Homebrew 1/4 wave copper pipe dipole

This is the place to discuss any general CB radio related topics. Getting started, installations, operation etc.
Post Reply
108EH002
Top Poster
Top Poster
Posts: 1933
Joined: 13 Mar 2013, 22:23

Homebrew 1/4 wave copper pipe dipole

Post by 108EH002 »

Have made a simple 1/4 wave homebrew dipole made with 15mm copper pipe and the coax connections ( live + and earth - ) are held in place with a jubilee clip on each side,each end of the wire being connected,only has to be 25mm or 1 inch in length,and this will be plenty of wire to slip under each jubilee clip.You can insulate each connection with insulation tape just to be safe.Each leg was cut to 102 inch,8 1/2 ft,259 cm or 2.59m in length per leg.I also installed a rf choke about 1ft under the connections from the coax/feedline,which consisted of 6 whole turns on a piece of 4 inch/115mm plastic pipe,held inplace with gaffer tape,and you can also use cable ties to keep it nice and tidy.My homebrew copper pipe dipole is suspended from the attic rafters with fishing line,and is in an inverted V ( looks like /\ ),at the angle of the roof either side ;)

I usually just use copper wire/rg213 but always wanted to try it with copper pipe,just to see.

The swr readings were as follows =

1.3 on 26.965
1.0 on 27.500
1.1 on 27.991.25

Have managed 20 miles today on fm to another local in his house,so not too bad for something in the attic :D

Hope this helps someone in the future,looking for an alternative dipole antenna :thumbup:
Plenty are talking worldwide on 27.555 usb,
Some are too far up their own @rse to admit it,
Many happen to know otherwise dx-ing test free,
Showing a complete lack of respect for the law.

27.555 Usb
108EH002
Top Poster
Top Poster
Posts: 1933
Joined: 13 Mar 2013, 22:23

Re: Homebrew 1/4 wave copper pipe dipole

Post by 108EH002 »

After doing some further research I have changed the distance of the rf choke,the rf choke is now a 1/4 wave away or the same size as one of the dipole legs = 2.59m or 8 and a 1/2 ft.
Plenty are talking worldwide on 27.555 usb,
Some are too far up their own @rse to admit it,
Many happen to know otherwise dx-ing test free,
Showing a complete lack of respect for the law.

27.555 Usb
User avatar
Farty
Veteran
Veteran
Posts: 3694
Joined: 20 Oct 2008, 14:40
Location: IO92ND

Re: Homebrew 1/4 wave copper pipe dipole

Post by Farty »

For even better function you can run the coax up the inside of the ground radiator to form a sort of boomerang antenna, a dipole with the appearance of a vertical. Good gain, low radiation angle, very efficient.
In Before The Lock Champion of Total Magnificenceness May 2016
The Collector
Legend
Legend
Posts: 8666
Joined: 23 Jan 2010, 19:26
Location: Bristol-ish

Re: Homebrew 1/4 wave copper pipe dipole

Post by The Collector »

108EH002 wrote: 27 Dec 2018, 23:15 After doing some further research I have changed the distance of the rf choke,the rf choke is now a 1/4 wave away or the same size as one of the dipole legs = 2.59m or 8 and a 1/2 ft.

Have you noticed any difference in swr or rf emissions (or whatever you technically call it) etc?
108EH002
Top Poster
Top Poster
Posts: 1933
Joined: 13 Mar 2013, 22:23

Re: Homebrew 1/4 wave copper pipe dipole

Post by 108EH002 »

After moving the location of the rf choke the swr was really just the same as before Collector.

But = I decided I was going to "turn" the antenna another 90° so it was more directional for east to west.When I got a chance over the festive break,I also altered the inside angle making it slightly bigger than before (closer to horizontal position)about 2 inch/50mm higher up at each end of the legs.I also changed the direction of the rg213 caox/feedline from the original positioning.

The swr readings were now as follows =

1.1 on 26.965
1.0 on 27.500
1.3 on 27.991.25

This might appear to be too strange to be true for most that understand antennas,but this is what the readings were on a Grant 2 V1 and a Lincoln 2 V3 built in meters,the same 2 radios used to take the first swr readings.I am getting good rx across the eu with the short skip,with far less static/white noise/chip pan crackle coming in compared to the Imax thats nearly 30ft up,resulting in stations being received crystal clear compared to being nearly inaudible on the vertical once they are below say a S3.The noise level on my latest Grant 2 is sometimes just the first light on the signal meter,and the meter is not lazy compared to other ones I have used in the past.

Collector = I really can't say if any of the alterations/experimenting I have done is going to massively change this homebrew dipole to be a super dx performer,but you never know eh.

I am just a CB'er with limited radio knowhow or an IQ Zero depending on how you see it,but I do know that this dipole can hear what a £130 vertical CB antenna sometimes CANT,the same as my other homebrew wire dipoles that heard what an 827 and S.G.M. didn't,that were far higher up than the dipoles were ;)
Plenty are talking worldwide on 27.555 usb,
Some are too far up their own @rse to admit it,
Many happen to know otherwise dx-ing test free,
Showing a complete lack of respect for the law.

27.555 Usb
108EH002
Top Poster
Top Poster
Posts: 1933
Joined: 13 Mar 2013, 22:23

Re: Homebrew 1/4 wave copper pipe dipole

Post by 108EH002 »

Have recently changed the copper pipe dipole into a horizontaĺ position (from being in an inverted v) at 30ft up and the swr is still fine,and I am still getting decent results for what it is.

Got a radio check from someone 15 mile away,and I was as follows,

Imax = S9
1/4 wave c.pipe dipole = S9+30

Will mean nothing to some but plenty to me ;)
Plenty are talking worldwide on 27.555 usb,
Some are too far up their own @rse to admit it,
Many happen to know otherwise dx-ing test free,
Showing a complete lack of respect for the law.

27.555 Usb
108EH002
Top Poster
Top Poster
Posts: 1933
Joined: 13 Mar 2013, 22:23

Re: Homebrew 1/4 wave copper pipe dipole

Post by 108EH002 »

^^ My mate was in his car 15/20 mile away parked up/static mobile using a Sirio 4000 ^^
Plenty are talking worldwide on 27.555 usb,
Some are too far up their own @rse to admit it,
Many happen to know otherwise dx-ing test free,
Showing a complete lack of respect for the law.

27.555 Usb
Post Reply