couple of inches under the ground be tuned via an
inductor and Can the radial all be connected to said inductor if they are the
same length. Infact can it be done and is there any gain by doing this ?
73John - M0ELS
_
Searchable Archives: http://www.contes
Hi, Julio,
Sorry for delay. I didn't see this post when it hit the reflector.
Around 2009 before publishing the FCP design, the change to polyimide
coated wire and Teflon sleeve brought a string of toroid device failures to
a sudden and permanent halt and turned previously "fragile" devices into
right on this
issue.73Adrian vk2wf
Sent from my SAMSUNG Galaxy S7 on the Telstra Mobile Network
Original message From: vk3io Date:
4/10/18 9:56 pm (GMT+10:00) To: Brian Campbell ,
topband@contesting.com Subject: Re: Topband: Inv L in Tree
Hi Brian and others.
Brian should
Luck and remember YMMV
>
> 73,
> Brian
> VE3MGY
>
>
>
>
>
>
> ________
> From: Topband on behalf of Gary Smith
> Sent: October 3, 2018 9:27 PM
> To: Topband@contesting.com
> Subject: Re: Topband: Inv L in Tree
>
> Ed,
ir. Or to put it another way, a poor antenna is much
better than no antenna at all.
Good Luck and remember YMMV
73,
Brian
VE3MGY
From: Topband on behalf of Gary Smith
Sent: October 3, 2018 9:27 PM
To: Topband@contesting.com
Subject: Re: Topband: Inv L in
October 3, 2018 9:27 PM
To: Topband@contesting.com
Subject: Re: Topband: Inv L in Tree
Ed,
FWIW, I'm using what used to be an INV-L.
I laid out a radial bed as well as
possible, next to a marsh. I am in a
hurricane area and with the winds, the
trees have fallen over. I originally shot
a line
Ed,
FWIW, I'm using what used to be an INV-L.
I laid out a radial bed as well as
possible, next to a marsh. I am in a
hurricane area and with the winds, the
trees have fallen over. I originally shot
a line over a tall branch with a spud gun
I made (see it on my QRZ page, at the
bottom), at
Hi Ed,
Yes, many times. When in Houston, TX on a 60' x90' lot I had one that was in
between two 70'+ pine trees (about 5' from each tree at the feed point). I had
one elevated radial up 15' that was shaped like an L to fit on the property.
150+ countries with 600 watts. The big issue was receive
s G4BGM
>
>
>
>
>
> -Original Message- From: Guy Olinger K2AV
> Sent: Sunday, September 23, 2018 11:06 AM
> To: navydude1...@yahoo.com
> Cc: TopBand List
> Subject: Re: Topband: Inv L in Tree
>
> Hi, Ed,
>
> Taking the vertical wire up n
as.
Best regards to you both and the Reflector group.
Chris G4BGM
-Original Message-
From: Guy Olinger K2AV
Sent: Sunday, September 23, 2018 11:06 AM
To: navydude1...@yahoo.com
Cc: TopBand List
Subject: Re: Topband: Inv L in Tree
Hi, Ed,
Taking the vertical wire up next to the tree
Hi, Ed,
Taking the vertical wire up next to the tree trunk will be fairly lossy.
That usually also means that some part of the horizontal wire is going
through the tree canopy, which will be further lossy. See k2av.com . Click
on the green index button "Place an Inverted L". Also read "Design an
I
Has anybody snaked a wire up a tall tree trunk to make an Inv L?
Any interaction? Success?? Has to be stealthy because the tree os my
neighbor's :-)
Thanks,
Ed NI6S
_
Topband Reflector Archives - http://www.contesting.com/_topband
Jim,
Did you build the isolation transformer exactly as described in K2AV's
article?? By exactly I mean using "teflon sleeved double polyimide insulated"
wire. I'm not planning on using it with more than 100W...
73,Julio VE3FH
Sent from Yahoo Mail on Android over Bell Mobility Network.
On T
Gary, I use an inv L with K2AV FCP and matching balun. I purchased a RigExpert
AA-30 to tune out the reactance. It worked great. No tuning cap or inductor
were needed. It took just a couple cuts to dial it in. My L is now 126 ft
long with a 65 ft vertical leg standing a few feet off a tree
With identical DC input to the transmitter final for each measurement, the
measured base current at the tower was exactly the same with either tuner.
Don k4kyv
From: donov...@starpower.net
Sent: 06 December 2016 05:28
To: REFLECTOR: Topband
Subject: Re:
On 2016-12-06 04:37, Jerry Keller, K3BZ, wrote:
or is it enough to "fatten" the vertical
(radiating) section ? How much BW will 3" diameter spacers give me?
About 16 years ago I modified an ordinary inverted L (with c60 feet
vertical) using 4 vertical #14 wires spaced in a one-foot square--
I just went over the RBN data for W0MU spots on Dec 3 and Dec 4. Dec 3rd
I had a top loaded Cushcraft MA-160. Dec 4th Inverted L about 50ft
vertical and the end pointing northish and going up toward 60 to 65 ft
in trees.
The only DX that spotted me was on the 4th PJ2T.Other than that I
c
REFLECTOR: Topband"
Sent: Tuesday, December 6, 2016 5:05:37 AM
Subject: Re: Topband: Inv L Config
The horizontal section also radiates, more or less than the vertical
depends on the specifics. Easy to see in a very simple NEC model. If you
are opposed to radiation from the horizontal on princi
I had plenty of bandwidth with my L. Maybe that means I have plenty of
loss too. :( I had no issues working nearly everyone I heard. I
wonder what making a "cage" on the vertical section would do. Someday I
guess I should really learn how to model stuff.
W0MU
On 12/5/2016 9:37 PM, Jerr
The horizontal section also radiates, more or less than the vertical
depends on the specifics. Easy to see in a very simple NEC model. If you
are opposed to radiation from the horizontal on principle, then put up a T.
But the radiation from an L's horizontal fills in the doughnut hole in the
patter
Is it advantageous to make both the vertical and the horizontal sections
"fat" (for improved bandwidth), or is it enough to "fatten" the vertical
(radiating) section ? How much BW will 3" diameter spacers give me?
73, K3BZ
_
Topband Reflector Archives - http://www.contesting.c
-boun...@contesting.com] On Behalf Of Charles
Moizeau
Sent: Thursday, October 20, 2016 5:34 PM
To: Topband
Subject: Re: Topband: inv. L
Before putting any kind of tape, gunk or goo on a fitting or soldered
connection with the expectation of weatherproofing it in an outdoor
environment, I ALWAYS do this firs
, parts of which had
migrated into the connection, mechanical or soldered.
73,
Charles, W2SH
From: Topband on behalf of Art Snapper
Sent: Thursday, October 20, 2016 9:16 AM
To: 160
Subject: Re: Topband: inv. L
I had a few hours free yesterday afternoon, so
gt;
> 73
> Marc on4ma
> - Original Message - From: "Art Snapper"
> To: "160"
> Sent: Thursday, October 20, 2016 3:16 PM
> Subject: Re: Topband: inv. L
>
>
> I had a few hours free yesterday afternoon, so I began the dual 80/160
>> radiator inv. L
I had a few hours free yesterday afternoon, so I began the dual 80/160
radiator inv. L project.
In the process, I found that water had entered the coaxial center insulator
that was used at the feedpoint of the antenna.
Does anyone have a favorite solution for a weatherproof, coaxial feedpoint
for
I have a 50 foot aluminum mast on my property, guyed at 32 feet and
mounted on a 6" x 6" pressure treated pine post. I put a 15 foot
stinger of aluminum tubing at the top to give it a height of 65 feet
and hung an arm on it at 50 feet that extends out 3 feet. This holds
the vertical part of my 160
AG6X
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Art Snapper
Sent: Monday, October 17, 2016 8:17 AM
To: 160
Subject: Topband: inv. L
I was considering adding a second vertical element to my 160 inverted L.
This one would be roughly a quarter wave
Thanks everyone. I plan to try it this weekend.
73
Art NK8X
ᐧ
On Mon, Oct 17, 2016 at 1:56 PM, Ray Benny wrote:
>
> - Original Message -
> From: Mike Furrey
> To: Art Snapper , 160
> Sent: Mon, 17 Oct 2016 12:32:20 -0400 (EDT)
> Subject: Re: Topband: inv. L
>
Art, I put one up this spring with the encouragement on this list. The
L's are back to back, e.g. the 160M L points north while the 80M points
south. The vertical sections are 45' and the spacing is about 18". Fed
with a decoupling choke at the base over 32 65' radials.
My amp tunes up with no
- Original Message -
From: Mike Furrey
To: Art Snapper , 160
Sent: Mon, 17 Oct 2016 12:32:20 -0400 (EDT)
Subject: Re: Topband: inv. L
Hi Art,Yes, I have done that and am doing that. I use tall trees as supports
and the 160 inverted L goes up one side of the tree then bent over
This comment applies only to a counterpoise which is a good to excellent
ground radial field for 160, and resonant L's. It does not apply to L's
over FCP's or elevated radials resonant on 160.
To make a double L work over the aforementioned good to excellent 160 meter
ground radials, feed the two
Hi Art,Yes, I have done that and am doing that. I use tall trees as supports
and the 160 inverted L goes up one side of the tree then bent over horizontally
to another tree over yonder. From the same feed point, the 80 meter section
goes up the other side of the same tree and the top actually fo
Subject: Topband: inv. L
I was considering adding a second vertical element to my 160 inverted L.
This one would be roughly a quarter wave tall for use on 80.
I tried modelling in Eznec, but wasn't comfortable with the results. I may
have screwed it up.
Has anyone tried it for real? Is it
I was considering adding a second vertical element to my 160 inverted L.
This one would be roughly a quarter wave tall for use on 80.
I tried modelling in Eznec, but wasn't comfortable with the results. I may
have screwed it up.
Has anyone tried it for real? Is it a big compromise on either band?
what is the loss?
Carl
KM1H
- Original Message - From: "Gary Smith"
To:
Sent: Thursday, July 25, 2013 1:22 AM
Subject: Re: Topband: Topband Inv-L Joy
Had a more difficult time getting the antenna up there this time. The
first spud snapped away from the fishing line & i
On a side note WD-1A conductors are a copper/cadmium alloy; whatever that
means in RF resistance. Fine for a Beverage but what is the loss?
Carl
KM1H
- Original Message -
From: "Gary Smith"
To:
Sent: Thursday, July 25, 2013 1:22 AM
Subject: Re: Topband: Topband Inv-L Jo
Behalf Of Gary Smith
Sent: Thursday, July 25, 2013 1:22 AM
To: topband@contesting.com
Subject: Re: Topband: Topband Inv-L Joy
Had a more difficult time getting the antenna up there this time. The first
spud snapped away from the fishing line & in the dense thicket I was unable to
find wher
Hi Gary,
Try getting your weight over the limb with a good fishing rod reel
combination. I use a Zebco-brand spin-cast reel here myself, & the longest
pole I can find...
To help find the landing spot of your weight in the underbrush, get
yourself a buzzer & tape it to a 9-volt battery. I did tha
Had a more difficult time getting the antenna up there this time. The
first spud snapped away from the fishing line & in the dense thicket
I was unable to find where it landed. Had to make another & the
mosquitos were so thick they posted a LUAU sign on my forehead.
Till I get something better
> 40 works on 40 & 17 meters
Correction. 40 works on 40 & 15 meters...
Gary
KA1J
_
Topband Reflector
Fellows,
Thanks for the many replies off and on list. I appreciate the
thoughts and the suggestions for wire and the liability of signal
loss and fragility of this kind of L.
While it might be possible to somehow get a pulley up via being
knotted to a rope, there's just no practical way for m
I do the same thing except I hang a 4" plastic clothes line pulley from
the rope. The antenna wire runs through the pulley.
Ended all the abrasion issues and I can easily lower the pulley if
necessary.
The actual antenna wire is from DavisRF.
73, Les W2LK
On 7/23/2013 4:55 AM, Gary Smith wro
[mailto:topband-boun...@contesting.com] On Behalf Of Bruce
Sent: Tuesday, July 23, 2013 12:29 PM
To: topband@contesting.com
Subject: Topband: Inv-L joy
Any suggestion as to a good rugged wire? Gary
WD-1A military field phone wire is strong, lightweght and very
inexpensive. It is ava
Any suggestion as to a good rugged wire? Gary
WD-1A military field phone wire is strong, lightweght and very
inexpensive. It is available on E-bay. ___Herb__
I used WD-1A for one, two direction Beverage antenna along a "neighbor
sensitive" boundry. Did not want insulators show
I use an EZ-Hang slingshot to throw rope over the tree limbs, and then use that
to pull the wire antenna into place. I remove a length of the outer insulation
from an old piece of coax and, once I see where the rope crosses the tree limb,
I slide the coax insulation onto that part of the rope.
> Gary, WD-1A military field phone wire is strong, lightweght and very
> inexpensive. It is available on E-bay. Be sure to use a spring and
> a
> counter weight at one end to absorb the movement of the branches and
> reduce the friction. This method will also mitigate somewhat the
> tendency f
On 7/23/2013 4:55 AM, Gary Smith wrote:
My Inv-l came down again. Went out to see what happened and another
storm weakened tree came down & it's upper branches brought my
antenna down with it. I really need to use a better wire than 8
strand computer cable for the antenna. This CAT-8 wire comes d
My Inv-l came down again. Went out to see what happened and another
storm weakened tree came down & it's upper branches brought my
antenna down with it. I really need to use a better wire than 8
strand computer cable for the antenna. This CAT-8 wire comes down at
least 2-3 times a year.
Since
Wireman #531 or #547 both are black PE sheathed. #531 is stranded
copperweld. #547 is fine stranded copper. 73, Guy.
On Fri, Sep 28, 2012 at 2:08 PM, Shoppa, Tim wrote:
>> Copperclad would probably be more durable but the contact with the tree
>> branches on exposed wire would be no good. Enamel
> Copperclad would probably be more durable but the contact with the tree
> branches on exposed wire would be no good. Enamelled copperclad would soon
> have the enamel worn off & there would be direct metal contact to the
> branches.
> I can't find any of the old copperclad two element telephone
On 9/28/2012 8:45 AM, Gary Smith wrote:
All that to say; since I have no choice
but to run the wire over the tree tops,
what would be a better wire?
I'm near the Pacific coast, and also get some pretty good winds. K2RD
showed me a really nice method of dealing with your problem. It takes
more
he heavy ice coats, as it
> frequently
> does here in the hills of NH.
>
> 73
>
> jim / W1FMR
>
>
>
> --- On Fri, 9/28/12, Gary Smith wrote:
>
>
> From: Gary Smith
> Subject: Topband: Inv-L wire in contact with tree branches
> To: topband@contesting
acts as a shock absorber for the the
endfed wire when the mighty wind blows and the heavy ice coats, as it frequently
does here in the hills of NH.
73
jim / W1FMR
--- On Fri, 9/28/12, Gary Smith wrote:
From: Gary Smith
Subject: Topband: Inv-L wire in contact with tree branches
T
I'm fortunate to have a nice radial
assembly of aprox 50 130' radials & half
of them on a salt marsh with the rest over
boggy ground. Unfortunately I have no way
to put up a pulley system with relief on
one end and the antenna in open air.
I use 6 & 8 strand ribbon "CAT wire" which
was used
sage -
From: Dan Bookwalter
To: topband@contesting.com
Sent: Tue, 24 Jan 2012 15:48:43 -0500 (EST)
Subject: Topband: Inv-L Issues - Still no luck
Ok , I am having a real problem here that I haven't been able to solve yet.
I have an inverted L out at the tower that is about 160' lon
...
as soon as i get an enclosure I will rework the feed system again so that it
isn't so susceptible to issues such as this...
Dan N8DCJ
From: Dan Bookwalter
To: "topband@contesting.com"
Sent: Tuesday, January 24, 2012 3:48 PM
Subject: Topban
1T1
- Original Message -
From: Dan Bookwalter
To: topband@contesting.com
Sent: Tuesday, January 24, 2012 4:48 PM
Subject: Topband: Inv-L Issues - Still no luck
Ok , I am having a real problem here that I haven't been able to solve
yet.
I have an inverted L out at the tower that
Ok , I am having a real problem here that I haven't been able to solve yet.
I have an inverted L out at the tower that is about 160' long , 70ft vertical
the rest sort of horiz , slopes down I have one run of RG213 to the RCS-10
remote antenna switch which is at the tower , it was very close
bject: Topband: Inv-L swr changing when adding radials
I installed an Inv-L for 160 of about 134ft , ~72 feet vertical , when i
checked the SWR initially it was about 1.2:1 , then when i connected the
ground rods it rose to 1.5:1 , today I added the first 2 radials and the
SWR is now 2:1. The anten
The Inv L over a very dense, excellent radial field will have a feed Z of
in the neighborhood of 20 or so ohms, NOT 50. It usually requires a unun
to bring it up to 50.
When you first put it up, your counterpoise system was, to put it bluntly,
awful, and apparently a very lossy series resistance
I installed an Inv-L for 160 of about 134ft , ~72 feet vertical , when i
checked the SWR initially it was about 1.2:1 , then when i connected the ground
rods it rose to 1.5:1 , today I added the first 2 radials and the SWR is now
2:1. The antenna is being fed directly , my question is basically
Funny how we're creatures of habit... I have 60 130' radials half on
a salt marsh & half on the boggy wood beside it. I used a spud gun to
get my 160 inv-l over the tops of trees at the marsh's edge. I have a
separate inv-l for 80 which is mostly vertical, a 40M vert & a 30M
vert & a butternut
I use an inverted L with 4 elevated radials. The vertical part of the L is
about 25 feet; the remaining horizontal part is about 30 feet high. The
radials run more or less at 90 degrees from each other and are 120 feet long
and 7-10 feet off the ground.
Running CW at 80 watts out, I have worked
80 matches
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