Narrowing It Down...Antenna & Changing SWR

Found myself in a warm (for January) location this past week with a couple hours to kill and got out my drill, measuring height stick, a new run of mini-8 coax, a Wilson FGT 4' antenna and a new stainless mount. Still trying to tackle the car hauler antenna mount/SWR thing.

Drilled for a new mount in a preferable location on the left outside rail of the rack between the first 2 cars on the top rack. The mount puts the antenna entirely above the steel rails of the rack, excellent grounding and it tuned out @ 1.2:1 across the channels after a half dozen climbs up & down the ladder. I removed the Predator 10K I had bullhorned on the front left...nothing wrong with it other than it's just too tall and even going with a 2 coil option to lower it...still too much. I had around 48" to work with at this new mount location and expect any life for an antenna. I opted for a Wilson FGT (fiberglass) 4' "Silver Load" after reading a lot of reviews and testing. Also, I was trying to get away from "bullhorning" the antenna and this antenna put me right at 13' 6" standing vertical after tuning. I wanted to go with a Wilson 5000 but even with the 5" shaft option, the whip gets extended and ends up around 15' on my mount. Wilson claims 800 watts capable on this FGT 4 footer...I won't be burning this antenna. I would like to heat it up a little if I can get this antenna deal right though. I'm just trying to keep from screwing up my radio with out of whack SWR for now.

(Removed my 30 day old "new" K40 mini-8 coax to run new Belden mini-8 after I noticed the grey insulation on the K40 cracked in several places with the wire exposed and obviously corroded. I remember the K40 brand as being a quality name back in the day but this was not as I had remembered. This coax was about 30 days old and was run and secured without any reason for this to happen other than exposure to the weather. So much for the k40 brand for me. At this point, I probably had found a lot of my problems but continued.)

So...new everything right to the back of the radio. Surprised at what a difference in receive immediately. Later that night coming back across I-78 in PA, actually talked to a guy that when we compared milemarkers...we were 14 miles apart with quite a bit of radio chatter on channel 19, going in opposite directions and he said my radio was still loud and clear as was his on my end. Just being pleased at a 14 mile transmission should tell you a little about my previous attempts at setting this truck's radio up...I know that's nothing compared to many of the rigs out there but small steps. Yeah...I'm still a mud duck but I'm going to get my wings one of these days.

Now for my next little puzzle for antenna theory discussion. The 1.2:1 SWR reading (cheap Workman meter) across all the channels after fine tuning was with the truck unloaded. After getting loaded with cars in adjacent positions closest to the new antenna location, I rolled around the channels testing it as I was driving home trying to beat the weather coming in central PA. I was actually looking for my antenna warning flasher (Stryker 447) to see if it started flashing. I didn't expect to see it flash with my 1.2 reading. Sure enough...from channels 12 to 40 I had the AWI flashing. From 1 to 11, no flash. By the way, the 14 mile talk noted above was with a load on. I know the flasher can be adjusted on the channel selector board per Shawn at Stryker but this is giving me an idea of what is going on with my SWR and reflection off the loaded cars even though I have mounted the antenna now in the most clear spot on the rig when loaded and the tip of the antenna is above the roofline of the cars onboard. I'm not going to mess with the AWI adjustment just yet because I believe this flashing on the higher channels is true and indicating a "too high" SWR condition. Discussing this with an unnamed CB shop guy...he said tune the antenna with a load on it and when unloaded it should only get better. Somehow I don't believe this will happen but that's my next thing to try. I should have checked the SWR with the load on that night but that arctic cold front changed the Daytona-like weather to a nipply wind chill and I didn't feel like climbing that ladder and tuning the antenna.

I'm getting closer to finding my feathers.

 

Well he may be right in the end but I am basing my doubts on the way the antenna tuned from start to finish. I'm going to check it with the next load on and tune it to that but I can't imagine it getting lower after unloaded. It may be that I might see acceptable SWR on both ends of the channels while not necessarily seeing it solid across all like I did when I was empty. In that case, it'll still be OK as long as I can find that sweet spot preferably 1.5 or near that. I read here (or somewhere) that there's not a big performance difference in SWR down in that range running a little radio like mine. I guess if I was undertaking a chat on channel 6 and had serious equipment, every little bit helps but with my set up, not a big deal. But nothing wrong with striving for perfection whether I reach it or not, huh?

 

Well now...that's thinking outside the box. Thank you, Cool Breeze. I was just looking at a post over on a CB forum from you and here you are solving my problem. I never even thought about that. I guess I could use an antenna switcher to swap between loaded and empty?

 

I got a tuner but have been told that wasn't the best way to go.

 

Really I could get one of Breedloves quick disconnects and snap one off and the other one on as I load/unload. Thx Cool Breeze...I'll get it figured out with that help.