Ham Radio - An end fed half wave cage antenna. How much wider bandwidth does it provide?

Ham Radio - An end fed half wave cage antenna. How much wider bandwidth does it provide?

 

Has he done it with a pair of wires spread apart at one end and terminated together at the feed end? That would be a simpler way to get a wider element for homebrew antennas. I would think that could add bandwidth without so much wire and weight. The hams in the old days has issues with antennas like that from weight, ice buildup, wind load, etc. that you would expect over a single wire.

 

Comme la bien expliqué W8AAZ, le poids de la neige en montagne est énorme.
UNE+Chris

 

Oh Jeez,

Should I build my Marconi shack also?

There are plenty of ways of getting acceptable bandwidth; the cage antenna is seldom used by hams because it is a large and cumbersome option.

 

Well, hey a good assessment.

 

I have built a few three wire dipoles for ten meters, the wire size and spacing can pretty easily be adjusted to work with 600 ohm open wire line. The additional bandwidth is a bonus, a three wire dipole with about two foot spacing will easily cover 2 MHZ of bandwidth at 2:1 SWR on ten. The thing with cage antennas is that to realize a lot of band width at frequencies below 14 MHZ, the physical dimensions become a problem.

 

Hello from kc8ikw Joseph Strauss I love how u made that If u can who made the rings can u send me that information thank u very much from kc8ikw Joseph Strauss as all way every one calls me Joey 73s

 

He went through the experiment to see what would happen and that's all he set out to do. He even said it didn't have any advantages due to being impractical but the antenna did in fact offer wider bandwidth. He took the time to satisfy his curiousity and cared enough to share the experience and the lesson. I learned something and others likely did too. Not sure why the sour attitude.

 

Not sour, just realistic. It is not unlike using spark instead of any modern mode.

Cage antennas still see occasional use in high powered applications, but not in ham radio in anything but an anecdotal way.

The most famous use of cage antennas is the DUGA array--very QRO.. Take a look at it on google, for example.

73
Chip W1YW

 

I agree it isn't realistic but it wasn't what he was aiming for. Only to answer a single question of bandwidth result of the design.

 

I could argue: to what end?

It is much more enlightening for us to see where cage dipoles are used, and when they are used.

Again: fun to look at the Duga for some fairly recent history. I will post one by my daughter in law's brother later. He was there! (I am jealous).

73
Chip W1YW

 

OK so impractical in most situations but interesting. I wonder if the old spark hams had any idea about the broader bandwidth. I know they had wide spaced flat tops with lots of wire, and they were considering that those has more "capacitance" than a single wire, for loading purposes, presumably. Gigantic capacity hats to make the feeder efficient as a radiator at lower freqs? Then again, their understanding of antennas was pretty rudimentary for a long time. Explaining some of the monstrosities seen in old literature. Adjust for maximum RF current on the feedline.

 

Here is a 2020 photo of the (defunct) DUGA (Woodpecker) array. The antenna was an array of caged dipoles with tapered-to-feed construction. 3:1 bandwidth from 7-21 Megs approximately.

 

C'mon Chip, you of all people should understand the urge to experiment.

 

C'mon what...

Here's a good experiment you can do with a cage antenna--

Run a parasitic wire (no connection) down the middle with distributed capacitors on its length (A CCD antenna) .

This will have an interesting effect on the bandwidth and beam pattern (at some frequencies) with the right choice of capacitors...which...as is the point.. one can experiment.