I am seeing your posts as a way to promote you product, not add to an antenna discussion. Since I am one of the most adamant posters here with a preference away from your antennas, there is always a post following anything I say. A slow eroding of my practical experience to justify claims I see on the CS website.
Quote:
Originally Posted by JER
You may want to remind readers that there is nothing wrong or deceptive about posting gain in dBi. If you look at the IEEE definitions of gain you will find that it is fundamentally tied to the concept of an isotropic radiator.
|
Sorry but I come from a practical old school. To me you can compare an antenna against a dipole, since an isotropic radiator doesn't exist. To me if you can't actually put up an isotropic radiator in the real world, how can you do a real world comparison?
Moreover since your company uses dbi, I find it interesting for the discussion suddenly to switch from a log periodic that EV found interesting to a discussion of dbi vs dbd. I would say it's to support your use of dbi, and to discount my position of saying dbd is a better scale. If it's not appropriate, why do other older TV Antenna companies use dbd?
Well I guess since I don't have an engineering degree but one in physics and math IEEE are to me just the way they look at things. Much of my parallel understanding of antennas comes from my background in optics. In optics there is the naked eye. Telescope "gain" or microscope "gain" is relative to the "naked eye", something that exists.
Quote:
Originally Posted by JER
Per IEEE definition, the word "gain" only refers to an antennas ability to focus power in a particular direction. It does not include mismatch losses! IEEE "realized gain" however does include mismatch loss.
Strictly speaking, if you only have a "gain" curve, you only know how well an antenna focuses and nothing more. This makes it easy to post a higher number since mismatch losses are left out.
|
Ok, from an isotropic viewpoint. To me it's the antenna's comparison to a dipole in it's radiation orthogonal to the dipole.
Oh, here we go again, adding to the discussion the talking points of CS antennas. That is just a sales job on a private forum. Saying what makes your design better is as much designed on mismatch as radiation pattern. My experience is on receive you can have VSWR as high as 2 with little loss in reception. Even if it's more loss that doesn't make up for antenna design.
Quote:
Originally Posted by JER
If, in addition to the "gain" curve, you also had a VSWR or Return Loss curve (referred to a particular transmission line impedance) you could compute mismatch loss and subsequently compute "realized gain" for the antenna connected to that line.
All the modern antenna simulators I have used output gain in dBi.
|
Well fine, the brave new world, and an implication that anyone that uses dbd is "old" and this is a new modern world. You and I know, antenna physics have not changed despite time passing or micro electronics revolution. If it were not relevant, then cell phone would be happy on much lower frequencies with some kind of compact antenna. It doesn't work. The physics remain the same.
Quote:
Originally Posted by JER
When making measurements in the lab, one might use a calibrated half-wave dipole antenna as a reference and then record gain numbers in dBd. I believe its safe to say that this is the only time most antenna engineers would be thinking about gain in dBd these days.
|
What is "safe"? I say it's safe to say since it requires a calibrated reference half-wave dipole in a real world lab test, it is the standard.
I hope this might add some clarity for those less familiar with the various antenna terms.[/quote]
It adds clarity to the fact you came here to advertise your product, to discredit my opinion, mired in the guise of discussing antennas. I have seen only you justifying your antenna and CS marketing, though I have seen on your site, the wording changed a little but still imply the C1,2,4 are VHF antennas.
Other manufacturers have showed up on forums and helped people find solutions. One of them helped me in a project I had. They didn't come in saying their antennas were indeed this or that, or that I was old school, which apparently I am and proud of it. They showed up to help individual people with problems concerning their antennas, not trying to sell their antennas.
I know you will dispute every word I say, and I have no desire for a flame war, but the constant posting of taking points about your antennas to me is well legally disguised advertisements.
Not to just pick on you but I also believe Escape Velocity though he adds real content to this forum is using to sell his wares as well.
Now Jay the forum owner if you want to take it to him can decide. But I am sick of people selling their products on this forum.
Linear Mode
