Tech Forum

You can download a complete manual for your Cobra at https://cdn.shopify.com/s/files/1/0661/9627/files/148GTL.pdf?12272.

You will discover there that ANY CB antenna will work just fine with this classic rig. SSB or AM  — they all use the same antenna on CB.

Whether or not the CB radio has SSB capability or not does not affect the antenna used with the radio. All CB radios designed for use in the USA (assuming unmodified, factory original) operate from 26.965 MHz (ch 1) to 27.405 MHz (ch 40). The antenna must be designed/tuned for this frequency range. There are many choices for mobile CB antennas. A web search will turn up countless suppliers. Determine how you want to mount the antenna (such as mirror bracket, trunk edge, magnetic, bumper) and then look at the length of the antenna you are comfortable using. If the vehicle must fit in a low ceiling garage a long whip antenna may be a problem.  Longer antennas will generally outperform stubby compact designs which use coils to load the antenna, although the performance difference is not likely a concern for relatively short range use that would be typical on a road trip. Many CB antennas can be “tuned” so they are optimized at one channel. Your 148GTL has a built in SWR meter for this purpose. For general use, tune for a low SWR on channel 20 (mid point on the CB band).

ANY CB antenna will work. SSB (Single Side Band) operation is merely a mode of the selected channel. AM operation is DSB (Double Side Band, with carrier) while SSB is only -1- side band of the frequency. No special requirements for an antenna. "An antenna is an antenna, is an antenna" is what I have always said. The main differences are, base loaded, center loaded or top loaded. No major difference in any of them if mounted properly and they are of good construction. Avoid nearby metal objects that may 'de-tune' the antenna and affect it's radiation.

I don't believe that side band requires any different antenna, but, if given a choice, I would select a unit with the best gain since side band signals are sometimes weak.

Here is what Advanced Specialties has to say about antennas  www.advancedspecialties.net/cb-radio-faq.htm

"WHAT IS THE BEST ANTENNA FOR MY MOBILE CB RADIO?
A - This is tough to answer, & there are many variables, but here are some good general guidelines & "Rules of Thumb" to follow. First, The Taller the antenna, the better it will work. Mount your antenna as high as possible on the vehicle, & try to get at least 50% of it over the roof line. Usually, all else being equal, the Tallest, longest antenna you are comfortable with, mounted as high as possible, will give the best performance. For Example, mounting a new 4 foot CB antenna in the same spot where you were using a 2 foot, will usually give better results. It wouldn't really matter what "brand name", color, or style the 2 ft antenna was. Mounting Height on the vehicle, & the antenna length should be more important than other considerations. Keep in mind that, generally, CB antennas that are less than 3 feet tall, those that "stick to the glass", & the AM/FM/CB "combo" antennas & adapters usually do not give the best performance, they are bought & sold mainly for "convenience" & "cosmetic" reasons"

Yes you do need a special antenna, one designed for CB use. The antenna does not care if you are transmitting AM, SSB, or even FM. That was a trick used years ago, tell people they need a new and “special” antenna for SSB.

It’s like with TV antennas, years ago they sold you special antennas for color and now they sell you special antennas for HD signals. The truth is the antenna does not care what kind of modulation there is, it’s sole purpose is to convert the electromagnetic waves into a usable voltage on the coax/cable. The only thing that does matter is that the antenna is cut to the frequency it is designed to transmit/receive for optimum operation.

Unless you plan to run an illegal amplifier your stock CB antenna will work for you. If you don’t have a wattmeter (swr meter) you may want to see if a friend has one so the antenna can be tuned for maximum output.

First let me say that no matter how the signal is encoded, the antenna stays the same. The radio waves have not changed, only how we encode the information has changed and this does not affect or change the type of antenna needed to receive the radio waves upon which the information is encoded.

So, the bottom line is that you do NOT need a special antenna for the radio simply because it is using SSB as well as AM modulation. In fact, SSB is exactly the same as AM except that the carrier and one side band are suppressed. So you’re using less bandwidth, and about 2/3rd of the energy that was going into the other side band and the carrier are now able to go into the one remaining side band, thus increasing the distance you may be received.

You are still limited to 4W of output RF energy to the antenna, so the antenna doesn’t need to handle more power, it is not handling different RF frequencies, so the bottom line is that nothing has changed as far as RF and power are concerned.

I will say that if you want to use it mobile and have the best range possible you should use a full 9 foot long quarter wave antenna as we used to use back in the 60’s when I got started in CB. I hope that helps.

Any CB antenna will work.

Antennas are frequency specific, not mode specific. Any properly tuned CB antenna will work fine, regardless of whatever urban legend you might have heard.