Ground plane

[Cplchaos]

Hey yall, I have a 2020 Nissan Titan XD, with a panoramic moonroof. I am running a ranger rci x9 into sirio performer 5000 on a home made mag mount. I could not get the sirio and the factory mag under 2.6 swr when running any power, I took it a part and made my own, grounded things and now have a 1.13 swr on ch 1 a 1.00 swr on ch 20 and a 1.16 on ch 40. My questions are, is it worth adding a ground plane to try and lower the swr more? I understand a 1.1 to 1.5 on any channel is good, but is it worth trying to make better? Last but not least are there any good quality ground plane kits for an antenna like the sirio 5000? Please keep in mind I'm a newbie, and I'm trying to learn.

 

[bharvey2]

Hey yall, I have a 2020 Nissan Titan XD, with a panoramic moonroof. I am running a ranger rci x9 into sirio performer 5000 on a home made mag mount. I could not get the sirio and the factory mag under 2.6 swr when running any power, I took it a part and made my own, grounded things and now have a 1.13 swr on ch 1 a 1.00 swr on ch 20 and a 1.16 on ch 40. My questions are, is it worth adding a ground plane to try and lower the swr more? I understand a 1.1 to 1.5 on any channel is good, but is it worth trying to make better? Last but not least are there any good quality ground plane kits for an antenna like the sirio 5000? Please keep in mind I'm a newbie, and I'm trying to learn.

I wouldn't bother. Those are pretty decent numbers as far as SWR goes.

 

[mmckenna]

I used to run a Larsen NMO-27 dead center on the roof of a crew cab truck. I tuned the antenna with the $18,000 analyzer I use at work. Best possible ground plane. Permanent mount antenna.
I was getting similar numbers.

But, remember, SWR isn't the only measure of an antenna, it only tells you how much isn't getting radiated/lost in the coax.
The radiation pattern of the antenna will depend on the ground plane under the antenna. You want equal amounts of metal in all directions if possible.

 

[Cplchaos]

I used to run a Larsen NMO-27 dead center on the roof of a crew cab truck. I tuned the antenna with the $18,000 analyzer I use at work. Best possible ground plane. Permanent mount antenna.
I was getting similar numbers.

But, remember, SWR isn't the only measure of an antenna, it only tells you how much isn't getting radiated/lost in the coax.
The radiation pattern of the antenna will depend on the ground plane under the antenna. You want equal amounts of metal in all directions if possible.

What's the best route with a glass roof? Only other thing I could think of was installing a roll bar on the truck and welding a plate to it for the mount.

 

[bharvey2]

What's the best route with a glass roof? Only other thing I could think of was installing a roll bar on the truck and welding a plate to it for the mount.

Without an adequate ground plane (and a 1ft square plate isn't one at 10/11 meters) you'll end up with RF on your coax shield and likely have erratic SWR readings.

 

[mmckenna]

What's the best route with a glass roof? Only other thing I could think of was installing a roll bar on the truck and welding a plate to it for the mount.

There is no good solution with a roof like that. Roll bar is just a tall rail with an antenna on top, and no real ground plane at all.

Probably your best option is bed rail or front fender. That's going to skew the radiation pattern, but you don't really have any options unless you put an aluminum topper on the bed and mounted the antenna in the center of that.

 

[Cplchaos]

Thanks guys, guess I'll just leave it alone