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Longer whip on A99

74IN said:
Don't waste your time.
Click to expand...

Agreed!

mackmobile43 said:
Most likely it would move the resonant point of the antenna closer to 12 to 15 meters instead of 10 to 11 meters.
Click to expand...

Agreed as well.

This "upgrade" has been around for at least 30 years and was first talked about as an "upgrade" to the Shakespere Big Stick. Notice how I keep using " " around the word 'upgrade'? :biggrin: The claims waaaaay back then said that using a Firestick whip at the top would give you 14 dB gain. Imagine that!! A Big Stick with as much gain as a Moonraker Four and in ALL directions at the same time. :headbang I think that idea was formed during a coffee break in a smoke shop somewhere.I'm thinking the kind of smoke shops that are prevelent in Amsterdam. :biggrin:
 
QRN, you're right, but I think the cause goes way beyond a little smoke. It's more like a trait of human nature.
 
Doesn't sound right.

Bizarre.

The feed point of a 1/2 wave antenna (like the A99) should be somewhere between 1000 & 2500 ohms before matching, so the matching network must be set to compensate for this high impedance and the reactance present.
A 5/8 (.64) however, is closer to 100-150ohms, so how the fartballs is a ~2000 ohm 1/2 wave matching system supposed to work with a ~150 ohm 5/8?

Interestingly, he states that the F-99 has the same resonance as the original top section. Duh, that sounds the same to me. Sounds like he's offering a different wrap of the same thing as stock!

I'd pass. Get an Imax2000 instead if you HAVE to have a radial-less fiberglass antenna. That WILL give you 2 S-units gain over the A99, at least it did in my tests.

And regarding the 7' Firestick mod to a Big Stick, I tried it. I did it while working at a camp facility near Sebastopol, Ca in 1986.
I expected it to do nothing, but it truly helped. I saw about 2-3 S-units gain to several Santa Rosa stations from my hidden spot in the coastal range mountains about 16 miles out of town, and near Bodega Bay.

I was truly surprised because, up to that point, nothing had ever worked for me regarding antenna mods, including that additional reflector wires mod farce for the Moonraker which a friend talked me into helping him do to his. Shortly after that we UNdid it.

73zzzzz
 
Yeah, I passed on the A99. $70 is a fair price for what you get, but I opted for the IMAX 2000 for a little more money. It's .64 design made it attractive, and its broadband ability sold me. It's still a fiberglass dipole with ultra-efficient copper radiator material. Cheap, but efficient design. Since an antenna is an important part of any system; I felt the money was well-spent. Why waste the $20 on adding a whip when you can spend the extra $20 and get the IMAX? Of course, if you have the A99, I think I would send it up another 20 feet rather than adding the whip mod. Unless - of course - you already have it or someone gave it to you.
 
ive read many post of folks saying the i-max 2k is broad banded . im of the impression that a larger diameter radiator is more broad banded than a smaller diameter on is . seems a 14 gauge wire shouldnt be as broadbanded as the aluminum tubing used in most other types of antennas . but , i'm still learning........ ;)
 
"ultra-efficient copper radiator material" ... Really? What's so "ultra-efficient" about copper? Oops, my mistake, confused reality with advertising. Sorry... :)
- 'Doc
 
Why not? Typically because the difference in conductivity is so minuscule that the difference that would be heard is nonexistent. And then the other characteristics of copper may not be suitable for the application, weight and strength for instance. Use whatever is suitable for the situation, be that copper, aluminum, or whatever.
Broadbandedness.
The diameter of the conductor does play a small part in that. But when you're talking about the typical "broadbanded" antennas, the broadbandedness usually results from something else entirely. Rather than try to explain that, go take a look at 'K0BG's web site, it's there and he does a much better job of explaining than I do.
- 'Doc
 
There are indeed a lot of things that come into play other than thickness to make an antenna broadbanded. My 2m/70cm mobile antenna is a Comet CA-2X4SR and has an SWR of 1.5:1 from 140-160 MHz and from 430-465 MHz and is no thicker than any other mobile antenna. It was designed to be broadband to cover amateur freqs as well as public safety/search and rescue freqs adjacent to the 2m/70cm bands.It's all part of that little black magic stuff that antenna manufacturers do. :biggrin:
 
i did not know bare wire has a velocity factor .
i thought it just had resistance that varys depending on diameter and length .
 
W5LZ said:
Why not? Typically because the difference in conductivity is so minuscule that the difference that would be heard is nonexistent. And then the other characteristics of copper may not be suitable for the application, weight and strength for instance. Use whatever is suitable for the situation, be that copper, aluminum, or whatever.
Broadbandedness.
The diameter of the conductor does play a small part in that. But when you're talking about the typical "broadbanded" antennas, the broadbandedness usually results from something else entirely. Rather than try to explain that, go take a look at 'K0BG's web site, it's there and he does a much better job of explaining than I do.
- 'Doc
Click to expand...

agree 100%, some people like to measure with a micrometer,... and then cut with an axe:confused1: compare apples to apples, don't try to compare tubing dia to wire dia. larger dia wire compared to smaller dia wire will tend to be broad broadbanded. also larger dia tubing compared to smaller dia tubing will tend to be broad broadbanded , but at the expense of more weight, windload, ect.

there is a difference between AC, DC, and RF... think skin effect and frequency (wave length). what looks to be a dead short @ AC freqs may be an open @ RFfreqs. this info is what the guy at LOWES is missing.
 
Everything has a 'velocity factor'. The 'speed' of an electron through anything will change depending on what that 'something' is. The velocity factor of wire is sort of 'close' for almost any size of wire, so in general it's a 'one size fit's all' thingy, typically about 98% give or take some. Vacuum is considered a '1', everything else except for "super conductors" is less than '1', till you get to insulators and then it's '0', sort of.
- 'Doc
 

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