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"....the current will flow into the properly placed resonant radials without insulating anything."

no it doesn't. if this was the case then everyone who simply added a radial system would report improvements in performance. this forum is replete with posts reporting exactly the opposite scenario. simple rf current measurements comparing the total current in all radials to the current in the radiator will bear this out. until total radial current equals radiator current the system is operating out of balance. furthermore, a 1:1 current balun is (required) not an option as long as unbalanced feedline is being used to feed a balanced antenna design.

the best materials i have found for isolating the support structure from the antenna are teflon and delrin because of their high (k) dielectric properties. the objective is to insure that all common mode current flows ONLY in the radiator and the radial system, thereby insuring that maximum current in the e-plane is transferred to the initial primary electric field. this condition is defined as "perfect elevated ground".

reference:
E-PLANE H-Plane

as was previously posted, a reduction in overall average noise in the system is the result of the suppression of common mode current present on both the support structure and the outer shield of the feedline.

signal strength increases on the order of 1.0 - 2.5 S-Units are not actually occurring as the common s-meter (asynchronous) reads much less than 6 dB. per S-Unit below S-9 but improvement in signal strength does occur nonetheless. my measurements indicate that actual figures are more on the order of 1.5 - 3.75 dB..

Not necessarily. You may benefit from using such a balun if you experience RFI, but there are thousands (and maybe hundreds of thousands) of dipoles -- balanced antennas -- being fed with coaxial cables of various types -- unbalanced feedlines -- with excellent results. In fact, I have one up now for 20 meters, fed with RG-213 and no balun. It works just fine.

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If you're like everybody else,
you're about average.
73 de K7KBN

isnt rg213 a balanced feedline ? isnt all coax balanced ?

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RFI is only ONE of several shortcomings resulting from feeding balanced antennas with unbalanced feedline. no one is disputing that good results can be had, it's just imperfect and offers plenty of room for improvement. the currents in dipole antennas fed with unbalanced feedline are just as out of balance in the two poles as they are in the antenna type that is the subject of this thread. if you haven't made the rf current measurements for yourself then i'm not debating the issue with you.

the pole connected to the feedline center conductor always has more current present than the pole connected to the shield and this imbalance prevents a dipole fed in this fashion (WITHOUT a BalUn) from ever developing maximum current in the electric field of the e-plane. if maximum electric field is not achieved then the magnetic field in the h-plane never fully develops either. (electro-magnetic field) the current missing from the pole connected to the shield winds up on the outer shield of the feedline and any conductive structure that may be supporting it, period. anyone wanting to argue the point needs no response from me. make the measurements and you will find that i know exactly what i'm talking about because you'll see the same thing too.

if you want OPTIMUM performance from a dipole or an earth ground independent ground plane type of antenna then the BALUN is a NECESSITY. if you disagree then you are unfamiliar with ALL of the shortcomings which are inherent in the design. MAXIMUM RADIATION from either one of these antenna types depends solely on IDENTICAL AMOUNTS OF CURRENT in both "HALVES" of the antenna completely cancelling each other out for the generation of MAXIMUM ENERGY IN BOTH ELECTRIC AND MAGNETIC FIELDS. Any CURRENT imbalance between the two halves DIMINISHES THE MAGNITUDE of the resultant ELECTROMAGNETIC FIELD.

in any event there are thousands (and maybe hundreds of thousands) of dipoles that could be performing far better than they presently are.

BM. all single "coaxial" feedline types are by their very definition "unbalanced." on the other hand all twin lead and ladder line type feedlines utilizing identical parallel conductors are "balanced."

hope that clears it up for you.

thanks jack . i guess this info is wrong then .
Antenna Notes

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read it again....

paragraph 7, sentence 6.
"parallel line is often refered to as balanced line."

paragraph 8, sentence 5
"coaxial cable is often refered to as unbalanced line."

same thing i just told you....thanks for the link.
Walt's got some good information there.

im an idiot , not that yall didnt know that already .

thanks again freecell .
its good to know Jack .

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...odd. In a two conductor system, how can you have more current flowing in one of those conductors than in the other? If there is a difference in current flow, where does that 'extra' current come from?
That's not some more of that 'NPC' stuff, is it?
- 'Doc

How many angels can dance on the head of a pin?

'Doc, freecell is right and IMO Walter Fair address the issue you raise in the following statement. The problems of an unbalanced condition are valid and it is no way more of that "NPC" stuff: That's not too hard to understand---is it?