Homebrew off center fed dipole

[bpotanka]

Just built this antenna today and it works great. The parts cost me $18 from Home Depot, but had some common things in stock. As well as a nice place to mount it. It is mounted about 17ft in the air on a old direct tv mount minus the dish. I used RG6 cable to feed my BR330T and it works great. I used to pick up a range of 10 miles with my back of set antenna. I improved to at least 30MI or 35MI on UHF and a little less on VHF HI. Although I am receiving a town about 40 Miles away on VHFLo so there are many variables, but overall a great cheap antenna for the beginner like me.

Plans from Homebrewed Off-Center Fed Dipole - The RadioReference Wiki

Build time 30MINS - 45MINS
Installation Time 1 Hour 30mins (Old direct TV dish hard to get off )

 

[Skypilot007]

Nice job. One tip for ya. I noticed you have end caps on there. Unless you water sealed the top element to the T the bottom element will fill with water from rain. You can either poke a hole in the cap or water seal the top element into the T.

I had this problem with my home made UHF 4 dipole array I just finshed.

 

[N_Jay]

You need to put a weep home in the bottom even if sealed.

If not water will build up due to water vapor migration.

If you don't believe me, look at any twin-pane window that has even the smallest break in the seal.

 

[bpotanka]

Thanks For the info, I will put a weep hole in it tommorow. Does any one know what would happened if i make a simalar model and make the over all size smaller, but keep the same ratio of legnth difference from the top section to bottom section ? Was also wondering about changing the pipe size on my smaller unit maybe to 1 1/2" insetad of 3/4" if that would change anything ? Any ideas are slways appreciated.

 

[digitalanalog]

Nice job, Love the home brew antennas

 

[nanZor]

Was also wondering about changing the pipe size on my smaller unit maybe to 1 1/2" insetad of 3/4" if that would change anything ? Any ideas are slways appreciated.

Due to the way the lobes go kind of crazy on ocfd's, mostly upwards on uhf and 800 mhz, you might get more bang for the buck by not making it truly vertical. I'd slant it no more than about 20 degrees either side of center and listen for awhile. If you have a system you are truly interested in, you might enlist a friend to slant it for you while you listen, or maybe take a handheld up on the ladder and play. If you are doing 800 mhz optimizing, make fine adjustments before locking it down - those lobes can get finger-thin.

For a little less stress on the mount, you can also hang it so that the short end is on top - the results are nearly the same.

 

[cassidy1190]

Very nice antenna! When making this antenna are you supposed to solder the balun connectors to the copper rods?

 

[bpotanka]

I will try moving it around a bit this weekend for 800mhz. The only things i listen to in 800mhz is a town that i am receiving about 20 miles away and the NJSP Trunked system which one tower is a mile or so away so its not that important to me. As for the question about soldering i did not but suppose you could. Where the CPVC tee meets the copper pipe i used #8 x 3/4 self taping screws to join the pieces and simply used two screws to connect the balun to. The one i purchased had forke connecters on it and slid them underneath, however i did see plans for another antenna this week that used stainless steal pipe clamps as connections so that you have a tuneable adjustment.

 

[Fred1]

Nice job. I made mine out of an old RS scanner antenna. I use the 18 inches on top over 48 inches. Fed with RG6 to tv balun up 30 ft. Works great 27 mhz to 800 mhz.