Suggested designs/products

[PilotKeeg]

High gain omnis.

[SENTRY]

There is more to it than just what the pattern looks like. Something like so:

http://www.kaonetics.com/solutions.php

[IBCrazy]

Actually Sentry, I'm working on just that with the help of Hugo (Hugeone). I have been developing an antenna I call the "Pinnacle". The problem is the axial ratio shifts across the Z-Axis. I used the findings to develop the cloverleaf and dismiss the Pinnacle.

However Hugo found that spacing and phasing of two of his fan antennas gives a more or less consistent radiation pattern, but it changes the gain considerably. He dismissed this as he needed to use 93 Ohm coaxial cable to make it work.

Here's the thing: Phasing two Pinnacles should fix the axial ratio problem. Building them to a 100 ohm impedance rather than a 50 ohm impedance allows the use of 50 ohm cable so long as we use a multiple of 1/2 wavelength. While that is limiting in it's phasing, we can still change the spacing. That's what we are working on. VAS and TrueRC are joining forces

The other option is a phased quadrafiliar helix. It's hard to build, but I found a good radiation pattern by changing the element sizes.

-Alex

[SENTRY]

Well I don't mind being the test dummy for it. May end in a foxhunt but I'm definitely interested. This antenna could give fpv the "safety" factor by reducing our altitude. Less distance for the plane to glide if we lose link. Less interference with full-scale aviation. Better resolution from onboard and flight cams with the altitude decrease - etc.

[TallyHoe]

You can make your own coax to more or less any impendance you like by using the freely available thin brass tube model shops sell and some tinned copper wire for the center conductor.

I do this to make air cored coax (velocity factor of one) using tiny disks of ptfe at the ends to hold the center conductor central.

[volto]

What we need is an inexpensive sync pulse generator for analog video, so that any display will show static instead of a blue/black screen.

[IBCrazy]

RCA converter boxes do that. They are hard to find anymore. However the video recorders RMRC sell will generate an artificial sync pulse if you filter the video through them.

-Alex

[pesbra]

Hey Alex, how about an antenna like this:

http://www.antenna-theory.com/antenn...ing/spiral.php

One antenna to cover all our frequencies? Maybe even embbed it on a wing?

regards,

[Drednox]

A plasma antenna for my ground station?

[Danub]

Alex is it possible/reasonable to build a "turnstile" antenna for 2.4 or 1.2 vtx. . . . the idea being to keep all antennas 100% flat with the wing??
Why would it work or not work???
Thanks it was just a random thought as I gaze at my 200mph Demon . . . man I need to build a launcher. LOL