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The Lil Wilsons, K30s etc are all designed to work out of the box on piss poor mobile installations because that is what the majority are. Stick them on a vehicle that presents a decent ground plane and the SWR will be too high on the CB band because the antenna is too long when used with a good ground. Putting it on the trunk of the car you're replacing a good ground with a piss poor one so it works exactly as the manufacturers designed it to work, with a poor ground. They would've worked on the vans etc but you would need an antenna analyser to see just how much below the CB band they were actually resonant at and get the cutters out to shorten the whips because they usually need shortening more than the adjustment in the antenna allows.

You shouldn't get too obsessed about trying to get a low SWR other than that needed to keep the transceiver finals happy. An analyser is better than a SWR meter because a SWR meter tells you very little. To quote K0BG,

Trying to get 1:1 SWR is pointless. There's nothing to gain from it and you usually find antennas which can give a SWR of 1:1 quite easily tend to be because they're not very good performers and the low SWR is an indication of losses. As I've said elsewhere, the feedpoint impedance of a 1/4 wave over perfect ground is 36.8 Ohms at resonance. 36.8 Ohms doesn't give 1:1 SWR, it maybe gives around 1.5:1 depending on other factors. If you've got 50 Ohms at resonance you've got issues.

<blockquote data-quote="M0GVZ" data-source="post: 534358" data-attributes="member: 22312">The Lil Wilsons, K30s etc are all designed to work out of the box on piss poor mobile installations because that is what the majority are. Stick them on a vehicle that presents a decent ground plane and the SWR will be too high on the CB band because the antenna is too long when used with a good ground. Putting it on the trunk of the car you&#039;re replacing a good ground with a piss poor one so it works exactly as the manufacturers designed it to work, with a poor ground. They would&#039;ve worked on the vans etc but you would need an antenna analyser to see just how much below the CB band they were actually resonant at and get the cutters out to shorten the whips because they usually need shortening more than the adjustment in the antenna allows.You shouldn&#039;t get too obsessed about trying to get a low SWR other than that needed to keep the transceiver finals happy. An analyser is better than a SWR meter because a SWR meter tells you very little. To quote K0BG,Trying to get 1:1 SWR is pointless. There&#039;s nothing to gain from it and you usually find antennas which can give a SWR of 1:1 quite easily tend to be because they&#039;re not very good performers and the low SWR is an indication of losses. As I&#039;ve said elsewhere, the feedpoint impedance of a 1/4 wave over perfect ground is 36.8 Ohms at resonance. 36.8 Ohms doesn&#039;t give 1:1 SWR, it maybe gives around 1.5:1 depending on other factors. If you&#039;ve got 50 Ohms at resonance you&#039;ve got issues.</blockquote>

[QUOTE="M0GVZ, post: 534358, member: 22312"] The Lil Wilsons, K30s etc are all designed to work out of the box on piss poor mobile installations because that is what the majority are. Stick them on a vehicle that presents a decent ground plane and the SWR will be too high on the CB band because the antenna is too long when used with a good ground. Putting it on the trunk of the car you're replacing a good ground with a piss poor one so it works exactly as the manufacturers designed it to work, with a poor ground. They would've worked on the vans etc but you would need an antenna analyser to see just how much below the CB band they were actually resonant at and get the cutters out to shorten the whips because they usually need shortening more than the adjustment in the antenna allows. You shouldn't get too obsessed about trying to get a low SWR other than that needed to keep the transceiver finals happy. An analyser is better than a SWR meter because a SWR meter tells you very little. To quote K0BG, Trying to get 1:1 SWR is pointless. There's nothing to gain from it and you usually find antennas which can give a SWR of 1:1 quite easily tend to be because they're not very good performers and the low SWR is an indication of losses. As I've said elsewhere, the feedpoint impedance of a 1/4 wave over perfect ground is 36.8 Ohms at resonance. 36.8 Ohms doesn't give 1:1 SWR, it maybe gives around 1.5:1 depending on other factors. If you've got 50 Ohms at resonance you've got issues. [/QUOTE]

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