Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 2 3 [4] 5 Next   Go Down
  Print  
Author Topic: Heliax Loop Antenna  (Read 20252 times)
N3OX
Member

Posts: 8853


WWW

Ignore
« Reply #45 on: September 20, 2012, 10:07:03 AM »

That would make the helically-wound, higher-Q, higher-energy-storage antenna appear more "efficient" on receive, but on transmit the higher energy storage would reduce radiation and reduce efficiency - right? But what about antenna reciprocity? Does that not apply when we add energy-storing inductance into an antenna?

Energy *storage* by itself is basically independent of the steady-state power flux from antenna to RX.   If you change the energy storage of an antenna without changing the pattern or losses and it changes the voltage supplied to the receiver input then you've actually changed the matching conditions of the antenna... if you always match the antenna to 50 ohms before you do your tests this should not be a problem.

Here's a dumb but pretty illustrative example.

I have a dipole that's extracting 10 nanowatts from an incoming plane wave and delivering it to a 50 ohm receiver input.  That's my reference.  Now I take a perfectly lossless series resonant LC circuit that's physically small or in a shielded box and put it in series with one dipole leg.

From a field perspective, I haven't really changed anything.  There's a massive magnetic field in the inductor and a massive electric field in the capacitor and they're exchanging energy but this all happens in a way that doesn't interact at all with the outside world.  From a steady-state circuit perspective, I've inserted 0+j0 into one dipole leg, so the power delivered to the receiver is unchanged.

The antenna bandwidth is much narrower, the energy stored is higher, it will ring longer, and all of that, but the steady state power extracted from the incoming wavefront and delivered to the receiver is identical.  Putting a zero loss lumped inductor in a magloop, especially next to the capacitor, would work almost identical to this.  You re-adjust the capacitor and nothing really changes except that the inductor and the capacitor are exchanging energy.

If you do add energy storage in a way that increases the voltage delivered to a 50 ohm RX input you've either changed the pattern of the antenna to capture more energy from the incoming wavefront (i.e. more gain) or you've mismatched it which you can check easily.
« Last Edit: September 20, 2012, 10:19:54 AM by N3OX » Logged

73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
W8JI
Member

Posts: 9304


WWW

Ignore
« Reply #46 on: September 20, 2012, 02:47:50 PM »

To summarize: (1) Can a helically-wound loop be validly compared against a non-helically-wound loop using inverse field strength measurements, or must actual radiated field strength be compared? (2) If the answer to the previous question is "no, inverse FS cannot be used," then how does that relate to the notion of antenna reciprocity?

Any extra energy storage only can increase losses by increasing voltage and/or current. The amount of current contributing to radiation OR reception for a given field strength remains exactly the same, the only thing that changes is losses due to stored energy.

The more energy we store, the higher losses within the area storing energy become for fixed loss resistance values.

Stored energy and energy related to radiation really are two separate things. For example, if we simply parallel a high-Q tuned circuit across the feed terminals of an antenna, it increases stored energy in the system but it does not ever increase field strength. The same is true when that energy storage is intergrated into the antenna.

The notion of a helical loop winding on a small loop increasing performance is rubbish. It will do just the opposite, unless the antenna is loaded so heavily with an antenna diameter so large the antenna behaves like a bent or folded dipole. Even then you have so much loss it would unlikely to improve anything.
Logged
KA4NMA
Member

Posts: 317




Ignore
« Reply #47 on: September 20, 2012, 11:33:45 PM »

I am disabled and do not have the mechanical skills or  tools to build a loop antenna.  Does anybody have one that I could get?  It will be used inside.

Randy ka4nma
Logged
JAHAM2BE
Member

Posts: 276


WWW

Ignore
« Reply #48 on: September 21, 2012, 11:28:24 PM »

I am disabled and do not have the mechanical skills or  tools to build a loop antenna.  Does anybody have one that I could get?  It will be used inside.

You may already know this, but in case not: MFJ sells a pretty well-constucted and positively-reviewed loop antenna. The designer of that antenna is participating right here in this eham thread.

http://www.mfjenterprises.com/Product.php?productid=MFJ-1786

Another option is the MFJ small loop tuners, that provide a tuning capacitor and a capacitive matching network. You provide the loop element and screw it onto the tuner with wing nuts. The loop element can be wire (pretty inefficient), copper tubing, copper strap, maybe even aluminum foil.

http://www.mfjenterprises.com/Product.php?productid=MFJ-933

Anyone have any comments on how well these tuners work compared to a properly-built loop? I'm paranoid about losses that would be incurred placing the capacitor box on the ground or a table, as well as losses through the wing nuts.

There's also a smaller QRP version of the MFJ loop tuner, the MFJ 932, but I don't see it on their site anymore. Maybe it's out of production.

I have no affiliation with MFJ, and actually have never bought anything from them, but they do seem to offer interesting products not offered by other companies.
Logged

K8NDS
Member

Posts: 7




Ignore
« Reply #49 on: September 22, 2012, 12:28:13 PM »

I am reading all of this and actually it is quite comical.
Since I designed the Helically Loaded magnetic loop antenna my QRZ page has grown over
14,000 hits in one year. The reason is that people that hear my signals on the bands are blown away with the results,
thus they go to my page to see what I am using for the antenna.
I constantly get reports that I am the strongest signal that is being heard on the particular band, this is an everyday
occurrence. I constantly break pile up's even when I have the disadvantage of the east coast stations that are 10 to 20 Db
stronger then me, or should be. I have a 1800 mile disadvantage to Europe but I still compete on a regular basis with
my magnetic loop antennas that are less then 5 ft off the ground.
If you are still a non believer look for me on 17 meters, no matter where you are located if there is a band opening
you will hear me.
It cracks me up to hear all the naysayers that only believe what their calculations are telling them.
I really don't care if someone doesn't believe, if you have a restricted CC&R or HOA issue build one of these antennas
you will not be able to get a better signal out with anything else that you can erect on your lot.
What actually matters in the end is that I can work ANYTHING on the band and I can hear better then most antennas.
Most of my signal reports are excellent.
I also logged over 200 contacts comparing my single element Helical loop to a dual element design.
Averaged over 200 contacts plus switching multiple times to factor out QSB.
By the way I am very good at this, I spent thousands of hours in my career doing comparison/reference field testing gathering data like this.
So the person stating that this type of data is not correct, I guarantee you are assuming too much.

Also for the guy that stated that my comparisons between the dipole and the loops are not correct, you are right!
The problem is that no matter which direction either antenna is pointing the end result is that the average signal strength
is always better or equal with my loops. I also have an elevated fed single band ground plane which utilizes 45 deg  sloping radials.
It has a flat vswr and works as good as could be expected on 17 meters. It is basically a text book perfect ground plane tuner for only one
band, no compromise. My 2 element helical magnetic loop in which the lower loop is only 4 ft above ground blows the vertical away, all the time.
It also receives so much better then the vertical that many times I cannot even work the same station when I switch to the ground plane vertical.


This reminds me of the way a pharmacist will tell you that all these drugs that you are taking will help you.
All they do is complicate the underlying issues and kill you in the end with a slow and painful death.
Basically allot of BS to cover up something that facts will show you that it works.
Unless you build one of these antennas and do it correctly; you will never know.
There are at least 20 stations that have built these and communicated back to me that there loop works as good
as any of their other antennas plus receive is far superior.
If you check Google you will find dozens of web sites that picked up my YouTube video's when they heard me on the air.
Many of them are European sites.
I guess that all that matters in the end is that the math doesn't work.....Hi Hi Smiley

If you go to my QRZ page you will see a quote from VK2DX; "Best punch for antenna footprint" I've ever heard on 20m.

This may not outperform a large beam at 60 ft but it works the same stations Q5 all the time.
So nit picking a few Db is worthless.
No tower needed, only a step ladder....................

Now I am waiting for all the flack from you know who!

Have fun and make sure that you listen carefully to all the GURUS that respond to this!

Yours Truly...........73 from K8NDS Cottonwood Arizona


Logged
WD8KNI
Member

Posts: 141




Ignore
« Reply #50 on: September 22, 2012, 01:15:57 PM »

K8NDS -- Thanks for jumping into my thread with absolutely no information on the subject that I find reverent.  Before starting this thread I had already read just about everything I could find published by you and others, had already read all of the arguments, and already dismissed you because of your testing standards, and you inability to state anything empirical other than "listen to my signals" it proves it everything

At any time I can find a signal on the band that is the "strongest" at that point in time, other days I can hardly hear them, and I have been doing this for many years.  Your arguments do not hold water.  I will not drink your coolaid.  The media our signals go through is kinda like testing a receiver sensitivity with a variable attenuator inline that we are not allowed to look at or know how it is set, all the while it is constantly being changed.

While I don't doubt that your antenna is a good antenna for you and others, if you and the others don't compare with other better constructed antenna, others are simply drinking your coolaid.  It totally amazes me that you have the gull to, without empirical data  dismiss other designs as inferior to yours.  You are like our current president, tell lies often enough and people will believe, except your tactic is to shout often enough others will use.

As long as you have been arguing regarding your design on the internet I would have thought you would have published absolute data by now just to shut up the people you are arguing with.  I suspician that you already have done the testing and don't like your results or you would have published it by now.  According you your own rant you certainly know how to do the testing.  Hell for all I know you could have a huge amp on the loop or a 10 db attenuator on the dipole.  My previous statement may not be true, but how do we know, you expect us to simply accept your conclusion, or others conclusions that you could have easily rigged.

As I won't accept your conclusion I won't accept the consulions from other that build using your design, why?  Because I don't know if the antenna they are comparing to was essentially a dummy load. 

You can stop the trolling for arguments and just go away as far as I am concerned, as you add nothing to the conversation without data.  No matter how hard and long you shout, you can not argue with physics or the math describing physics.  Fred   
Logged
K8NDS
Member

Posts: 7




Ignore
« Reply #51 on: September 22, 2012, 02:17:57 PM »

WD8KNI..........   First of all E-ham is open to any member, since I was being discussed here I thought I would defend my design.
Where do you get from my comments that I stated that my design was better then anyone else's?
What I have stated was that basically if you understood my design;  it works as good as a full sized mag loop being at least 30% smaller
in diameter then loop calculations. Also compares to local hams on 20 meters using 3 element beams, I have done this several times now.
Seeing that I do not getting into business to sell these antenna's, absolute data is not necessary to me or others requiring this type of antenna.
These antennas allow many hams in restricted areas to get on the air with a very good signal, I did this for the amateur community.
If you didn't tell me here that your a Republican I would have thought the opposite from your post here,
you sound more like the current President then I do. I usually leave politics out of my hobby but since you had the gull to bring it up,
back to you.
I don't really give a darn if YOU accept my conclusions or not, I am the one using the antenna' and others that are experiencing great results;
especially in restricted area's.
We already know and you OPINION means nothing with out you being here to observe, you know what they say concerning opinions.
I have had stations drive for 400 miles to come here, I believe it was because they were non- believers until they sat here and their jaw dropped.

Have a nice day, I am.

OH Yes, don't forget to vote for Romney!

Rich K8NDS
Logged
N4CR
Member

Posts: 1655




Ignore
« Reply #52 on: September 22, 2012, 08:50:40 PM »

What I have stated was that basically if you understood my design;  it works as good as a full sized mag loop being at least 30% smaller in diameter then loop calculations

Where is your proof of this? It's the one thing that everyone has requested of you and the one thing you never bring.

Proof, man. Proof. Proof doesn't require understanding. Proof stands on its own.
Logged

73 de N4CR, Phil

We are Coulomb of Borg. Resistance is futile. Voltage, on the other hand, has potential.
W8JI
Member

Posts: 9304


WWW

Ignore
« Reply #53 on: September 23, 2012, 05:54:15 AM »

If an antenna like this actually worked as claimed, and was not just someone's overactive imagination or bad experiment, you would see a rush of commercial enterprises building the magical antennas.

It would not take months, let alone years, before the inventor was a wealthy man with universal recognition by people who have some idea how antennas work, or those who sell antennas. They would be everywhere quickly!

This helical loop is following the EXACT repeating pattern of other nonsense antennas, like the EH antenna and CFA.

1.) The author proclaims abuse by others who dare question him

2.) The  author alone understands the antenna

3.) No one other than the author or his group obtain the claimed results in a valid test setup

4.) The author is generally abrasive and will not discuss technical points

5.) The antenna is often claimed to not be able to be modeled, and usually has some new physics that violates old science

Watch and see if all this is not true. In about five years, market popularity will be exactly the same. A small core group will think it works. When others try to verify, the results will never pan out. No commercial enterprise will touch it.

I'm serious about this. If it really worked and was really a good idea, it would be commercially marketed and accepted within a very short period.

Instead of that, success is now based on the number of U-tube views.  :-)
Logged
W8JI
Member

Posts: 9304


WWW

Ignore
« Reply #54 on: September 23, 2012, 07:21:58 AM »

Quote
I don't really give a darn if YOU accept my conclusions or not, I am the one using the antenna' and others that are experiencing great results;
especially in restricted area's.
We already know and you OPINION means nothing with out you being here to observe, you know what they say concerning opinions.
I have had stations drive for 400 miles to come here, I believe it was because they were non- believers until they sat here and their jaw dropped.

http://www.youtube.com/watch?v=-KFir-f6uEI

They have 6,000 hits on this video, and come from thousands of miles. It is the same thing, except she wasn't a Ham.
Logged
K8NDS
Member

Posts: 7




Ignore
« Reply #55 on: September 23, 2012, 01:12:12 PM »

W4CR....If you want proof I can give you call signs of many that are enjoying this antenna, they email me weekly to give me feedback on the great results they are having.
One main reason that commercial enterprises are not jumping on this bandwagon is that the main important part to this antenna is very expensive if purchased new.
A seasoned Amateur with some decent Electro-mechanical background can find the part cheap, many have already done it.

W8JI....Speaking of abrasive along with the biggest ego and arrogance that I have ever experienced!
It takes real arrogance to call someone a lire when you don't even know them & you have no proof.
I have never told someone on the air that I was using a certain antenna while using something different.
The people that have built these other then me will tell you the same.
Do you know how many stations that I have talked with on the air that are laughing at your Eham response from my first article.
I have heard repeated statements that they ran across your response, they state in a laughing manner that I guess
your 20 over S-9 signal shows that it can't work according to W8JI.
You have not done yourself justice by spouting out without facts.

W8JI......The author alone understands the antenna....Hi Hi.....I have had a large number of people from the RF field email me stating that the design is great.
Thanking me for all my work, they are RF people and they do understand the design.

W8JI..... There is a difference between questioning someone and calling them a lire when you have no clue.

I mentioned this in anther debate a while back, I am not going to drag this fine gentleman into this so I will not repeat his name here.
He is an expert in this area, a physicist; he thinks the design has allot of merit. He even stated that he has thought about it
in the past but never had the time.


By the way, it has not just been an experiment; I use these everyday exclusively now.
In fact I am ready to remove all my other antennas, they are no longer needed.
The only reason that I have left the erected this long is for comparison data.

By the way some of the largest corporations that I know will take empirical data and in the end use the data from what
actually performs the best in the field; A/B comparison. I have been involved in this situation.

I will say it one last time, because many here don't seem like they are reading carefully.
I don't have a need for the time and cost involved to set up FS measurements.
The purpose of these antennas was to give HOA stations a good antenna to work with, one that they can hide and still get out a good signal.
This design allows that to happen and many are already enjoying it.
It is giving up just a few db and getting on the air without the requirement for a tower and allot of expense.
A few db in the Amateur radio hobby isn't usually even noticeable.
These antennas far outperform the poor efficiency short verticals that many HOA hams are forced to use.




,
Logged
W8JI
Member

Posts: 9304


WWW

Ignore
« Reply #56 on: September 23, 2012, 01:47:17 PM »


An experiment without some reasonable reality check isn't advancing the state of art, it is advancing the state of graffiti.

73 Tom
Logged
N4CR
Member

Posts: 1655




Ignore
« Reply #57 on: September 23, 2012, 04:33:49 PM »

W4CR....If you want proof I can give you call signs of many that are enjoying this antenna, they email me weekly to give me feedback on the great results they are having..

That's not my call sign, but I guess you're replying inline to me...

Proof of how an antenna works is found on a test range.

http://www.antenna-theory.com/measurements/antenna.php

Your testimonials are nothing more than anecdotal evidence. Anecdotal evidence is considered the least certain type of scientific information. Researchers may use anecdotal evidence for suggesting new hypotheses, but never as validating evidence.
Logged

73 de N4CR, Phil

We are Coulomb of Borg. Resistance is futile. Voltage, on the other hand, has potential.
N4CR
Member

Posts: 1655




Ignore
« Reply #58 on: September 23, 2012, 05:04:02 PM »

I will say it one last time, because many here don't seem like they are reading carefully.
I don't have a need for the time and cost involved to set up FS measurements.

But you do have the audacity to make claims as if you do have proof.

Quote
it works as good as a full sized mag loop being at least 30% smaller

And now you again admit you do not have proof and have no intention of getting any.

'nuff said. Your work here is done. You continue to make a complete fool of yourself by making unsupported claims. And when people ask for proof, you march out the same old tired and lame excuses.

It didn't work the first time, it didn't work the second time, it won't work this time.

Come back when you have proof and not excuses.
« Last Edit: September 23, 2012, 05:05:35 PM by N4CR » Logged

73 de N4CR, Phil

We are Coulomb of Borg. Resistance is futile. Voltage, on the other hand, has potential.
W8JI
Member

Posts: 9304


WWW

Ignore
« Reply #59 on: September 23, 2012, 05:11:01 PM »

That's not my call sign, but I guess you're replying inline to me...

Proof of how an antenna works is found on a test range.

http://www.antenna-theory.com/measurements/antenna.php

Your testimonials are nothing more than anecdotal evidence. Anecdotal evidence is considered the least certain type of scientific information. Researchers may use anecdotal evidence for suggesting new hypotheses, but never as validating evidence.

A person does not need an antenna test range to obtain useful general data, but the person needs some common sense and reliable methodology to be sure he hasn't come up with total nonsense.

If a test indicates a small loop has 6-15 dB gain, or 400% or more efficiency, it might be good to question the reliability of the information, but we don't really need a test range if we are careful, use common sense, and use good references.
Logged
Pages: Prev 1 2 3 [4] 5 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!