metal antenna compared to fiberglass

[North Texas Mudduck]

i ran a antron 99 almost 2 years

took it down went to my granddads took down the penetrator and got home set it up

the transmit was about 1 to 1 1/2 s unit more than the antron
the receive was up to almost 2 s units compared to a guy i talk to for 4 years at 15 miles
same setup at guys house

so yes a metal antenna does work better than a fiberglass

course most on here don't even remember what a penetrator was back in the days

[BigBubbaBD]

I have to agree 100%. I plan on never running a fiberglas antenna again.

Now I just cant wait for my I-10K to make it past the christmas rush and get here already

[Alabama Tick]

Mudduck, just curious, but what wavelength size is the your Penetrator? The Antron is a 1/2 wave antenna. If your Penetrator is a 5/8 wave, then no kiddin, it will be better than the Antron. Material has nothing to do with it. Length is everything (and height, too). What the metal antennas like the I-10K offer is, superior quality and a higher cost. If you don't believe me, put up an aluminum 1/4 wave, and then compare it to the Antron. The Antron will blow it away.

And as far as TVI, I will say it again. The reason most metal gound planes are better than fiberglass in TVI, is because the fiberglass antenna do not come with ground planes. You have to add them on yourself later. Ground plane have a huge impact on TVI. As does overmodulation, coax quality, radio, and power you are running.

So, for anyone wants good base antenna, follow these simple rules:

1. Make sure it's 5/8 wave

2. If cost is of no issue, then get a I-10K or similar high quality metal ground plane.

3. If cost is an issue, then get a cheaper fiberglass 5/b wave, AND ADD THE GROUND PLANE TO IT !

4. If #3 is still too high in costs, then get an Antron 1/2 wave.

5. if #4 is still too high, then make a 1/2 wave dipole out of wire

6. Try and stay away from 1/4 wave antennas as a base antenna.

[North Texas Mudduck]

does it need to be a true 1/2 wave Antron?

The A99 is a half wave over a quarter wave variable mutual transductance tuned antenna..

I'm willing to learn something

[Alabama Tick]

No such animal. That 1/2 over 1/4 is a gimmick. Most of those have wave over half wave, are usually used on 2M bands or such, because their size is small. The Antron is a 1/2 wave. Always go by size. 18 feet is have wave.

[fireball894]

If you look at the guts of an a-99, its nothing more than a 18 ft (1/2 wave) radiator that is inductively matched to the coax at the bottom. That makes it basically a end fed 1/2 wave with coils to impedance match it to the coax (end fed 1/2 waves have a high feed point impedance). That being said, I've been pretty happy with mine over the last 10 years, but no doubt a 5/8 wave is going to edge it out in performance.

Fiberglass has NOTHING to do with it. The fiberglass radiates NOTHING. Actually it's an insulator. The copper that is coated with the fiberglass is what is radiating.

[North Texas Mudduck]

and those that talk on them antrons only talk on a piece of copper not much bigger than 22 guage

[drdx]

Wow, this is an old thread. I've ran both and given the choice I'd run aluminum but sometimes convenience kicks in and takes over. I've been an Imax/antron person for a long time just out of ease of use but that's just due to being lazy. The antron and Imax type antenna to me is essential. Within every hobby there is a big bunch of nuckleheads. The simplicity of the fiberglass antenna makes it possible for them to get an antenna up and working. While properly assembling an aluminum antenna isn't rocket science it does take more thought. Many of today's operators are just plug and play. They'd never spend a saturday properly assembling an antenna. Then, after they didn't get it right, they'd get on here and bash them.

The nucklehead antenna for the mobile crowd is the little wil.

-drdx

['Doc]

Yep, just something the size of an 18 - 22 gauge wire, and it works just dandy. There's no benefit to using a larger conductor if it isn't needed for some specific or particular reason.
How about conductor size and power handling ability? That depends a great deal on how/where and why some conductor is carrying power. Some things like coils have to be spaced properly, of a strong enough material so it can support it's self, and so on, practical stuff.
And face it, an 'A99' or Imaxx were never intended for gigawatts of power handling, so why expect it? I expect 60 mpg from my car, but I really don't think I'm gonna hold my breath, you know?? It'd be nice though, wouldn't it?
- 'Doc

[Lost Ram]

Its a very old thread indeed!!!! LOL. Its only makes since that the .64 wave Penetrator works better then a .50 wave antenna. It should not have been that much better though, 6DB?! Either the Antron was a **Censored** and not working 100% or there was another element changed (improved) such as better coax or height or something like that. If both antennas systems are 100% identical there should have been no more then about a 2DB change or so. Aslo the take off angles at equal height differ as well, so that may play a factor a too. I am not saying that these gains are false, I am saying that if an Antron user replaces his perfect working .50 wave fiberglass antenna for a .625 or .64 wave aluminum antenna that they are NOT going to gain 6-9DB. If one has an ill working antenna system and upgrades to a set up that works as untented then huge gains can be expected.

[Sheriff Bart]

the biggest difference is that both the antron 99 and the Imax 2000 have inductance match which is inefficient when compared to aluminum antennas,and the inductance match causes a heat build up and loss before your signal reaches that 22ga wire.


3's

[Lost Ram]

The Imax uses #14 wire. Every .50 and .625 (5/8) uses a matching device that creates loss.
I am not really sold on either one of them really, fiberglass or metal. I lean toward the fiberglass.
I have both the Imax and the Maco 58V. I have switched with and without telling the local crowd and no one hears any noticeable difference. The reason why my Imax is up and not my 58V is just simply because the Imax is so much more easier to work with and its more broad banded. If you talk on the cb channels 1-40, either work great. If I said one was really better then the other on CB channels it would be a lie. If an operator uses the freeband's (upper and lower channels) the Imax offers a better SWR range then the 58V. The only thing I notice on the Imax is that there is alway just a tiny hint of white noise where the 58V would go quiet when the channel is dead.
I do agree with DRDX as well.

['Doc]

All this 'fiberglass'/metal antenna stuff is blown way out of proportion to it's importance. There are a number of things that influence how an antenna is made/constructed. One of those influences is cost, another is easy of use, how comfortable you may be with working with metal or fiberglass.
The electrical characteristics of an antenna are the deciding factors of which may be 'best' for some particular circumstance. No antenna has a 'natural' input impedance of 50 ohms with out some type of impedance matching device being used, there are all kinds of those, take your pick. From there, particular 'sizes' of antennas, 1/4 w, 1/2 w, 5/8 w, whatever, have different characteristics. You pick the one that suits your purposes, that does basically what you want it to do. The 'trick' with that is keeping realistic ideas and expectations. There are no 'miracle' antennas that do everything 'perfectly'! (Except my antenna, and that's cuz it's mine, which means better than yours, and because it's the one I happen to decide I wanted and paid too much for so it's gotta be perfect, right? It doesn't have to make sense, it's the way I look at it, so what! I can justify anything if I try hard enough.)
Oh well, enough of all this. I'm going to go sit on the porch for a while. Watch the birds, plot destruction on them @#$ 'tree-rats', generally spit, **Censored** and belch when I feel like it. Whistle at the neighbor women, tell lies with the mail-lady (former chopper pilot), and try to figure out how to take all these @#$ prescription drugs I'm supposed to take. I hate pneumonia, she's a real **Censored** to get rid of...
- 'Doc

[Six Liter]

It is true that a radiating element will perform better in transmit and recieve when you increase the diameter..............flames anyone?

[231]

It is true that a radiating element will perform better in transmit and recieve when you increase the diameter..............flames anyone?

Actually I agree with Doc. And a larger diameter element usually means a little more band width (aka "broad banded"). That's usually about it. No two installations are exactly the same. But I can see a 5/8 (.64 on that one) wave beating out a 1/2 wave antenna no problem...especially when you factor in the ground plane radials and overall design of the Penetrator. But as Doc mentioned, the fact the A99 takes literally a fraction of the time to assembly & install, it works pretty well.

My Imax also out performs my A99 but at least a full s-unit (if not a little more). I'd guess the Penetrator might out perform the Imax too. But I don't think the aluminum elements have as much bearing on that as one might like to think. I made my tubular Moxon out of 1/2" copper pipe, but I suspect aluminum would have worked just as well and been lighter weight (if it wasn't so expensive at the time). Just my view point.

OH, and Doc you need more medication. I have the best antennas! My wife told me so, so therefore it's true.

[Sheriff Bart]

Hello Doc and Lost Ram, in my sig you see I run an Avanti Astro Plane. It has no matching device and if we are to believe the Avanti engineers and the patent then I'm using a 5/8 wave antenna w/o a matching device which has been at a 1.00:1 match from channel 1>40 since I put it up and attached it to the grounding rod. I'm even able to go on 10 mtrs. with the match only increasing slightly 1.5:1...no the biggest thing to me and what would concern me is the fact that inductance match's do heat up which increases resistance and generally not good for any electrical device. Your
V 5/8's and Sigmas matchers although there is a minor loss they do not heat up. The I-10k with its trombone match (beta I think) does not heat up. There has to be some advantage there I would think. And some might think "well the Astro Plane doesn't have a matching circuit how does he get the SWR down that low". Answer is I read what Avanti said in the instructions when I bought it...for lowest SWR if using foam dialectic coax use 14' multiples, if using 213 type coax use 12' multiples. I was skeptical at first but now after having it up 4 years and running like it is you can add me to the list that believes coax length (at least in my case), does make a difference.


3's

[Lost Ram]

No Flames here, just info about my experience with my equipment. And please feel free to share your own, every set up is a bit different.
Hello Sheriff,
The astro plane is a .25 (1/4) wave antenna. They do work awesome!!! I worked a few in my day, very amazing antenna. Maybe its the take off angle? I would like to have one again!

I have read in a few different articles that True SWR needs to be measured at the antenna. Somewhere along the way many years ago there was literature made about using 3 foot increments of coax (something along these lines) if you where measuring SWR at the radio itself. Many claim this is where the coax length rule came into existence. I have never been in a situation where reasonable coax lengths made any difference. (Does anyone else now about where this came about??? Please let us know.)

I also agree that larger diameter material makes for a more broadband antenna but, with the Imax their matching system with that double coil load and gamma match must have something to do with making it more broadband then my 58V. Its a big difference between the two, I can not recall the exact difference but its a very noticeable amount. Does anyone know for sure what makes the Imax so broadband?

When I got my new 58V to replace my Antron(years ago) the biggest report I got was about 1/2 an S unit at about 50 feet. I was not in the position to buy new coax, pipe or anything at that time so the only difference was only the antenna. Maybe I should have kept that Antron, it seems to have worked better then anyones that I have ever talked to!!!!!! LOL

[drdx]

The coax deal comes from the fact that a piece of coax that is exactly 1/2 wavelength long will give the same reading that you'd see at the antenna. Coaxes have published velocity factors but coax does vary, so the real way to tell for a given piece of coax would be to put it on an analyzer with a 50ohm load to confirm. So, buying into that, using exact half wave multiples would give you the same swr picture in the shack that you'd have at the antenna. Those lengths Sheriff Bart posted were probably ballpark half wavelengths for those coaxes at the time, taking into account the velocity factor, as signals travel slower down coax.

Does that make sense?

On the 5/8 performance deal, reading I've done over the years seems to indicate that a really good ground plane is needed to really see the benefit of the extra length. In the Orr vertical book, they had to lengthen the ground plane radials to 3/4 length on a vhf 5/8 to see real performance increase.

For the 5/8 to be a good match, it needs the missing length to bring it up to 3/4, a good match. I've still wondered, despite the charts I've seen on 3/4 vertical patterns, if they'd be good domestic skip antennas due to their high takeoff angles. I think they would. I may try that some day with aluminum I have and make a ground mounted one out of old army surplus tent poles. Nothing says simple antenna like one that is a good match without help at the bottom.

-drdx

[Sheriff Bart]

I never even remotely thought about any flaming where the Astro Plane is concerned. There are so many descriptions...e.g..., it's an inverted J-pole, it's a .25 wave, it's a 5/8 wave etc. Since Avanti was given so many props on all their other designs I figured the option of their fudging the truth on the AP even on the patent, was slim to non existent. It's a subject (it seems) that everyones opinions differentiate about but at the same time due to the AP's design, no matching circuit, a top hat that would electrically "shorten" the antenna and the co-inductance design which the
PDL II shares with it, which differs from the inductance design of the A-99 and the Imax makes the AP a conundrum wrapped in a mystery at best. In truth all I can attest to are the reports I get from dx on 10 and 11 mtrs and this flat match showing on my Realistic MTA-20. And it is possible that the 12' increments for solid dialectric coax may have originally been a ballpark figure but in my personal experience with the antenna it's been a grand slam.. The coax info that's in the Avanti owners manual is here on page 15. [Please login or register to view this link]


3's

[drdx]

Man, the astroplane brings back memories. A friend of mine had one. His mother was a big operator back in the cb craze, which at the time was only a few years before. They had an astroplane at one end of the house and a Starduster at the other end, about 5 feet higher. The Starduster would cover up the astroplane locally but I can't say it was the antenna. There were 2 totally different setups of barefoot radios going to each and the coax was anyone's guess on length and fitness. Later, the astroplane was moved and was the only antenna on the house and with a barefoot Dwight D. it was a known strong base. They called his mother "linear lips" as the signal was a prominent one for the time. I still have to scratch my head and wonder when I see one, but they do work well and I think much of it is the elevated feed. Install to install, that gives you an edge over other styles.

Speaking of fiberglass, wasn't there a push or a law for making omni antennas fiberglass to help reduce injury when installing the antenna, as in if it hit power lines? I seem to remember something like that in the late 80's. The early fiberglass models like the rat shack crossbow and bigstick had been around a long while by then but the first antron I ran across was in mid 1987 in my area. After that they exploded in popularity along with the export scene.

-drdx

[Lost Ram]

I never even remotely thought about any flaming where the Astro Plane is concerned. There are so many descriptions...e.g..., it's an inverted J-pole, it's a .25 wave, it's a 5/8 wave etc. Since Avanti was given so many props on all their other designs I figured the option of their fudging the truth on the AP even on the patent, was slim to non existent. It's a subject (it seems) that everyones opinions differentiate about but at the same time due to the AP's design, no matching circuit, a top hat that would electrically "shorten" the antenna and the co-inductance design which the
PDL II shares with it, which differs from the inductance design of the A-99 and the Imax makes the AP a conundrum wrapped in a mystery at best. In truth all I can attest to are the reports I get from dx on 10 and 11 mtrs and this flat match showing on my Realistic MTA-20. And it is possible that the 12' increments for solid dialectric coax may have originally been a ballpark figure but in my personal experience with the antenna it's been a grand slam.. The coax info that's in the Avanti owners manual is here on page 15. [Please login or register to view this link]


3's

No,No, I was referring to six liters comment about flames. LOL.
I like your posts, they are all from experience and not hearsay. You are right, there is a lot of theories about the AP is!

[Six Liter]

It's all good! Wasn't actually thinking down the lines of differant wavelengths, only we have noticed a slight gain in experimenting with a tried and true steel whip vs a full length fighting stick out of 1 in. copper pipe. Maybe the material used makes the biggest differance?

[Sheriff Bart]

drdx I remember hearing (or more like hearsay) during the 80's that the FCC was campaigning against aluminum antennas, which coincides with the rise of the A-99 then later the Imax 2k. Six Liter as far as increased diameter increasing bandwidth (and Jo Gunn would say it increases audio output) here's an excerpt from Radio-Electronics.com "In order to increase the bandwidth of an antenna there are a number of measures that can be taken. One is the use of thicker conductors. Another is the actual type of antenna used. For example a folded dipole which is described fully in Chapter 3 has a wider bandwidth than a non-folded one. In fact looking at a standard television antenna it is possible to see both of these features included." Here's a link to the page
[Please login or register to view this link]
go down to impedance bandwidth.


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[drdx]

Just remember, the fatter the element, the shorter it will tune out at. On this band I'm not sure the diameter needed for increased bandwidth but I've had 102 inch whips that were good in the swr department clear into 10m phone band. A great example of an antenna made fat for bandwidth would be a cage dipole or cage vertical, used on the lower bands. On this band I've used 1.5 inch diameter aluminum pole for a vertical and it didn't really have more bandwith than anything else I've used. Picture the diameter vs. frequency used on this band with antennas used on lower bands. Folks use thin elements on frequencies that are a small fraction of this band and do fine. In comparison, using #14 wire on 160 meters (1.8-2 mhz) is kinda like using a piece of wire the size of a thread on this band, and those antennas do fine. The wavelength is roughly 15 times our cb one, so imagine using a wire 1/15 the thickness.

-drdx