FLAT COILS-VS-ROUND COILS

[Guest]

WHATS THE DIFFERENCE BETWEEN ROUND-COILS ANTENNAS VS FLAT-COILS ANTENNAS

[Stormbringer]

The Flat coils are "Flat" & the Round coils are...well, "Round"! Seriously though, I'm no antenna expert, but, the way I understand it......its the radiation pattern coming off the coils that make the difference. The signal transmits 360 degrees off the round coils, whereas the flat coils direct the signal off the sides? I dunno for sure however! Is there an antenna specialist in the house!?!

[spiderman716]

flat coils generate more audio because more surface area to transmit from :shocked:

[Roadrunner]

In theory, the flat coil should be a little better due to what is called the "skin effect" which means the signal travels on the outside surface of the coil. The larger the surface area is, the more effieicent the antenna. But in the real world, at 11 meter freqs. & low power, you wouldn't see much of a difference.

[Amp|-|ibious]

Hey guys, I didn't want to change your alls subject. I am having SWR problems with my base antenna. With just the radio on my swr is find through out the am channels but after turning on power my swr is higher on 1 than on 40... 1 being at 1.6 and 40 being at 1.4. Any suggestion how to get it below 1.3?

[North Texas Mudduck]

well im looking at a blank wall trying to picture your setup

give some ideas to put in our head to kind see what your setup is
and antenna

basically give us the who what when where

[Amp|-|ibious]

Sorry about that, it use to be listed at the bottom of each post. Not sure what happened to it but here it is. I have a SWP Galaxy 2547 with a Excalibur by Coily. Thanks for the help :D

[jessejamesdallas]

Hey guys, I didn't want to change your alls subject. I am having SWR problems with my base antenna. With just the radio on my swr is find through out the am channels but after turning on power my swr is higher on 1 than on 40... 1 being at 1.6 and 40 being at 1.4. Any suggestion how to get it below 1.3?

Sounds like your radio and amp are a miss-match. I would sugest taking the radio and amp somewhere so they can be matched together.

I had a similar problem with one of my mobiles once, and took the box and radio over to Peakaboo's, and he set the amp to match-up with the radio...after that, problem went away!

[Sly Dog]

WHATS THE DIFFERENCE BETWEEN ROUND-COILS ANTENNAS VS FLAT-COILS ANTENNAS

For all intensive purposes there is an significant difference between the 2 types as far as transmit.

[Century21]

I have always heard the Flatter coils, because of the skin effect produce a lower angle of radiation.
And for the man with the SWR problem, if you still have it. How are you measuring it, off the radio or a meter after the amp.
With the meter after the amp, SWR in most cases dont change with an increase in power, even when your watt meter shows it, Simply because alot of people have rf coming back on the shield of the coax. Atleast what i been told.

And if your using the built in one on the radio, If its accurate, which most aint, then your need to tune the input on the amp. People like carrying amps and radios to little shops and have it done. But when they take it home they see something different. And they always will. Surrounding objects, line voltage, SWR changes, cant be duplicated in a shop. Pay someone to come to your house with the right equipment and do it.


Just my 2 cents

[mopar2ya]

The construction of the coil is merely aesthetic. Choose whichever you think looks pretty. The radiation pattern of the antenna is not determined by the shape of the conductor in the coil.

A coil in an antenna is there to cancel capacitive reactance by providing an equal amount of inductive reactance thereby making the antenna purely resistive. Nothing more, nothing less. Cut it out of a beer can, string paper clips together, wind it out of a railroad rail, it still does the same thing.

Mopar

wan•na•boo (wah-nah-boo) Informal n. Derived of wan-na-bee 1. One who aspires to be a Peakaboo. 2. One who imitates the behavior, customs, or dress of a Peakaboo. 3. A product designed to imitate the qualities or characteristics of something built by a Peakaboo.

[Slowdraw]

The shape of the wire, like Mopar2ya said has next to nothing to do with angle of radiation and just a very little to do with efficiency.

Flat wound coils "can" have a higher "Q" (think lower loss here) in most cases due to the fact there is less surface area facing each other between windings resulting in lower capacitance between turns. This allows one to use just a little less wire for the same inductance. At the size of the coils that are used on antennas like the Predator, Monkey, etc., the difference would not be noticeable outside a laboratory.

3 things in respect to loaded antennas (anything shorter than a 1/4 wave whip) that do matter.

Coil shape: There is an ideal proportion for highest Q and lowest loss, that is twice as long as it is wide or a 2x1 shape factor. An example would be a coil that is 8" tall by 4" wide. Again, with the larger coils on the higher end antennas, a little deviation is a moot point, it won't matter.

Coil position: The higher the coil is from the base of the shaft, the less current flows through it and therefore will have lower resistance (Q) losses. power= current(squared)*Resistance..... in other words... if you could measure the current through the coil, and square it, and multiply it by the resistance of the coil, you would have the power lost by the coil.

There is also more loss due to your ground system, which is never perfect, if the coil is closer to the base or feed point of the antenna. This is usually the LARGEST LOSS of any mobile antenna system.

Coil surface conductivity: Most people are aware of this one. A shiny gold plated surface would be ideal, but costly. (I'd pay for this, but who makes one?) Copper, next for a few days until it corrodes. Aluminum would be next best. Hams prefer cadmium plated aluminum, but nobody does this for CB'rs? Why not? Never bother with a shiny chrome plated antenna coil. It looks pretty, but chrome makes a great resistor. Remember the Predator (NOT THE PREDATOR 10K) antennas the truckers used to like many years ago. There was a reason the SWR was flat for so many channels.. It made a great dummy load!

This is probably wordy enough that most ppl won't read it all the way through, so I'll end it here. If anyone cares for more info, I'll write some more. There is still a lot of misunderstood information out there about antennas.

Examples: 2.5/1 swr may mean your antenna is great and you have a really good ground plane for your short efficient antenna. There is a way to achieve a perfect match.

A 1/4 wave whip above a perfectly conducting ground plane would have a 1.5 to 1 SWR reading.

The higher Q or lower loss an antenna is, the narrower the operating bandwidth of the antenna will be. (Beware antennas that show flat across 120 channels) Ground losses figure can into this. I had to learn about this and the two items above, the first time I put an Audio King on the roof of my van and the SWR was 3 to 1!

There is an ideal length of coax, but probably not for the reasons you think!

I can go on, but I run the risk of putting ppl to sleep... LOL

[mopar2ya]

******************************************. Who are you? I think I recognize the writing style, I just can't put it together....

LOL!

Mopar

On edit... Sorry... I was reading your posts trying to figure out who you were and saw that you wish to remain incognito. So I edited out my guesses. Anyway, good to see you posting, you are obviously very well informed and I will be watching and learning from you I think.

wan•na•boo (wah-nah-boo) Informal n. Derived of wan-na-bee 1. One who aspires to be a Peakaboo. 2. One who imitates the behavior, customs, or dress of a Peakaboo. 3. A product designed to imitate the qualities or characteristics of something built by a Peakaboo.

[clutch]

go ahead and keep teaching that's one reason i joined

[Slowdraw]

If you know me, you should know my handle... LOL You can always PM me and I'll let you know if you are right.

I'll post more about antennas if I see a good question, and I don't mind ppl disagreeing with me. If you do have a different point of view, please support it with book knowledge, not anecdotal evidence....

[Shaft]

If you know me, you should know my handle... LOL You can always PM me and I'll let you know if you are right.

I had only heard stories about you and guessed who you were from your first post.

[BtyMONSTER]

mr coily went from flat to round coils and its now a 10k wannabe/lookalike ....................for what ever its worth .
of course.............................
theres nothing like the real thing baby <<<<<someone should use that in a song .

[MOONSHINER]

mr coily went from flat to round coils and its now a 10k wannabe/lookalike ....................for what ever its worth .
of course.............................
theres nothing like the real thing baby <<<<<someone should use that in a song .

i noticed that, kinda looks like a 10k copy to me...

[209 first class]

10k copy? i hope you guys dont think 10k invented this style of antenna. (center loaded whip) :D i dont know who did, but in the city library there are ham books from the 50's-60's with those kinds of antennas. 209

[Circuit Breaker]

flat coils generate more audio because more surface area to transmit from :shocked:

Um, no. No antenna in the world is going to make your audio louder because it has absolutely nothing to do with the audio chain.

[BtyMONSTER]

flat coils generate more audio because more surface area to transmit from :shocked:

Um, no. No antenna in the world is going to make your audio louder because it has absolutely nothing to do with the audio chain.

true dat CB .

it seems nobody in the past 20 or 30 years has made a "new" antenna that hasn't been done before . the seemingly different ones to us newbies just seem to be different aspects of old designs combined in shinny new ways that the old timers so gleefully point out to temper our enthusiasm and make us feel ashamed for our excitement . my point was that a major maker switched his design from flat coils to round and now his current antenna looks like a 10 k .

its all good 209 , just felt like tossing a rib bone at ya .

[403]

Were do yo suggest i buy one from???10k is what i want!!!My 102" whip is not doing the job!!!!!

[Foxhunter]

WHATS THE DIFFERENCE BETWEEN ROUND-COILS ANTENNAS VS FLAT-COILS ANTENNAS

That sounds like a trick question. To a "junior" operator still learning like myself one difference is obvious and that would be strength----I'd think the tubular design would be much improved. Perhaps the question could be what is the ADVANTAGE of the two design methods. As another post-er stated that naturally skin-effect will always come into play with a radiator or ground---but without an actual circumferential measurement the "apparent size" of a flat-coil can be deceiving. Take any small tubular section of pipe, a copper pipe coupling for instance and cut it lengthwise and unroll it----wow----now it's a "wide looking" flat piece. I went thru that whole argument with a co-worker over his MonkeyMade vs my Predator10K and demonstrated that my "tiny tubes" as he called them, were slightly more surface area than his "wide-looking" flat bands. The appearance is deceiving but measured and electrical length leaves no guesswork. Tubular designs are much stronger structurally so that is a definite difference and advantage.

Now I wouldn't be sure though either what effect, radiationally, the flat, "2 sided" bi-directionally opposed MM-type antenna would have as opposed to the omni-directional shape of a tubular coils such as the 10k-type. That's really had me wonder and have any of our antenna engineers here considered or know what the advantage one might have over another in that respect. That is my humble observation only and have read at-length on antenna theory vs antenna fact and realize that even antenna engineers and experts disagree in many instances.

[KI4MSJ]

Can't he just retune with the amp in line?

[Foxhunter]

WHATS THE DIFFERENCE BETWEEN ROUND-COILS ANTENNAS VS FLAT-COILS ANTENNAS

Back to the original topic: Anyone who really understands antenna design/theory care to tell us, for comparison's sake, DOES ONE DESIGN HAVE AN ADVANTAGE OVER ANOTHER in regards to either flat or coiled shape and resulting performance ???