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I'm running a Siro 5000 here which must be at least a decade old or more now. Its mounted with a fixed SO239 mount in the roof of the car so yes that means drilling a hole. I've also bonded the hood and trunk lids to the main vehicle body too. Like all the CB antennas I put on my car mounted via this method I had to get the dremel out and cut a few inches off the whip, 4 inches in this case because it was resonant at just below 26MHz. Antenna whip lengths are usually selected to work with the lowest common denominator installation and as you improve the RF ground you need to shorten the antenna. The same issue happens with Hustler BTV antennas for amateur radio base stations which if you have a good RF ground and not just a ground rod you find you have to move the traps.

With the car running driving down the road out of town I get S0 on the S meter and can hear stations who are S0 too. Fixed mounts and bonding is definitely worth the time and money to do.

In regards to the grounding, all grounding for RF needs to be take care of where the braid of the coax ends at the antenna end. "Grounding" a radio bracket doesn't fix the problem, merely masks it. Common mode RFI is the cause of the noise and thats a result of a poor RF ground.

www.k0bg.com and the sections on mounting, grounding and bonding are worth a read.

<blockquote data-quote="M0GVZ" data-source="post: 578697" data-attributes="member: 22312">I&#039;m running a Siro 5000 here which must be at least a decade old or more now. Its mounted with a fixed SO239 mount in the roof of the car so yes that means drilling a hole. I&#039;ve also bonded the hood and trunk lids to the main vehicle body too. Like all the CB antennas I put on my car mounted via this method I had to get the dremel out and cut a few inches off the whip, 4 inches in this case because it was resonant at just below 26MHz. Antenna whip lengths are usually selected to work with the lowest common denominator installation and as you improve the RF ground you need to shorten the antenna. The same issue happens with Hustler BTV antennas for amateur radio base stations which if you have a good RF ground and not just a ground rod you find you have to move the traps. With the car running driving down the road out of town I get S0 on the S meter and can hear stations who are S0 too. Fixed mounts and bonding is definitely worth the time and money to do. In regards to the grounding, all grounding for RF needs to be take care of where the braid of the coax ends at the antenna end. &quot;Grounding&quot; a radio bracket doesn&#039;t fix the problem, merely masks it. Common mode RFI is the cause of the noise and thats a result of a poor RF ground.<a href="http://www.k0bg.com" target="_blank">www.k0bg.com</a> and the sections on mounting, grounding and bonding are worth a read.</blockquote>

[QUOTE="M0GVZ, post: 578697, member: 22312"] I'm running a Siro 5000 here which must be at least a decade old or more now. Its mounted with a fixed SO239 mount in the roof of the car so yes that means drilling a hole. I've also bonded the hood and trunk lids to the main vehicle body too. Like all the CB antennas I put on my car mounted via this method I had to get the dremel out and cut a few inches off the whip, 4 inches in this case because it was resonant at just below 26MHz. Antenna whip lengths are usually selected to work with the lowest common denominator installation and as you improve the RF ground you need to shorten the antenna. The same issue happens with Hustler BTV antennas for amateur radio base stations which if you have a good RF ground and not just a ground rod you find you have to move the traps. With the car running driving down the road out of town I get S0 on the S meter and can hear stations who are S0 too. Fixed mounts and bonding is definitely worth the time and money to do. In regards to the grounding, all grounding for RF needs to be take care of where the braid of the coax ends at the antenna end. "Grounding" a radio bracket doesn't fix the problem, merely masks it. Common mode RFI is the cause of the noise and thats a result of a poor RF ground. [URL="http://www.k0bg.com"]www.k0bg.com[/URL] and the sections on mounting, grounding and bonding are worth a read. [/QUOTE]

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