Indoor CB Antenna Help

[angelofwar]

What do you all think about using this as an indoors CB antenna?

http://cgi.ebay.com/ws/eBayISAPI.dl...3&ssPageName=ADME:L:OC:US:1120#ht_1290wt_1344

I have a little Cobra in my garage that will be part of my bug-in comm's, and I currently have a non grounded whip style antenna hanging diagonally on the wall. Will this give me a little more tx/rx range? Tips for setting it up? I'm guessing they would spread in a "T" or "V". Do I NEED to ground it? It doesn't appear to have a Mfg/Model #, but anybody have experience with such a set-up??? Thanks in advance for any help!

 

[W8RMH]

I hope you saw this in the listing:

"This antenna generally needs tuning and unless you are familiar with the process
it is not recommended that you purchase this item."

Personally I have never seen anything like this for CB, but I am not an expert.

If this antenna is not properly tuned it could ruin your radio.

 

[angelofwar]

Thanks for the reply W8RMH. I did not see that, however, while new to radio, I'm pretty tech savvy, and am here to learn. I have seen tuners that go for roughly $35, is that all I would need? Or is there a "conventional way" to tune them?

 

[jaspence]

CB antenna

Due to their size, dipole antennas are often set up for horizontal polarization. A normal CB whip or base antenna is vertical in polarization. The amount of signal loss is very high and even if you got it tuned, it would be less effective than a simple vertical loaded whip that has a good ground plane.

 

[angelofwar]

Thanks Jaspence. So, are these antenna's obsolete? It apperas there is a still a (small) market for them. All I need now is an SWR meter, and I should be able to tune it fairly easy, right? I'm think of putting it in my attic, but your saying a standard non-magnetic antenna grounded to a plane (metal object?), will work better?

 

[ermin]

What do you all think about using this as an indoors CB antenna?

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

I have a little Cobra in my garage that will be part of my bug-in comm's, and I currently have a non grounded whip style antenna hanging diagonally on the wall. Will this give me a little more tx/rx range? Tips for setting it up? I'm guessing they would spread in a "T" or "V". Do I NEED to ground it? It doesn't appear to have a Mfg/Model #, but anybody have experience with such a set-up??? Thanks in advance for any help!

This is just a plain dipole. You can make your own with some coax and 2 9' + pieces of wire. Cut an insulator from the thickest plastic bottle you can find and solder the wires to the coax using the plastic piece in the center holding everything together. Make the wires originally a little longer than 9'. Mount it vertically (like a sideways T) and use an SWR meter to tune it then see what happens.

Making your own antenna is always much more fun and you'll learn a lot more. Good luck and let us know how you make out.

73

Ermin

 

[nonperson]

It's an antenna it's not obsolete!

No you do not need to "ground" that antenna to anything else. Unless your attic is 18 feet tall you may have to mount it horizontally. Like the above poster said most CB antennas are vertically polarized so you would not be able to receive or transmit to those stations. However I have heard of folks making contacts with a horizontally polarized antenna. BTW it would be bidirectional also unless you mount it vertically.
Another issue you would have with mounting in the attic would be a loss of signal at those frequencies. I don't know how much but if you have a metal roof it would be much more.
I also wanted to point out you can easily make a dipole antenna yourself. Check the radios forums and You Tube for home brew designs. There are some how to designs for a dipole antenna using two 4 foot mobile (fiberglass style) CB antennas for the attic. I believe they run from $10 to $16 per antenna depending on make and design. Heck if you can solder you can get two wires and build one even cheaper.
Just consider though the antenna and coax system has to be 50 ohms to work efficiently on your radio. Other wise you would have to use a matching piece of coax or balun to get it within range. Getting two Mobile CB antennas would take the guess work out of that because they would all ready be 50 ohms rated. But even they may need trimming or extending (tuning) to the channels you would be using.

 

[gewecke]

If you are set on a dipole for your cb, then try google and type "inverted V dipole" and follow the directions.

73,
n9zas

 

[LtDoc]

A dipole antenna will work on any frequency it's designed for. 'Tuning' an antenna isn't a biggy, it's just something you may not be familiar with. Basically, it means adjusting the length for best results.
For CB, a vertical antenna is usually preferred, that's because most CB'ers use them on mobiles. There's a big difference in reception because of that polarization (vertical/horizontal) thingy. So how you hang the thing does make a difference. Lots of ways to do that, just depends on what you have the space for, or what's most practical for you.
Wanna try making one? Why not? Rather just buy something? Okay, why not? I wouldn't recommend a tuner unless you just have to use one. They do work, but aren't always necessary.
Have fun.
- 'Doc

 

[angelofwar]

Thanks geweke and doc. Doc, any tips on manually tuning a CB with a dipole? Would you do it using the squelch? I know antenna "gather" electricity (RF signals), but how accurate would it have to be tuned to prevent damage to a cheap vehicle CB? I'm learning a lot, and don't want you all to think I'm too lazy to "google" a lot of this (although I will google the "V" dipole), but I'd rather get it from you guys.

Thanks again!

 

[angelofwar]

A little more reading on the dipole, it seems they have to be tuned (cut/positioned?) for the freq. they are going to be used at. Between what I've read and seen on the calculators, if I planned on using it primarily on ONE CB channel, it should be rather easy to tune. And since the CB band is so small, tuning should be fairly easy, and being off an inch or two shouldn't effect it much, correct? Or am I not digesting this stuff right?

EDIT: Just read an article stating that vertical/V dipoles are not good for local comm's, since they both bounce signals off the ground/ionosphere...so would a horizontal "T" dipole work better? My intended uses are local CB comm/traffic.

Thanks again for all the help!

V/R,

AOW

 

[jhooten]

Save your self some hassle. Buy a quality mag mount like one of the Wilsons and stick it on top the fridge/dryer/any large metal mass in the apartment and chat away.

 

[popnokick]

Hopefully you live in a single family house (not apartment/condo) and not with people who watch TV or use other consumer electronics (home audio system, etc.). That will help reduce the likelihood of TVI (Television Interference) which is present whenever you are using an indoor antenna with CB. Try it first, but be prepared to add TVI filters, both on the antenna and the affected consumer electronics equipment.

 

[LtDoc]

Just a few things to keep in mind.
A dipole is a fairly 'forgiving' antenna. They can be bent, positioned in several ways and still 'work'.
An inverted 'V' isn't a vertically polarized antenna to start with. You'll find that if you 'droop' the legs of a straight dipole a bit, the SWR will lower a bit. That's one of the ways of tuning one. Not being a vertically polarized antenna those 'V's can have quite a bit of attenuation when talking to a vertically polarized antenna. Change that dipole's positioning a little, make it sort of 'L' shaped, one leg pointed up, the other off to the side, does make it a vertically polarized antenna. Again, varying the angle between those two legs will change the input impedance (SWR). 90 degrees is the 'limit', gives the lowest input impedance/SWR, which typically is lower than you will want resulting in a higher SWR. Lots of things affect that input impedance/SWR, including the antenna's environment, what's around it. So, there's no particular 'exact' angle that's going to always be 'right'. You have to find the right angle for your particular set of circumstances. (Sounds more difficult that it really is.)
Unless it's rally, really outrageous, SWR isn't going to harm a radio. It helps if you can measure SWR so having a meter that does so is nice, helps a lot. Don't obsess about SWR, it isn't as important as most people think. If it's around 1.5:1 or so, it'll work just dandy. Getting a 'perfect' 1:1 SWR is one of those 'dreams' everybody wants, but seldom ever get.
Every one of those commercially available antennas started off as one made in someone's garage/backyard. If you want to take advantage of someone else doing the 'work', get one. But then you will miss out on the fun of doing it your self. (Some weird people actually enjoy that sort of thing!)
Have fun, that's the whole point!
- 'Doc

 

[angelofwar]

I have a house, so I'm a little more flexible in that sense, and I also plan on getting a mag mount for my Cobra in addition to the dipole for mobility (I already have one for my GE, but it's uses RC connections). My Cobra has an RX/TX meter on it...can that be used to assist in "manually" tuning my dipole? Can I use my scanner and/or my handheld CB's to assist? Since the scanner and the CB both measure signal strength?

Thanks for all the info Doc. So from what I gather, since my CB will be used for local bug-in comm's, the "L" shape would be the best bet? Also, my garage has one wall that is wood/brick/outdoors, one side is a metal roll-up door, and the other two side go to the house. The one that "touches" the outside has a neighbours house ~10' away. Considering this, would the attic be a better bet? Also, what about grounding? I work with things that go boom, and have a fairly good understanding of all things r.e. grounding, discharge, RF interferrence, etc., but if the CB is polarized and plugged into a circuit breaker, is there any need to ground the antenna? Or do dipoles need to be grounded period?

I'm really soaking up a lot and want to say thanks again for all the awesome info/help!

 

[popnokick]

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Attic would be next best to outside on roof, assuming no metal covering on roof.
An SWR meter for CB use is about $12 to $20 on Amazon or dozens of other sellers. At that price not lab grade, but will tell you if something is grossly wrong with antenna or feedline/connectors.

 

[grogan]

Here is an idea
CBRadioMagazine.com - A Stealthy Homebrew Vertical CB Dipole
And something else for you to look at
No room for your base antenna? Try a dipole
There is also info for useing a SWR meter on that site somewhere as well as a lot of other info.
Have fun.

 

[LtDoc]

Would that 'L' be the 'best' solution? Just depends on what you have available to work with, your limitations. It can certainly be -a- solution.
If more range is the primary idea, getting that antenna (no matter what kind) higher is sure to extend it's coverage. Quit at something like a 1/4 mile high (yeah, right). If you think of height in 'chunks' of the length of the antenna you'll have some idea of what might help. A foot or two probably won't make a world of difference, something like 10 - 20 feet certainly can though. There are diminishing returns with height, so do what you can or what's practical.
From there, extending range get's complicated real fast. It involves having more room for the antenna, larger antennas, maybe multiple antennas. None of which is all that practical for everyone.
Got trees? How about a chain-link fence, or any kind of fence you can tie something too (under one of those trees is very nice). Hang that dipole from the tree, the feed point at the fence, then string that other leg along the fence (in the case of a metal fence, use that fence as the 'other half' of the antenna). Best thingy in the world? Nope, but it can work.
Ground mounting an antenna (1/4 wave one) is more common than you might think, and it works. The usual 'catch' to that is that there will usually have to be a lot of ground radials, dirt just is very lossy when used as an antenna. Thousands of broadcast stations use them though, and they all can't be wrong.
A dipole doesn't have to be grounded for RF purposes, it's a 'complete' antenna all by it's self. A safety ground is a different story, it doesn't hurt to have a safety ground with any antenna. It depends on how much electrical discharging is done in your area (lightning). (From what you've said, I figure you're at least somewhat familiar with 'safety grounding', right? My only experience with things that go boom came in 500/1000/2000 pound sizes, and what went into those 'boomers', making them. Probably not the same thing. )
Lots of possibilities! Have fun...
- 'Doc

 

[angelofwar]

Would that 'L' be the 'best' solution? Just depends on what you have available to work with, your limitations. It can certainly be -a- solution.
If more range is the primary idea, getting that antenna (no matter what kind) higher is sure to extend it's coverage. Quit at something like a 1/4 mile high (yeah, right). If you think of height in 'chunks' of the length of the antenna you'll have some idea of what might help. A foot or two probably won't make a world of difference, something like 10 - 20 feet certainly can though. There are diminishing returns with height, so do what you can or what's practical.
From there, extending range get's complicated real fast. It involves having more room for the antenna, larger antennas, maybe multiple antennas. None of which is all that practical for everyone.
Got trees? How about a chain-link fence, or any kind of fence you can tie something too (under one of those trees is very nice). Hang that dipole from the tree, the feed point at the fence, then string that other leg along the fence (in the case of a metal fence, use that fence as the 'other half' of the antenna). Best thingy in the world? Nope, but it can work.
Ground mounting an antenna (1/4 wave one) is more common than you might think, and it works. The usual 'catch' to that is that there will usually have to be a lot of ground radials, dirt just is very lossy when used as an antenna. Thousands of broadcast stations use them though, and they all can't be wrong.
A dipole doesn't have to be grounded for RF purposes, it's a 'complete' antenna all by it's self. A safety ground is a different story, it doesn't hurt to have a safety ground with any antenna. It depends on how much electrical discharging is done in your area (lightning). (From what you've said, I figure you're at least somewhat familiar with 'safety grounding', right? My only experience with things that go boom came in 500/1000/2000 pound sizes, and what went into those 'boomers', making them. Probably not the same thing. )
Lots of possibilities! Have fun...
- 'Doc

You mean these things Doc???

I might know more about them than ya might think

(This is an old pic...circa '99, Operation Allied Force...I no longer has such a nice mane...mostly skin now a days, thanks to hereditary balding...LOL!)

Well, I should have my dipole in a day or two, and will start messing with it. I have every intention of building my own, but buying one and messing with it is the best way for me to learn...once I have the basics down, I do a better job of building one.

I have a decent back yard, and from what I gather, hanging it outside, even if close to the house, is still 100 times better than hanging it inside? I just don't see the wife letting me bring that CB into our main living area....but who knows.

As long as I keep the antenna away from my natural gas line, I should be good not grounding it I assume.

I do have a Privacy fence Doc, so maybe hanging it at the top of that is an option...less interference as well, although I may have to get more RG cable...but having a longer cable affects performance as well, so what's better...A) Having an 8' cable to your antenna indoors or B) having a 50' cable to your antenna out-doors? As long as I can communicate at least a mile I'll be good, based on my current bug-in plan.

Those links you provided were awesome grogan...I would have googled some stuff, but I'm still learning alot, and wasn't sure what to google exactly.

I'm still looking for info on manually tuning this bad-boy...what order should I mess with it? Length of antenna first, or height/position first? I'm guessing Antenna length until I get the least amount of static, and I'm ASSUMING this can be done based on how low I can get the squelch? Once I get that low, then I can raise/lower the antenna for best reception, correct???

 

[jassing]

Completely unrelated to the topic -- Great pic -- but the hard hat made me laugh -- like that will protect you if one of those things drops on your head....