I installed a new cb
setup in my pickup: Larsen nmo27 whip antenna and Uniden Grant LT. The nmo mount was installed on the pickup roof by a professional shop. They also routed the cable to a location under the dash. The nmo mount has a factory 17 foot coax. I installed the radio under the dash. Seemed like a good clean install for all components.
Before I did any tuning I checked the antenna system for continuity, ground, and shorts. Everything checked out okay. So I did my first check with an swr meter and also confirmed first readings on the radio. First readings came back 2.3, 3.0, and >3.0 on channels 1, 20, and 40 respectively. SWRs were high, so I proceeded to tune, with each tune about a quarter inch off the antenna. Here are the readings, after each successive tune. Numbers are in order for channel 1, 20, and 40.
2.1 2.8 >3
2.2 2.4 3
1.9 1.8 2.4
2.4 1.7 2.1
Then since swr on channel 1 exceeded channnl 40, i stopped trimming and adjusted the whip up a bit. So the final numbers are:
2.2 1.7 2.2 on the swr meter and
1.9 1.3 1.9 on the cb
So in essence i have 2s on 1 and 40, and about 1.5 on 20.
Since everything seemed like a good install i was hoping to achieve better swrs. Am
i missing something?? Are these numbers acceptable? Could i have missed something wrong in the system check? Could a ground show good on multimeter but be improved?
After tuning i attached my antenna spring to see if i might get better readings if I tuned with the spring. The swrs went way up again, i suppose because it lengthened my antenna. When i checked the swrs with the spring, it blew the inline fuse twice, so i stopped any more tuning and called it quits.
On a side note, i do have some engine rpm-like noise coming through. Could that indicate a problem? i powered to accessory power in the ignition harness.
Thanks for your help!!! One of these days ill figure all this out. Or maybe im just being too picky and its good to go.