Unscientific antenna "tests"

[mackmobile43]

ya might want to "CONQUER" some basic math skills,

i'm done with you and your hillbilly attitude. are you from appalachia?

He apparently has much "book learnin" Mmmm Hmm.

 

[Marconi]

Nothing there that refutes my assertion that ground wave conditions can change from hour to hour and day to day. They can and do.

You are right that ground waves do vary at times and has a great affect of communications, but the following does refute your specific assertion that it applies to the high end of HF and in particular 10-11 meters, or do you just choose to ignore this factor in the facts.

Effect of frequency

As the wavefront of the ground wave travels along the Earth's surface it is attenuated. The degree of attenuation is dependent upon a variety of factors. Frequency of the radio signal is one of the major determining factor as losses rise with increasing frequency. As a result it makes this form of propagation impracticable above the bottom end of the HF portion of the spectrum (3 MHz). Typically a signal at 3.0 MHz will suffer an attenuation that may be in the region of 20 to 60 dB more than one at 0.5 MHz dependent upon a variety of factors in the signal path including the distance. In view of this it can be seen why even high power HF radio broadcast stations may only be audible for a few miles from the transmitting site via the ground wave.

If you want to base your claims in science, that is fine, but then get your science at least close enough to make a good argument, and check your specific terms for their full and applicable meanings. I don't mean to put words in your mouth, but you likely meant "direct waves" ie., line of sight, a typical signal path for 10-11 meter communications.​

I agree with you for the most part otherwise, but very little we do here on the forums qualifies as science...it is more like opinion and the relating of experiences and observations.​

Is that alright with you 821?​

 

[Kamikaze]

What is the point of trying to compare omnidirectional CB antennas using testing that has too many variables to be meaningful? Different mounts, heights, feedlines, times of day, conditions (yes, groundwave conditions vary a great deal on 10 and 11 meters) .

RX stations with a possible agenda or incompetence, insistence on using SSB (dumb) instead of a constant carrier mode. How do you know if you take one down and put another up, a big panel truck didn't just park in front of your RX station's house, affecting the incoming signal as much as any potential difference between antennas? How do you know that there wasn't another transmitter on the air near your RX station's house, de-sensing his RX for one of your antennas, but not by the time you got the other one on the air?

Nothing wrong with playing around, as long as you know that that's ALL you are doing with such stuff. Coming here on the forum and stating as fact that one antenna has more gain than another based on this kind of flawed, uncontrolled, invalid testing means is VERY misleading and invalid.

Thanks. You're not alone.

AND non-skywave CB signals most certainly change strength with weather fronts. Some people will not see this in their neck of the woods. In mine it's a regular occurance.

 

[Beetle]

Thanks. You're not alone.

AND non-skywave CB signals most certainly change strength with weather fronts. Some people will not see this in their neck of the woods. In mine it's a regular occurance.

You don't hear the stations during a storm because the storm has taken them away, where they'll drop on a witch and kill her. (Cue the flying monkeys...)
:whistling:

 

[Kamikaze]

You don't hear the stations during a storm because the storm has taken them away, where they'll drop on a witch and kill her. (Cue the flying monkeys...)
:whistling:

What happens here is increased direct wave propagation due to ducting.

I'm on the coast and I work on the coast up the road a ways.

When FM broadcast, VHF amateur and TV signals start popping in from New England I start to hear CB signals from NYC and Long Island.

This usually is brought on from a weather front.

When I lived inland this was not noticed. If it ever happened there I missed it.

 

[jazzsinger]

You are right that ground waves do vary at times and has a great affect of communications, but the following does refute your specific assertion that it applies to the high end of HF and in particular 10-11 meters, or do you just choose to ignore this factor in the facts.

If you want to base your claims in science, that is fine, but then get your science at least close enough to make a good argument, and check your specific terms for their full and applicable meanings. I don't mean to put words in your mouth, but you likely meant "direct waves" ie., line of sight, a typical signal path for 10-11 meter communications.​

I agree with you for the most part otherwise, but very little we do here on the forums qualifies as science...it is more like opinion and the relating of experiences and observations.​

Is that alright with you 821?​

Many people misname the surface or direct line of sight/reflected wavefronts at 11m as groundwave Eddie, your correct that the actual groundwave at 11m doesn't propagate very far due to ground attenuation.

it still doesn't change the fact though that what highlander 821 is saying is unscientific tests of antennas are pointless unless its only for your own personal knowledge, once people come on forums promoting their tests as an "accurate" indication of the merits of one antenna against the other it starts geting into the realms of fantasy as we've seem many times lately on here with some outrageous claims.

i constantly see references to if you don't put your hand in your pocket to test something then your view is pointless, the irony of that is those who make those sort of statements rarely have any technical knowledge behind them that would enlighten them on the foolishnes of their claims that often defy the laws of physics.

my favourite saying in 30 years in and around radios is "all the gear with no idea" i think that sums up many of the reviews i read on t'internet.They just can't grasp the fact "if they need to buy all that gear to test it,they made a huge number of bad investments", something those with technical knowledge rarely if ever do,because they do their homework before they dip their hands in their wallets.

As for testing antennas via ssb without using a tone generator or skywave, there is simply no point at all.

 

[GnG8d]

i'm done with you and your hillbilly attitude. are you from appalachia?

What does that have to do with the price of eggs?

 

[C2]

is that some kind of new math?


get a quad :bdh::bdh::bdh:

The thread seemed like a shot at someone specific...


YouTube - Tom Lehrer: New Math

 

[Charlie Brown]

i think you,ll find most 5/8 wave anttenas perform about the same.
with that said you can try a maco 5/8 ,sirio 827 ,sirio2016
if ya really feel u did better with the a-99 ever consider going
back to it?i know the imax is noisy i sold mine for 50 bucks
to just get rid of it

cool !!!! Thanx!!!

ya might want to "CONQUER" some basic math skills,

i'm done with you and your hillbilly attitude. are you from appalachia?

Nope. Just fishn and u keep biting. One day you gonna be big enough to keep.

 

[bob85]

kamikaze,

with all this talk of antenna tests and multiple paths i decided to make a mental note, nothing scientific just an observation using my foxhunting radio with BIG external s-meter,

last night i listened to my buddy the cobraman 15 miles from me atcf,
his signal was rock steady most of the time as usual but on 4 occasions in the space of just over 1 hour his signal and the signal of the weaker guy he was talking to fluttered up 2 s-units then back down to normal signal with the typical whoosh woosh fm sound, they peaked at near full quieting for about 10 seconds then fluttered back down to normal signal,

today the effect is even more notable especially with stations that live down in a hole,
dealerman is up and down like a fiddlers elbow from a steady s-1 fluttering up to s-5, woosh wooosh "does anybody want to buy a ranger 2950dx"

i am getting the same effect with many stations within about 30 miles of me,
conditions here at the moment are no good at all for even the crudest of antenna tests.

 

[Highlander_821]

You are right that ground waves do vary at times and has a great affect of communications, but the following does refute your specific assertion that it applies to the high end of HF and in particular 10-11 meters, or do you just choose to ignore this factor in the facts.

If you want to base your claims in science, that is fine, but then get your science at least close enough to make a good argument, and check your specific terms for their full and applicable meanings. I don't mean to put words in your mouth, but you likely meant "direct waves" ie., line of sight, a typical signal path for 10-11 meter communications.​

I agree with you for the most part otherwise, but very little we do here on the forums qualifies as science...it is more like opinion and the relating of experiences and observations.​

Is that alright with you 821?​

What I meant when I said groundwave was non-skywave. Doesn't change the greater point that I was trying to make--local propagation on 10/11 meters is sometimes better or worse than other times due to changing conditions. As this applies to antenna testing, it means that you might test antenna A at 10 AM, bring it down, put up another, and by the time you have antenna B tested at 1:00pm, conditions may have changed. So how would you know if an apparent improvement over antenna A is because the antenna is better, or because conditions may have changed? You can't know it, because you haven't controlled for that.

I understand that you are just goofing around. Bless your heart, that is absolutely fine with me. Just don't expect it to result in anything that is worth more than an arbitrary opinion.

 

[Marconi]

That is what I figured 821.

I also agree with you on the rest of you're conclusions as well, even testing with exactly the same setup is fraught with possible issues and the biggie is time.

 

[15minigrass]

Maybe Myth Busters can help out.

 

[W5LZ]

Or, you might just not depend on 'on the air' reports and do it like the antenna ranges do. Take your own readings and factor in distance and position from the antenna of the measuring devices. That certainly will make the whole thing take longer and be more work. But it will also give you some factual/repeatable numbers to 'play' with.
- 'Doc

 

[triple nickel]

ya might want to "CONQUER" some basic math skills,

i'm done with you and your hillbilly attitude. are you from appalachia?

Wow here we go again with the typical B.S. Just for your info, I TOO IS A HILLBILLY FROM THE GREAT STATE OF MISSOURI AND DAMM PROUD OF IT. I have not got back into the base station side of life, But i do understand ground waves, I run mobile antennas on semi trucks starting back in '77 with The Hustler Antenna company. And from there on i have tried a lot of different mobile antenna set ups on semi-trucks. If i ever decide to put up a base station, I will refer to this episode of The life style of the CB Base Antennas.