How are you mounting the antennas - on a crossmember or are you bracing between members to handle this?
Thinking - maybe not to focus on the SWR as the MOUNTING issue itself...
Are you able to use something similar to Catamarans and other pleasure sailboats use for stability.- or does it restrict/disqualify you from your ability to compete...
On the Left your vehicles Roof (similar?) - Right - Internal Brace- but used for Fiberglass older model Surburbans that had the removeable Fiberglass top.
Ok, here's what I'm looking at, I did something similar to a Toyota Scion xA not for competition, but to survive the outback woods area I used to live in...
I built a brace on it's roofline to the antenna wouldn't torque off while I drive - used Francis Amazer, 102" and 5' Hot rods - so the roof cargo carrier - like above - also had a brace using the Crossmembers of the framing inside and used washers as spacers to bolt that "bar" to the skin of the roof.
I'm showing you the Crossmembers so you'd have a means to utilizing that which Catamarans have a a means to stay upright - spreading out the loading if the Roof Rack can't - use a "bar" or other thick metal to "raise" the driven element - but use this "bar" not just to the Driven, but to the rear Reflector too - bolted to it.
This may not seem like much and more of a bother, but look, you know that by roof area is square feet alone, your feedpoint impedance is going to be roughly 36ohms or less, that is one "ding" against you...
You're lifting your feedpoint if only by inches - up - to change the feedpoint impedance to help with the SWR.
You already have the holes, just use them to attempt the method to add on height using the bar. But the Crossmember Bracing can help offset the twisting torque loading the Bar may not fully handle from side to side.
When using Beams - they always have a "Hot" element but it's isolated from the Boom - the Reflect and director elements are part of the boom but at a spacing making the Driven element more in-step with the other two.
With this in mind. is your mounting of the Driven, "raised" from the Roof - so the pitch angle that element uses for "image" to the truck - raises the question of the Bracing to work in your favor of elevated feedpoint of the driven element using the Bar to offset the Feedpoint problem with "too much metal".
So, if you got down to here to hear all that, thanks for reading the above...you said you've tried many different ways, with this recurring problem - did any of those include some type of Roof rack or raised roof system?
Thinking - maybe not to focus on the SWR as the MOUNTING issue itself...
Are you able to use something similar to Catamarans and other pleasure sailboats use for stability.- or does it restrict/disqualify you from your ability to compete...
On the Left your vehicles Roof (similar?) - Right - Internal Brace- but used for Fiberglass older model Surburbans that had the removeable Fiberglass top.
Ok, here's what I'm looking at, I did something similar to a Toyota Scion xA not for competition, but to survive the outback woods area I used to live in...
I built a brace on it's roofline to the antenna wouldn't torque off while I drive - used Francis Amazer, 102" and 5' Hot rods - so the roof cargo carrier - like above - also had a brace using the Crossmembers of the framing inside and used washers as spacers to bolt that "bar" to the skin of the roof.
I'm showing you the Crossmembers so you'd have a means to utilizing that which Catamarans have a a means to stay upright - spreading out the loading if the Roof Rack can't - use a "bar" or other thick metal to "raise" the driven element - but use this "bar" not just to the Driven, but to the rear Reflector too - bolted to it.
This may not seem like much and more of a bother, but look, you know that by roof area is square feet alone, your feedpoint impedance is going to be roughly 36ohms or less, that is one "ding" against you...
You're lifting your feedpoint if only by inches - up - to change the feedpoint impedance to help with the SWR.
You already have the holes, just use them to attempt the method to add on height using the bar. But the Crossmember Bracing can help offset the twisting torque loading the Bar may not fully handle from side to side.
When using Beams - they always have a "Hot" element but it's isolated from the Boom - the Reflect and director elements are part of the boom but at a spacing making the Driven element more in-step with the other two.
With this in mind. is your mounting of the Driven, "raised" from the Roof - so the pitch angle that element uses for "image" to the truck - raises the question of the Bracing to work in your favor of elevated feedpoint of the driven element using the Bar to offset the Feedpoint problem with "too much metal".
So, if you got down to here to hear all that, thanks for reading the above...you said you've tried many different ways, with this recurring problem - did any of those include some type of Roof rack or raised roof system?