Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old August 15th 04, 12:02 AM
Yuri Blanarovich
 
Posts: n/a
Default "Miracle" DLM RI short vertical

Howdy NGers,

I was curious about another "miracle" short vertical, being subject of great
interest, patent by Robert Vincent and Physics dept. of University of Rhode
Island. I got up at 4 am, drove to Boxboro ARRL convention and eager to see
what are we missing.

Not much!

Giveaway was opening statement something like: how to make shortened antenna
with more gain (compare to what? I guess light bulb :-)

In the "theoretical" portion of the presentation audience was told that current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant. Due overcrowding of "inventor" I did not
persist in breaking through and asking for enlightenment.

Author claims more gain (familiar), better bandwidth (doesn't get it why) and
small size (of course). Showing measured graphs with current and phase
distribution along the radiator. Works very well! (Many stations worked.)

He showed how to measure current at the antenna using ferrite pickup
transformer way up the antenna and cables to the instrument (handsomely
detuning and distorting the measurements).

I suspect that "broad bandwidth", (SWR 2:1) was achieved thanks to losses in
the coils and dielectric, as "confirmed" by his statement that coils were fried
when power was applied.

What is it? Basically helically wound coil starting from the base, about half
way up the radiator, then piece of straight tubing, than loading coil, then
tubing and in some case top hat (works better :-). Matching to 50 ohms is done
by picking tap at the base, few coil turns up. That is 3D version.

He showed some "2D" versions, having "coils" made of basically coil formed as
hairpin loops instead of classic solenoid, also the loading coil. So kind of 2D
- 3D antenna :-)

I wanted to make a bet that my single loading coil loaded vertical would cream
the "miracle", but there were so many worshippers paying compliments to the
inventor, that I resigned not to stay for the second hour of lecture how to
build it.

I saw no trace of any modeling, just experiments using wrong tools.

So brace yourselves for another "miracle" in the arsenal of very small and more
efficient antennas. It should be a hit with CBers and other suckered users.

So that's it (oh, no chokes in the feedlines), I hope U of RI is proud of this
breakthrough, I can sleep well now. Back to DR1.

Yuri, K3BU
with more info that could have saved lotsa experimenting at
http://www.k3bu.us/loadingcoils.htm
  #2   Report Post  
Old August 15th 04, 01:45 AM
Howard
 
Posts: n/a
Default

On 14 Aug 2004 23:02:01 GMT, oUsama (Yuri Blanarovich)
wrote:

Howdy NGers,

I was curious about another "miracle" short vertical, being subject of great
interest, patent by Robert Vincent and Physics dept. of University of Rhode
Island. I got up at 4 am, drove to Boxboro ARRL convention and eager to see
what are we missing.

Not much!

Giveaway was opening statement something like: how to make shortened antenna
with more gain (compare to what? I guess light bulb :-)

In the "theoretical" portion of the presentation audience was told that current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant. Due overcrowding of "inventor" I did not
persist in breaking through and asking for enlightenment.

Author claims more gain (familiar), better bandwidth (doesn't get it why) and
small size (of course). Showing measured graphs with current and phase
distribution along the radiator. Works very well! (Many stations worked.)

He showed how to measure current at the antenna using ferrite pickup
transformer way up the antenna and cables to the instrument (handsomely
detuning and distorting the measurements).

I suspect that "broad bandwidth", (SWR 2:1) was achieved thanks to losses in
the coils and dielectric, as "confirmed" by his statement that coils were fried
when power was applied.

What is it? Basically helically wound coil starting from the base, about half
way up the radiator, then piece of straight tubing, than loading coil, then
tubing and in some case top hat (works better :-). Matching to 50 ohms is done
by picking tap at the base, few coil turns up. That is 3D version.

He showed some "2D" versions, having "coils" made of basically coil formed as
hairpin loops instead of classic solenoid, also the loading coil. So kind of 2D
- 3D antenna :-)

I wanted to make a bet that my single loading coil loaded vertical would cream
the "miracle", but there were so many worshippers paying compliments to the
inventor, that I resigned not to stay for the second hour of lecture how to
build it.

I saw no trace of any modeling, just experiments using wrong tools.

So brace yourselves for another "miracle" in the arsenal of very small and more
efficient antennas. It should be a hit with CBers and other suckered users.

So that's it (oh, no chokes in the feedlines), I hope U of RI is proud of this
breakthrough, I can sleep well now. Back to DR1.

Yuri, K3BU
with more info that could have saved lotsa experimenting at
http://www.k3bu.us/loadingcoils.htm

Does it also plug into the house wiring for improved TV reception?
Gotta love junk-science!
Howard
  #3   Report Post  
Old August 15th 04, 02:47 AM
Yuri Blanarovich
 
Posts: n/a
Default

m

Does it also plug into the house wiring for improved TV reception?
Gotta love junk-science!
Howard


Not sure, but it is apparently very easy to scale up or down by simply
reducing/enlarging it on the copier by factor x. No kidding! Apparently works
well into the UHF bands :-) Who needs EZnec.

Can you picture all them wizards joining forces for FracEHDLMCFA gizmo?

Yuri
  #4   Report Post  
Old August 15th 04, 03:34 AM
Cecil Moore
 
Posts: n/a
Default

Yuri Blanarovich wrote:
In the "theoretical" portion of the presentation audience was told that current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant.


I've often wondered at exactly what crossover point a helical coil
turns into a loading coil. If one adds a one inch stinger to a helical
coil, does that turn it into a loading coil? How about a one foot stinger?
Is a one foot long loading coil not a helical coil? Does a one foot long
loading coil really have less phase shift than a one foot long piece of
wire? On a center-loaded mobile antenna, how can the ARCCOS of the current
at the feedpoint be zero degrees and the ARCCOS of the current at the tip
be 90 degrees without there being 90 degrees between the feedpoint and the
tip? (When are you going to invite everyone over to Bar-B-Q that sacred cow?)
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
  #5   Report Post  
Old August 15th 04, 11:10 PM
Yuri Blanarovich
 
Posts: n/a
Default




I've often wondered at exactly what crossover point a helical coil
turns into a loading coil. If one adds a one inch stinger to a helical
coil, does that turn it into a loading coil? How about a one foot stinger?
Is a one foot long loading coil not a helical coil? Does a one foot long
loading coil really have less phase shift than a one foot long piece of
wire? On a center-loaded mobile antenna, how can the ARCCOS of the current
at the feedpoint be zero degrees and the ARCCOS of the current at the tip
be 90 degrees without there being 90 degrees between the feedpoint and the
tip? (When are you going to invite everyone over to Bar-B-Q that sacred cow?)
--
73, Cecil http://www.qsl.net/w5dxp



We have to wait for the patent 'splaining the "miracle".
One thing I "discovered" that winding the wire either as a coil or simply
taping it to the wood or plastic dielectric detunes the heck of it (losses,
making it look more "broadband"). I taped the wire of quarter wave vertical to
the bamboo pole, and it was way off resonance. When I put plexiglass spacers,
insulators, bingo, right on frequency.
Coil is a coil and in the antenna circuit it behaves that way.
One thing is comapring quarter wave electrical length (loaded) radiator to
quarter wave monopole, another thing is making it electrically longer, loading
it and then comparing to quarter wave radiator. From presentation it was hard
to judge what exactly was DLM electrically equivalet to.

We might have clinic on verticals over "perfect" salty water soon, we are
closing on waterfront property near the Ocean Gate old AT&T huge Rhombic
antenna farm and looking for some juicy coiled sausage to BBQ.

I think that hanging cow bell and flourescent light on the DLM would make it
one class better, maybe 120% efficient antenna :-)

What will they think of next?

73 Yuri, K3BU.us



  #6   Report Post  
Old August 15th 04, 04:01 AM
Reg Edwards
 
Posts: n/a
Default

Yuri, your criticism is perfectly sound.

To sum up, the key to antenna radiating efficiency is SIMPLICITY.

The more simple the construction of an antenna the more efficient it will
be.

It is intuitivly obvious. Every complication is sure to introduce loss.
---
Reg


  #7   Report Post  
Old August 15th 04, 04:12 AM
Cecil Moore
 
Posts: n/a
Default

Reg Edwards wrote:
The more simple the construction of an antenna the more efficient it will
be.


An isotropic is pretty simple but I don't know how to feed it. :-)



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
  #8   Report Post  
Old August 15th 04, 10:07 AM
Ed Price
 
Posts: n/a
Default


"Cecil Moore" wrote in message
...
Reg Edwards wrote:
The more simple the construction of an antenna the more efficient it

will
be.


An isotropic is pretty simple but I don't know how to feed it. :-)



From the inside.

Ed
wb6wsn

  #9   Report Post  
Old August 15th 04, 07:55 AM
Hal Rosser
 
Posts: n/a
Default

I wish someone WOULD come up with a 10-ft vertical for 80 meters with the
same gain and bandwidth as a simple dipole

"Yuri Blanarovich" wrote in message
...
Howdy NGers,

I was curious about another "miracle" short vertical, being subject of

great
interest, patent by Robert Vincent and Physics dept. of University of

Rhode
Island. I got up at 4 am, drove to Boxboro ARRL convention and eager to

see
what are we missing.

Not much!

Giveaway was opening statement something like: how to make shortened

antenna
with more gain (compare to what? I guess light bulb :-)

In the "theoretical" portion of the presentation audience was told that

current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant. Due overcrowding of "inventor" I did not
persist in breaking through and asking for enlightenment.

Author claims more gain (familiar), better bandwidth (doesn't get it why)

and
small size (of course). Showing measured graphs with current and phase
distribution along the radiator. Works very well! (Many stations worked.)

He showed how to measure current at the antenna using ferrite pickup
transformer way up the antenna and cables to the instrument (handsomely
detuning and distorting the measurements).

I suspect that "broad bandwidth", (SWR 2:1) was achieved thanks to losses

in
the coils and dielectric, as "confirmed" by his statement that coils were

fried
when power was applied.

What is it? Basically helically wound coil starting from the base, about

half
way up the radiator, then piece of straight tubing, than loading coil,

then
tubing and in some case top hat (works better :-). Matching to 50 ohms is

done
by picking tap at the base, few coil turns up. That is 3D version.

He showed some "2D" versions, having "coils" made of basically coil formed

as
hairpin loops instead of classic solenoid, also the loading coil. So kind

of 2D
- 3D antenna :-)

I wanted to make a bet that my single loading coil loaded vertical would

cream
the "miracle", but there were so many worshippers paying compliments to

the
inventor, that I resigned not to stay for the second hour of lecture how

to
build it.

I saw no trace of any modeling, just experiments using wrong tools.

So brace yourselves for another "miracle" in the arsenal of very small and

more
efficient antennas. It should be a hit with CBers and other suckered

users.

So that's it (oh, no chokes in the feedlines), I hope U of RI is proud of

this
breakthrough, I can sleep well now. Back to DR1.

Yuri, K3BU
with more info that could have saved lotsa experimenting at
http://www.k3bu.us/loadingcoils.htm



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.732 / Virus Database: 486 - Release Date: 7/30/2004


  #10   Report Post  
Old August 15th 04, 02:34 PM
Cecil Moore
 
Posts: n/a
Default

Hal Rosser wrote:
I wish someone WOULD come up with a 10-ft vertical for 80 meters with the
same gain and bandwidth as a simple dipole


Heck Hal, a 66 ft. vertical for 80m doesn't even have
the same gain as a dipole.



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Inverted ground plane antenna: compared with normal GP and low dipole. Serge Stroobandt, ON4BAA Antenna 8 February 24th 11 10:22 PM
QST Article: An Easy to Build, Dual-Band Collinear Antenna Serge Stroobandt, ON4BAA Antenna 12 October 16th 03 07:44 PM
HF Vertical design(s) H. Adam Stevens Antenna 1 August 23rd 03 03:07 AM
Poor vertical performance on metal sheet roof - comments? Kristinn Andersen Antenna 23 August 8th 03 11:08 PM


All times are GMT +1. The time now is 07:55 AM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017