CB copper water pipe Antenna

[kd2goe]

I am working on a 1/4 wave Copper water pipe Antenna there is a few stuff i need to go over or any tips you guys can give me before i start cutting stuff up.

the parts i have now is 150" 1/2" copper water pipe. 2 – 1/2" copper end caps
Some PVC end caps and 1' tube to mount the pipe in 10' of 2.5” PVC pipe to get 16" off the groung.

Home made mount to mount on my deck with muffler clamps to hold the PVC <<<<< ill add pics.

I see I need to cut the 1” pipe down top 102? and I see some where say 108?
and how long would it have to be if I change it up and make a ½ wave antenna?

And with the ground plane it had to start off as the length of the antenna?
and if i add a NPT fitting at the base to take it apart with that fitting affect the antenna in any negative way?

 

[mmckenna]

108 inches would be the place to start. You need to assemble it all and mount it, then check the SWR and adjust accordingly. You can measure a million times, but there are variables outside the radiator length that will affect the proper resonance of the antenna.

1/2 wave antenna will require some impedance matching. I'd just stick with 1/4 wave. A 1/2 wave is going to be 18 feet long, and you'll run into issues with being able to keep that up in the air if there is any wind.

The copper pipe should work well, but it'll only bend so far before it kinks. I'd recommend finding something to go inside the pipe to help with rigidity. See if you can slide some 1/2 inch PVC pipe inside before you put it all together. You need to find something that will fit snug and not allow the pipe to kink and fold over.

If you are making your own ground radials, you should start with 3 evenly spaced 108 inch long radials. The other option is to use copper wire and string it out away from the antenna.

Solder you connections if you can. If you rely on slip fitting, it will corrode over time and cause all kinds of issues. While you are at it, solder the coaxial connections to the copper if you can.

Always fun to build your own antennas, especially when you start talking to someone and realized that it works!

Good luck to you!

 

[kd2goe]

Ok 1/4 wave it is..
I'll get started this week

 

[NITROTURBO4U]

Dipole...

Could use sched 80 pvc to slide the copper into...
I used a old drop cord..2 # 14 guage wires ...I got the swr down to 1.1
Ended up at 102 inches on each end.
Inserted it into pvc pipe useing a pvc t.Then fed it at the canter.
up 10 foot.Talk all over..
Anyone notice New Zeland on low side of 38 in afternoon????
Eastern seaboard that is.

 

[ghz24]

Kink a 1/2 hard walled copper pipe ? I find that hard to imagine. From the wind you think? Hams have been making copper pipe antennas for quite a while I've never seen any kinked ones reported.
Has this happened to anyone? <--------- Serious Question,
As diameter of the elements increase the length required to achieve resonance is reduced (thicker elements need to be shorter than thin ones.
Models show a 1/4 wave dipole with 1/2 inch thick elements to be resonant at ~103.8 inches .
Keep in mind this is in a perfect world. So "mileage may vary" but it should be close.
I'd cut them long (as suggested earlier ) and use a grinder to shorten /tune.

 

[LtDoc]

There's nothing particularly 'magical', or beneficial, about copper as the conductor for RF. In some circumstances it can be a definite liability, a 'mechanical' thingy. That's why a 'springy' steel is typically used for making mobile antennas. Copper is easier to work with than steel, but that's about where it's 'benefits' end. I've never had an antenna made from copper 'kink', but then, I've never used an antenna made from copper on a vehicle. (I stuck a 'J'-pole in a pickup's stake pocket once, but I don't think that counts.)
- 'Doc

 

[kd2goe]

There's nothing particularly 'magical', or beneficial, about copper as the conductor for RF. In some circumstances it can be a definite liability, a 'mechanical' thingy. That's why a 'springy' steel is typically used for making mobile antennas. Copper is easier to work with than steel, but that's about where it's 'benefits' end. I've never had an antenna made from copper 'kink', but then, I've never used an antenna made from copper on a vehicle. (I stuck a 'J'-pole in a pickup's stake pocket once, but I don't think that counts.)
- 'Doc

Ummm it is going on my house

 

[mmckenna]

Thin wall 1/2 inch copper water pipe, the kind you get at your local hardware store, will absolute kink. I've recycled the stuff, and it's easy to just bend across your knee. Take that 102 inch piece and stick it in the air above the roof, and a strong enough wind will bend it. Trouble is, if it bends far enough, it'll kink and you'll have a permanent weak spot in the pipe. Aluminum coaxial cable, just like the cable companies use, will do the exact same thing, same with heliax.

If you haven't experience this, you've been fortunate.

If you are using a thick wall copper pipe, then you are probably OK, but you are probably also paying a lot of money for that copper, and it's not going to make enough difference to warrant the extra cost. Standard copper wire will work just fine.

 

[TheSpaceMan]

I used a 2x2 piece of lumber with wire taped to it, and on top I put a telescopic leg from an old TV rabbit ears antenna! For the bottom I just used three 108" wire radials. My SWR was no more than 1.2 to 1 across the band!

 

[LtDoc]

Very basically, an antenna is an electrical conductor. That means that almost anything that will conduct electricity can be used/made into an antenna. If you have something handy, copper pipe, fence top-rail, or some other 'thingy' that will stand up by it's self, it could probably be used for your antenna. It's a matter of what'cha got, what's handy to get, and what you can work with. So ...
- 'Doc

 

[kd2goe]

well i got the copper pipe from working on the house 7 years a go uncut at 10' i can hold it horasontal and it is stiff, bring cut down to 108" i am 100% serton it will with stand any thing sort of a tornado.
i will be cramming a hard wood dole in the base to give it a little extra support from kinking

 

[LtDoc]

Sounds like it ought'a work. What do you plan for the 'other half' of the antenna, the radials?
- 'Doc

 

[mmckenna]

i will be cramming a hard wood dole in the base to give it a little extra support from kinking

That's a good idea. The most stress will be near the base, where it's attached to the support. A length of dowel will work great. I think you said you were going to cap off the top, which is a good idea. Water will find it's way in if you don't and rot away that dowel over time.

Let us know how it goes. Building your own antennas can be a lot of fun, and really rewarding when you get them on the air. I made a 6 meter band dipole once out of 1/2" copper pipe. Worked a number of stations on about 12 watts, some about 300 miles away.

 

[kd2goe]

well here are some update pics i got most of the bisness end done ill get more done tomarrow
ill get more pics as i go there will be a ring of copper inside the tube next to the SO-239 where my ground plane will atach and branch out.


gorilla glue working its magic.





here are the parts of the bisness end




Wire soldered in. i take a pic but there is a pice of 5/16 rubber fule line that is protecting the centor condrutor.




filled the cavity with great stuff, drill a few holes for the air to get out. ill plug them when it is done

 

[kd2goe]

more pics

 

[kd2goe]

I got it up and tested it out i got a SWR of 1.1 on ch40 and 1.5 on ch1 i got the cable in the house and now I got a SWR of 3 my cable sucks i have some RG-8u on order be here wednesday...

 

[kd2goe]

 

[LtDoc]

What kind of coax are you using now? And is that what you used when you tested it?
- 'Doc

 

[kd2goe]

Radio Shack RG-58U 50'. Used to test and run in the house

 

[kd2goe]

Well the coax I got is in I got 50' of Belden 8214 ill let you Gus know tonight how or if my SWR drops. If myfrend is home ill see if he can hear me on the short wave
Last time I was barely a wiper.