Why not give the shell and the camper their own dedicated antennas? Unplug and replay as necessary. A big reason you see truckers running dual antennas is it tends to give a dir criminal radiation pattern and duals goes a fair way towards eliminating the need for the ground plane. As long as about 65-ish percent of each antenna is visible to the other you're good to go. A 9ft spread between is optimal, but good luck with that. As long as you can exceed 5.5 ft spread you will be ok. Less than that and swr tuning becomes an issue.
School me on Compact CB Radios
- Thread starter Wasatch
- Start date
The firestik antennas with a built in "ground plane" basically use a dummy load as a counterpoise. There's some debate as to how effective this is, especially with an electrically shortened antenna. The Antron 99 base station antenna does essentially the same thing, but with a full quarter wave radiator, and the Antron is pretty much THE standard for base station radios.
An antenna is sort of like a seesaw. Ideally you want both ends to be the same length, with the same load on it. Electrically shortened antennas are sort of like sawing off your end of the seesaw and putting more weight on it to compensate. The shorter you go, the more weight (inductance) you have to add to keep a balanced ride(SWR). Having an insufficient ground plane is like sawing off your friend's end of the seesaw and not giving him any weight to help him out. Having no ground plane is like sawing off your friend's entire side and laying the board on the ground and expecting you will still be able to bounce up and down. A built in ground plane is basically having your friend's end be only a few inches long, with a MASSIVE amount of weight on it. It will make the seesaw still function, but poorly.
Regardless of the balance of the seesaw, having a really short seesaw still means you can't bounce as high, which translates to not transmitting as Well.
An antenna is sort of like a seesaw. Ideally you want both ends to be the same length, with the same load on it. Electrically shortened antennas are sort of like sawing off your end of the seesaw and putting more weight on it to compensate. The shorter you go, the more weight (inductance) you have to add to keep a balanced ride(SWR). Having an insufficient ground plane is like sawing off your friend's end of the seesaw and not giving him any weight to help him out. Having no ground plane is like sawing off your friend's entire side and laying the board on the ground and expecting you will still be able to bounce up and down. A built in ground plane is basically having your friend's end be only a few inches long, with a MASSIVE amount of weight on it. It will make the seesaw still function, but poorly.
Regardless of the balance of the seesaw, having a really short seesaw still means you can't bounce as high, which translates to not transmitting as Well.
rayra
Expedition Leader
See, that's exactly what I'm talking about. HF standard antenna voodoo applied to convoy comms. It's ludicrous, even if it's technically correct or 'wise'. You're faulting a circumcised antenna for not being something it was never intended to be.
The customer makes choices on various criteria and value judgements. Different criteria for different people. Lot of folks don't have room for a 102" (8-1/2'+) 1/4-wave whip on their rig. Lot of folks don't have need for a 102" whip. LOT of folks aren't going to drill a hole in the middle of their vehicle roof. Lot of folks need antennae that will fit in garages or parking structures. Compromises. Criteria. Tire rack mounts, roof rack mounts, bumper mounts. There's reasons and trade-offs in all of them.
Instead of saying something sucks or is sub-optimum, how about instead presenting the various options and the rationales behind them? Educate instead of pronounce. Help a person pick what best suits their criteria.
The customer makes choices on various criteria and value judgements. Different criteria for different people. Lot of folks don't have room for a 102" (8-1/2'+) 1/4-wave whip on their rig. Lot of folks don't have need for a 102" whip. LOT of folks aren't going to drill a hole in the middle of their vehicle roof. Lot of folks need antennae that will fit in garages or parking structures. Compromises. Criteria. Tire rack mounts, roof rack mounts, bumper mounts. There's reasons and trade-offs in all of them.
Instead of saying something sucks or is sub-optimum, how about instead presenting the various options and the rationales behind them? Educate instead of pronounce. Help a person pick what best suits their criteria.
I never once said short antennas suck. I was just trying to illustrate the physics between the different types of antenna and counterpoise. 3 days ago. Just chill. I'm the one who recommended using a mag mount 30" mini-whip like a k30 or lil wil a couple pages ago.
Honestly, if all you're looking for is a few car lenghs... Maybe a quarter mile of range, a Cobra 38 handheld will do the job just fine, and work around camp too.
Honestly, if all you're looking for is a few car lenghs... Maybe a quarter mile of range, a Cobra 38 handheld will do the job just fine, and work around camp too.
4x4junkie
Explorer
Doors can be very hit-or-miss (apparently you managed a 'hit' on yours). What often helps with door (or mirror)-mounting is putting ground straps at the door hinges to the door jamb (known as "bonding" the door electrically to the vehicle body). The door itself however is a much smaller piece of metal than the roof or body, and is why I normally suggest avoiding them (especially without bonding).
If your camper has an aluminum skin, you should be fine mounting an antenna to it. Just make sure it's bracket is in good contact with the aluminum, and that any sections of the skin are all well-bonded to each other (front to sides, roof, etc).
If you have ever read all the bickering, whining, pissing, moaning and groaning about CB radios in the Communications section of the forum here (as well as earlier right here in this very thread too), it's pretty obvious that people DON'T always make wise choices when it comes even to simple trail convoy comms. Others such as anickode and myself are only trying to make it clear that compromised setups will have severely compromised range. Anyone certainly is free to choose whatever antenna or radio they want, however they need to also understand the ramifications of their antenna (and/or radio) decision too.
No, I am not of the mindset you absolutely MUST have a 102" whip, however there does come a limit to how short of an antenna you can use and still expect reasonably decent range (which I mentioned in an earlier post, 60" is about that limit). Whatever one can do to fit an antenna at least that long on their vehicle (and have it mostly in the clear) will do wonders for their radio's performance, yes, even at distances <2 miles while on the trail.
60" is not exactly huge... There are plenty of options available for someone who has clearance issues or is worried about low-hanging limbs. A quick-release mount allows easy removal of the antenna if the vehicle is a DD and you don't normally use it while driving around town (it is not a requirement to have your antenna on the truck when you're not using it lol). A fold-over mount is another option for when entering underground parking, garages, etc. Then there's also the spring I already mentioned earlier that allows the antenna to flex out of the way of a low branch (or a drive-thru overhang) for those times when you are using your radio.
FRS units would actually work a lot better for that. The better ones can very often go a couple miles or more.
underdrive
jackwagon
Yup we have the door-to-jamb ground straps on both trucks, figured it could help and guess I was right.
Camper skin is electrically one big piece, everything was seamed together and then they painted it, meaning there are no layers of paint to act as insulators between the different sections. Then there are the corner rails that are screwed to the walls and roof. Bracket will be directly on the skin, with stainless bolts to avoid dissimilar metals galvanic reaction between aluminum (mount and skin) and steel (hardware) parts.
Thanks for your advice!
True, but if everybody else is already running CBs then it's a bit silly for them to all carry a wallowing talkie too.
I like the cobra 38 handheld Because you can pop the rubber ducky antenna off and with a 5 dollar adapter from radioshack, plug any pl-259 antenna into it. ********** a short magnetic mount on the roof, and it improves it's performance 10 fold.
JimBiram
Adventurer
While MURS gets you around the license issue, you are still limited to 2 watts, and you have to find a Part 95 certified MURS radio. More expensive than your inexpensive Baofeng radio.
Every Day is a Good Day Surfing...Some are just Better Than Others
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Every Day is a Good Day Surfing...Some are just Better Than Others
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Martinjmpr
Wiffleball Batter
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More significantly you have to have someone else who uses a MURS radio if you want it to be anything other than a paperweight.
JimBiram
Adventurer
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More significantly you have to have someone else who uses a MURS radio if you want it to be anything other than a paperweight.
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craig333
Expedition Leader
Nope. Need both. I run a 3' firestik on my Jeep (oddly enough not a single Jeep pic shows my antenna) on a homemade bracket that rides above the spare tire. It does okay for trail rides. Now ask me how many firestiks I've broken driving into the garage when I'm tired forgot to take it off first. It sure works better than the Cobra 75 WX ST in the truck which actually has an excellent ground plane.
Do they make MURS handhelds? Because theres no way I'm adding another radio just for small handful of people.
Do they make MURS handhelds? Because theres no way I'm adding another radio just for small handful of people.
4x4junkie
Explorer
Legal MURS units can be had for around $60. That's $20 more than a Baofeng (and is likely much higher quality than a Baofeng too)... Is that that much of a problem if you must find a pt-95 certified radio? If MURS' popularity really takes off, a case could easily be made for the FCC to expand it's granting certification to more radios, perhaps with expansion of the channels as well (the entire band surrounding MURS 1-3 has essentially been deserted by it's previous users since the narrowbanding mandate went into effect a few years ago).
2W on MURS also very often goes considerably further than 4W on 27MHz CB when the noise floor of the CB band is elevated by ionospheric conditions during the day, and again you don't have "skip shooter" guys running high power that such atmospheric conditions encourages. MURS is VHF FM so you aren't dealing with other things that HF AM (CB) brings either (the long antennas, vulnerability to static, the poor audio quality of Cobra 75s, etc.).
I find responses like this peculiar... As it was only a few years ago that almost no one had a ham radio on the trail either. As more people began to suggest it, it's popularity infact began to tick up somewhat (though is still far & away from that of CB units). How MURS is different I don't understand... If people heard they can get the clarity and noiselessness of 2M without the license & exam, they'd probably be onto it quicker than flies on poop..
More significantly you have to have someone else who uses a MURS radio if you want it to be anything other than a paperweight.
http://www.amazon.com/Dakota-Alert-1167025-2-Way-Handheld/dp/B003802GLA
http://www.amazon.com/TERMN-8R-Amateur-Commercial-Portable-Two-Way/dp/B00QMOA940
Looks like the price of the Dakota one has crept up a bit since I checked last.
I stand by what I said about increased popularity bringing forth more radios and possibly more channels. Eventually we could see it like with CB radios (and FRS radios in particular) where numerous different retailers stock them at all different price points.
But when people keep saying crap like: "But it's still limited to 2W" "But nobody else has one" "But it's... but, but but...", everyone who can't/doesn't want to get licensed for ham will be stuck having to listen to skip-shooters on their 27MHz CBs.
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Hilldweller
SE Expedition Society
MURS is viable if more users get it, for sure.
Or family radio.
But handlhelds are clumsy on the trail ---- noting beats a hard mounted radio with a mic on clip.
A CB is ubiquitous and easy. But it has limits.
A HAM ticket is a very easy thing to acquire and opens a doorway to a myriad of options. Tennmogger and I can hit the same repeater from our homes (4 hours away) and maintain coms on 2M as we move toward our campsite. If either one of us has a problem along the way, help is just a cq in the coming.
There's more to radio than just convoy use.
When we're in camp, it's fun to hoist an antenna up a tree and talk to the middle of Europe.
Or family radio.
But handlhelds are clumsy on the trail ---- noting beats a hard mounted radio with a mic on clip.
A CB is ubiquitous and easy. But it has limits.
A HAM ticket is a very easy thing to acquire and opens a doorway to a myriad of options. Tennmogger and I can hit the same repeater from our homes (4 hours away) and maintain coms on 2M as we move toward our campsite. If either one of us has a problem along the way, help is just a cq in the coming.
There's more to radio than just convoy use.
When we're in camp, it's fun to hoist an antenna up a tree and talk to the middle of Europe.