My first homebrew antenna

[Spirittalk]

Ok look what you guys got me doing, I am building homebrew aerials now lol

After looking through the forum for simple designs, I come across the double bazooka dipole.

Have hummed and arred aboutt building this for a bit to be honest then went and decided to do it.


I have a local electronic store near me who happed to sell a dipole kit with all the bits and pieces.

However, I decided to splash out and pay £3:99 for a m ore sturdy centre feed that has a screw in section rather than loose brading

I wasnt to scared to tell the guys I was a novice dipole builder and they offered help and advice.

My soldering is pretty good so manged to construct the dipole in no time at all.

The dipole was raised via a pully system stuck on to a post we have allready to hold the washing line up.

It now means, I can raise and lower the dipole for any work or replacement if somehow if got damaged.

The lowest part of the dipole is now 20 feet tall.

I decided to go and buy some RG58U low loss coax instead of the cheap stuff as the coax feed line is 55 feet in the air and that is quite alot of coax inst it?

The antenna itself is made up of RG58 coax and is black and fits into the surroundings.

Pleased to say it is very 'stealth' like.

I laid it on the ground at first to see if it would resonate a signal and managed a QSO on SSB 70 miles away with a 4/7 report.

Nothing to write home about but showed it was resonating in the required way.

Even that was a thrill to think I had just made a contact with an antenna I had made myself

Will I require an Earth wire or any other type of earthing with this ?

At first it will be 20 feet up but once it has been in situe 12 months with no objections can raise it higher.

I am thinking of adding a second element to it, would it matter if the reflector was lower down ?

Any other ideas on improving performance will be most welcome/

But this has to be better than a ground mounted verticle, verticle on it's side or attic mounted whip doesnt it ?

Again guys thanks for the inspiration to go out and build, a new dipole fan is born

As I dont kow a lot about electronics , it has also given me the incentive to go and study at a local night school for the Noivce Radio ham ticket.

 

[Beetle]

Sounds like you're having fun experimenting - congratulations! That's a part of what ham radio is all about.

However, "RG58/U Low Loss Coax" is an oxymoron if there ever was one .

 

[231]

Sounds like you're having fun experimenting - congratulations! That's a part of what ham radio is all about.

However, "RG58/U Low Loss Coax" is an oxymoron if there ever was one .

X 2 on all accounts.

Congrats! 8)

 

[freecell]

"However, "RG58/U Low Loss Coax" is an oxymoron if there ever was one "

that all depends on what frequency it's being used at. what would be considered lossy in long runs at 10 meters would be considered low loss at 80 meters.

 

[W5LZ]

Spirittalk,
Sounds like you've gotten bit by the 'antenna bug'! Good for you.
The RG-58 at about 50 - 60 feet will work just fine, not really enough losses to make much diffrence. You will see more 'loss' from the antenna being horizontal, rather than vertical (assuming the other guy's antenna is vertical), than from feed line loss.
Grounds. You don't need an 'RF' ground for a dipole. Having a 'station ground' is for safety, helps you not to get shocked from the AC going to the radio stuff when you ground them. Never really hurts to have one of those. Doesn't hurt to ground the feed line either, but with 'RF' grounds, their length does make a difference. The 'ideal' is as short as possible, and not close to an odd number of 1/4 wave lengths long. 'Even' multiples of a 1/4 wave length is okay, but only if that's the shortest way of doing it. That feed line ground should also be done outside of the house.
A second element as either a director (shorter than the driven element) or a reflector (longer than the driven element), turns your dipole into a beam. May not be able to 'turn' it, but still a beam. That's with the 'new' element parallel to the driven element and off to one side or the other (front or back of it). Another element under the dipole can help. It can also not be apparent that it's even there, for that matter. Sort of acts like an 'electrical' ground, improves ground reflections, other stuff too, sort of. How much is 'shorter' or 'longer'? Something around 2% - 4% of the dipole's length, added to, or subtracted from, the length of the second element. How far apart should they be? That's a good question! And the answer is "It depends". Something more than 3 feet and something less than about 9 feet. Adjust to suit your results (experiment).
- 'Doc