Need little help putting a temp antenna up

[JW20VT]

Had asked in a similar forum but I have better luck here sometimes ...you guys are great
I have a cheapo wire dipole I purchased long ago that I stashed away and found when I dug my radios out again to fix . Until I get a few more bucks and have a more permintent base antenna setup I wanted to use either the wire or mag-mount on my A/C , i know mag-mount meant for car and all Just wanted something temp for a few weeks to make sure the radios are good before I mod and get used to being back on the air . That being said I'm guessing the Wire dipole might work out better for a few weeks or however long I need to get my permanent antenna picked and setup .

Its very similar to this one on amazon - Amazon.com: DIPOLE Indoor Base Antenna 18 Ft for CB Radios: Automotive doesn't have the wingnuts to change wire though . My "shack" is bedroom , top floor of my house only thing above me is the attic which I can't get into . Should I try to hang this against a wall like a inverted V ? or just run it along the trim / ceiling ? When I hung this last I was young and really had less knowledge about it then I do now . Used to just put the center balun in the air and have the wires hanging down . said it don't work and I packed it away went back to my mag mount smart me huh

Anyways , thanks for any help and for reading

[Bombero]

Hey Jeremy..

Until you get your permanent base antenna...run the wires along the ceiling.

Good Luck

[joekillowatt]

shoot that puppy up in the trees if you have trees close by

[JW20VT]

joe -- GREAT pics in your sig .

When you guys are putting this style antenna into tree , are you getting it up there horizontally or a vertical setup ? only big tree near window of room (Where "shack" is) isn't mine and also isn't really accessible on that side of house . I put my mag-mount out on my air cond. also for the heck of it and its terrible I remember it being little better but just noise. I put the (spelling??) on ceiling in my room and ran the wires in a L shape sorta . From my experience scanning I have a opening to the south , and seems like the skip im hearing is in NC SC GA . I'm guessing this is going to be the best I get til I find a permanent setup

[joekillowatt]

hi and thanks.. i got my di pole flat in a "T" shape and im getting dx all over,,,,,,i am in new orleans and i hit penn ohio kentucky south carolina bare foot!!

[taco429]

hi and thanks.. i got my di pole flat in a "T" shape and im getting dx all over,,,,,,i am in new orleans and i hit penn ohio kentucky south carolina bare foot!!

this is real encouraging, I was thinking of putting up a flat T dipole for a barefoot setup, too. First it was going to be a vertical 1/2 wave but now I'm thinking T dipole.
Glad you posted this.

[JW20VT]

Going to try to put mine in " T " style corner to corner inside , I have mine layed out on roof to try it out and like I said got a ton of skip but all weak nothing crazy . After some advice I am going to try it corner to corner , but starting end of week Im going to be starting on a bazooka antenna project . and I hope ill get good results to keep that for a perm. setup , If not Ill be shopping for something premade .

[taco429]

Going to try to put mine in " T " style corner to corner inside , I have mine layed out on roof to try it out and like I said got a ton of skip but all weak nothing crazy . After some advice I am going to try it corner to corner , but starting end of week Im going to be starting on a bazooka antenna project . and I hope ill get good results to keep that for a perm. setup , If not Ill be shopping for something premade .

Do you need a balun for a T dipole? If so, what kind? I thought I read that you could do 4 or 5 turns of coax on a 2L bottle.

['Doc]

Time for some definitions.
A 'Balun' is a means of changing from a 'balanced' state (antenna with two 'sides', both being equal in length) to an 'unbalanced' state (coax cable feed line, for instance). If that 'balanced/unbalanced' thingy isn't accounted for it introduces some imbalances, or distortion, to how something radiates a signal. Instead of the radiation pattern being a 'perfect' shape, it get's sort of lop-sided. Not a huge amount, but some. It also changes a couple of other characteristics of RF, probably the important one being that some currents start flowing where they shouldn't be flowing (outside of that coax) thereby causing some signal/power not being radiated, or wasted (also a fairly common occurrence which shouldn't be worried about a huge amount, you want to minimize it as much as practical). So, using a balun between a balanced antenna and an unbalanced feed line ain't a bad thing. It's also not a 'dead-nutz' absolutely necessary thing either.
A balun can also do some impedance transforming. The two most common transformations are '1:1', or no change, and '4:1' meaning one side is 4 times the impedance as the other side. It can act as a transformer just like the ones that change 120 Vac to 12 Vac (which can then be rectified to 12 Vdc). If you really know that there's a 4:1 difference in impedances then using a 4:1 balun is a pretty good idea. If you don't really know what that impedance difference is, stick to a 1:1 balun, it just makes things easier to handle some other way. If you are talking about using an antenna on more than one band, that impedance will change from band to band and you will have no idea of what it'll be at any particular frequency. Use a 1:1 balun, it's just simpler. And then things can really get weird if you connect that balun (or transformer) backwards! In stead of getting that 12 Vac out of that 'wall-wart' you'll be getting 1200 Vac. Not good, right? Baluns also have power ratings because doing that impedance transformation involves some pretty high voltages or currents at times. Another instance where larger than -thought- necessary is a VERY good idea! There ain't no "one size fits all" baluns.
So what does all that mean? It means that if you want to use a balun you certainly can. It also means that if you don't want to use one, or if you don't have one, then it isn't gonna make a big difference. Some, but usually not enough to matter.
Coaxial 'chokes', 'ugly-baluns', coils of coax. They all mean the same thing, just different names. They have a characteristic of 'choking' off currents flowing on the outside of coax where it doesn't belong. When you make a coil out of coax it affects AC flowing on the -outside- of that coax (tends to stop it) but has nothing to do with what's happening on the -inside- of that coax where your signal is. They can work pretty good depending on finding the 'right' size of coil. Without some fairly complicated math, I don't know of any 'exact' way of figuring how big that 'coil' should be. For frequencies around 10 or 11 meters, something like 5 - 6 coils ought'a work. More coils won't hurt, but that can get sort of 'big', you know? The biggies about coiling up coax for a choke are that keeping it sort of uniform is good, and don't make those coils too small or you'll damage the coax. The more 'force' you have to use to make that coil a smaller diameter, the less 'good' it is. Does that make sense? The various sizes of coax mean various different col diameters to keep from damaging that coax. The bigger the coax size, the bigger the size of those coils. In most cases, something the size of a 2l bottle, or a 5# coffee can ought'a work just dandy as a coil form. (Don't even ~think~ about making a choke out of 4" hard-line! You can't afford it. )
- 'Doc

[taco429]

Time for some definitions.
Coaxial 'chokes', 'ugly-baluns', coils of coax. They all mean the same thing, just different names. They have a characteristic of 'choking' off currents flowing on the outside of coax where it doesn't belong. When you make a coil out of coax it affects AC flowing on the -outside- of that coax (tends to stop it) but has nothing to do with what's happening on the -inside- of that coax where your signal is. They can work pretty good depending on finding the 'right' size of coil. Without some fairly complicated math, I don't know of any 'exact' way of figuring how big that 'coil' should be. For frequencies around 10 or 11 meters, something like 5 - 6 coils ought'a work.
- 'Doc

Hmm that sounds easy enough to do without too much build work. I guess that keeps the coax from acting as a radiating portion of the antenna, then? Sounds like a good thing to me. Although at 4 watts I don't think it's going to be a problem if a little bit does radiate.

[taco429]

Should I try to hang this against a wall like a inverted V ? or just run it along the trim / ceiling ?

Sorry I jacked your thread, so I owe you a comment on your question. I did some reading and it looks like you could run it just about anywhere in the room, as long as you don't hang it near anything that radiates or interferes with the field. Hard to know what's in the walls near where you're hanging it, but maybe go around the room with an AM radio and avoid areas that put out a lot of interference? As long as you don't have aluminum siding or big metal screens in your wall, you should have good luck with an indoor dipole.

I think the orientation of the wires relative to each other will affect SWR a lot, yes?

Also, how does that mag mount work on your A/C? Big enough ground plane?