| Author |
Message |
    
Maxgain
Junior Member
Username: Maxgain
Post Number: 27
Registered: 3-2007
| | Posted on Wednesday, April 18, 2007 - 4:22 pm: | 
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Someone should do a comparitive test on all Omnidirectional CB base antennas past and present to find out wich ones are REALLY best.
The test should be in "real-world" conditions.
The test should be at two different hights , say, 20 feet and 40 feet.
Only one mast location should be used so the signal radiates from the exact same point.
Signal measurements should be taken at 2 miles, 10 miles and maybe 30 miles.
Of course an AM carrier shoud be used with a FIXED power level and stable power source voltage.
Once the RX stations are set, NO adjustments should be made ,not NB/ANL or even fine tuning.
The RX stations radios should have Analog signal strength meters because bar graph meters do not have the ability to show small changes in signal strength. I imagine that most of the changes in signal strength will be within ONE S-unit.
RX station antennas should be guaranteed to be secure and unmovable and far enough away from nearby reflective objects that can move .(vehicals, metal trash-cans etc...)
The testing should be done at least twice-through during the course of a week (or so) because of possible effects of temperature and other weather related factors even time of day.
And most importantly, the people that conduct the test at the transmitting location should not tell the RX stations which antenna is being tested to prevent possible "brand" or "desighn" favoritism.
Your opinions? |
Romstar
Member
Username: Romstar
Post Number: 97
Registered: 3-2007
| | Posted on Thursday, April 19, 2007 - 3:19 am: |
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My opinion is that it would cost a lot of money. Between the antennas, the mast and tower, the coax and the time spent testing and the gas for the vehicle it would add up pretty darn quick.
You're looking at thousands of dollars there.
Romstar |
Marconi
Advanced Member
Username: Marconi
Post Number: 696
Registered: 11-2001
| | Posted on Thursday, April 19, 2007 - 9:18 am: |
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Maxgain, Romstar is probably right. Besides, what value could you find important among all the antennas you would consider that would make 1 S-unit difference (your estimate) really worth knowing. At the ranges you note, a typical good working CB should produce good results with signals in the range of S5-S9 and better. Anything within this range (S5-S9 at 2 to 30 miles) should produce full copy. If it doesn't, then something on the ground is likely between the stations testing or one of the stations is in a possible dead spot.
If you sit accross the room from your radio and listening, can you tell how far off the TX'ing station is? Nope! Can you always tell the difference between a mobile and a base? Nope!
If you can hear stations making signals from S1-60/S9, then what does 1 S-unit really mean within that range. Just a difference on your meter, that's all. Now if you could consistently communicate with a buddy, say 93 miles a way on only one antenna and could not communicate with the rest that you put up to compare, then you might have something important to consider and then you could forget about the signal.
Don't get me wrong, I like to check and test with the best of em', but in the end and with all that I have attempted to do, I don't see enough difference (excepting noise) between em' all to really be concerned about.
I have just about all of the popular antennas, even the old 1/4 wave Starduster and an original Avanti Sigma IV, and I don't see much difference if I get em' all about the same tip height.
If you have some time and a good mobile, spend your time driving around to find a good Hot Spot to work your radio. You might be surprised at how much difference a Hot Spots on the earth can make. If you are near flat land salt water coast line then you will likely find more Hot Spots.
At times I have seen spots that produce 3-5 S-Units better signals than the typical location around it. I have also found other spots where you can hardly hear a thing. That is a difference worth noting and it has little to do with the antenna at all. |
Sitm
Intermediate Member
Username: Sitm
Post Number: 207
Registered: 1-2004
| | Posted on Thursday, April 19, 2007 - 12:40 pm: |
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I agree with Marconi, I also believe based on what I have read from the qualified technicians in this forum, that antenna grounding and proper equipment install are paramount to the quality of your receive and transmit. All radios receive differently to some point and depending on the quality of the alignment that could affect both. When we get down to discussing a better receive and transmit with omni directional antenna, I think that the difference is nominal. |
Maxgain
Junior Member
Username: Maxgain
Post Number: 29
Registered: 3-2007
| | Posted on Thursday, April 19, 2007 - 10:34 pm: |
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Guys, I'm not talking about hot spots or radios that recieve differently or alighnment matters.
I'm talking about the relative difference in signal strength at a specific location regardless of hot spots( whatever those are) or quality of radio ect...
Base to base, Point to point, Relative readings on the S meter.
Mobile RX stations would not work.
Everyone thinks that their antenna is the best.
But is it really?
I have a hunch that most omni-base antennas will be within an S unit of each other. |
Tech833
Moderator
Username: Tech833
Post Number: 1665
Registered: 8-2002
| | Posted on Friday, April 20, 2007 - 10:57 am: |
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Those results would not be 'real'. Different antennas react differently to variables like ground conductivity and surroundings. The antenna that 'wins' the test you describe might fail a similar test done at my location.
Takeoff angle is more important than gain on HF. Yes, I will stand by my words (let the flaming begin!). Antenna gain is the answer to the test you propose. Takeoff angle will determine the 'winner' in the real world of user installations.
I have spent thousands of dollars on professional antenna range rental to test antennas for Copper at no charge to them. Those results are found elsewhere on this forum.
If you have the financial means to do the same, I highly suggest you do. Your results would be a very interesting read. |
Road_warrior
Senior Member
Username: Road_warrior
Post Number: 2088
Registered: 7-2004
| | Posted on Friday, April 20, 2007 - 12:08 pm: |
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I agree Tech833 |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 183
Registered: 9-2004
| | Posted on Friday, April 20, 2007 - 12:50 pm: |
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I agree with Tech 833 that takeoff angle is more important.Often times when using a multi band verticle it will beat a yagi with more gain due to the lower take off angle. Now this is not always the case , depends on the skip angle, sporatic e skip which we are soon going to start hearing is typically of a high angle , unless its multi hop. F2 has both high and low angle components which are continually changing as well as the polarization, so what works well one minute might not work well the next.
Bob CEF451
Robert L. Spicer
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Maxgain
Junior Member
Username: Maxgain
Post Number: 30
Registered: 3-2007
| | Posted on Friday, April 20, 2007 - 1:32 pm: |
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No , I'm not talking about skip or polarization other than vertical.
YES , take off angle is everything (maximum gain at the horizon), and the lowest take off angle is best on HF.
I guess almost everyone is not grasping the concept as I am trying to present it.
Hmmm, I think I will quit on this one. |
Forummaster
Moderator
Username: Forummaster
Post Number: 498
Registered: 11-2001
| | Posted on Friday, April 20, 2007 - 1:49 pm: |
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Maxgain,
I think you might find Tech833's article "How to Choose a Ground Plane Antenna" an interesting read. You can find it under :
Subscriber (Preview) » Articles » How to Choose a Ground Plane Antenna
Forummaster
CEF001
CVC001
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Tech833
Moderator
Username: Tech833
Post Number: 1666
Registered: 8-2002
| | Posted on Friday, April 20, 2007 - 2:14 pm: |
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Max-
I understand what you want to do. All I am saying is that it will provide the results you want at YOUR location. At another location, your test results would be different.
That is why we use antenna gain as a base for antenna performance and suitability for our own installations.
The good news is, antenna gain can be calculated with software. The bad news is, antenna gain figures calculated by sales/marketing departments are almost always highly inflated.
Your idea is a good one! All I am trying to get through is that your results will not be duplicate-able anywhere else but at your house.
Let's say an A99 during your test gives a 100 uV signal at 20 feet and 130 uV at 40 feet to your receive stations, and let's say the Skylab does 110 uV at 20 feet and 140 uV at 40 feet. Move the antennas to my house and your numbers would be drastically different if my ground conductivity is different than yours by even a slight margin. At my house, the A99 might get 150 uV at 20 feet and 190 uV at 40 feet while the Skylab would get 80 uV at 20 feet and 100 uV at 40 feet. The reason would be the ground conductivity and terrain reactions with the end fed 1/2 wave vs. the center fed half wave (Skylab).
You see? The Skylab would be a better antenna at your house, but the A99 would beat the Skylab at my house.
Given this reality of variable, does that help explain why your test would not be useable anywhere but your location? The part that bothers me most is that someone might spend a great deal of money and time doing something that will only help a handful of people in their immediate area, but might actually hurt someone elswhere in the country if your results steer them away from a product that may have improved their station.
Experimentation is encouraged, and all results shared with the community! The thing to remember is that all info must be compared with other info and opinions formed on a base of wide input parameters. In other words, your mileage may vary. |
Sitm
Intermediate Member
Username: Sitm
Post Number: 208
Registered: 1-2004
| | Posted on Friday, April 20, 2007 - 3:05 pm: |
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In other words if you don't have your do mahicky hooked up to your squazzlewanker then the other guys farfignuton won't be the same and the butterscotch pudding won't taste the same....right? |
Maxgain
Junior Member
Username: Maxgain
Post Number: 31
Registered: 3-2007
| | Posted on Saturday, April 21, 2007 - 11:00 pm: |
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I always thought that even with ground conductivity issues the antenna that produces the strongest signal at point "A" should always produce the strongest signal to any other base station location as well.
Antennas are always the most fascinating part of this hobby! |
Drgrant
Junior Member
Username: Drgrant
Post Number: 10
Registered: 6-2007
| | Posted on Friday, June 22, 2007 - 1:57 pm: |
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IMO it is never that simple. All a given person
can really do is test out the antennas they
own, and try out different ones or run more than
one to see what works best.
I think "formally" testing vertical base antennas
is a lot to do about nothing. Most of them are
all made out of the same handful of basic
designs and aren't going to be that much different
performance wise. After a certain point the
law of diminishing returns kicks in pretty
harshly.
The biggest differences are with somewhat less
tangible things... like how the antenna mounts,
how hard it is to assemble, resistance to
weather, power handling capability, etc.
Given that the cost of antennas is relatively
low (most are less than $200, many less than
$100) experimenting is not a bad thing to do, if
you have the real estate for it. I can't wait
until I get another antenna up so I have something
to test my IMAX 2000 against.
The answer to "which is best" is subjective.... it
is going to vary depending on the user, their
location, and so forth.
Just my .02...
-Mike |
Allagator
Advanced Member
Username: Allagator
Post Number: 766
Registered: 9-2002
| | Posted on Tuesday, July 03, 2007 - 5:51 pm: |
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HEY MAX Ive tryed many antennas over the years and even moved a tower over 6 foot and found a diff reading with that same antenna and same tower with the same ground !
so it would be a win and lose thing to spend all that time and money to do what you are talking about !
but in a another way it would be funny to see what antenna they use in each state and see what state use what antenna ! now that would be a challange ! LOL
ALLAGATOR
CEF115 |
Walterb
New member
Username: Walterb
Post Number: 7
Registered: 12-2007
| | Posted on Wednesday, December 19, 2007 - 9:16 pm: |
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Back when I was doing a lot of testing on a weekly bases I talked to a Base station who was at 2500 ft elevation using a PDL2 and a Kenwood 830, I was using a moded K40 and a Messinger 350 and a President Jackson we talked 145 air miles and could have talked farther but my voice gave out on me. Now a Wilson 1000 is a louder antenna but its not quieter on receive than that K40 so if you can't hear them you can't talk to them! So about 3 weeks ago I brought another Mag mound K40 and was going to test it against my little K30 I have on my little SUV, when out 25 miles from my Base (MACO 5/8) and low and behold the K30 smoked the K40 so bad that I didn't even do much of a test. Had no problem talking back to the base on the K30 using a new Cobra148GTL at 25 miles bask to the base, had a recorder on at the base and could not believe my ears on how good that 3 1/2 watt Cobra sounded with the K30 on er. So as the old saying goes if it ant broke don't fix it. There is a real lot to what others have been saying about low take of angle of an antenna............walterb (Oldtimer) |
