How do I reattach antenna?

The antenna cable is invariably a coaxial type screened cable to reduce interference. There is a centre core carrying the signal and an outer braided conductor surrounding the centre.

The antenna cable is sometimes in assembly with the antenna and sometimes separate - in the case of a separate cable it will be terminated at each end with a suitable connector - one end to fit the radio and the other to fit the aerial, usually retained by a threaded outer nut.
The cable, if separate, is semi universal and so could be bought as a spare part for the vehicle or as an accessory.

Replacing or fitting is usually far from simple or easy...

It is the top[ lines in the rear glass. If you look close, you can see the separation. Most new window tints are metallic, and ruin the antenna, I made sure they didn't tint the antenna on my 2003 Civic. Any aftermarket antenna will work, the antenna cable coming out of the radio is just like any other.

Best way to check your SWR is with a separate SWR meter installed between the radio and the antenna. Be sure to check the input and output sides of the meter. With the meter in-place, key up your radio and adjust your antenna for max output / minimum loss. This may require that you change the length of your antenna and repair any questionable connections. Also, be mindful of the fact that CB radios broadcast in AM. That means your antenna should be well grounded to your vehicle. AM radios rely on "ground plane" antennas, which means that your entire vehicle (with good grounding) becomes apart of the antenna system. Hope this helps.

I would check the connections on the grid, if they are ok you have to live with yagi effect.

If your unit has digital display as most do now, RADIO-B will supply constant power to power the units memory so it can remember the preset channels, starting volume etc. The power antenna is usually controlled by a separate wire from the unit (normally blue) this wire supplies a low voltage signal to the antenna, The antenna will also have its own power supply and earth at the base of the antenna, the problem could be there. depending on the antenna, some have a controlling relay that is separate, again another possible source. there will also be a fuse in the main fuse box. These will all need to be checked, along with connecting a power source to the antenna to ensure the antenna does actually work.

The only reason to have an electrical wire going to the antenna is for a motor that raises and lowers the antenna. The antenna cable to the radio is the only wire on the antenna.
To replace the antenna, you have to remove it from where it connects onto the car, then lift it out from there. The antenna and the cable cannot be separated, it's all one piece. You pull the cable off of the back of radio, and tie a strong string onto it, because when you lift out the antenna, the cable will be pulled out from under the dash and to wherever the antenna is situated and out that hole. Now tie the string onto (hope you had a long string, lol) the end of the cable on your new antenna and cable, and stick the end of the cable into the antenna mounting hole. Pull the string from under the dash by the radio and you will bring the cable back into the dash and where you can plug it into the old radio and listen to good old music again !

First, we recommend you do not press the PTT button with the antenna removed, as it can damage your radio's reference ocsillator (final amplifier). That being said, you have a unique problem which could be caused by a poor connection in the antenna port of the radio. It is possible screwing the antenna on is slightly separating the internal antenna connection from the component board, or you have a hairline crack in the board in that area.

Also, you may want to check the programming of your frequency and PL code. Sometimes in a close proximity radio will work with one another when set to a "near" setting. Never hurts to double check.

Best regards.

Replacement is possible, the back of the radio needs to come off and there is a screw at the bottom of the antenna. Remove this and the old one will slide out and simple to install new one. Call Eton for replacement, can be foung with a google search....

maybe its broken internally,its unusual

Unfortunately, your description of the problem means that your radio must be taken apart to be fixed. Replacement antennas can be found purchased. It would require installing the new antenna and most likely soldering it to the broken wire. Do you have a picture?