Marconi comparing New Top One vs. Old Top One

[Marconi]

Here is my New vs. Old Top One antennas and the Old with a full 1/4 wave as the top element.



View attachment New Top One vs. Old Top One.pdf

YouTube - Marconi's New Top One vs. Old Top One full length 1/4 wave radiator

The things I see different are the New Top One has a wider bandwidth, a better match at the middle of the CB band, and the RX is quieter and the clarity is often better in many cases. On some occasions I can get a better copy of a particular signal in the distance on the New Top One. This may be due however to a slight difference in the typical noise level between my two mounts with one being closer to my electrical service out back. The other day when I first mounted the NTO I wasn't able to get it mounted quite as high as the OTO, it was a few feet lower. The advantage was obviously in favor of the OTO, but since then I've raised the NTO up about 2.5' feet more and now, according to my Signal Reports, both antennas respond about the same.

 

[HomerBB]

H'lo, Marconi.
Still working it out, I see.
perhaps if you swapped the to on the mounts you could see if the location is why one seems different in some ways.

 

[Marconi]

H'lo, Marconi.
Still working it out, I see.
perhaps if you swapped the to on the mounts you could see if the location is why one seems different in some ways.

Thanks Homer, but I've done that several times with different antennas, so I think I've accurately described the situation as to why the differences. That said however, I don't think I typically see a noticeable signal difference between the stations, the responses I describe are far more subtle and probably would not be easily noticed unless the antennas were side by side on a switch box.

I you ever decide to put your AP back up with a full length radiator to test, I think maybe I would start with the base element 46 3/8" x 3/4" + 45" x 1/2" with enough overlap to end up with an overall of 87.5". I think I used 88.5" on this current antenna and it made the resonance drop down into the high end of 26.000 mhz. With such a wide bandwidth however, I don't believe it made any difference to performance, but I'll have to take it down to check and be sure. In my hast to get it up, I believe I forgot to check the overall measurement in the top element.

 

[HomerBB]

Cool. I wondered what the measurements are for doing that.

 

[Marconi]

Cool. I wondered what the measurements are for doing that.

Homer, when I first tried a full length 1/4 wave on one of my Old Top One antennas, it took about three iterations to get to the tune at 27.205 mhz.

I first tried the length suggested in the AstroBeam manual for the top element, but it worked out to be way short and high in frequency, so I lengthened the radiator, and then ended up too long. Again I settled on 87.5" using the 46.25" x 3/4" base element provided and the 45" x 1/2" tip from my Sigma4. When I compared my Signal Reports for this OTO antenna, the one with the extended radiator did show a bit better signal, but for some reason at the time I was not impressed with the overall responses I got and fixed it back to the stock setup. Maybe my bias was working on my mind at the time, because I can't find where I made any notes describing why.

This said, I find there is little to no difference between these two antennas even considering the variables and the differences. So, when I hear these guys all clamoring about this and that concerning their idea of what theory says with regards to such a comparison, I say maybe they should do some actual testing before coming on so strong with their categorical type claims.

I read a post the other day that should be considered by some of these would-be Dr. Watson's, but I doubt it'll help.

Actually when the results do not agree with the theory a smart person would question why that was so and repeat the process to find out taking care that all procedures were followed exactly as it should have been. Myself and a few other broadcast engineers I know have often been in a situation where we said "That is just plain impossible and no way in hell can it happen." only to find out after closer research that things were not as they appeared and in fact the results were possible.

In my opinion this is good advice.

The attached video is the full video of the edited one posted above. There are not many signal reports to consider, so I will continue to test these two for a while. Like I said before, these guys around here don't like it when DX rolls, so they set their radios aside until nobody can talk over em'.

http://www.youtube.com/watch?v=KdIxla7KaEc

I don't have any technical links either that definitively declare one way or the other regarding the comparative use of a Top Hat vs. a full 1/4 wave radiator, but IMO if the top hat is an appreciable portion of the wavelength, approaching 50%, it can and does seem to work as well.

As far as bandwidth differences go, I'm not sure about how significant a difference that might play with this issue, but I could be convinced if anyone has some good evidence one way or another. Since the Avanti patent is reported to seem contradictory on this issue, concerning the AstroPlane, does anyone care to offer up and opinion as to which model makes or should make the best bandwidth?

 

[HomerBB]

Marconi.
Impossible to play the video at the moment due to my schedule, but I'll be able later. Looking forward to it.

 

[tuner]

height?

Here is my New vs. Old Top One antennas and the Old with a full 1/4 wave as the top element.

View attachment 4448

View attachment 4449

YouTube - Marconi's New Top One vs. Old Top One full length 1/4 wave radiator

The things I see different are the New Top One has a wider bandwidth, a better match at the middle of the CB band, and the RX is quieter and the clarity is often better in many cases. On some occasions I can get a better copy of a particular signal in the distance on the New Top One. This may be due however to a slight difference in the typical noise level between my two mounts with one being closer to my electrical service out back. The other day when I first mounted the NTO I wasn't able to get it mounted quite as high as the OTO, it was a few feet lower. The advantage was obviously in favor of the OTO, but since then I've raised the NTO up about 2.5' feet more and now, according to my Signal Reports, both antennas respond about the same.

Marconi, could you pleas tell me what height you have both antennas at in the pic please??

 

[W5LZ]

So tell me, what have you 'proved' other than a top-hat can take the place of a 'full-length' radiator?
- 'Doc

 

[Marconi]

Tuner here is the signal report I did on these two back then that indicates the tip height for each antenna in the image you see above.

So tell me, what have you 'proved' other than a top-hat can take the place of a 'full-length' radiator?
- 'Doc

Not much Doc', are you disappointed? This looks to only prove that I try to do some work testing what I say before I say it. I was always curious as to how these two would compare, and I did it just to see for myself if I could see a difference. I never saw a difference before I could produce evidence <gotproof> of what I did nor after.

Most will categorically tell us that the full 1/4 wavelength model will produce a much better signal than a shortened radiator with a top hat, but as you can see...this report does not seem to support such idle words.

View attachment New Top One vs. Old Top One.pdf

 

[W5LZ]

Am I disappointed? No, I was wondering what you were getting at.
There are, or have to be some differences between the signals radiated by the two types of antennas, but I honestly can't see where there would be a big difference. As for 'quality', I guess that would depend on what's meant by 'quality'. Strength or range I can see where it would have some affect, but as for the make-up of the signal it's self, how would any antenna affect that? An antenna can only radiate what it's presented with, it can't 'clean up' or 'better' anything by it's self. They just don't have that ability.
- 'Doc

 

[Marconi]

Doc' if you check the video below at about 1:36+ minutes, when I switch and no one is talking, you might be able to see the signal difference that I suggested was probably due to static.

If this signal difference is really due to static, then that may make some difference in the perceived audio quality in our receiver too, but IMO we would likely never notice such a difference unless we also had two antennas up while comparing and using a switch box.

Marconi's New Top One vs. Old Top One with full 1/4 wave radiator #2 - YouTube

This is too far back to remember for sure, but I have experienced this before with other antennas tested side by side, and sometimes it makes the difference in being able to communicate well.

Of course I considered that this could also be due to a difference in gain, but after watching a few CB antenna comparison videos by other's...where they also talked about static, I am convinced that static can be an issue that might also appear like gain at a long distance, and for sure if one does not even consider static.

Homer may have experienced such before since he does testing with two or more antenna up at times. How say you Homer?

 

[tuner]

Thanks Marconi, I was curious about the height. My mast is 27' high and I had an Imax2000 mounted on it. That put it about 51' feet to the tip. I'm happy that I mounted my Sirio Top One on the very same mast at 27'. The Top one mounts roughly 8' 9" leaving the total at almost 36' to the tip. This little 1/4 wave is performing the very same mounted 15' lower than the 5/8 Imax 2000. I wonder if it will do better up a little more?

 

[Marconi]

Thanks Marconi, I was curious about the height. My mast is 27' high and I had an Imax2000 mounted on it. That put it about 51' feet to the tip. I'm happy that I mounted my Sirio Top One on the very same mast at 27'. The Top one mounts roughly 8' 9" leaving the total at almost 36' to the tip. This little 1/4 wave is performing the very same mounted 12' lower than the 5/8 Imax 2000. I wonder if it will do better up a little more?

If the physical bottom of you antenna is already above the top of the typical buildings in your general area, then you might have to raise your antenna 10' feet or more to see any increase in signal. I see noticeable attenuation of signals when the physical bottom of my antennas are at or below about 19' feet which is a little below most roof peaks.

I live on flat terrain for 30-100 miles all around me, so your results may vary.

What is your <2.0:1 SWR bandwidth? My antenna shows 4.5 - 5.1 mhz depending on the height and mast size I use.

 

[tuner]

The land around my area is fairly flat although , my house is a story and a half. I have a two story house on both sides and behind me.

 

[Marconi]

The land around my area is fairly flat although , my house is a story and a half. I have a two story house on both sides and behind me.

These remarks are considering local contacts only.

What you describe here probably means the bottom of the NTO is well below the top peaks of the houses around you. In my experience, raising a little above the peaks will likely result in a noticeable increase in your RX/TX signals even if the house is all wood with tar shingles on the roof.

For me, the only way to really know is to increase the height and compare as best you can.