Hello folks,
I've been into CB radio for years, I have a base and 3 mobile set ups. On two of the mobile rigs I have roof mounted antennas and don't have any issues.
So here's the issue. I have an old jeep wrangler yj. I installed a Uniden 980 USB along with a little RM Italy KL 203 amp. Lowered the dead key on the radio, opened up modulation to 100% and it's a great low power set up. I have the standard 18 ft length of coax, using RG-58 since we're only talking about 175 watts pep. I bought the standard mount for behind the taillight, I have made sure the mount is grounded to the body of the jeep. Running the coax to the antenna without any coils, all has been checked, no shorts, good continuity, etc.
When using a 4 foot firestick antenna with tunable tip I have no problem achieving a 1.08 swr at 52 ohms. However when I try using a 5 or 6 foot skip shooter antenna with tunable tip I can't get the SWR below 2.8 at 130 ohms. My buddy brought over his rig expert analyzer over and we checked it. This is at the end of the coax hooked into the analyzer. Radio and amp out of the picture.
He's a long time CB'er and said certain antennas work better with certain vehicles. Now I understand that having the antenna mounted above the taillight isn't ideal and the roof is always the best location, however my roof is fiberglass so it's not an option. What would cause this and is there an easy fix? Basically a 4 foot antenna works great and the numbers are right, anything longer and the numbers jump up so I don't want to risk it. I did ask for a radio check from 4 miles away with the 4 foot antenna and he reported back that my signal was a 9 over 13. I tried the 6 foot skip shooter with the high SWR's and he reported my signal increased to a 10 over 19. Even so, I'm leery to run it until I can get the numbers lower.
Any ideas? I figured I'd ask before I start experimenting with coax length, etc.
Thanks!
I've been into CB radio for years, I have a base and 3 mobile set ups. On two of the mobile rigs I have roof mounted antennas and don't have any issues.
So here's the issue. I have an old jeep wrangler yj. I installed a Uniden 980 USB along with a little RM Italy KL 203 amp. Lowered the dead key on the radio, opened up modulation to 100% and it's a great low power set up. I have the standard 18 ft length of coax, using RG-58 since we're only talking about 175 watts pep. I bought the standard mount for behind the taillight, I have made sure the mount is grounded to the body of the jeep. Running the coax to the antenna without any coils, all has been checked, no shorts, good continuity, etc.
When using a 4 foot firestick antenna with tunable tip I have no problem achieving a 1.08 swr at 52 ohms. However when I try using a 5 or 6 foot skip shooter antenna with tunable tip I can't get the SWR below 2.8 at 130 ohms. My buddy brought over his rig expert analyzer over and we checked it. This is at the end of the coax hooked into the analyzer. Radio and amp out of the picture.
He's a long time CB'er and said certain antennas work better with certain vehicles. Now I understand that having the antenna mounted above the taillight isn't ideal and the roof is always the best location, however my roof is fiberglass so it's not an option. What would cause this and is there an easy fix? Basically a 4 foot antenna works great and the numbers are right, anything longer and the numbers jump up so I don't want to risk it. I did ask for a radio check from 4 miles away with the 4 foot antenna and he reported back that my signal was a 9 over 13. I tried the 6 foot skip shooter with the high SWR's and he reported my signal increased to a 10 over 19. Even so, I'm leery to run it until I can get the numbers lower.
Any ideas? I figured I'd ask before I start experimenting with coax length, etc.
Thanks!