gainmaster vs i10k a quick test with locals

[BOOTY MONSTER]

another analogy could be a bucket of water sitting on the ground . a high TOA 1/4 wave being the water in the bucket . everything in the bucket/city is saturated with signal/water . now , if you could just lift the sides of the bucket up leaving the bottom on the ground the water inside will flow out in all directions . the area where the bucket was will still be plenty wet , but the water/signal that was in the bucket has covered a much greater area .

 

[W5LZ]

Something else to keep in mind is that all antennas have a "lowest radiation angle", but they also have 'higher' radiation angles too. It isn't a clearly defined 'hard' cut off point with nothing above or below that particular radiation angle. There's usually -some- radiation at all angles. Maybe not much, but some.
You also have to keep in mind that since there will be at least two antennas involved, transmitting and receiving, you have to factor in the best/worst angles of both.
There's no such thing as a 'DX antenna' and a 'local antenna' as such. Particular antennas may have a radiation pattern that tends to favor what you are trying to do at some particular time, but there's no antenna that does it all every time.
Oh, and then you get to factor in how 'Momma Nature' happens to have her propagation working at any particular time. Pour all that into the mixer and crank the handle. What you get is what's happening at that one particular time. That can change drastically in a very short period of time.
DX and local signals don't always arrive at any particular 'angle', it can happen at almost any angle depending on a very large number of factors. Wait a while, it'll change...
- 'Doc

 

[NRG]

another analogy could be a bucket of water sitting on the ground . a high TOA 1/4 wave being the water in the bucket . everything in the bucket/city is saturated with signal/water . now , if you could just lift the sides of the bucket up leaving the bottom on the ground the water inside will flow out in all directions . the area where the bucket was will still be plenty wet , but the water/signal that was in the bucket has covered a much greater area .

help im drowning in confusion!

 

[gamegetter]

Study shockwaves previous post, i think it is the best analogy and remember this post is about local line of sight communications. He makes this distinction at the end of his comment. I copied and pasted here for you.

"When it comes to line of sight contacts, having the angle of radiation close to 0 degrees is a benefit. This is true even if the other station is only a mile away. We would not want to change the angle from 0 degrees to increase a local signal unless there were extreme differences in elevation. Actually achieving 0 degrees over real earth on this frequency is about impossible but for this example let's assume it is possible.

The short 1/4 wave may have a beamwidth that is 30 degrees wide and aimed at the horizon. The Sigma may have a beamwidth 15 degrees wide aimed at the horizon. The closer two stations are together, the less important aiming the beamwidth becomes. Think of a beam of light emitting from one antenna to another. If we compress the light beam into a narrow 360 degree beam, it will reach out further in all directions.

At the same time it will only place a small bright spot of light on the antenna that is very close. If the beamwidth of light were many degrees wider, we could illuminate a larger section on the close antenna but there will not be any visible light in the distance. Lighting up a bigger section of the closer antenna is likely to show more total energy locally then one small bright spot.

This is a very rudimentary analogy and over simplifies several things including how ground reflections affect RF in terms of beamwidth and take off angle. RF at HF frequencies cannot be controlled or focused nearly as effectively as light either, but if you follow the concept you can see how it applies to targeting different locations with an antennas beamwidth and take off angle.

Targeting skywave DX requires different radiation angles then line of sight. At first one might think a high gain vertical with low angle radiation on the horizon would be poor in DX. The good news is most antennas of this type cannot avoid producing secondary lobes above the horizon that are very useful for skywave DX"

 

[BOOTY MONSTER]

this video Marconi made to help me with something may help you too .

YouTube - ‪Booty Monster's question re: a full wavelength Vector 4000‬‏

at the 1:45 ol' grandpa shows on the graph how the antenna with the lower TOA puts more signal down on the ground where the contacts are . if we're talking to helicopters and planes or down in a deep hole or valley the higher TOA could benefit us .
thanks again for the helpful video OGP

 

[gamegetter]

yes the models help.

 

[W5LZ]

But then, those 'higher' angles do bounce off of the ionosphere and come back to earth (skip). So, those higher angles certainly are not useless. considering the variableness(?) of propagation, how do you know what angle that signal will arrive at?
- 'Doc

 

[W5LZ]

double post, sorry.

 

[Shockwave]

But then, those 'higher' angles do bounce off of the ionosphere and come back to earth (skip). So, those higher angles certainly are not useless. considering the variableness(?) of propagation, how do you know what angle that signal will arrive at?
- 'Doc

As I understand it, angles above about 30 or 35 degrees are basically useless unless you're working satellites. Sharper angles tend to pass through the ionosphere rather then reflecting off it.

 

[NRG]

Study shockwaves previous post, i think it is the best analogy and remember this post is about local line of sight communications. He makes this distinction at the end of his comment. I copied and pasted here for you.

"When it comes to line of sight contacts, having the angle of radiation close to 0 degrees is a benefit. This is true even if the other station is only a mile away. We would not want to change the angle from 0 degrees to increase a local signal unless there were extreme differences in elevation. Actually achieving 0 degrees over real earth on this frequency is about impossible but for this example let's assume it is possible.

The short 1/4 wave may have a beamwidth that is 30 degrees wide and aimed at the horizon. The Sigma may have a beamwidth 15 degrees wide aimed at the horizon. The closer two stations are together, the less important aiming the beamwidth becomes. Think of a beam of light emitting from one antenna to another. If we compress the light beam into a narrow 360 degree beam, it will reach out further in all directions.

At the same time it will only place a small bright spot of light on the antenna that is very close. If the beamwidth of light were many degrees wider, we could illuminate a larger section on the close antenna but there will not be any visible light in the distance. Lighting up a bigger section of the closer antenna is likely to show more total energy locally then one small bright spot.

This is a very rudimentary analogy and over simplifies several things including how ground reflections affect RF in terms of beamwidth and take off angle. RF at HF frequencies cannot be controlled or focused nearly as effectively as light either, but if you follow the concept you can see how it applies to targeting different locations with an antennas beamwidth and take off angle.

Targeting skywave DX requires different radiation angles then line of sight. At first one might think a high gain vertical with low angle radiation on the horizon would be poor in DX. The good news is most antennas of this type cannot avoid producing secondary lobes above the horizon that are very useful for skywave DX"

it seems to me if you got a narrower beam of light you got higher intensity so wouldn't you you still have more energy in that one spot? if the other antenna is like a flood lamp then wouldn't it be all below and above the other small spot so much it would be off of the antenna and wasted on the ground and in the sky?

 

[Shockwave]

it seems to me if you got a narrower beam of light you got higher intensity so wouldn't you you still have more energy in that one spot? if the other antenna is like a flood lamp then wouldn't it be all below and above the other small spot so much it would be off of the antenna and wasted on the ground and in the sky?

The short answer is no. Remember the light analogy is not perfect. In the real world with RF there are many more factors to consider. Such as the beamwidth of the second local antenna you're testing against. If it has a wide beamwidth also, then it's more likely to show favorable results to a local 1/4 wave. The easiest way to sum it up is that the closer two antennas are together, the more they will respond to signals at elevation angles other then 0 degrees. Not the angles that will increase signal in distant line of sight communications.

 

[NRG]

The short answer is no. Remember the light analogy is not perfect. In the real world with RF there are many more factors to consider. Such as the beamwidth of the second local antenna you're testing against. If it has a wide beamwidth also, then it's more likely to show favorable results to a local 1/4 wave. The easiest way to sum it up is that the closer two antennas are together, the more they will respond to signals at elevation angles other then 0 degrees. Not the angles that will increase signal in distant line of sight communications.

i'm confused. the second antenna i'm "testing against" not testing "to" would be the wide one if the first was the narrow one so how could the first one be "also wide"? when i got my gainmaster i treid it on the short mast where i have a old rasdio shack quarter waver hooked to a cobra89 to listen to the truckers chanel and i got reports of 2 to 5 pounds better from the stations around here mostly 3 to 5 miles away and most of them have stardusters or antorn99s

 

[Shockwave]

i'm confused. the second antenna i'm "testing against" not testing "to" would be the wide one if the first was the narrow one so how could the first one be "also wide"? when i got my gainmaster i treid it on the short mast where i have a old rasdio shack quarter waver hooked to a cobra89 to listen to the truckers chanel and i got reports of 2 to 5 pounds better from the stations around here mostly 3 to 5 miles away and most of them have stardusters or antorn99s

The second antenna would be the other person's helping with the test. If they too have a wide angle 1/4 wave, your 1/4 wave is more likely to give them a better signal because it responds to wider angles on local signals.

With respect to the Gain-Master coming in 2 to 5 S-units lower then a 1/4 wave, there are no two omni directional base CB antennas with this much difference on the market. Sounds like inaccurate reports or the GM was real low to the ground.

 

[NRG]

im not yelling accurate or nothing like that but they just told me what they see on there meters. the pole they was on is a 2 part telescopping mast about 18 foot above my 14 foot high roof. i use 75 foot of rg8. one guy has a yazoo and said i went to almost an 8 from a 5 and he didnt believe i didnt turn on a lineur

 

[Shockwave]

im not yelling accurate or nothing like that but they just told me what they see on there meters. the pole they was on is a 2 part telescopping mast about 18 foot above my 14 foot high roof. i use 75 foot of rg8. one guy has a yazoo and said i went to almost an 8 from a 5 and he didnt believe i didnt turn on a lineur

Just so you know 5 S-units to 8 S-units is an 18 db increase! You would have to go from an Antron 99 to a Laser 500 beam to see this signal increase. This is not even close to being possible without severe meter inaccuracy or improper installation.