best ever base vertical survey ??

[Moleculo]

Supergonzo...I think you need to do a little more studying (start with the ARRL Antenna book) on how a coil in an antenna works. Actually the way a coil works in any circuit, for that matter. When a coil is present in a circuit, the current does not pass through the coil winding around the turns of the coil. It passes straight through the coil and creates a field.
The radiation pattern of an antenna does not change to horizontal when the current reaches the coil. A coil causes inductive reactance, meaning it stores energy, and induces a voltage on the circuit that follows. Normally with a 1/4 wave vertical antenna, the current is at maximum at the bottom of the antenna, then tapers off to the tip. Picture the current being similar to the hypotenuse of a right triangle. With a load coil in the middle of the antenna, the inductive reactance causes the current to stay almost constant with no taper until it reaches the end of the coil, then it tapers off. This actually can help the performance if the antenna is designed properly.

The reason competition style antennas use big, wide open coils is because you need wide spacing on the coils to handle the power that will be applied. However, the real wide spacing doesn't have much inductance. To compensate, the coils are made wider (bigger) which increases inductance.

BTW, the comments made about the Beta matching system in the Interceptor also require further study. The beta match also adds inductive reactance to the circuit, and it does not change the radiated pattern to a horizontal polarization. I'm familiar with how programs such as EZNec model the Interceptor, but remember...those are mathematical models only and must be taken only as a starting point for analytical purposes. To truly understand what is occurring in any antenna, you have get out field test it.


Moleculo

 

[mrcoily]

professionalism,

Lastly, it will be interesting what people think about the new .64 wave antenna (dare I say, KNOCKOFF) put out by another member of this forum. Do to his lack of professionalism, I'll never run, test, own, or evaluate that antenna.[/quote]

Well your so very wrong! and i find your opinion of me and my professionalism very offending and somewhat ignorant,But thats ok i am use to being attacked whenever possible!
Anyway with that said i find it unusal that you did not include probably the finest onmi ever built The dispatcher dp-257
also
Devant one&Devant special
Devant one& Devant special
I would aslo like to point out these also have a very standard dual trombone?Lets not start in with the knock off stuff,,10-4 Good buddy.Now i am posative the enforcer will perform as well as anything out here and the price will be lower Not $300.00 like people would like you to belive.And as i told people who called and asked me a million questions that i answered in full,I must add theres that Lack of proffesionalism again,The price was not set.But i can tell you this the performance of the enforcer .64 will be hard to beat by any builder,and it will be in the same price range {less} weight is less and the power rating is only 5 kw enough to get you a pile of fcc leters.Thanks just wanted to clear a few things up about all that.And for whatever it worth i apolagize if you don't like me but ia m what i am and if you don't ever run a coily,then that just one thing you did not do in your life,,,,,Thanks again and have a great day.

 

[supergonzo]

"The reason competition style antennas use big, wide open coils is because you need wide spacing on the coils to handle the power that will be applied. However, the real wide spacing doesn't have much inductance."

I agree,which is why since the BIG coil antenna is not acting like a inductive coil and it is not needed. You basically have proven my point. The reason SMALLER coils are used is to make up the difference electrically in wavelenght. They DO NOT add much radiation & NO power. In fact in smaller coils, the power is lost as heat. DOn't think so??.........Run 2000 watts through your Wilson 1000 and put your hand on the coil when doing it.

1. I have every ARRL Book since 1973
2. I DO have an antenna farm, and have tested over 100 antennas.
3. You would be surpised how accurate modeling antenna programs are. Send me an email with your modeling program of the 10K
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An Mobile antenna with any coils: big, small, wide, flat...etc.etc. will
NOT outperform a 9 foot steel whip, in a similar placement on a mobile vehicle Period. If you don't understand this then you can't discuss antennas intelligently. There is NO test where a loaded antenna has out performed a non-loaded resonant antenna, it is NOT possible. A antenna like a whip needs NO coil, because it is resonant(it does not need to be matched)!! A shorter antenna needs a coil, because its NOT resonant. Therefore you have introduced loss. There is NO way around this.
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Starduster is a 1/4 wave ground plane with drooping radials. Had a few of those back in the 70's. Thought they would rule the world (based on advertising claims)back then. They are NOT a top performer. The reason why the guy with a Starduster is doing 60 over is that he has a linear amp. Or he lives next door.
-----------------------------------
When you test an antenna you do NOT use high power, in fact you use very LOW power, to avoid reflections and other anomailies that can enter into the equation.
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I am trying to provide useful information, I know probably none of you have ever been to a antenna farm, not ever used an antenna analyzer or a field strenght meter. Thats okay. I am not here to argue. I will present the facts as they are, if you choose to disregard them, then good, thats your choice....your'e a typical CB'er.

Buy yourself a Henry and be happy.

 

[bob85]

i do agree that overall my 1" diamater copper tube does beat the 10k if you take an average of vehicles but on my particular car i cant get vswr down low enough to run my amplifier hard without damaging it, in my situation the 10k tunes so low that my meter wont register any reflected power i can run the amp flat out and that means it overcomes the quarterwave tube or my whip, on my buddies large car both antennas give good vswr results and the straight 1/4 wins by a small margin, maybe i could try a dollar match on the 1/4 wave tube and redress the situation im not sure as i have no analyser so i dont know if the 2:1 vswr is presenting a high or low impedance and hense i dont know how to tackle the problem i have, does anybody have ideas on how to lower vswr on my copper tube when the problem is a basic lack of metalwork for a groundplane??..

 

[Hc714]

F R A N K

 

[Moleculo]

...then you can't discuss antennas intelligently

You've got some guts to tell me what I can and can't discuss intelligently on my own forum. :roll:

I suggest you read the section in the ARRL Antenna book on mobile antennas. Specifically the part that talks about how a well designed coil can prevent some radiation loss to ground that occurs in a standard 1/4 wave antenna. I'm not saying that ALL antennas with coils perform better than a 1/4 vertical. That would be foolish. I am saying that it is possible that some can if they're designed well. In the context of talking about the amount of radiation toward the top half of mobile antenna as compared to a mobile with a high Q coil 1/2 way up, here's a quote from the ARRL antena book, 19th edition, page 16-7:

This higher current flow results in more radiation than would occur from the equivalent section of a 1/4 wave antenna.

Is there some loss in a coil? Yes. But if the coil changes the radiation characteristics so that it is more suitable for RF communication, then in essence you may have better "performance". For example. If you have an antenna with zero loss, but all the radiation is sent straight vertical into the sky, it will "perform" worse than an antenna with loss, yet puts the radiation pattern out on the horizon.

BTW, even a coil with wide spacing cases inductive capacitance. Whether or not it is enough for the application is a different story.

When you test an antenna you do NOT use high power, in fact you use very LOW power...

That depends on what you're testing for.....

 

[Red Ranger/444]

I thought we were talking base antennas? :bounce

 

[supergonzo]

"You've got some guts to tell me what I can and can't discuss intelligently on my own forum."

Hey Man I'm not into politics, just trying state what I know to be true.
--------------------------------
"I thought we were talking base antennas?" Me too
--------------------------------
NO CB mobile antenna with a coil will outperform a 9 foot whip.
The quote from the ARRL is taken out of context..... on 160 meters a wavelenght is 550 FEET!! OF COURSE you need a coil! Then your statement about coil loss would certainly apply.
--------------------------------
"If you have an antenna with zero loss, but all the radiation is sent straight vertical into the sky, it will "perform" worse than an antenna with loss, yet puts the radiation pattern out on the horizon."

Yes thats true, BUT is NOT the case with a 9 foot vertical whip. Which is what we were discussing.

 

[Moleculo]

The quote from the ARRL is taken out of context..... on 160 meters

Read the text. It's not in the context of any particular band. I didn't take it out of context at all. It's in a chapter about radiation resistance. Note the excerpt I used said "1/4 wave antenna" not 9' CB whip. Look at the diagrams on the page of current flow of both a 1/4 wave whip and an antenna with a well designed, high Q center placed coil.

BTW, the coils on "competition" type CB antennas can't be a very high Q, otherwise they wouldn't be so broad banded.

Lastly, if what you're saying is true, then how come so many people on this forum and others who have done their own comparison of both a 9' whip and a well designed antenna with a coil have reported stronger signal reports with the coil antenna? Not everyone, but many have. If nothing else changes but the antenna then how can you explain those results if a 9' whip will ALWAYS outperform the coil antenna?

Maybe we should start a new thread...somehow we got sideways on mobile antennas...hehehe

 

[Red Ranger/444]

I already know about mobile 9'ft'ers, I use 3)-1/4 waves in one to do the job, which is getting to be worldly :bounce Plus, I'm not even set up in a optomal location, YET, on the vehicle. 73's

 

[Master Chief]

Back to BASE ANTENNAS!

"10K an upgrade to the original Penetrator" Yes maybe the term I used Knockoff wasn't quite fair. But it is based on the Penetrator (even stated so on Jay's web site) and IS Identical except for the matching system.

Having been around from the beginning of Jay's attemps to rebuild the P500, I know what I'm talking about here. Yes, he started out trying to rebuild and upgrade the P500. When that didn't work to his liking, he continued to move forward and whatcame out of the 4+ years of testing and building is the I10K. It is VERY different than the P500! I can point them out to you if you wish.

I think this antenna is the best CURRENTLY available Omni around, and have measured it as such as well. And I have used the MiniNEC and EZNEC antenna modeling programs and they agree.

Could I get a copy of the .EZ file?

However, I have found as a general rule...... The matching system of ANY antenna should be as small as possible. The reason you have one is to match the antenna electrically.. that is all. Otherwise you risk losing radiation in unwanted directions from the matching system into free space. There is no getting around this....

It needs to be the proper size to do the job intended. Jay's IS.

The 10K uses a trombone section which is almost it is 22" end to end, but then it is folded back on itself, so in reality it is 40" long!! And it is in a horizontal position, next to the ground radials. And it is a normal diameter of a typical radiating element. 3/8 ". IMO ...TOO Big, TOO Long and wrong placement.

If you look at the original Penetrator, you will see that Hygain used a VERTICAL matching system that was very thin, and considerably shorter. WHY do you think they did that?? They did it as to NOT interfere with the normal radiation pattern of the antenna. They only needed to match the antenna. Not create any other issues, so they kept it small, as it should be.

Here is where we differ. First off, the MAGIC of the 5/8 wave antenna is the 5/8 wave radiating element! You can make it out of a wire, a single diameter tubing, or stepped tubing. After all the correct math has been done and the electrical length corrected, you will have a 5/8 radiating element for a partciular frequency. You do NOT wnat to interfere with this radiating element by putting ANYTHING in the vertical plane. This is only ONE of the problems of the P500 and in direct contradiction to what you are saying.

Avanti's loop on the Sigma 5/8 wave was used to take the antenna to the next 1/4 wave multiple in order to feed it with a 50 ohm feedline. It was placed as a horizontal loop so as NOT to affect the radiating pattern of the VERTICAL 5/8 element. This is direct from one of their engineers. Makes perfect sence to me. Putting that "hairpin" in the vertical plane does affect the radiation pattern of the antenna. Jay learned this with the Mastadon5K and anbandoned its use.

The trombones were needed to tune the antenna over many megahertz. This matching system is nothing new as it has been around for ages. If Jay was building a "40 channel ready" antenna, he could have eliminated the tuneable trombones and used a single diameter tubing in the same configuration. This matching system is more efficient and does not interfere with the 5/8 vertical radiating element....as designed.

I've said it before; a 5/8 is a 5/8 is a 5/8. Jay's advantage is the efficiency of the matching network! Less loss means more signal in the air! Do the trombones radiate? Maybe, but it is insignificant due to the design of the network.

Most antenna manufacturers take cost into consideration when designing and building antennas. How do they build a $20.00 antenna that they can sell for $75.00? Everyone needs to make a few bucks on them! Take away the cost consideration and you get a better antenna.

Is the I10K perfect? Nope. It IS however, the best antenna on the market today and worth EVERY PENNY!!!

In head to head, real world, tests against the P500 (Jay's favorite) and the Sigma 5/8 (my favorite), the I10K beat both handsomely!

 

[supergonzo]

"Is the I10K perfect? Nope. It IS however, the best antenna on the market today and worth EVERY PENNY!!! ""

We mostly agree, except over the matching system, AHH so what!
--------------------------------------------------
Anyway The statement "best antenna on the market today" would apply to a vertical antenna AND I agree. And have tested it as such.

Earlier comments that it out-performs a 4 element cubical quad are still nonsense however.
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As far as Mobiles go: LONG antennas that are resonant are better than shorter antennas with coils. This is an undisputed fact. Radiation resistance (with proper length antennas), goes up, Thats good.

Coils:coil resistance is usually the main problem. Improving coil Q greately reduces that loss. Here's what can help:
Moving the coil up increases the current in the whole whip.
Larger diameter whips have more capacity than smaller whips and reduce coil inductance and thus coil loss.
Capacitor hats above the coil can help, unless they are too close to the coil itself.

ALL of these things can help, BUT they cannot make up for the physical lenght of the antenna.
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If what you were saying was accurate, that coils are an improvement over the whip, Then manufacturers would have quickly made lots of whipless antennas, and you would see them everywhere. Who wants a 9 foot whip on their car anyway today?? For that matter ANY whip??
Why hasn't this happened??? Because coils cannot be a substitue for a resonant proper length antenna.

Even your cell phone has a whip, and thats only 5 inches. Don't you think they could have used some type of small INVISIBLE coil if they could??

 

[Moleculo]

Gonzo...in your last post you didn't dispute or disprove anything I or the ARRL Antenna book I quoted said earlier. I never said that the whole antenna should be a coil and it will perform better....that's ridiculous. I never said all antennas with coils perform better. I made a statement about what CAN be achieved under the right circumstances, and I quoted a credible source.

A lot of the things you said, I agree with, but when you started out with saying the RF goes "round and round the coil and gets confused" (paraphrased), I still think some further study is required on how coils work.

(BTW, speaking of cell phone antennas, did you ever notice how EVERY externally mounted car Cell antenna has a load coil? They sure don't have to use it at the frequencies in use, but it's just an observation. I don't know why they do it....)

I don't know how everything works and I don't have all the answers, but when I certainly try to read as much as possible to understand. When I read something from a credible source that is contrary to the conventional thinking, I certainly want to try and investigate it more.

 

[Marconi]

what do you guys think was the best ever performing base vertical, and which is the best currently available ??, i have tried countless antennas since 1976 and my vote would have to be the avanti sigma 4 if wind survival matters and the ham international big mack if it don't, although the avanti is much more difficult to get working correctly, adjusting tapping point gamma length and antenna length to get best results its not just a case of getting a flat vswr you have to take signal readings over say 40+ miles and keep adjusting for best signal and flat vswr, i currently use a homebrew 7/8 sigma its got a 4 legged basket and is 32 feet long not 27 like my original avanti's but it does work better over longer distances like 70 miles mounted 10 feet from the ground, if i could just get it back up at 73 feet to the base like all my others where i would be real happy, and if they all blow away in the wind what do you think i should replace them with ( don't say imax 2000 lmao ).


</p>

This old thread from 2004, sounds a lot like Bob85.

 

[edfiero]

Have had very good results with a A/S Starduster, very broad banded, quiet when grounded properly, and easy to set up.

I was wondering what everyone thought of the Starduster? Back in the 80's I use to have a 1/2 wave GP from Radio Shack. A station across town ran a StarDuster and always seemed to be able to reach stations I couldn't. Local it seemed it was a bit better than me, but for Skip it was much better.

In recent years I ran a Maco 5/8 wave. No complaints, but always wondered if there was something a little better out there.