Topband: 2 wl loop, worth the effort?

[Rob Atkinson]

Hi Gary, It would make a nice receiving antenna.

Let's start with a question:  Would you put up a loop for 20 meters
that is 6 feet off the ground?  Height for horizontal antennas must
always be thought of in terms of _wavelength_.  There is only one
effective transmitting antenna for medium wave, assuming you do not
have 200 foot tall supports for stringing up a horizontal wire
antenna, and that is some sort of monopole over a good ground system.
Period.  And good ground system means a lot of radials.  A lot.  Not
10 or 20.  You don't get to cheat on the laws of physics.  You have to
bite the bullet and do the work.  The excited vertical part has
options.  T, inverted L, or an insulated tower are all fine provided
the vertical part is at least 50 feet tall (more is better).

Don't take this personally--it's just that I get tired of piss weak
signals on 160 from hams who seem to think they have an exemption from
Mother Nature.  A dead giveaway that a ham is using a low dipole, 20
feet or so, is rapid deep QSB.  Even 50 feet is too low.  Inverted Vs
are worse.  the effective height is halfway between the apex height
and the height of the ends.  A big horizontal loop on transmit does
nothing for you but cause more of your RF to get lost to ground
coupling.

73

Rob
K5UJ
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: 2 wl loop, worth the effort?

[Mike Waters]

I should have added that in some types of weather, a dipole may have more
corona (which makes noise) off the ends than a loop.

I have an EZNEC model of a low loop, if someone wants it.

73, Mike
www.w0btu.com

On Wed, Dec 2, 2015 at 2:25 PM, Mike Waters  wrote:

> Model a low 1-wl loop, and you'll see why it was quieter.
>
> 1. There's not quite as much low-angle response. Most local noise comes
> from very low angles.
> 2. More ground loss.
>
> 73, Mike
> www.w0btu.com
>
> On Wed, Dec 2, 2015 at 2:07 PM,  wrote:
>
>> two years of playing on 160 the 1 wave length loop was quieter but didnt
>> have the coverage of the dipole,
>>
>
>
_
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Re: Topband: 2 wl loop, worth the effort?

[Tom W8JI]

You are misinterpreting the model data by looking at the shape of the 
pattern rather than the relative strength of the pattern at angles of 
interest. Example -- the so-called "take off angle" simply shows the 
vertical angle where the signal is the strongest. FAR more important to 
look at the field strength at various angles as the height is varied.


Many people talk about and look at TOA, and it causes them to pick antennas 
that are actually worse just because the TOA is at the correct angle. :)


If you look at a low dipole, it has just about the same gain as a low loop. 
Being a loop helps moderate impedance on harmonics, but not much else.


I have 300 ft of height here. For the most part, a vertical did as well or 
better than a dipole at any height and distance. The exceptions were at 
sunrise or in magnetic storms, or within 50-200 miles (where a dipole below 
150 feet works much better).  Compared to a vertical, there could be 10-30 
dB difference in favor of a low dipole (less than 150 ft high) within a few 
hundred miles. 


_
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Re: Topband: 2 wl loop, worth the effort?

[Don Kirk]

Hi Rob (and gang),

I would like to make one point that should be considered in this discussion.

A true vertical which is what I use (not an inverted L) on 160 meters is
sometimes horrible on 160 meters for skywave that originates from close in
(200 miles or less as an example).  During contests I sometimes can't hear
a station calling me on my vertical since it's deaf to NVIS signals
(signals arriving at a very high angle), but when I switch to one of my
pennants suddenly I'm hearing the station 18dB to 38 dB over my noise floor
(really an amazing phenomena).  The pennant RX antenna gain is only 5 dB
down on NVIS (for signals arriving directly overhead) compared with the max
gain of the pennant which is at 31 degrees above the horizon.  In
comparison my 68 foot base loaded vertical has a gain of -20 dB or worse
for NVIS at an angle 85 degrees or higher above the horizon compared to its
max gain at 22 degrees.

Therefore while I don't disagree that a vertical on 160 meters is a great
antenna especially for DX work, for working stations in close it sometimes
can be a disadvantage.  Based on modeling it looks like a dipole only 15
feet off the ground on 160 meters would perform much better than my
vertical for signals arriving at very high angles (as an example).

Therefore depending on Gary's goal, a true vertical on 160 meters may or
may not be in his best interest (but an inverted L might be).

Just one of the many things to consider.

73,
Don (wd8dsb)



On Wed, Dec 2, 2015 at 12:53 PM, Rob Atkinson  wrote:

> Hi Gary, It would make a nice receiving antenna.
>
> Let's start with a question:  Would you put up a loop for 20 meters
> that is 6 feet off the ground?  Height for horizontal antennas must
> always be thought of in terms of _wavelength_.  There is only one
> effective transmitting antenna for medium wave, assuming you do not
> have 200 foot tall supports for stringing up a horizontal wire
> antenna, and that is some sort of monopole over a good ground system.
> Period.  And good ground system means a lot of radials.  A lot.  Not
> 10 or 20.  You don't get to cheat on the laws of physics.  You have to
> bite the bullet and do the work.  The excited vertical part has
> options.  T, inverted L, or an insulated tower are all fine provided
> the vertical part is at least 50 feet tall (more is better).
>
> Don't take this personally--it's just that I get tired of piss weak
> signals on 160 from hams who seem to think they have an exemption from
> Mother Nature.  A dead giveaway that a ham is using a low dipole, 20
> feet or so, is rapid deep QSB.  Even 50 feet is too low.  Inverted Vs
> are worse.  the effective height is halfway between the apex height
> and the height of the ends.  A big horizontal loop on transmit does
> nothing for you but cause more of your RF to get lost to ground
> coupling.
>
> 73
>
> Rob
> K5UJ
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
>
_
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Re: Topband: 2 wl loop, worth the effort?

[Mike Waters]

160m is a band for vertical polarization.
www.w0btu.com/160_meters.html
I am a happy user of an inverted-L hung from a tree.

Those that don't have room for resonant elevated radials like mine can use
K2AV's compact counterpoise, or lay as much wire on the ground as your
space permits.
www.w0uce.net/K2AVantennas.html

73, Mike
www.w0btu.com
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: 2 wl loop, worth the effort?

[Jim Brown]

On Wed,12/2/2015 11:02 AM, Don Kirk wrote:

Therefore while I don't disagree that a vertical on 160 meters is a great
antenna especially for DX work, for working stations in close it sometimes
can be a disadvantage.  Based on modeling it looks like a dipole only 15
feet off the ground on 160 meters would perform much better than my
vertical for signals arriving at very high angles (as an example).


You are misinterpreting the model data by looking at the shape of the 
pattern rather than the relative strength of the pattern at angles of 
interest. Example -- the so-called "take off angle" simply shows the 
vertical angle where the signal is the strongest. FAR more important to 
look at the field strength at various angles as the height is varied. I 
did exactly that in an extensive modeling study comparing vertical and 
horizontal antennas of various heights. While I concentrated my work on 
80M and 40M, the results are directly applicable to 160M if heights in 
feet are doubled from the 80M plots.


http://k9yc.com/VertOrHorizontal-Slides.pdf

Bottom line -- for 160M, we mere mortals simply can't get a horizontal 
antenna too high for local QSOs, and higher is better, at least up to 
200 ft.


73, Jim K9YC
_
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Re: Topband: 2 wl loop, worth the effort?

[Mike Waters]

Forget I said all that. I looked at the model and found some possible
mistakes. And I don't have any more time now to fix it.

73, Mike
www.w0btu.com

On Wed, Dec 2, 2015 at 2:35 PM, Mike Waters  wrote:

>
> I have an EZNEC model of a low loop, if someone wants it.
>
>
> On Wed, Dec 2, 2015 at 2:25 PM, Mike Waters  wrote:
>
>> Model a low 1-wl loop, and you'll see why it was quieter.
>>
>> 1. There's not quite as much low-angle response. Most local noise comes
>> from very low angles.
>> 2. More ground loss.
>>
>> 73, Mike
>> www.w0btu.com
>>
>> On Wed, Dec 2, 2015 at 2:07 PM,  wrote:
>>
>>> two years of playing on 160 the 1 wave length loop was quieter but didnt
>>> have the coverage of the dipole,
>>>
>>
>>
>
_
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Re: Topband: 2 wl loop, worth the effort?

[kolson]

Well Rob, if you read Gary's email, you will find that he is interested in 
communicating "...with the hams I daily keep in touch with in the 500-600 mile 
range." The loop may be a great antenna for this but not, as you say, so much 
for DXing. 
  
But there is, in my view, a deeper issue here. I t's  the "it's just that I get 
tired of piss weak signals on 160 from hams who seem to think they have an 
exemption from Mother Nature" theorem. For many of us, compromise is built in 
to our situation, we are not being obstinate just to pee you off. In my case, I 
have a 110 X 50 foot property in a residential neighborhood and I am limited to 
a "T" transmit antenna (40 ft up, 92 ft flattop) and a K9AY RX array in a 
somewhat noisy neighborhood. So no, I don't hear or TX like those with a more 
favorable QTH, but I enjoy 160 meters, I have fun and do the best I can with 
what I have. So if I occasionally call out of time (I try not to) because I 
don't have the "ears" you do, don't take it personally... 

73 Kevin K3OX  


- Original Message -

From: "Rob Atkinson"  
To: topband@contesting.com 
Sent: Wednesday, December 2, 2015 12:53:39 PM 
Subject: Topband:  2 wl loop, worth the effort? 

Hi Gary, It would make a nice receiving antenna. 

Let's start with a question:  Would you put up a loop for 20 meters 
that is 6 feet off the ground?  Height for horizontal antennas must 
always be thought of in terms of _wavelength_.  There is only one 
effective transmitting antenna for medium wave, assuming you do not 
have 200 foot tall supports for stringing up a horizontal wire 
antenna, and that is some sort of monopole over a good ground system. 
Period.  And good ground system means a lot of radials.  A lot.  Not 
10 or 20.  You don't get to cheat on the laws of physics.  You have to 
bite the bullet and do the work.  The excited vertical part has 
options.  T, inverted L, or an insulated tower are all fine provided 
the vertical part is at least 50 feet tall (more is better). 

Don't take this personally--it's just that I get tired of piss weak 
signals on 160 from hams who seem to think they have an exemption from 
Mother Nature.  A dead giveaway that a ham is using a low dipole, 20 
feet or so, is rapid deep QSB.  Even 50 feet is too low.  Inverted Vs 
are worse.  the effective height is halfway between the apex height 
and the height of the ends.  A big horizontal loop on transmit does 
nothing for you but cause more of your RF to get lost to ground 
coupling. 

73 

Rob 
K5UJ 
_ 
Topband Reflector Archives - http://www.contesting.com/_topband 

_
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Re: Topband: 2 wl loop, worth the effort?

[Don Kirk]

Hi Tom,

You said "Compared to a vertical, there could be 10-30 dB difference in
favor of a low dipole (less than 150 ft high) within a few hundred miles.",
and I was pretty much trying to make the same point but indirectly since I
don't have a dipole on 160 meters.

The original poster mentioned relatively short distance work on 160 meters,
and that is why I mentioned that a true vertical may not actually be his
best choice (he might actually go backwards in performance if he is trying
to work stations in adjacent states as an example).

Don (wd8dsb)





On Wed, Dec 2, 2015 at 3:04 PM, Tom W8JI  wrote:

> You are misinterpreting the model data by looking at the shape of the
>> pattern rather than the relative strength of the pattern at angles of
>> interest. Example -- the so-called "take off angle" simply shows the
>> vertical angle where the signal is the strongest. FAR more important to
>> look at the field strength at various angles as the height is varied.
>>
>
> Many people talk about and look at TOA, and it causes them to pick
> antennas that are actually worse just because the TOA is at the correct
> angle. :)
>
> If you look at a low dipole, it has just about the same gain as a low
> loop. Being a loop helps moderate impedance on harmonics, but not much else.
>
> I have 300 ft of height here. For the most part, a vertical did as well or
> better than a dipole at any height and distance. The exceptions were at
> sunrise or in magnetic storms, or within 50-200 miles (where a dipole below
> 150 feet works much better).  Compared to a vertical, there could be 10-30
> dB difference in favor of a low dipole (less than 150 ft high) within a few
> hundred miles.
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
>
_
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Re: Topband: 2 wl loop, worth the effort?

[Gary and Kathleen Pearse]

Try putting a closed reflector wire under a 1 WL horizontal loop. Lay it on the 
ground or bury. Use insulated wire and size per typical loops…~+5% at design 
frequency. Experiment by listening to weak signals while opening and closing 
the ends of the reflector. 

At our latitude (64N) loops (and Inv-L’s) work well if a full size vert is 
unavailable. Some have suggested it’s due to our tilted Ionosphere. That’s been 
my experience on 40-160.

73, Gary NL7Y


_
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Re: Topband: 2 wl loop, worth the effort?

[James Rodenkirch]

Kevin - I'm in a more tenuous position with Rob than you!!!   I operate QRP on 
160  you can bet if Rob gets wind of that he'll think I'm REALLY peeing in  
his Wheaties, 'eh 

71.5/72 de Jim R. K9JWV


From: Topband  on behalf of kol...@rcn.com 

Sent: Wednesday, December 2, 2015 11:48 AM
To: Rob Atkinson
Cc: topband@contesting.com
Subject: Re: Topband: 2 wl loop, worth the effort?

Well Rob, if you read Gary's email, you will find that he is interested in 
communicating "...with the hams I daily keep in touch with in the 500-600 mile 
range." The loop may be a great antenna for this but not, as you say, so much 
for DXing.

But there is, in my view, a deeper issue here. I t's  the "it's just that I get 
tired of piss weak signals on 160 from hams who seem to think they have an 
exemption from Mother Nature" theorem. For many of us, compromise is built in 
to our situation, we are not being obstinate just to pee you off. In my case, I 
have a 110 X 50 foot property in a residential neighborhood and I am limited to 
a "T" transmit antenna (40 ft up, 92 ft flattop) and a K9AY RX array in a 
somewhat noisy neighborhood. So no, I don't hear or TX like those with a more 
favorable QTH, but I enjoy 160 meters, I have fun and do the best I can with 
what I have. So if I occasionally call out of time (I try not to) because I 
don't have the "ears" you do, don't take it personally...

73 Kevin K3OX


- Original Message -

From: "Rob Atkinson" 
To: topband@contesting.com
Sent: Wednesday, December 2, 2015 12:53:39 PM
Subject: Topband:  2 wl loop, worth the effort?

Hi Gary, It would make a nice receiving antenna.

Let's start with a question:  Would you put up a loop for 20 meters
that is 6 feet off the ground?  Height for horizontal antennas must
always be thought of in terms of _wavelength_.  There is only one
effective transmitting antenna for medium wave, assuming you do not
have 200 foot tall supports for stringing up a horizontal wire
antenna, and that is some sort of monopole over a good ground system.
Period.  And good ground system means a lot of radials.  A lot.  Not
10 or 20.  You don't get to cheat on the laws of physics.  You have to
bite the bullet and do the work.  The excited vertical part has
options.  T, inverted L, or an insulated tower are all fine provided
the vertical part is at least 50 feet tall (more is better).

Don't take this personally--it's just that I get tired of piss weak
signals on 160 from hams who seem to think they have an exemption from
Mother Nature.  A dead giveaway that a ham is using a low dipole, 20
feet or so, is rapid deep QSB.  Even 50 feet is too low.  Inverted Vs
are worse.  the effective height is halfway between the apex height
and the height of the ends.  A big horizontal loop on transmit does
nothing for you but cause more of your RF to get lost to ground
coupling.

73

Rob
K5UJ
_
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_
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Topband: adding another inverted l to the existing

[james soto via Topband]

Actually iam using an inverted L for 160 with few radials.I would like to build 
another one for 75 meters band. my questio are:1. How close they could be? 2. 
could i use the same radials existing from the 160 inverted L?Thankskp2bh/jimmy
_
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Re: Topband: 2 wl loop, worth the effort?

[NC3Z Gary]

Thanks for all the replies, guess the consensus is it is not worth the 
effort to put up a 2wl loop over a 1wl.

I know several mentioned verticals but I really was interested in the 
loop option. This is for QSO's with stations 500-600 miles from me, 
currently they report that my signal is strong and very consistent with 
the 25' high dipole believe it or not.

But the dipole is fed with coax and has a limited bandwidth. I am 
switching to ladder line and was thinking the loop may be the next 
evolution.

I also could move the dipole back to get it up to about 50' and feed it 
with ladder line as an option.

My height is limited to what I have for trees. No tower planned for the 
new QTH since we are in hurricane/coastal storm country.

As far as a receive only antenna that is in the plans soon.

Gary Mitchelson
NC3Z/4 Pamlico County, NC FM15


On 01-Dec-15 22:00, NC3Z Gary wrote:
> I have been contemplating a sky loop to replace my coax 160/80M fan
> dipole. The loop would be fed with ladder line so I could use it on 160-40M.
>
> It would take a bit more effort clearing an area to get up 2wl of wire
> but it could be done. Is the effort worth it over a 1wl loop? An
> additional issue is I can only get it up about 50'.
>
> Right now the dipole is at 25' and works very well with the hams I daily
> keep in touch with in the 500-600 mile range, but is limited in it's
> bandwidth.
>
>
> Gary Mitchelson
> NC3Z/4 Pamlico County, NC FM15
>
> _
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>
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Re: Topband: 2 wl loop, worth the effort?

[Tom W8JI]

You said "Compared to a vertical, there could be 10-30 dB difference in
favor of a low dipole (less than 150 ft high) within a few hundred 
miles.",

and I was pretty much trying to make the same point but indirectly since I
don't have a dipole on 160 meters.

The original poster mentioned relatively short distance work on 160 
meters,

and that is why I mentioned that a true vertical may not actually be his
best choice (he might actually go backwards in performance if he is trying
to work stations in adjacent states as an example).


I've done hundreds or thousands of tests. I was test crazy when I moved 
here.


Within around 100-200 miles, at night, the verticals and a dipole up about 
1/2 wave are really dead compared to a "low" dipole.


That problem rapidly vanishes with increased distance, and during daytime 
skip zone of the high dipole moves in closer.  From my house the skip zone 
of a 280 ft high dipole is about 10-50 miles. The  vertical never really has 
a skip zone in the daytime. Groundwave fills it in.


I initially thought a low dipole (or a high dipole) was worth it, but I 
outgrew that. I just live with the weaker signal in the skip zone. The 
vertical does so much better at most distances most of the time it is just 
not worth worrying about.


If I wanted to work 50-200 miles, I'd probably just use a low dipole. 


_
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Topband: Fwd: 20th Stew Perry TopBand DX Challange

[Lew Sayre]

Greetings to the Ditters and Dawters of the 160M Realm,
  The evil snow, ice, winds and politicians are all afoot now... but
the bright spot is
coming your way 1500Z Dec. 26 to 1500Z Dec. 27 in the form of the 20th
Edition
of The Stew Perry TopBand DX Challenge sponsored by The Boring Amateur
Radio Club.
This is the fairest contest in our known galaxy. It is a Morse Code (CW)
contest where
the exchange is your call-sign and your grid-square. Through magic, the
astute log
checkers of our massive club are able to determine how far away your
contact was
with another station. The idea is that far away contacts are worth more
than close in
contacts. Also, you get extra points for working low power and QRP stations
which delights
the lesser powered stations and rewards you for sticking with that -27dB
signal in the mush
until you can discern the call and grid-square.  You should really browse
on over to:
 www.kkn.net/stew/   and read the rules and see the other cool stuff
there.
  The following Giants of Contesting are sponsoring plaques for The
Stew. These Luminaries
have offered up a category to spur on the radio combatants and have sent in
the $60
($63-PayPal) to spice up the competition.  Please give positive
affirmations to these
radio competition Stalwarts when you see them...or at least buy them a
beverage.
 Yes, We are aware that KL7RA is SK.  He was The Boring Amateur Radio
Club
Chairman of the Contest Food and Drink Committee among other duties.
 We miss him greatly.

KL7RATop # of QSOs
North Pole Contest Group  To be decided
K7FL/5H2DATop Score 100% Search & Pounce
KR2Q  Golden Log Award
N0TTTop Score < 21y/o, >200 QSOs
K7CA   Top Score China
TF3KX  Aurora Borealis Award- Top Score North
of 60 deg N
geomagnetic Latitude
Dr. Beldar-L1ARTop Score,S/O, Temp Antenna erected after
Dec.14
UX1UA  Top # NA + SA QSOs by Zone 16 Station
UX1UA  USA Station with Top #  QSOs with Zone 16
K6NDK6ND Memorial- Top Score, S/O, World
K1EPTop LP score between 30deg N and 40deg
N latitude
(Any station located in  xM##  grid
square)
KH6LC  VK-ZL Challenge- Top Score,S/O, VL/ZL
N6TQ/A25TQ California Dreaming- Top # of QSOs with
California
 stations by a non-California
station
W2GD Team  Top # QSOs with NA/SA, by a EU station
W7RHTop Score, Low Power, Asia
K7CA Top Score from Zone 24, 27 or 28
K7CA Top Score from either Zone 19 or 25
VK6VZ- Flying DoctorsTop Score- N. Hemisphere station working
of VK Baseball hat   S. Hemisphere stations

To see if you have remembered to pay for your plaque go to:
http://www.kkn.net/stew/plaques.txt

 You also may join this stellar group by proffering a suitable category
you would like to see emphasized and then sending along the funds.
 We have been petitioned to have a Stew Perry SSB contest.
After vigorous and protracted discussions among our various committees
we strongly feel that the language of 160M is CW.  There will be no SSB
version sponsored by The Boring Amateur Radio Club unless we are
bought out by Amazon, Google, Facebook or Yahoo. And maybe not
even then.
  Please get on the 160M airwaves this weekend as the ARRL has
nicely scheduled a great Stew warm-up called strangely enough
The ARRL 160M Contest- CW.
 The winning plaques for the 2014 Stew Perry will be sent to the winners
very soon as the little old plaque-maker has been working on them
diligently.
See you in The Stew!
73 and I remain,
Lew  w7ew
   w...@arrl.net
_
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Re: Topband: adding another inverted l to the existing

[Gert Meinen]

James,

You can add another inverted L in the same plane as the 160m one. If you keep 
'm seperated 1 or 2 meters they 'll work  great, they don' t "see" each other.
You can put 'm on the same feedpoint and just add some more capacitance to an L 
network on 160m to match the antennas to the feedline.

73 Gert PA3AAV
_
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Topband: 2WL loop

[Katz Ajamas]

Nc3Z

I use a 1wl vertical plane loop for DX on 80-20. It does about as well as
the 80m inv V with apex at a little under twice the height. If I had room
I'd try a 1WL on 160, even with the 50' height limitation. For local...I'm
lazy. I'd try the 1WL before doing all the work to clear space for the 2WL
:-)

73, -Bob ah7i/w4 and no decent 160m antenna yet.
_
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Topband: 2nd inverted L

[james soto via Topband]

In the previous post i did not mention that the antennas will be feed
individually.thanks kp2bh / jimmy
_
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Re: Topband: adding another inverted l to the existing

[Greg Zenger]

I have a 80m free standing 1/4 vertical on 80m, over 60x 65' radials.  A
coil between the feed-point and the radial plate matches the antenna.
Large ferrite beads were added to the feed-line at the feed point. The
feed-line is about 250 feet of LMR-400-DB/

Last year I decided add an inverted L for 160 to the feed point.  I
couldn't get it to work well with both the 80m vertical and 160m inverted L
attached, until I added a 1:1 balun at the feed point.

The 80m element is 3" OD aluminum at the bottom and tapers to 1/4 inch at
the top, about 74 feet tall.  The vertical section of the 160m inverted L
is only about 40 or so feet tall  and is at approximately 20 degrees angle
to the 80m vertical before going horizontal across my yard. No other
dipoles are near it.

Performance on 80m appears unaffected, and the inverted L performs much
better than the 1/2 wave dipole I have on 160m up at 97 feet.

It has been on my to-do list to make measurements of the exact geometry of
the installation and run it through a few simulations to fully understand
what it is going on.

I think the key is the large number of radials on the ground and the balun.

Greg, N2GZ



On Wed, Dec 2, 2015 at 7:32 PM, james soto via Topband <
topband@contesting.com> wrote:

> Actually iam using an inverted L for 160 with few radials.I would like to
> build another one for 75 meters band. my questio are:1. How close they
> could be? 2. could i use the same radials existing from the 160 inverted
> L?Thankskp2bh/jimmy
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
_
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