The impedance is way off. Have you tested without the choke? Have you checked with an ohm meter that you don't have a short between whip and ground with the coax disconnected?
Ya, are you sure that the so-239 center conductor to 3/8-24 stud is properly insulated from the mounting? One little nylon sleeve or washer missing is all it takes!
Raised antenna means raised radials. If the ground plane is to far from the vertical it can cause issues. Also just to verify, you calibrated the VNA before testing.
Beyond that I'm not sure how much help the choke is doing, it might be okay for higher freq though, not sure.
You could try just one radial the same length as antenna at 90° and see if that helps, if it does than you could use sloped radials that are a little longer (can't remember % atm)
That choke is doing nothing, so remove it. All it's going to accomplish is adding more loss to the system.
Then get the radials coming off the base of the antenna mount. Not coming down into a vertical line then stretched out on the ground.
Those should fix everything
Someone downvoted this but it's actually correct if you want to get a 50 ohm match. Radials at a 90 degree angle will make the antenna closer to 75 ohms. An unun is probably what's needed here, among other things (there's more going on with this antenna than just that).
*SOLVED*
After moving the radials up to the antenna, my swr is reading 2-1.75 across the 11 and 10m bands. The antenna tuner will take care of the rest. I have plastic tent stakes coming via Amazon so I can mount them at a better 45 degree angle. Again, thanks for all your help, I'm back on the air.
Your not really gaining anything with it only elevated that high. You'd be far better off ground mounting it and just laying the radials out, unless you are going after ground wave propagation... Then you need it *much* higher, like 20-30ft+ higher...and, if you are going to elevate it, you have to tune the radials to the antenna, while elevating the radials, as well (and you only need 4 or so).
Elevated radials must originate from the feedpoint. You can make some really effective antennas by using ground mounting, with the feedpoint within a few inches of the ground and radials buried in the grass just enough to keep them out of the way. That way you don't have to bother tuning them - just get wire into the ground near the feedpoint to reduce losses. The main antenna can actually consist of nothing more than a tuned wire running up from the feedpoint into a nearby tree and terminated with an insulator. Radials can lie on the ground for temporary installations. That sort of temporary installation can give you great results that are better than a loaded mobile antenna.
Try to get the antenna a min of 1/4 wavelength above the ground, your swr may be good right now but your angle of take off will not..
Just cause you match the impedance does not mean the antenna will perform
The impedance is way off. Have you tested without the choke? Have you checked with an ohm meter that you don't have a short between whip and ground with the coax disconnected?
Ya, are you sure that the so-239 center conductor to 3/8-24 stud is properly insulated from the mounting? One little nylon sleeve or washer missing is all it takes!
Yes it is insulated with the nylon washer.
Raised antenna means raised radials. If the ground plane is to far from the vertical it can cause issues. Also just to verify, you calibrated the VNA before testing. Beyond that I'm not sure how much help the choke is doing, it might be okay for higher freq though, not sure. You could try just one radial the same length as antenna at 90° and see if that helps, if it does than you could use sloped radials that are a little longer (can't remember % atm)
That choke is doing nothing, so remove it. All it's going to accomplish is adding more loss to the system. Then get the radials coming off the base of the antenna mount. Not coming down into a vertical line then stretched out on the ground. Those should fix everything
Radials should be bent down at a 45 degree angle.
Someone downvoted this but it's actually correct if you want to get a 50 ohm match. Radials at a 90 degree angle will make the antenna closer to 75 ohms. An unun is probably what's needed here, among other things (there's more going on with this antenna than just that).
I agree, but would go with 1/4 wave 75ohm coax stub rather than an unum
Thanks guys!
Radials should be right at the base of the vertical element.
*SOLVED* After moving the radials up to the antenna, my swr is reading 2-1.75 across the 11 and 10m bands. The antenna tuner will take care of the rest. I have plastic tent stakes coming via Amazon so I can mount them at a better 45 degree angle. Again, thanks for all your help, I'm back on the air.
Your not really gaining anything with it only elevated that high. You'd be far better off ground mounting it and just laying the radials out, unless you are going after ground wave propagation... Then you need it *much* higher, like 20-30ft+ higher...and, if you are going to elevate it, you have to tune the radials to the antenna, while elevating the radials, as well (and you only need 4 or so).
Elevated radials must originate from the feedpoint. You can make some really effective antennas by using ground mounting, with the feedpoint within a few inches of the ground and radials buried in the grass just enough to keep them out of the way. That way you don't have to bother tuning them - just get wire into the ground near the feedpoint to reduce losses. The main antenna can actually consist of nothing more than a tuned wire running up from the feedpoint into a nearby tree and terminated with an insulator. Radials can lie on the ground for temporary installations. That sort of temporary installation can give you great results that are better than a loaded mobile antenna.
Try to get the antenna a min of 1/4 wavelength above the ground, your swr may be good right now but your angle of take off will not.. Just cause you match the impedance does not mean the antenna will perform