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5 vertical antenna, monopole shoot out (date to be announced) All welcome : )
Topic Started: Saturday, 5. September 2015, 16:27 (1,797 Views)
Henry HPSD
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19 Charlie Tango 249

Northern Crusader
Monday, 7. September 2015, 10:17
What method of measuring the signals are you going to use? Please say field strength meter with its antenna base at the height of the base of the test antennas (or centre in the case of any vertical dipoles) and not someone with another CB a mile or two away saying antenna X is 5.1S points and antenna Y is 5.2 S points.

I dont see anything wrong with comparing to a "S" meter.
In the avanti 4 debate there was a manufacturer who "looked" serious as he had a "pro" field strength meter.
Reading the manual it actually indicated it was no good for vertical antennas.
It however looked "pro", but most likely it had infuenced his judgment.

Besides most fieldstrength indicators need to "measure" at relative short distance.
At short distance a lot of measurements are influenced do to ground reflections
(it is very plausible that one is walking away from the antenna and see the signal go up and down which is of course ...strange..)
Now it is possible to illuminate those, however that does to "deep" for this test.

So im not "scared" of using a CB S-meter or so..


However...i would do it the other way around...

Set a CB set at the testing location.
Measure Signal strength at that location...as precise as possible...
(perhaps a second meter measuring microvolts as detailed as it can ?)

And drive around with a car and transmitter.
Drive around in a circle at 10km ...30km..50 km or so
And write down each time the strenght received...

As for signals receiving and transmitting is the same..

I think in such a way the normal guy can have a relative good indication of what is going on..
(with keeping in mind antenna tip height (current) and things like common mode currents)

73s Henry
Edited by Henry HPSD, Monday, 7. September 2015, 10:41.
www.hpsd.nl www.CB-ANTENNAS.com

1 watt into a dipole will work DX !,
100 watt into a antenna which is only 1 percent as efficient as the dipole will work the same DX.
Keep that in mind when someone claims good results from a small antenna.
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Northern Crusader
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26 Charlie Tango 1760

Oh lordy lord.

Quote:
 

In the avanti 4 debate there was a manufacturer who "looked" serious as he had a "pro" field strength meter.
Reading the manual it actually indicated it was no good for vertical antennas.


They typically use a loop antenna but even when they don't, as long as the antenna they do use is orientated in the same plane as the antenna being tested then they work just fine and even if they aren't, we know that the difference in the results is 20dB due to cross polarisation. There is no such thing as a field strength meter which doesn't work on vertical or horizontal antennas.

Quote:
 

Besides most fieldstrength indicators need to "measure" at relative short distance.
At short distance a lot of measurements are influenced do to ground reflections


Again, rubbish. The short distance is a few feet because RF field density drops off a cliff quite quickly. The effect of ground reflections does not have an effect at that distance.

Quote:
 

And drive around with a car and transmitter.
Drive around in a circle at 10km ...30km..50 km or so
And write down each time the strenght received...


So you're going to have a car driving around at different elevations to the antenna and receiving signals being bounced off all kinds of stuff as well as having them affected by things like nearby powerlines and all done at different times and you think that's a valid method of testing?

And somehow you see yourself as an expert when it comes to antennas to the point of writing an article. :whistle:
Edited by Northern Crusader, Monday, 7. September 2015, 10:49.
26CT1760 / M0GVZ
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Henry HPSD
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19 Charlie Tango 249

hmm...
by using the same S-meter for the received signal each time he could actually get a rough "gain" difference indication.
As it is relative easy to measure power (accurate)
Doubling the power ...going from 4 to 8 watts is 3 dB
The difference seen on a S-meter by doing so equals 3dB

Obvious it wont hold up in court....but it gives a rough indication...

73s Henry 19DX348

www.hpsd.nl www.CB-ANTENNAS.com

1 watt into a dipole will work DX !,
100 watt into a antenna which is only 1 percent as efficient as the dipole will work the same DX.
Keep that in mind when someone claims good results from a small antenna.
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Northern Crusader
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26 Charlie Tango 1760

Henry HPSD
Monday, 7. September 2015, 10:49
hmm...
by using the same S-meter for the received signal each time he could actually get a rough "gain" difference indication.
As it is relative easy to measure power (accurate)
Doubling the power ...going from 4 to 8 watts is 3 dB
The difference seen on a S-meter by doing so equals 3dB

Obvious it wont hold up in court....but it gives a rough indication...

73s Henry 19DX348

Absolutely no problem in doing that if the RX antenna is placed at a suitable point however that suitable point is going to be so close that a S meter on a radio is going to show it at full deflection even with a watt thrown into the test antenna. Its certainly going to be at a point on the meter where it is impossible to give an even remotely valid reading. We are literally going to be "well it looks like its half a needle width better" assuming its not pegged all the way across.
26CT1760 / M0GVZ
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Henry HPSD
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19 Charlie Tango 249

No, I dont see myself as an expert..

If you would read the manual it clearly states it is not "valid" for vertical measurments.
Now you may claim otherwise, i will however stick to the statement made by the manufacturer.
Bare in mind these things are used for FCC regulations etc.

If you measure at a few feet, you are in the NEAR FIELD of the antenna.
The far field hasnt esthablished yet, any measurment done there...doesnt tell you anything about how the performance is in the FAR field
What is your intention about measuring at such a close range ?

Third, if actually have a measuring field such a field should be at least 10 wavelengths long.
Now in the "pro world" you will notice there are "antennas" in the between the Rx and TX location.
These are there for a reasons...that reason is: ground reflections.

The more you know about how to "measure"things the more you will found out how easy things are mixed up due to "measuring errors".

Now, you can continu to go on make me look like i think im an expert or say mention things i havnt said.
You can continu trying to disagree im fine with that, but i wont respond...as i allready dont have much time and not interested in "quarrels"

I would however like that you would go into the debate, and provide facts or ask questions

You are rigth about one thing and that is the "tx" location...yes ....at that location things will have influence.
But one has to do the best he can with "limited" means.
Im sure he can find several "clear" spots to do his best.

Hope it is of use,

Henry
www.hpsd.nl www.CB-ANTENNAS.com

1 watt into a dipole will work DX !,
100 watt into a antenna which is only 1 percent as efficient as the dipole will work the same DX.
Keep that in mind when someone claims good results from a small antenna.
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Henry HPSD
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19 Charlie Tango 249

Northern Crusader
Monday, 7. September 2015, 10:53
Henry HPSD
Monday, 7. September 2015, 10:49
hmm...
by using the same S-meter for the received signal each time he could actually get a rough "gain" difference indication.
As it is relative easy to measure power (accurate)
Doubling the power ...going from 4 to 8 watts is 3 dB
The difference seen on a S-meter by doing so equals 3dB

Obvious it wont hold up in court....but it gives a rough indication...

73s Henry 19DX348

Absolutely no problem in doing that if the RX antenna is placed at a suitable point however that suitable point is going to be so close that a S meter on a radio is going to show it at full deflection even with a watt thrown into the test antenna. Its certainly going to be at a point on the meter where it is impossible to give an even remotely valid reading. We are literally going to be "well it looks like its half a needle width better" assuming its not pegged all the way across.
Thats why i said..
I was thinking more in the lines of a car parked at a clear spot 10km ..20km ..30 km way from several directions.
I dont think it will show "full scale".. with pushing 4 watts..in such a situation.

Kind regards,

Henry
www.hpsd.nl www.CB-ANTENNAS.com

1 watt into a dipole will work DX !,
100 watt into a antenna which is only 1 percent as efficient as the dipole will work the same DX.
Keep that in mind when someone claims good results from a small antenna.
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RadioDaze
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Henry HPSD
Monday, 7. September 2015, 09:55
If im allowed...

Please do use a RF choke on all the antennas.
In case of a halve wave vertical place it say 1 meter below the feed point
In all other cases ...directly underneath the antenna.

When i wrote this article:
http://cb-antennas.com/wp-content/uploads/2014/12/Sigma-IV-1.01-Jan-2015.pdf

It became more and more clear difference in antennas is often due to commen mode currents and antenna TOP (current) height.
What im trying to say...
Antennas like the Vector 4000 (and 5/8 waves) often outperform the 1/2 wave ...but not due to antenna gain.
Often its simply because the other one is higher and can "see" further.

Statement:
"The difference seen in signal strength for most who compare vertical 27 MHz antennas is not due to the additional gain of the "winner" but most likely do to different reasons causing the other not performing to its abbility."

Good luck !!! Keep us posted !!!! and Great work !!!
I appreciate your point of view, but where does this end ? I am already mounting them in 2 very different ways. They are being used as they came out of the box in 2 very different scenarios out the box.

If they need a choke at 1M and at feed point they should have shipped with it attached as per design !

Given any antenna can be mounted in multiple ways these variables would be present on any other type of mount.

Let's say common mode is present in coax because there is insufficient ground plane. That should circumnavigated in my 4M gate mount in the test. (A large gate grounded at both ends into farmland soil by 3-4 feet is better than most will achieve at home.)

Ultimately you can go on forever tweaking and I am not up for that. I have not all day to mess around for a test that will show no better results. Too long a wait and everyone will just leave the test, that will not help the end results either. We have to strike a balance but I thank you for your interest and input.
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RadioDaze
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Northern Crusader
Monday, 7. September 2015, 10:17
What method of measuring the signals are you going to use? Please say field strength meter with its antenna base at the height of the base of the test antennas (or centre in the case of any vertical dipoles) and not someone with another CB a mile or two away saying antenna X is 5.1S points and antenna Y is 5.2 S points.

It's a fun test that involves people. I won't be using a field stength meter other than real world ones on people radios... that's a field strength meter isn't it ? And a real world one at that.

This is empirical relative finding based experiments, not a lab mate.

Feel free to do you own lab experiments if you want to just pick holes in this. Oh and post the results for us yeah? We are waiting with great interest.
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RadioDaze
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Northern Crusader
Monday, 7. September 2015, 10:28
26PS001
Saturday, 5. September 2015, 16:34
I have to say Ive used wire dipoles and found they work just as good as my antron, I dont use the antron any more just wire upto now but the results of this could change what I use in the future.
Horizontal dipoles outperform all vertical monopoles when they're placed at least half a wavelength above ground due to the benefits of ground reflection.

Any test is only as valid as the measurement techniques used. Sadly I fear this is going to be yet another completely unscientific test with a RX station at either a lower or higher height than the antennas with signals being multipath as they're reflected off all kinds of buildings and fractions of S points or needlewidths being mentioned as the differences so I would take the results with a pinch of salt if they're done using anything other than a field strength meter with its antenna base at the same height as the base of the test antennas within a few feet of the antenna.
What is the point of scientific experiments if they cannot mimic real life prop and terrain. Pointless I would say. That is merely a guide as well, stick it in the air and screw the nice perfect lab plot up and bin it.

You cannot have it both ways and real world relatives at distance for me is more important and interesting than non existent lab conditions.

Graphs provide reference. Base points from which to proceed. Interest for consideration and pondering.

Real world testing is no better or worse than scientific in my mind. We are doing it for fun and enjoyment, we just have to hope experienced radio users can make their best estimations upon what they see and hear. I have trust in the operators as their diligence in comparing as closely as they can will ultimately inform. :cheers:

Do not underestimate eyes and ears, there people on this board that have been staring at S meters and listening with great intent for years, don't dismiss that. They know background noise increases and decrease when they hear it, they have stared at their S meter for years on end !
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Henry HPSD
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19 Charlie Tango 249

@radio daze
Indeed...if the antenna needed a rfchoke..they should have supplied one !

Thanks for your logical responses !
Seems you have plenty of "good mentallity"
I understand your point of view.

Good luck...looking forward to the outcomes !

Kind regards henry

Edited by Henry HPSD, Monday, 7. September 2015, 12:02.
www.hpsd.nl www.CB-ANTENNAS.com

1 watt into a dipole will work DX !,
100 watt into a antenna which is only 1 percent as efficient as the dipole will work the same DX.
Keep that in mind when someone claims good results from a small antenna.
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RadioDaze
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Henry HPSD
Monday, 7. September 2015, 12:01
@radio daze
Indeed...if the antenna needed a rfchoke..they should have supplied one !

Thanks for your logical responses !
Seems you have plenty of "good mentallity"
I understand your point of view.

Good luck...looking forward to the outcomes !

Kind regards henry

Thanks... we will know more and each be able to make our own conclusions and comparisons in the test. This could be a very long thread !
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RadioDaze
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Another small addition... if anyone using a digital bar signal meter sees their meter pegged on the first antenna due to being close by they can just knock that down to an S7 or so using their RF Gain.

What I sometimes do if someone is asking a signal check between 2 aerials who is close by is use RF gain to create an S7 right up the last bit before it jumps to an S8 with the smallest of extra gain. This way you are reading a very small signal increment if it jumps to a S8 (probably 1dB). And if it drops down to an S6 you know that's close to a 6dB drop (not exactly accurate but it is a significant drop down for a whole S point. and allows a little more sensitivity/meaning to the meter than just whole S points. I will also pay attention to noise floor on FM

What I will do is give a long 1 min over or a dead key for a while on the first antenna so any calibrations can be made, if required.

It would also be useful if known keyers scale back their power to hit me an S7 or thereabouts so I am not seeing end stops from locals. (Locals can easily be 30miles away from me on the hills and the good stations hit the end stops on my rather sensitive and generous S meter)
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RadioDaze
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The other handy hint is a flickering bar. People who use the Chinese modern digital bar meter radios get to see that often. When the modulation flickers it on FM probably means it's just about triggering that bar on. Over time you get to know your own signal meter.
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Turbo
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26 Charlie Tango 491

It's quite obvious by what Geoff has said his tests will involve that no elaborate testing equipment ie field strength meters etc will be used, he is using what he has available to make an interesting and fun couple of hours of testing which should at least give an indication as to what works better from that given environment on the day, and tbh signal strength is not the be all and end all anyway as I often switch between my verticle and my wire whilst listening to ground wave Qso on the 11 metre bands and 9 times out of ten the wire will be down by at least 2 s points but will always have a cleaner and more audible signal, and as Geoff has already stated that comments of such a report ie 'better or more audible' signal would be appreciated with the S reading I'd say he's got his nice little venture all covered as best as he can with the equipment available, stupid obnoxious comments serve no purpose other than to discourage people from experimenting which is what radio is all about isn't it? I would have thought a licenced op would have had a more encouraging attitude towards such a thing...keep it up Geoff :thumb:
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RadioDaze
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I have noted you down as a known keyer on the day for an RX report my end. You are not held to it of course but I will get a few peoples names down who show interest in that part of the test.
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Gazby
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26 Charlie Tango 1766

I think its a great idea !
anyone new to the forum(like myself) there is a button below the post that allows you to 'track topic' so you wont miss the post containing the date

Good luck Radiodaze
Edited by Gazby, Monday, 7. September 2015, 19:26.
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RadioDaze
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Thanks, thing is the entire thing relies on everyone else taking S readings as much as myself setting a time for play. All I am is the antenna labourer.
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RadioDaze
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This is looking likely to be a valid test bed for these antennas at least for local groundwave/line of sight contacts. I managed to test a Solarcon MAX 2000 on the gate yesterday at a SWR of 1.4:1 which compares well to the T2LT with identical SWR and a GM on gate at 1.3:1 SWR. The Silver Rod manages a 1.1:1 SWR which is great showing it is a very unfussy antenna mount wise.

We are talking around 0.030 dB differences between all but the Silver Rod with these values.

(on the day I can even SWR the Silver Rod to a 1.3:1 to further narrow the differences)

On just 2 poles the IMAX2000 achieved an almost non meter needle moving 1.1:1

This of course assumes that my TEAM 1180P is accurate. (which we can guarantee it won't be !)

So all the large verticals SWR on the which was an initial concern that some would not be happy. They will all occupy an identical spot on the gate mount 0.7m above ground and the identical pole mount (6-7.5M above ground)

Identical coaxial feed line and identical power level will also apply.



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Mark in Essex
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26 Charlie Tango 037

Excellent effort Geoff... count me in for this one, I shall hook up my Icom PRO to the 11m vertical antenna for this (I don't normally use my amateur radios for CB or 11m unless I'm on holidays abroad) as it has a needle S meter and also a bar meter, and should give a more accurate reading than one of my 20 year old 11m radios....


Never a problem to qso you Geoff from most of your locations, so we should be good to go :thumb:

I can also document this on video Geoff and post up on my YouTube channel if you would like for future reference.

Mark 037
[][img][/img][/url]

https://www.youtube.com/user/26TANGOMIKE037/videos



Nembutol numbs it all
But I prefer alcohol
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RadioDaze
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That sounds like a very interesting plan for the wider, dare I say global radio community, good job Mark. I better dot my i's otherwise I will have the radio heavy weights picking holes in my methodology like every shoot out in history. :X

It is as good as you can get, real world at least, same poles, same mounts, same VSWR's, same power, same coax and multiple data from various RX stations where people can make up their own minds. Very happy to have this testing hosted at CT forum.

I will have to be fairly organized in order to keep a nice flow. As I mentioned I will keep chat to a minimum only enough to get the technical side running ok.

Fingers crossed for good weather conditions. Otherwise it will be twice the job for us.

If you are willing as a known keyer that would be great.

Having CT331 and/or Farmer Richard as known keyers would be good, plenty of time to decide.

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