End Fed Zepp counter poise/ground question

[Lazybones1222]

Hi,

I have built a north south inverted V dipole that is fed like this:

3 ft of rg-213 coax from radio to Dentron Super Tuner, tuner to 8 feet rg-213 to a 4:1 balun, 600 ohm ladder from balun to feed point of dipole. It is working great for me and tunes up EVERYWHERE.

Building wire antennas is getting addicting...............

I want to try a end fed zepp running east west and the way my lot is configured the antenna must be end fed. I know a good ground is critical with this type of antenna. I want to stay with the 4:1 balum and coax into the shack. My question is, should I run the ground wire off the ground lug of the balun, or off the feed side of the balun that feeds the open wire that goes nowhere? I plan on burying two couterpoises 1/2 wavelength off the balun.

Or....is it an absolute must to run the twin lead right to the tuner?

Does any of this make sense or have I lost it again? lol

 

[W5LZ]

Very simply, what you are talking about is an affective RF ground system. How that 'end fed Zepp' is configured will determine what it's name should be, 'Zepp' or 'random wire' or whatever. It's just a matter of how it's made, sort of, which is getting 'picky', but names do have meanings. Which isn't really the point, so don't worry about it.
The 'best' RF ground system is typically as much wire in the ground as you can possibly get, as long as you can get it, and as symmetrical as you can get it. After that, it's a matter of what is practical for your particular location, what you can get done without some sort of problem, and before you get fed up with the whole idea. When do you quit? When you don't 'see' any improvement in things. That point is variable, almost always more than what you counted on doing, and you really will get fed up with the whole idea after a while.
Very few people really have a 'good' RF ground. Most are only 'adequate', sort of, till you get to something approaching what commercial broadcast stations use. It's up to you to decide when you have a 'good enough for your purpose' RF ground. Even with that option, be prepared for a lot of not so easy work (I hate digging!). That doesn't mean 'deep', just lots of shallow stuff. 'Deep' isn't beneficial. Ground rods aren't very beneficial except as 'place holders', sort of. Burying lots of wire IS beneficial. The whole idea is to increase the conductivity of the dirt under that antenna, you figure out which/what/how to do that, and you got the 'best' solution for your particular location.
You're gonna have so much fun you will only barely be able to stand it!
Good luck.
- 'Doc

 

[dudmuck]

I want to try a end fed zepp running east west and the way my lot is configured the antenna must be end fed. I know a good ground is critical with this type of antenna. I want to stay with the 4:1 balum and coax into the shack.

I would be interested in knowing how or where you got the idea that the end-fed zepp needs a ground.
I google for it and everywhere i read there is no mention of needed a ground because it uses balanced feedline. Re: [TenTec] End Fed Zepp

 

[wy0mn/7]

Zepp (zeppelin) antennas are full wavelength long with a half wave radiator, the other half is folded back upon itself and is shorted strategically for use as a tuning stub (built in counterpoise), matching the impedence of the rig/feedline. Ladderline is recommended but not critical. Its the grand-daddy of the j-pole and was flown suspended from derigibles and blimps (no ground rods nor radials there!). Zepps are single band antennas, when pruned and tapped correctly you can & should omit the insertion loss of the tuner (bypass the bugger).

http://www.m0ukd.com/Slim_Jim/index.php

I ran 30m CW exclusively for 3yr with a homebrew zepp. That was my only band/mode/antenna.

Another idea you might want to consider is a 1/2wave end fed with a matchbox built in! Its 1/3 shorter than the physical length of the true zeppelin antennas (discounting the offset 1/4 of the zepps tuning stub). Contact Dale Parfett at http://parelectronics.com/, I have had my EF-40 up for a week or so and the performance is actually better than my home-made dipole. http://www.zerobeat.net/g3ycc/endfed.htm
(If you want to build it yourself, maybe you want to research matchbox construction.)

73
Lex

 

[HiDef]

An end fed Zep is typically fed with ladderline which is a 1/4 electrical wavelength long at the frequency of interest. The flat top portion of the zep is typically an even mutiple of a quarter wave.

Example for 40 meter end fed zep.

66 foot long flat top 30 foot long ladderline feeder.

66' is 2 X 1/4 WL on 40 meters and 30' is 1/4 ELECTRICAL which means adjusted for feedline velocity factor wavelength.

The feedpoint impedance of the Zep is supposed to be very high on purpose.
The 1/4 wavelength feeder transforms that high impedance to a low impedance at the shack end. This means a 4:1 BalUn is NOT desirable at the tuner. A 1:1 will give you much lower loss in the tuner. You could actually use only a 1:1 BalUn on the ground and juggle the feeder length for low SWR without any tuner at all.

There will be a small unbalanced antenna current in the feeders. This exists because it is a counterpoise. Being voltage fed or high impedance feed is a must for this kind of antenna if it is to work well. If you were to use a current feed, the whole situation falls apart. That means this same antenna will not work well on 20 meters. R.F. problems in the shack are more likely in this situation. Some people might mistake this for a lack of an adaquate ground system.

Maximum radiation occurs in the vicinity of the current nodes of this antenna. This means the CENTER of the flat top should be as high as possible for typical benifits associated with low angle radiation and lower ground loss. In other words the ends of the antenna can be lower than the center like as with a center fed inverted V.

 

[hookedon6]

I would be interested in knowing how or where you got the idea that the end-fed zepp needs a ground.
I google for it and everywhere i read there is no mention of needed a ground because it uses balanced feedline. Re: [TenTec] End Fed Zepp

apples and oranges. that article "changes horses in mid stream" only one "side" of the feedline is connected on an EFZ, the "ground" side is "open".

it starts out talking about EFZ's (and correctly states " The key to "RF" in any shack is a very well defined ground system that is actually very near RF ground potential".) and then it switches to a discussion about double zeps (center fed)

also, if you lengthen each side to 5/8 wave , you get a
collinear with gain, the Double Extended Zepp

 

[Lazybones1222]

I would be interested in knowing how or where you got the idea that the end-fed zepp needs a ground.
I google for it and everywhere i read there is no mention of needed a ground because it uses balanced feedline. Re: [TenTec] End Fed Zepp

FWIW - I got the need for a ground from this:

http://www.hamuniverse.com/wb1gfhzepp.gif

 

[W5LZ]

Lazybones1222,
Well, that certainly explains where you got the idea. That particular antenna type can also certainly be used and have decent results. Unfortunately, it isn't a 'Zepp', and so shouldn't be called one. I can certainly understand why it could be mistaken for one though.
A couple of things about that referenced picture. It goes a little too far in one direction, and not really far enough in another. Unless you happen to be blessed/cursed with a home that has several structures, do you really think a neighbor is going to let you attach an antenna to their house? (If so, could I move in with you??) Another thingy is that "as long as possible" description. It's 'right', but it also means that tuner is going to be more than just 'average' in abilities, sort of. Huge number of "but's" in that. It may work, but is it doing what you want it to do, put a signal where you would like for it to go? Beats me, too many variables in that equation to make a guess. And since it's not really variable much, how about the -next- contact in a different place/direction? There's just no such thing as a "one size fit's all" antenna. What 'works' for you might not work for me, and visa-versa. Doesn't mean that a particular antenna is not 'good', just that it isn't 'good' for a particular circumstance. If a particular antenna 'fits' your circumstances, at the very least, it get's you on the air, which is certainly better than no alternative, right? If you only have ever used one antenna and never thought about changing it to something else, you are the exception, not the average 'radio nut'! Probably the 'best' reason I can think of for all the different kinds/styles of antennas in the world.
What's the best antenna in the world? The one before my last one. Except for my next one. Perfect and practical are almost never the same thing.
- 'Doc

 

[N9RZD]

Very simply, what you are talking about is an affective RF ground system. How that 'end fed Zepp' is configured will determine what it's name should be, 'Zepp' or 'random wire' or whatever. It's just a matter of how it's made, sort of, which is getting 'picky', but names do have meanings. Which isn't really the point, so don't worry about it.
The 'best' RF ground system is typically as much wire in the ground as you can possibly get, as long as you can get it, and as symmetrical as you can get it. After that, it's a matter of what is practical for your particular location, what you can get done without some sort of problem, and before you get fed up with the whole idea. When do you quit? When you don't 'see' any improvement in things. That point is variable, almost always more than what you counted on doing, and you really will get fed up with the whole idea after a while.
Very few people really have a 'good' RF ground. Most are only 'adequate', sort of, till you get to something approaching what commercial broadcast stations use. It's up to you to decide when you have a 'good enough for your purpose' RF ground. Even with that option, be prepared for a lot of not so easy work (I hate digging!). That doesn't mean 'deep', just lots of shallow stuff. 'Deep' isn't beneficial. Ground rods aren't very beneficial except as 'place holders', sort of. Burying lots of wire IS beneficial. The whole idea is to increase the conductivity of the dirt under that antenna, you figure out which/what/how to do that, and you got the 'best' solution for your particular location.
You're gonna have so much fun you will only barely be able to stand it!
Good luck.
- 'Doc

i knew a guy , who had taken old chain link fence
and stretched it out all over his yard
then covered it with a few inches of dirt before reseeding
this was his "ground"
apparently it worked pretty well !