TYT TH-9800 is a CB radio -- sorta

[OkieBoyKJ5JFG]

The TH-9800 has the capability to receive AM CB channels, so ever since I got one, I wondered if it could transmit on those frequencies as well. With a minor software tweak, you can "unlock" them, but the radio doesn't have the hardware to transmit AM. I finally got around to checking it out, and the answer is yes, the 9800 can transmit on CB frequencies, but only in FM mode. It works great in FM mode, both transmitting and receiving. Not that it really matters, because literally nobody in the US uses FM CB, but it's kind of cool anyway. I only keyed up for a few seconds 3-4 times because on my 2m/70cm antenna, I was getting an SWR around 19. Obviously, to use it I'd need a different antenna. However, the radio has 10 meter capability, and when I start using it, I may be able to find an antenna that will do 11 meters as well. As I said, not very likely to be useful, but if the capability is there, you might as well be able to use it should you want to.

 

[prcguy]

You can cross band AM CB receive to VHF or UHF on that radio. Not that its legal of course.

 

[mmckenna]

FM on CB uses an 8KHz bandwidth. Looks like this radio does 12.5 or 25KHz bandwidth.
It's going to sound over deviated on CB.

 

[OkieBoyKJ5JFG]

FM on CB uses an 8KHz bandwidth. Looks like this radio does 12.5 or 25KHz bandwidth.
It's going to sound over deviated on CB.

This is more "gee-whiz" than anything useful anyway. I just got a kick out of finding out what it can do. It has 3 choices for bandwidth, although the manual doesn't say what they are. I assume "Narrow" is 12.5 and "Wide" is 25 kHz. I can't find the bandwidth for the "Mid" setting, but the software selects it by default. So, yeah, it could sound funny but in my brief test, it was clearly audible. Again, I'm not proposing to regularly use this thing as a CB, but I think it's kind of cool that it can do it.

 

[prcguy]

This is more "gee-whiz" than anything useful anyway. I just got a kick out of finding out what it can do. It has 3 choices for bandwidth, although the manual doesn't say what they are. I assume "Narrow" is 12.5 and "Wide" is 25 kHz. I can't find the bandwidth for the "Mid" setting, but the software selects it by default. So, yeah, it could sound funny but in my brief test, it was clearly audible. Again, I'm not proposing to regularly use this thing as a CB, but I think it's kind of cool that it can do it.

In a pinch you can program a CB channel for AM receive on the correct frequency and transmit in FM mode 5KHz off and people listening in AM mode will hear you ok. Of course I did this into a dummy load with a radio nearby to receive.

 

[OkieBoyKJ5JFG]

You can cross band AM CB receive to VHF or UHF on that radio. Not that its legal of course.

True, but it would be kind of pointless, since you can't transmit AM to respond to CB transmissions. It can receive AM CB just fine as it is. The left bank can send and receive 70cm, 2m, 6m, 10m, and 11m bands, but the right bank can only send and receive 70cm and 2m. I have the CB frequencies programmed in. On a routine basis, I set the left bank to a favorite frequency, usually a local repeater, and the right bank to scan. If I'm on the highway and think I might need more road information, I reverse it so that the left bank scans the CB channels. If there are slowdowns or hazards, people on CB will be talking about it, so the ability to transmit doesn't add much anyway.

 

[prcguy]

True, but it would be kind of pointless, since you can't transmit AM to respond to CB transmissions. It can receive AM CB just fine as it is. The left bank can send and receive 70cm, 2m, 6m, 10m, and 11m bands, but the right bank can only send and receive 70cm and 2m. I have the CB frequencies programmed in. On a routine basis, I set the left bank to a favorite frequency, usually a local repeater, and the right bank to scan. If I'm on the highway and think I might need more road information, I reverse it so that the left bank scans the CB channels. If there are slowdowns or hazards, people on CB will be talking about it, so the ability to transmit doesn't add much anyway.

Try what I mentioned above, it can work just fine.

 

[OkieBoyKJ5JFG]

In a pinch you can program a CB channel for AM receive on the correct frequency and transmit in FM mode 5KHz off and people listening in AM mode will hear you ok. Of course I did this into a dummy load with a radio nearby to receive.

Interesting. Potentially useful in an emergency, I suppose. Does it need to be 5 kHz above or 5 kHz below the frequency?

 

[prcguy]

Interesting. Potentially useful in an emergency, I suppose. Does it need to be 5 kHz above or 5 kHz below the frequency?

Above or below, doesn't really matter. The CB receiving you will be using slope detection in AM mode.