Suggested designs/products

[Jameson]

Alex, I know nothing about antennas (but your inverted vee works pretty good!), but I thought about something like this: http://www.gaorfid.com/index.php?mai...roducts_id=675 - but I'm not sure if it will work for UHF TX well... That "Quagi" sounds pretty good, something like frog speach :-) Quagi...quagi...krrrr :-)

[IBCrazy]

is it true though IBCrazy that if you triple the size of a patch you double the gain? If so than I'll just make some extra large patches

Sort of... For the most part, the dimensions triple (except the air gap), but it's not exact. Better to go the BiQuad route and add bowties to it. That is higher gain, efficiency and a smaller package.

-Alex

[PilotKeeg]

I think I read that a stacked double biquad was 14 dBi so if you add a bowtie to make a triple stacked double biquad it would be 15? Or what about making it a triple biquad?

[IBCrazy]

You can only stack once. Otherwise you make what's often referred to as a "quagi". Quagis are basically a yagi with quad side elements.

Now a stacked double BiQuad might be doable. Probably 16 or so dbi and a package that's not too big. I could look into that one.

-Alex

[PilotKeeg]

I have an Ezuhf system coming, I could do some beta testing...

[volto]

Alex, I was trying to find a compact CP antenna design for 2.4ghz to use on my FrSky receivers, since space is usually limited by a receiver and you don't want bulky antennas popping out all over your plane. I was researching GPS antennas for about an hour, (and not learning much)... I was wondering how an antenna tuned to 1.1-1.5ghz could be so small, circularly polarized, and so effective. I was wondering if the same designs could be used for 2.4ghz and other frequencies to have a compact CP antenna?

Maybe something like this:

source

or this
http://www.ece.uci.edu/rfmems/public...tenna/J009.pdf

Jerrod

[IBCrazy]

That could work. It's fairly high gain for an antenna on your airplane, though. The only problem with these types of designs is that they are terribly inefficient. You see, most GPS manufacturers can safely assume that the GPS will be upright or close to it. Therefore, they build a compact antenna with high gain but get away with low efficiency due to the size requirements. This allows them to still get a signal and compact antenna.

-Alex

[Marcantonio]

Hello Alex,
if you could take the time to explain me how this antenna works, and how it is fed, than I can give you an idea of what product to try and come up with.
I can't understand where the ground is in this antenna, is it the center hole?
http://www.mwjournal.com/Journal/Com...tenna/AR_8587/

[IBCrazy]

That's a pretty cool idea but only circular on the horizon... If you look at my rotary reactor antenna (somewhere in this forum I can't remember where) you'll see I came up with a 3 dimensional antenna of similar style. The problem is that realizing the antenna proved to difficult.

On first glance it looks like the ground is connected to a ground plane underneath the element, but I can't be sure.

-Alex

[SENTRY]

How about an antenna design with terrain hugging / ground hugging wave propogation for flying low(ish) and far? Something that radiates like the green M&M in this pic. I'd love to test something like this.