what can make one antenna seem louder than another

[CDX-007]

Static.

About 6 months ago I got laughed at & prodded by an older local op who said I was "Having a CB'er moment" when I told a guy that he sounded better when I was on my Penetrator than he did on my Imax.

What I found was that it was due to the fact the Penetrator has a bleed to ground the Imax radiator doesn't, and the increased level of static coming into my radio from the Imax was causing the NB to activate more and a little was still coming through on his signal causing a slight artifact of grundge to piggyback on his audio, which wasn't an issue with the Penetrator.

The Penetrator actually "Sounded better" than the Imax, on receive.

However, another local guy said my audio was "Clearer" on the SGM than on the Penetrator, but I discounted that particular 'Maker's Mark' RST.

I could imagine a scenario where one mobile antenna design could cause a little RFI to piggyback on the audio, or have a low SWR but poor reactance causing it to sound less clear than another depending on how the radio responds to differing loads.

When I travel over the Yolo causeway which is an elevated hiway with a lot of rebar, built level with the surrounding ground but over a low area of damp rice fields, I see a big increase of signal and drop of static making everyone sound louder like I just jumped to a base antenna.

 

[HomerBB]

Thanks, 007. Structural conditions, and a better built antenna . . . careful now.

 

[BOOTY MONSTER]

AGC influences the output levels from the radio speaker as I understand it. Would AGC suddenly decide to make one signal seem louder than another when the antenna is switched out? (I don't think so, but. . .) Could there be other factors that do?

good question BB !
can a AGC circuit be fine tuned to work better with one antenna than another ?

 

[jazzsinger]

good question BB !
can a AGC circuit be fine tuned to work better with one antenna than another ?

Don't think you guys are quite grasping what agc is/does.

typical agc on a cobra 148 gtl would be less than 10db change in audio output for signals between 5uV
- 50,000uV.

as you can see over a vast range of signal strengths the audio remains fairly constant, as it takes around 10db of audio change for your ears to perceive a slight increase in volume.

signals ouside the agc range or if the agc had somehow become inactive may be more susceptible to audio change but allowing for localised noise sources/static etc it pretty much covers the whole range of signal strengths that are useable on an average cb in an average setup where noise pretty much covers up anything lower.

if you have little noise you may notice an audio increase on a mobile signal that is bottom of the box (approx .25uV) and rises to about 5uV, but as it rises further in signal strength the audio will generally be similar to what it was around 5uV.

it's not antenna specific.it's a design feature to stop you constantly having to adjust the radio's volume for different signal strengths. you get a similar sort of thing on computer cd writers/software (rec level adjust) that levels the record level for the exact same reason it's done in radios, to prevent you constantly having to change volume levels.

 

[AudioShockwav]

Ok, ok I am sure we all see where this is going booty..eh?
Subtle differences.....
Many many thing`s influence the way an antenna reacts both tx and rx.
One good example comes from Bob85 as posted here:

you should see what happens between me and my buddy the other side of this hill when a plane comming in to land at leeds/bradford flys over,
i get the multipath flutter that has his noisy s-4 start swaying faster and faster up to s-8 and sometimes more with full quieting,
then the flutter slows back down signal drops untill the plane gets over near me and it starts again, how high they are also effects what we see on the radio,

So at the risk of dieing a flaming death here on the forum,
Question:
what can make one antenna "seem" louder than another?
Answer:
Many things.
Now, I am going to open the "can of worms" that you are tip toeing around.

This is the question that was wanting to be asked, but was not:

In what way can antenna be built that will make it louder than another antenna?
( with the focus here relating to a misstatement that was made on the forum about increasing modulation)
Answer:
An Antenna is inline AFTER the transmitted signal has left the radio, and as such has no effect on the Modulation of the signal coming from the transmitter, therefor , it can not effect the "modulation" of the signal.
So lets look at the next obvious statement, but if it increases the signal will it not seem louder?
Answer:
It can be "perceived" to be louder because, if the antenna is built/designed to have "gain" as in a phased array, a yagi, or a quad antenna the signal strength can increase.

Is this the question you are getting at?

73
Jeff

BTW, not done yet, but we will get there...

 

[BOOTY MONSTER]

i know a drop in the bucket about antennas compared to some of you guys . ive been to a lot of sites online , some good and some bad .... and some i thought at first was good info i later learned wasn't so good . but , the only place ive ever read any mention of antenna loudness is on CB radio forums and cb antenna sellers . so i dont believe antennas add modulation/loudness to the signal .

i wasnt trying to get at how to make a louder antenna , im just asking what things can REALLY be happening to give folks the impression they are louder . i do believe being in the EXACT SAME LOCATION is very important when comparing antennas . i think every one has been in the car listening to the stereo and stopped at a light and noticed the station fet very staticy or drop out and that simply moving forward 1 or 2 feet will bring it back in crisp and clear ..... and louder LOL .

 

[AudioShockwav]

im just asking what things can REALLY be happening to give folks the impression they are louder . i do believe being in the EXACT SAME LOCATION is very important when comparing antennas . i think every one has been in the car listening to the stereo and stopped at a light and noticed the station fet very staticy or drop out and that simply moving forward 1 or 2 feet will bring it back in crisp and clear ..... and louder LOL

Very good observation booty.
And very true.
I know you have been following the thread on the Gain Master, it has been going for quite some time, there is a truckload and a half of info about that antenna in there, and, there is also a truckload of info to be had in there about good ways to test antennas.
This testing has been going on for a while now, and more than a few guys have been testing them, and after all of the testing and post`s and opinions, and sharing ideas, there is a good idea being formed about how the antenna works and how well it works.
One of the things( among many things) that I think we all can learn is that:
It is a VERY bad idea to judge how well a antenna works, from one single test, one day, on one mode, in one location.
In the example of the Gain Master, the company that builds it has spent a lot of time, with very expensive equipment, and modeling programs before it even was released for sale.
And now all of the good work from all these guys both here in the U.S. and the UK is starting to tell the tale.
You with me on that one?
You ask a lot of question`s Booty, that is a good thing.....it inspires thought.

73
Jeff

 

[GnG8d]

it takes around 10db of audio change for your ears to perceive a slight increase in volume.

I'm not sure where you read that. Most would agree that 3db is a halving/doubling of power and perceivable by ear, and as little as 1db can be discerned in a controlled environment.

 

[GnG8d]

So lets look at the next obvious statement, but if it increases the signal will it not seem louder?
Answer:
It can be "perceived" to be louder because, if the antenna is built/designed to have "gain" as in a phased array, a yagi, or a quad antenna the signal strength can increase.

Omni "A" can't have gain over omni "B"?

I see what you are saying, arrays and beams have gain over a dipole due to design and energy focusing, but can't one vertical have gain over another?

 

[AudioShockwav]

Yes, of course one type of vertical can have gain over another, I just used the beams as a example.
Most , but not all, verticals show gain due to manipulating the takeoff angle.




73
Jeff

 

[BOOTY MONSTER]

in audio terms 10 db is a doubling of sound pressure level .
1 db is barely detectable by the human ear and doubling the power from an audio amp will increase the SPL by 3 db when driving the same speaker under the same conditions .
it takes 10 times the audio watts to double SPL .

 

[BOOTY MONSTER]

Yes, of course one type of vertical can have gain over another, I just used the beams as a example.
Most , but not all, verticals show gain due to manipulating the takeoff angle.




73
Jeff

when i got my initial home-brewed 5/8 up to about the same feedpoint as the 1/4wgp was the signal was much much stronger on both tx and rx . everyone agreed my audio was much louder and i had reports of up to 4 s-units of gain on their meters . i know the 5/8 wasn't a louder antenna . it just put more signal in the areas that benefited me , that area was lower to the ground . their radio made the signal "louder" because it had more signal ....... i think . LOL

 

[DIRTYWHITEBOY]

is that how you get out so well Mack? the old hannah montana antenna ball giving you an extra couple of db's/

I can't believe i fucking looked through them all,lol.

my personal favourite was the whopper ball, i can't think of a more appropriate one for a cb antenna going by all the whoppa's i've heard coming through my cb's over the years.

I looked for a couple of numpty or spastic balls for JJD but i couldnt find any

 

[WR0220]

What would cause one antenna to appear to be louder than another to a listener.. . .Could there be other factors that do?

Off the top of my head:

Changes in atmospheric conditions
Changes in signal polarity
Changes in signal strength
Location
Ground conductivity
Terrain
Elevation

 

[Marconi]

BM, I've experienced the difference I think your talking about...and I agree it is possible even though some will disagree and say it's not possible while other's say it absolutely can happen. Most of the time I think the claim is that the antenna does it, but I don't think so.

IMO it's the luck of the draw and location...maybe it's a combination of skywave, direct, and/or reflected waves for a particular signal between particular stations. For me it is typically noted with both TX/RX that effectively or NOT combine at some distant point(s) on the Earth. This point is probably unique for such an event and may happen at other points at the same time I believe. I've had multiple reports of such at the same time before.

I don't think you'll ever notice such a nuance unless you have two antennas up with a switch box so you can switch rapidly enough to realize the difference however. Otherwise, if it ever happens for you...it will likely be unnoticeable between antennas trying to test for it at different points in time. It's not the same as Joe Bob's big truck with a new antenna sounding louder this week than last either.

I guess the guys that discount this as impossible, whatever the cause, will also claim that there are no such things as hot and dead spots on the Earth also. I believe Homer when he talks about such. Years ago I had a friend that worked on Galveston Island. You would think it would be a radio hot spot being surrounded by sea water, but I could not copy him after about 30 miles of the 60 mile trip...including over the causeway and on land. I couldn't hear him until he parked on a couple of hot spots he located. Then we talked showing about S9 signals between us, the same kind of signals as guys that ride the Intercoastal ferry and talk of their CB's back to Houston mobiles 50-70 miles away.

Well, after I posted I read BM last post and I was wrong about what he was asking, he was talking about actual signal strength making the audio louder, but what is so hard to understand about that? Billy Bob does that every day in his Big Truck on channel 19.

Never mind!