Need Gain Figures for These Antennas

[Midlander]

Need to know what the gain is for a 102 whip, and the predator 10K w/ 27" shank. Thank you.

The reason I am asking is because I found this antenna, and was wondering how they might compare.. Thanks.

GoldenRod 45 SpiderA - [Please login or register to view this link]

[Black Lightning]

Need to know what the gain is for a 102 whip, and the predator 10K w/ 27" shank. Thank you.

The reason I am asking is because I found this antenna, and was wondering how they might compare.. Thanks.

GoldenRod 45 SpiderA - [Please login or register to view this link]

A 102" whip, under ideal circumstances, has 'unity gain'. Unity gain is 0 gain. Any loaded mobile including a Predator 10K will have negative gain (loss).

[Mr B]

With mobile antennas think this
LONGER IS BETTER ... COILS REDUCE PERFORMANCE

On the transmit side
A 102" whip is the ideal mobile antenna if you can mount one.
If not then you must compromise performance with a shorter antenna.
When mounting ANY mobile antenna remember that the bottom third is what radiates most of your signal.
Are you radiating it into the air or into the metal body of your vehicle?

On the receive side
A shorter antenna with a center coil will hear about as good as the 102" whip.

If you really need to "get way out" consider a small (50 - 125 watt) linear amplifier.

[Grump]

102 whip cant beat the tried and tested

[treetall]

i have never heard of this company or this antenna before. that might tell ya something. i dont know i say if you can run a 102 and if you cant then run the biggest 10k you can. just my 2 cents. im back out

['Doc]

The first thing is knowing the differences in the 'type' of gain quoted, dBi, or, dBd, or just plain old dB. That's because it tells you what the antenna is being compared to. If it's got an "i" on the end it means an 'isotropic' antenna in free space, an ideal or perfect antenna. If it has a "d" on the end it's being compared to a typical dipole antenna which is typically closer to the truth, but there are 'catches' to it. If there's nothing on the end of that 'dB' then they are not telling you what the antenna is being compared to. Another antenna, or a beer can laying in the yard?
A sort of 'ROT' for those isotropic antennas is deduct about 2 dB to start with. Not exact by any means, but it'll get you in the ball-park. The catch with comparing with a dipole, or any other 'real' antenna is that you ave to have some idea what that 'other' antenna is capable of to start with. Is it mounted in such a way as to be at least sort of comparable to the tested antenna? Lots of 'maybe's in that so take it with some 'salt'. And then there's the 'other' thing you should always be careful of, advertising. I very seldom ever believe everything the manufacturer says about their product. (Gee, I wonder why?) Another aspect is that when 'they' do the testing, they make things as 'perfect', or 'optimal' as humanly possible to get the 'best' numbers. When I take that antenna home you can bet that things are NOT going to be 'optimal', or probably 'good' in any way as compared to 'their' set up. Know what I mean?
So, 'gain' figures are -sort- of a -fair- indication of what an antenna will do. Not always the best by any means, but fair, sort of. A very rough 'ROT' (Rule Of Thumb) is that 1/4 waves don't do as well as 1/2 waves. 1/2 waves don't do as wll as 5/8 waves. And after about 5/8 wave, things start going to 'pot', really get "iffy". The next thing to consider is that the longest one ain't always the most practical for any number of reasons. Have you got room for it? Will your "significant other" approve? Can you afford the @#$ thing? And so on. (That second 'if' is more important than the other ones if you're smart!)
- 'Doc

I can sure complicate things cain't I??

[Midlander]

Very good information,

But it is impossible for an antenna to have 0 gain, if that was the case then I wouldn't be hearing anything. Most 5/8 wave base and vertical antennas have about 3.5dbi rating. So there must be some sort of number information on the gain of a 102" whip.

I tried the 102" on my truck and could never get a really low swr even after grounding everything. So I purchased the longest predator 10K I could and got everything working good with that. The diesel truck has a RCI-2950DX and a 1x4 worldwide (Got rid of the MS700 from XForce) and things seem to be better. I can hear the difference between 102" and the 10K, but I am really wanting some dbi numbers on these two antennas. Does any one know?

Thanks for info guys.

[fatboy803]

Seen two guys putting 102 whips on their big trucks tuesday . Im anxious to see how they come out

[fatboy803]

Seen two guys putting 102 whips on their big trucks tuesday . Im anxious to see how they come out

I really wonder is this a good idea tho ?

[Black Lightning]

Very good information,

But it is impossible for an antenna to have 0 gain, if that was the case then I wouldn't be hearing anything. Most 5/8 wave base and vertical antennas have about 3.5dbi rating. So there must be some sort of number information on the gain of a 102" whip. ...

Gain on an antenna is a measurement of effective radiated power (ERP) increase over a particular source. In this case, the source is a full physical length 1/4 wave antenna - such as a 102" whip. So, when the word 'gain' is used, that's an ERP increase over that offered by a 1/4 wave antenna - an antenna with unity gain.

[drdx]

There will be no "gain" but rather reduced loss. Anything with a coil, as Mr. B mentioned wisely, reduces things. The 102 inch whip is the best for this band mobile wise, followed by open coil center loaded ones I'd guess, followed by lesser quality center loaded ones, then the wilson center load close wound crew, then the base loade ones, then there is the fiberglass crowd, ranging from short to tall, taller usually working better.

-drdx

[jessejamesdallas]

There will be no "gain" but rather reduced loss. Anything with a coil, as Mr. B mentioned wisely, reduces things. The 102 inch whip is the best for this band mobile wise, followed by open coil center loaded ones I'd guess, followed by lesser quality center loaded ones, then the wilson center load close wound crew, then the base loade ones, then there is the fiberglass crowd, ranging from short to tall, taller usually working better.

-drdx

You people just don't know when your beat, always talking about those 102" Whip antenna's...I'll put my Dual Stick-On Midland Window Antenna System up against ya any day of the week!

[drdx]

Settle down there. I never include cellular antenna lookalikes. This is not a professional discussion, we're just hobby guys here. If I wanted to bring in the big guns I'd call my mother over with here 21ltd and little will. I'll have you know she DOES have a T connector and another little wil so she can go 2 hot if the whippersnappers get to back talkin and yes she does run the extra thick wire on that cigar plug, that is when she's not lighting up. Yep, I said cigar, not cigarette. My mother smokes the big ones, not those purse swinging filtered wannabes. She might be jaw packin some chaw there too, and she don't need no sissy spittoooon like some do. She's all business, so move over when she drops the hammer unless you'd like a pat on the back that could club a baby seal and melt your manhood. -drx

[jessejamesdallas]

Bring her on drdx...I prefer a fair fight! But if she's going to be cheating by going to two-hot's using one of those illegal T-connectors, then the gloves come off!

I'll be putting my Ground Plane Kit's back on my antenna's! She'll be seeing lightning bolts flying off the 6 tipped star shaped radials, and never know what happened! Granny will be heading back to the nursing home, using those lil Wilson's for cruches...

[drdx]

Well, I'm not bragging, but since the grandkids started wearing the foil hats when they ride with here, that webbed foot deal they had has slowed a little in growth. I told my wife it was genetic, on her side, just to guilt trip her, and I do the fake crying thing to get out of valentine's day and our anniversary, but that's a whole other story. Is that one of those Too much information deals? -drdx

[jessejamesdallas]

Well, I'm not bragging, but since the grandkids started wearing the foil hats when they ride with here, that webbed foot deal they had has slowed a little in growth. I told my wife it was genetic, on her side, just to guilt trip her, and I do the fake crying thing to get out of valentine's day and our anniversary, but that's a whole other story. Is that one of those Too much information deals? -drdx

Think I may have seen her before...Was she in that movie "Water World?"...Look at the bright side...least she doesn't have 3 eye's or a long scaly tail!

[Midlander]

Well now that this topic has gone really off topic, I guess no one knows this information. Thanks anyway.

[bettyboop]

Who cares about the DB GAIN. It is all about the REAL world out there.

IT IS A 10K WORLD

[drdx]

It is a "10k world" for those who don't choose to run a full size antenna, and for many who can but have invested money well beyond something else that would perform better but need a realistic assurance. I'm guessing that in the past, before the web, some said things like "it is an 8 track world" or "it is a 23 channel world" or "Betamax video tapes rule, and vhs sux" but we all know that things evolve and sometimes they do not, as in the case of the coil free whip, as the laws of the universe keep it superior to a coil loaded anything in the same mounting location. Are the convenient and the best choice for many? Certainly, but that doesn't mean they are the best. Maybe when they say "10k world" they're talking about the numbers of them ran compared to the real whip. Maybe one day that will be the case, but as in this hobby just to name one, the many many that choose to do the same thing does not mean they are the strongest out there. -drdx

[lonesome 500]

gain is relative term......when going ant to ant

everything has a gain.......your cel phone look alike....has more gain than a v8 can...but a wal-mart magnet mount has more than the cel.......now

length is not the only factor that adds gain.....surface area

lets compare the 17 or longer shaft 10k to the 102......overall length across the coil will be close to same.....but since rf travels the surface of the ant......the 10k has waaay more surface area....

diameter of shaft....dia of coil wire......dia of stinger of 10k greater than 102

coil loss figured on xmit.....not rx

[drdx]

So, do you think the surface area of a 10k makes it work better than a coil free antenna of a narrower diameter, although the physical length of the coil electrically shortens in reference to how it radiates? On many coil diameters, it takes twice as much length to equal a single length for resonance.


I posed this question on another topic wondering the same thing.


-drdx

[Black Lightning]

I am going to try to explain this one more time in a different manner.

Effective radiated power = transmitter output power plus or minus gain.

Gain = ERP over output power.
Loss = ERP lower than output power.

For example, if the transmitter has an output power of 100 watts, and the effective radiated power is 100 watts, this is called 'unity gain'. That is, ERP and output power match (not taking into account things such as line loss, etc). A 1/4 wave vertical is said to have 'unity gain'.

If an antenna has 3dB gain, then if it is driven with 100 watts, it will have an ERP of 200 watts. Most 5/8 ground plane types have such real-world gain. Ignore the marketing hype.

If an antenna has 3dB loss, then a 100 watt drive has a 50 watt ERP.

A physical length 1/4 wave whip, under ideal conditions (perfect grounding, etc) has unity gain.
If you throw a loading coil on that antenna and reduce its physical size, that antenna has a loss - meaning, it is no longer unity gain. How well an antenna with a loading coil is constructed will determine how close to unity gain (meaning, the least amount of loss) that antenna will achieve. Better loaded antennas such as the Wilson 1k/5k, Monkey Made, Predator 10K etc, will have low loss figures. None of them will ever outperform a full 1/4 wave physical antenna. It's just laws of physics at work here.

[lonesome 500]

So, do you think the surface area of a 10k makes it work better than a coil free antenna of a narrower diameter, although the physical length of the coil electrically shortens in reference to how it radiates? On many coil diameters, it takes twice as much length to equal a single length for resonance.


I posed this question on another topic wondering the same thing.

-drdx

pound vs pound.....i'd say yes.......here is my reasoning and testing

rf travels surface......straighten out the coil.....check length of shaft...straightened coil...and stinger....now

it is a given fact......the ONLY way to add gain to a fixed length radiator......is to increase diameter = surface area

take a standard 102.........compare it to 102 inch piece of 2'' dia pipe.....the 2'' pipe will kill it

the overall surface area of the 10k is what stands out.....as long as the shaft is longer in given comparison

ps....GAIN WORKS BOTH WAYS....NOT JUST TX......GET AWAY FROM THE TX ONLY MIND SET...THE COIL IS ONLY IN LOSS STATE WHEN ''HOT''.....THE OVERALL LENGTH WILL STILL BE A CLOSE 1/4 WHEN THE COIL IS STRAIGHTENED.....D.....RF TRAVELS THE SURFACE OF EACH COIL

[Black Lightning]

So, do you think the surface area of a 10k makes it work better than a coil free antenna of a narrower diameter, although the physical length of the coil electrically shortens in reference to how it radiates? On many coil diameters, it takes twice as much length to equal a single length for resonance.


I posed this question on another topic wondering the same thing.

-drdx

pound vs pound.....i'd say yes.......here is my reasoning and testing

rf travels surface......straighten out the coil.....check length of shaft...straightened coil...and stinger....now

it is a given fact......the ONLY way to add gain to a fixed length radiator......is to increase diameter = surface area

take a standard 102.........compare it to 102 inch piece of 2'' dia pipe.....the 2'' pipe will kill it

the overall surface area of the 10k is what stands out.....as long as the shaft is longer in given comparison

ps....GAIN WORKS BOTH WAYS....NOT JUST TX......GET AWAY FROM THE TX ONLY MIND SET...THE COIL IS ONLY IN LOSS STATE WHEN ''HOT''.....THE OVERALL LENGTH WILL STILL BE A CLOSE 1/4 WHEN THE COIL IS STRAIGHTENED.....D.....RF TRAVELS THE SURFACE OF EACH COIL

You're right, the loss is more pronounced on TX than RX but it's not as big a delta as you think it is. Remember, the best receive antennas are the ones with the most physical length. This again puts the 1/4 wave physical in the lead.

If you want to do an experiment to verify what I am saying, make a 5/8 wave loaded antenna (restrict the vertical length to 12'), and then compare it with a V58 or better yet, a Sigma II or Penetrator 500. Don't worry about the TX performance, just use it to determine how you can pull in stations on SSB. Compare one against the other. I guarantee you the loaded antenna will not receive as well as the full length antenna.

Now, while increasing the diameter of an RF conductor could lead one to conclude that it will have more surface area, the power density will be lower so it balances out.

[Midlander]

Interesting information, many antennas on the market list gain figures. i know they are never exact, but they do give the individual some information about what the antenna can do. Why is it that so many manufacturers give gain figures, yet no one seems to know what the rating is for 10K or 102" whip? I find this very interesting.