Over the years I've seen many projects expounding the virtues of the J poles & Slim Jims. At first these appear like a simple and easy way to get on air but are they really?
Both can be made from copper or aluminium tube or even balanced line but they seem fiddly requiring far too much work for my liking. Their sturdiness is directly related to the builder's mechanical skill and in some cases they're awkward to mount. Many will say that the versions built from balanced line are great because they can be bundled into a pocket or bag - perhaps so. Some claim they are a cheap way to get on the air - probably but I think there is a better home brew antenna. Many hams still suggest the J pole or Slim Jim makes a good antenna for the newbie. There was even an article in AR recently.
The
flower pot antenna has been around for a long time and is nothing new yet it doesn't seem to gain the recognition it deserves. It doesn't matter what your skill level one flowerpot is as sturdy as the next. They cost well under $20 to build. You can cut away most of the PVC pipe and roll it up for easy transport an deployment and they are almost indestructible.
They are not a DX antenna but compare well against the lower range of Diamond X series antennas. For the price, there is no question the flowerpot gives you more bang for buck. Pack one with a $50 Chinese handheld and you have a very capable portable station for someone just getting into ham radio.
Isn't it about time we bade a fond farewell to the J pole and Slim Jim?
Quote:Isn't it about time we bade a fond farewell to the J pole and Slim Jim?
What are you Lou, some sort of hot-headed radical? You should be ashamed of yourself! Next you will be suggesting that we do away with the G5RV
hock:
In the old days such behavior would result in you being Wouff-Honged or Rettysnitched!
73
Wayne VK4WDM (pass me the smelling salts please, I feel faint).
I'm practical.
The point of all these antennas is to do something on the cheap to get you on air. I just think the flowerpot is simpler and more practical.
G5RV, yep they are cheap and simple but consider what the old blokes used to do with a doublet? Not going anywhere near using twin lead for feedline but for the man that wants an antenna to do everything then I advocate the doublet.
What say ye?
Obviously my last remark was very
but I agree about the doublet. Back in 1962 my "elmer", the then VK4DK said: "put up the longest doublet you can as high as you can and feed it with open wire line. It is the only (HF) antenna you will ever need."
Having said that, such an antenna is not really practical today for several reasons.
1. They need height and space. There were no height restrictions and many houses already had wooden masts for their household broadcast and short wave radios so 60ft ham masts were not a problem. Blocks were usually 1/4 acre and you could get a lot of wire corner to corner.
2. The old valve transmitters had PI or link couplers that tolerated high SWR (not that anyone bothered measuring it). Today's solid state finals would evaporate.
The best antenna I had in recent years was a horizontal delta loop cut for 40m at only 8m high and feed with open wire line. It worked on all bands from 40 to 6m. Unfortunately the new position of my shack does not allow me to use it anymore.
73
Wayne VK4WDM
Inclined to agree....J poles etc , never actually bothered with one myself.
The G5RV and its cousins is a pretty good all rounder The other thing is the supply of cheapo twin feed (ladder line) has just about evaporated, sure its available, but has to be ordered in at some cost.
Came across this the other day:
http://www.dx-wire.de/huehnerleiter-spreizer/ DIY twin feed.
VK4BZ posted an easy method to home brew OWL on the old logger using irrigation riser tubing and cable ties that works really well. Hopefully he will read this and post it here.
I have used G5RVs a lot but the trick is to tune them correctly. Owen VK1OD wrote an article on it but I am not sure if his stuff is still on line.
I have never used a flower pot but it looks an interesting design. We need a dual band 2m/70cm antenna at the RAAF Heritage Centre station VK4KG so that might be the way to go.
73
Wayne VK4WDM
Yep riser tube is easy to work with and lasts a long time outdoors. I used a roll of building wire I bought for a few dollars at a disposal store to make the horizontal section plus the feedline for my doublet. I cut & drilled the tube so the wire passes through the holes. I then fixed the spreaders to the wire so they don't slide around. You can use glue, string, cable ties, paperclips, wire - whatever, to hold the spreaders in place. It took SWMBO and I a few hours to make 6m of line that suited my purpose.
VK4WDM Wrote:I have used G5RVs a lot but the trick is to tune them correctly. Owen VK1OD wrote an article on it but I am not sure if his stuff is still on line.
His site is now under
www.owenduffy.net and maybe the following link may assist....
http://owenduffy.net/blog/?s=g5rv
Posted in the interests of finding things on the web.
Doug VK4ADC
Some of the younger guys maybe confused about the different between"doublet" and "dipole." The are often used interchangeably now days but in the "old days" a dipole was cut for a single frequency and would be fed with open wire line, electrical twin lead (yes it worked), or if the ham had the dollars to spend, coax.
A doublet was cut for the lowest frequency in use and always fed with open wire line. It would work on all harmonically-related frequencies, but such was the robustness of the coupling between feeder and transmitter the antenna could just be made as long as possible and it would still load OK. If you went to the trouble of measuring SWR then 5:1 was considered perfectly acceptable.
73
Wayne VK4WDM
Back to the "J" pole.
For 6m and 2m I'd recommend a 5/8. Three radials (1/4 wave) is all that are needed.
And a small coil that allows flex between the coax connector and the vertical's insulator.
And, the radials can be used to guy the vertical (in the 6m or 10m version).
It's just so easy.
Alan VK2ZIW