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CB Radio Forum - Discussions regarding Citizens Band Radio (CB)

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Old 06-14-2017, 10:38 AM
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Default Improving my 27 MHZ Base Antenna

Read some posts on here lately and it got me thinking. Allot of you probably remember me setting up my CB Base Station about a year ago. My schedule should slow down here soon so I may have some time to make some improvements. My current base antenna is about 12ft. of large gauge copper wire coiled around a section of pvc that is then connected to an approximate 6.5 ft. run of solid copper pipe. The total length making up close to the amount needed for a 1/2 wavelength at 27 MHZ.

I am thinking about pulling off the top 6.5 section and replacing it with a 102" section, then reducing the coiled wire section to 102". This would create a 1/4 wavelength of coil under a 1/4 wavelength of solid pipe. I will also then be setting a better mast that will take the antenna at least 8 feet above the roof line as opposed to the 3 feet above it sits at currently.

Does anyone believe this will be worth my time and have a chance to improve transmit and receive, or is the common opinion at there that it probably is not worth it. I believe I can make all the improvements for less than $100.00.

Currently I am transmitting clearly to truck drivers (standard 4 watts) at 5 to 6 miles. I am receiving to about 10.
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Old 06-14-2017, 11:24 AM
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Default Antenna

There is far more to an antenna than the length. The diameter and type of metal can also have an effect on the efficiency. In my CB days, I could count on 10 miles with a good commercial ground plane with radials on AM, and up to 20 miles SSB. A mismatched antenna is a quick way to destroy finals, even at 5 watts. When you think it is ready for use, at least check with a good SWR meter or even better an antenna analyzer.
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Old 06-14-2017, 12:30 PM
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Best improvement would be height. Sounds like a good plan let us know if you get much improvement.

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Old 06-14-2017, 12:51 PM
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If you turn it into a ground plane, you'll have good results! All you need is a 102 inch radiator (whip) and 3 or 4 102 inch radials! BTW, you can buy a brand new A-99 antenna for only $65 at www.Copper.com !!
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Old 06-14-2017, 12:51 PM
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A99 hard to beat.

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Old 06-14-2017, 4:00 PM
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I think if you put what you have in the trash and do anything else it would be an improvement. What you have made is not a CB antenna, its just random stuff and if you make any contacts now its pure luck. Believe it or not, your coax is probably radiating as much as the antenna part because of the way its put together.

Coiling up 102" of wire is completely different than the same length of wire stretched out and may take only 60" of wire or maybe 150" of wire to equate to 1/4 wavelength at CB when coiled up. Placement of the coil at the top, middle or bottom of an antenna completely changes the needed lenght of wire to equal 1/4 wavelength.

A half wavelength radiator (about 18ft long) would also be an incredibly bad match to 50 ohm coax if you did it right and it takes a complicated but reasonably easy to make matching circuit to make it work. Let me know if you want to continue down the full 1/2 wavelength radiator path and I'll send you some info on how to match it. You can make the equivalent of an A99 that will handle about 100w for less than $5.

Otherwise if you simply connected a 9ft whip or wire to some coax and made a couple of 9ft ground radials I guarantee it will work much better than what you have now.
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Quote:
Originally Posted by Nutes View Post
Read some posts on here lately and it got me thinking. Allot of you probably remember me setting up my CB Base Station about a year ago. My schedule should slow down here soon so I may have some time to make some improvements. My current base antenna is about 12ft. of large gauge copper wire coiled around a section of pvc that is then connected to an approximate 6.5 ft. run of solid copper pipe. The total length making up close to the amount needed for a 1/2 wavelength at 27 MHZ.

I am thinking about pulling off the top 6.5 section and replacing it with a 102" section, then reducing the coiled wire section to 102". This would create a 1/4 wavelength of coil under a 1/4 wavelength of solid pipe. I will also then be setting a better mast that will take the antenna at least 8 feet above the roof line as opposed to the 3 feet above it sits at currently.

Does anyone believe this will be worth my time and have a chance to improve transmit and receive, or is the common opinion at there that it probably is not worth it. I believe I can make all the improvements for less than $100.00.

Currently I am transmitting clearly to truck drivers (standard 4 watts) at 5 to 6 miles. I am receiving to about 10.

Last edited by prcguy; 06-14-2017 at 4:08 PM..
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Old 06-14-2017, 6:34 PM
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I also suggest a A99, it would be an improvement
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