10 meter radio in a truck - legal question.

Turbo,
I'm tracking the whole Antenna needs to be able to support the power output of your radio, as well as your SWR need to be no more than 1.5 i believe. I have an swr meter that i use to tune my antenna's as well as i like radios that have built in SWR meters to tune or auto tune as well. i've run Wilson antenna's in the past but have heard really good things about Firestik with tune tops just concerned about newer rigs with antenna's not supporting higher output radios. Thank you for the info.

 

IMOO.. RG8X is crap.. You can get better grade coax from any ham radio store, like LMR and a couple others that is a 100 times better.. the rg8x sold in truck stops and cb shops is all the same.. the only difference is the outside color.. once heard a guy in a shop say "Get the clear stuff, its higher quality...

The real problem with running higher power in your truck is the antenna and grounding... doesnt matter if its 10 or 11 meter.. Just a little note - I installed an echo board in my Uniden 78, and compared it to my stryker 447 one day at the T/S in West memphis... Most said the audio was almost the same on both radios..

 

Care to post some numbers to back up this claim? What are the specs at 10 & 50 MHZ?

 

I'm sort of surprised at this "RG8X is crap" thing. While I know there better grades of coax, 8X works just fine for most applications. For example, some of the better grades are stiff and hard to work with, more difficult to install. And at 27 MHZ the difference one might get with more expensive feedlines *may* be too small to measure when you take into account this and other factors. I've talked around the world with 8X, getting 5-9 plus reports and "Excellent signal from a mobile" from 75 Meters to 10 Meters. RG8X isn't exactly "crap". I don't doubt, however, that one must be careful of the source of one's coax cable. Truck stops and CB shops are mostly concerned with selling in volume and their cable quality may be less than desired. They are counting on the less knowledgeable customer not knowing the difference!

GF

 

I use 8X all the time for runs of less than 100 ft. It has specs that are close to RG8/U without the bulk...

 

Well you all know it depends on who (or here it was ) made the coax, I have some really good Belden 8x sitting on a spool I bought this past weekend for next to nothing, I expect it to be a bunch better than the 8x that I got from some truck stop expect cb guru that was made in Indonesia which had Beldon stamps on it.

 

On 27Mhz LMR can be over kill. If used in a mobile install 8X can be better than LMR400. Because of it being flexible. And the performance is about the same. There is LMR400 UF but at $1.50 a foot it's still pricey and not worth it.

 

Someone made the claim that this was the best of the best of the best coax and with his birdwatts, he can talk a long ways.

 

I have to chuckle at the "bird watts" thing. Don't people know that a watt is a watt is a watt? ALL this fixation on power, power, power when one can do so much with antenna, for example. So much misinformation out there. I passed a truck the other day whose antenna was pointed almost horizontal when, actually, due the the slope of the cab, the antenna would've cleared the whole of the truck without too much difficulty. A "smidgeon" of tilt won't hurt anything, but people, unfortunately, don't know that, at 27 MHZ a thing called polarity will affect your signal detrimentally! Most mobiles are vertically polarized due to limited space, thus the vertical whip. At 27 MHZ and above, if YOUR antenna is horizontal, like the popular trucker's notion, it reduces your signal IN and OUT because, RF "tumbles", if you will, and tends to "hit" the other local antennas at the "wrong" angle because it doesn't have "time" to right itself (a silly, elementary, but accurate way to put it). The result is a much reduced signal both TO and FROM your truck going down the road. Long distant stations, it doesn't affect; its just the local stuff that bothers it. Keep your antenna UP as much as possible despite....maybe it looks "cool"(?) to other truckers! You will have a more effective station WITHOUT the flat antennas.

Also forget about those little "ground plane" thingies you see at the truck stop. Even from those who don't like my posts here, TAKE MY ADVICE AND DON'T PUT THOSE THINGS ON YOUR ANTENNAS !! Length is your friend rather than fancy and multiple coils. Only use coils where you HAVE to. And we usually have to because of height of both your truck AND the frequency of operation. You see, coils introduce resistance, can add capacitance that has to be compensated for elsewhere (feedpoint?) OR is the reason that many CBers and shops believe in "coax length". Anyway, coils reduce your signal, not enhance it no matter HOW "cool" or "bad" they look! We use them simply because there is no other choice. So if your space is limited, do use the largest coil you can (without being ridiculous) to reduce the resistance as much as possible. But don't tilt the thing any more than you GOT to

Same thing with those "ground plane" things people think improve their signal. What it really does is........transfer cash from YOUR pocket to the seller's! Funny, eh? People think that these things somehow increase the "ground capacity", or reflection over ground. But LOOK at the thing carefully. It is connected in series AND part of the whip itself It is part of the antenna itself, not "ground", and reflects.................nothing other than what the rest of the whip would otherwise! Ever notice when you install one of these things, it makes the SWR go wild, and the antenna has to be retuned? Well, that's because you are adding surface and capacitance to the whip/coil. The whip then must be shortened to account for the change. Yet all is not lost. You could use one of these things IF your antenna wouldn't clear obstacles. Its better than leaning the whip WAY over forward horizontally. But the other day, that truck I saw had his antenna pointing FLAT forward, and also had a "ground plane" thing that looked sort of like a tiny beam. 'sa wonder he even got out at all.
Sad, really. So much bad info floating around in the CB world.

GF

 

On the SWR, you can go to 2.0:1 and be safe, however that's 11% of your signal not making it out (89% is going out)....1.5:1 is only 4 % of your signal not making it out....meaning 96% of it is going out....my 2 cents I want as much going out as possible.

The Wilson antennas have more metal wire vertically, and can see better. Those glass whips have it coiled around the glass and that hinders. The more air the antenna sees, the better.

While you are correct, in that there are better coaxes than RG8X, to say it's crap is not exactly true. Yes LMR 400 on CB is by far better than RG8X, however unless you're running a base station with a ton of power, you probably are not going to see any difference on LMR 400 vs. RG8X. Not on CB, or any of the HF bands.

NOW...the same cannot be said on 70 CM (440 MHz)......as you go higher in frequency, then yes, you can see a difference on RG8X as opposed to LMR 400.....HOWVER if it's a short run of less than 5 feet, you probably won't see much, if any difference. But yes there comes a point where RG8X becomes too lossy and a better coax like LMR 400 comes into play.

Finally, as said, for a mobile, LMR-400 would be an overkill as it's stiff and doesn't bend as well.

The only time LMR is better on 27 is if you plan to run a bunch of power.

The issue is the truckers run less than stellar antennas due to height restrictions. You are right, running the best antenna beats the pants off of running a box any day. That's why I think it sucks the FCC put CB on 27 MHz....because you need a 9 ft. antenna if you want the best antenna there is for CB...and a 9 ft. tall whip is not feasible on a big truck.

Now had they had put CB on 220 MHz (like they tried doing back in 1973) the truckers could run little foot long antennas that weren't all coiled up (like they do when they wrap 9 ft. of wire around a 4 ft. glass whip to make a Francis antenna) to make them physically shorter.....and they would not "need" amps either....because they'd be running the optimal size antenna....not to mention they would be on VHF instead of HF so they wouldn't have all the "skip" issues. Not all truckers like skip....some just want to talk to Bubba trucker 2 miles up the road....but when skip rolls in and they can't, then sometimes they flip on the old box hoping the extra oommpphh will help them bust thru the heterdyning pile up and they can finally reach Bubba trucker....same reason they sometimes migrate to "tham thar extree channels".

The way I see it, due to the FCC allotting CB on 27 MHz (which is suceptible to skywave propagation), which forced the truck antenna manufacturers to use shorter antennas with wire coiled around them, is part of the reason we have issues on 10 meters with "scofflaws" on their export radios.....or those "running heat" with their boxes in their trucks. No I am not putting the blame solely on Uncle Charlie, and I imagine back in 1958 the cost of VHF gear was probably out of reach of the average consumer....but again had CB been switched to VHF I don't think we'd have the issue with skip, amps on CB, "extree channel radidios" like we do today.

I am in agreeance though on the whole "CB myths" thing. Yes there's a lot of mis information on CB's floating around. Just like there is on automobiles; some people still think Flowmaster mufflers are the best thing since sliced bread.....if they only knew how restrictive they really are.....but that's another story for another day. Sadly enough, most truckers are not well educated on radios and think you "need" 18 ft. of coax, or that you "need" an echo board added if you want to get heard.