SpiroNET Circular Polarized Antennas

[george formby]

Well...
It appears I am the only one to have purchased and tried a set of these out.
Far too hot to do a flight. I was melting in the field.
Did some ground testing.
I only have a set of standard dipoles to compare with.
Being new to FPV.
New ones are quite good. Not by a huge amount, but better.
Makes me very sad to see you guys behave in this manner.
Please please, keep any bun fighting private, in this thread and any other.
You should all know better...

[ssassen]

The one I quoted from and addressed?

You must've missed the cola analogy?

Show me a 3 lobe circularly polarized antenna from the '50s.

The math describing the SPW antenna clearly describes an antenna with the number of elements/leafs n being >2. The fact that n is typically >3 is due to an axial ratio being better on antennas with more than three elements, hence most designs use 4 elements. So unless Alex actually worked out the equations describing the SPW antenna, which he hasn't, some smart guys in the '40s did, he can't claim he invented the 3 leaf as it is an intrinsic part of the equations describing the antenna.

But know what, how about you write to VW that they copied their 4-spoke wheel from BMW who had it first years ago, see if you can make that stick okay?

As for Trappy, he's right, we don't need this BS.

[volto]

The math describing the SPW antenna clearly describes an antenna with the number of elements/leafs n being >2. The fact that n is typically >3 is due to an axial ratio being better on antennas with more than three elements, hence most designs use 4 elements. So unless Alex actually worked out the equations describing the SPW antenna, which he hasn't, some smart guys in the '40s did, he can't claim he invented the 3 leaf as it is an intrinsic part of the equations describing the antenna.

I can't confirm or deny that claim, but if that's true then why didn't you just say that from the beginning?

[Teacup]

I can't confirm or deny that claim, but if that's true then why didn't you just say that from the beginning?

To quote from post #77

...

So considering the 3-leaf SpiroNET design, what does it have in common with the BluBeam cloverleaf?

Both are derivatives of the original 4-leaf skew planar design, which in turn can trace its roots back to the Lindenblad, circa 1940. The math describing the SPW antenna clearly describes an antenna with the number of elements/leafs n being >2. The fact that n is typically >3 is due to an axial ratio being better on antennas with more than three elements, hence most designs use 4 elements.

...

[volto]

Post #77 isn't exactly the beginning, it's like he pulled that out after the fact. Also curious how he went from thinking he wasn't calling it a cloverleaf, to defending using the name cloverleaf. Oh well I don't care anymore, I haven't researched the work of Lindenblad but it appears I was wrong, so apologies gentlemen, let's all have a beer and smoke a bowl some time.

[IBCrazy]

The math describing the SPW antenna clearly describes an antenna with the number of elements/leafs n being >2. The fact that n is typically >3 is due to an axial ratio being better on antennas with more than three elements, hence most designs use 4 elements. So unless Alex actually worked out the equations describing the SPW antenna, which he hasn't, some smart guys in the '40s did, he can't claim he invented the 3 leaf as it is an intrinsic part of the equations describing the antenna.

You're right, I never bothered with the math. Like many things, it was a bit of a mistake and all I did was play with empirical figures. Playing with the SPW geometry led to my design of it and the original designer's having about 15 degrees of pitch difference. While it worked, I was noticing some coupling at the base. Old Man Mike had increased the feedpoint gap to compensate and bring the arc to the proper length. I wanted to keep the added arc. In order to keep the arc but avoid the coupling I needed to remove a lobe. And it worked. From there, I tried coupling all 3 to a ground plane to try to make a 5 dbic directional antenna. Mictronics did the modeling for me with a little help from 4NEC-2. But I couldn't get the pattern I wanted. I still had the null. From there I simply removed the ground plane in an attempt to not restart from scratch... and was amazed at the results. Like many great things, it was a mistake. I wasn't trying to make another omni. I was trying to make a 5dbic directional antenna. Later attempts at the 5dbic directional revealed the Crosshair.

Let's face it, my educational background in RF is limited to a single 3 credit college course. The rest I learned via experimentation.

-Alex

[imagebuff]

Just got a set in the mail. They look awesome! Cant wait to try them. Had to take the hood off for a looksie.

[tree]

im willing to try them. but i do miss my bluebeams. i dont care for the true rc units i have now. going back to bluebeams.

[IBCrazy]

@imagebuff - Thanks for clearing this up. My suspicions confirmed,

One problem (Sander, are you reading?) is that linking a radome to an antenna is a bad thing in my experience. It seems well and good in theory, but in practice it actually damages the antenna with use (abuse). Inevitably what people end up doing is twisting the radome and breaking the antenna inside. How do I know? Volto and I built them for the TV production industry. They lasted about 3 days until we made the radome float. I highly suggest making the radome twist independent of the element inside. Bonding it to the coaxial cable works fairly well, though. I opted to make the entire radome a completely separate assembly.

Just a suggestion.

-Alex

[kenkos68]

i dont care for the true rc units i have now. going back to bluebeams.

Curious,
what didn't you like about them?