PowPow
Where's the beef?
I know you knew that, but I don't think others may have - hence my comment - not criticism. And I have read about QRP and knew what you were referring to.
CB Radio
- Thread starter Pinecone
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I know you knew that, but I don't think others may have - hence my comment - not criticism. And I have read about QRP and knew what you were referring to.
I didn't take it as criticism and tried to form my response as such. If I didn't do that, then I owe you a beer.
- Feb 4, 2013
- 28,175
CB Radio is on 11 meters (~27MHz), which is HF (3MHz-30MHz). (Studying for my Technician & General) It's just that 11 meters is not one of the Amateur Radio HF bands.
FYI, 11 meters used to be ham.
PowPow
Where's the beef?
The interwebs say this change happened on, get this....9/11/1958.
So, on MDshooters the truth is finally revealed. The 9/11 jihadis were angry with the FCC for taking 11 meters away from Amateur Radio! And it took them 43 years to exact revenge.
Crap. I am sorry. I totally misspoke. I meant FM. NOT digital.
FM is the advantage to GMRS. CB is AM.
Also perks in that you can use repeaters with GMRS, which there are none for CB. Much smaller antennas also, because you are talking about 1/16th the wave length of CB. CB isn't sufficiently low enough frequency to be over the horizon. It might perform better in really dense urban settings or mountains, but even there, 27MHz isn't going to punch through whole mountains.
Antenna limits on CB are 106" IIRC. That's 1/4 wave length. The ideal (minimum) for gain. Also nearly 10 feet long to get a 1/4 wave length antenna.
GMRS 1/4 wave length antenna is 6.8 inches.
So even with the much higher free path losses on GMRS frequencies, you can have significantly higher gain with GMRS antennas. Plus you can have MUCH higher transmit powers. And you can use repeaters. And it uses frequency modulation, so you can also get much better clarity on the reception/lower interference. So lower RX power broadcasts can be understood.
From my limited experience (with CB, I have a fair amount with GMRS) you get a little better range with a nicer GMRS (IE higher power, one of the larger antennas, vs like a 5w and little antenna) and definitely better range on handheld's for GMRS vs CB. The quality of the reception is a lot better with GMRS.
Also you can find GMRS sets that include AM/FM/Weather radio (you can find that with CB also, but doesn't seem as common).
PowPow
Where's the beef?
What radios are you running with it?
FM is advantageous to more than just GMRS and the associated bands (UHF), it is also advantageous and used in the HF bands, particularly in the 10m (28 MHz) and 6m (50MHz - 54Mhz) bands.
And comparing AM to FM for reception is comparing apples to oranges, FM will be infinitely better due to the modulation type regardless of the service it is used in.
Repeaters aren't "perks", they are a necessity to get further range. CB, by virtue of being HF gets better range and while it won't "punch through a mountain" (Neither will GMRS), it can be bounced off the atmosphere or used as ground wave and get much further range on 4 watts Am or 12 watts SSB on any given day compared to GMRS.
There are absolutely no limits to antenna size for CB, and while a full quarterwave is indeed roughly 106", once you start adding loading coils, you can indeed get a 1/4 over 1/4 vertical for a vehicle (Think firestick with multiple wraps from multiple feed points in a 30" antenna).
More gain and more power does not necessarily equal better signal, further signal, better reception. What provides most of that is the modulation type (FM), however, on any given day, CB at 4 watts FM can be heard world wide with very little issue, it is simply the nature of the frequency spectrum.
Since AM is not type accepted mode for GMRS, then any radio that does all three for the GMRS frequencies is NOT type accepted for the GMRS service under part 95.
As for mobile/base rigs, you can absolutely find radios that have AM/SSB and a small VHF FM receiver for the weather channels. The only reason you won't find true FM, is just like AM is not an accepted mode for GMRS, FM is not an accepted mode for CB.
I meant AM radio, as in 535-1060KHz RX only and FM 88-108MHz Rx only.
Don’t see a lot of CBs themselves that can do that and weather band.
Also I wasn’t aware CB was allowed to do FM. AM only (maybe I’ve missed the FCC allowing it. Or it’s just that generally available CB sets are AM only).
Retevis H777 handsets
Midland MXT115 in the cars with Nogoya UT-72 antennas. Midland XT511 as a basestation/camp radio.
The above would require three additional receivers for the three completely different bands. Base and mobile CB's with weather channels is a relatively new thing since it requires a receiver for the UHF band (Same band as GMRS), and it requires a bit more than re-tuning for harmonics of the CB frequencies to be an effective receiver for the weather channels.
FM is NOT permitted on CB, just as AM is NOT permitted on GMRS.
FM IS permitted in the amateur bands on 10m and 6m which are in the same band as CB.
Err, yes my point was though that if you want "one" radio. As in a handset, mobile set or base station rather than separate physical units, a CB usually won't get that for you. Just a thought. For me it is convenient that I've got a base station that can receive traditional AM/FM broadcasts for radio as well as weather radio. AND it can transmit and receive GMRS out to several miles if I have good line of sight, or at least half a mile or so in a really dense urban environment or in the mountains (and dozens of miles if I've got LOS between receivers in the mountains).
CB might be helpful in that there are likely more transmitters and receivers out there. At the same time, my very limited experience is, you find them around major highways and interstates and they are mostly just truckers (and plenty then don't).
If you are looking to get in touch with people dozens or hundreds of miles away, mostly you probably won't get that with CB in a useful manner. If you are looking for a way to stay in touch with family, friends or neighbors who are reasonably close, GMRS is way better is my 2 cents (MURS is even better if you CAN find a MURS radio).
Me personally, it would easily let me stay in touch with any neighbors, friends or family within my several square mile rural neighborhood. I can probably find ways to get dead spots if you have some of the hills in your way, but so far non-line of sight just with my 2.5w hand sets with ~1.5dBi aerials on it work just fine between each other in most of the parts of my neighborhood I've checked. Now if I went WAY down to the river it likely would not reach and it might not with that much earth between sets even with the vehicle mounted sets with a lot more transmit power and ~3dB more antenna gain on each side.
In a really nasty situation, I doubt I'd worry too much about hoofing it several miles from my house while leaving people home. But maybe I would/do need VHF (but CB still doesn't seem to be the solution to me for that).
- Feb 4, 2013
- 28,175
FM is not always an advantage over AM. Especially for longer range.
You may have more power, but FM requires more power for the same range.
Hmm, strange that 11 meters is not over the horizon, when I have made 10 meter contacts over half way across the country. And in sun spot maximums, you talk around the world. And the guy I know who got caught and prosecuted by the FCC for running high power on CB had talked all over the world.
Yes, CB handhelds don't make a lot of sense, but no HF hand held does.
Repeaters are a big advantage. But in real SHTF situation, how long will they be running.
Also, with AM, you can hear a signal that is much closer to the noise floor than with FM. With FM, if the desired signal is too close to the noise floor, you don't hear any thing as the Rx will not decode it.
That is the case for ALL radios that operate in any part of the HF band, whether it be CB, Commercial/Public Safety, or Amateur Radio.
CB does not require line of site to work, since it is HF and is over the horizon, so communications distance is much further than anything GMRS can do.
No offense, but there in lies the issue. I've played with HF (amateur radio, commercial/public safety, and CB) for over 30 years. I've also played with VHF, UHF, and SHF, in either a hobby capacity, or in a working environment.
HF, beats UHF for distance EVERY time.
Sure you can, I used do it on a nightly basis with folks over 300 miles away, and sometimes further. No illegal amplifier needed, just need to the right antenna to do it.
MURS actually isn't better than GMRS, given that no mobiles/bases/repeaters are permitted and it is limited to 4 watts max ERP.
so what about a cb radio that has both uppers and lowers and has been super tuned to 50 watts?? with an SWR of 1 to 1.75 firestick antenna?
TapRackBang
Cheaper Than Diamonds
What about it?
Pre-SHTF: Illegal and selfish to use it as it almost-certainly doesn't have an adequate low-pass filter after the amplifier.
Post-SHTF: Everybody will have bigger things to worry about than a shitty radio splattering RFI all over the bands.
Pre-SHTF: Illegal and selfish to use it as it almost-certainly doesn't have an adequate low-pass filter after the amplifier.
Post-SHTF: Everybody will have bigger things to worry about than a shitty radio splattering RFI all over the bands.
This thread has gotten me thinking about CB radio again. Is there still any SSB activity? Is there any SSB activity in the lower 23 channels? 16 used to be a popular SSB channel but i think that might be one of the "superbowl" channels now.
E.Shell
Ultimate Member
What about it?
Pre-SHTF: Illegal and selfish to use it as it almost-certainly doesn't have an adequate low-pass filter after the amplifier.
Post-SHTF: Everybody will have bigger things to worry about than a shitty radio splattering RFI all over the bands.
I had what they called a "Long John" with 2 rotators, one to rotate and one to go on the "flat side".
https://www.dxengineering.com/parts/hgn-lj-105ca
I used to build my own Knight kits, too. Fun.
