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Author Topic: Want to make a great end fed for 6-160...  (Read 13344 times)
KF7OCD
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Posts: 24




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« on: July 10, 2011, 05:42:53 PM »

I have been looking for an end fed antenna because of my location sooner or later I will need to have one.

So I have been looking on ebay and have seen some really good products like the...

ULTIMAX DXTREME END-FED ANTENNA
"QSO-KING" 160-6 meters 1.5 KW end fed / ham antenna

However I don't want to pay for something I can build myself (money is VERY tight right now).

So I am wondering where some free plans are so that I can make myself a really good end fed antenna the will do all the HF bands.

Thanks for your response!!!

-George  KF7OCD
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N3WAK
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Posts: 281




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« Reply #1 on: July 10, 2011, 06:14:09 PM »

George: 

Build it yourself--don't buy.  Go to your library and check out "The ARRL Antenna Book."  It will have a lot of antenna ideas in it.  Or Google "End Fed Wire Antenna" like I did--you'll get a lot of hits.  Or, read this on a doublet: http://www.qsl.net/wb1gfh/antenna.html  There's lots of info on the Internet if you look around. 

However, if I were you, I wouldn't worry about covering 160 meters to 6 meters right off the bat, unless you're already an experienced op.  You can have a lot of fun on 80-10 meters starting out.  Heck, a 40 meter dipole or inverted vee will cover both 40 and, most likely, 15 meters. 

Have fun.  But don't buy an antenna. 

73, Tony N3WAK
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WB6BYU
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« Reply #2 on: July 10, 2011, 09:02:28 PM »

I agree - don't worry about getting all bands in one wire at this point.  It might work, but the requirements
for efficiency on 160m and usable pattern on 6m are very different.  Besides, and end fed wire can be
a bit of a beast to get working properly, so it is better to start simple for a few bands and work out the
quirks, then go from there.

First of all, an end fed wire MUST have something to work against.  There certainly are commercial
antennas that appear to ignore this step, but for them to work the outside of the coax usually ends
up serving that purpose.

Second, an antenna for 160m will need to be at least 60' or so to get reasonable efficiency as an
end fed antenna (though there ways around it that may work for a monoband antenna.)  An antenna
that long on 6m will have lobes in 16 different directions, with nulls in between them.  While it is
quite possible to make contacts with such an antenna,  there will also be some directions in which
you can't hear very well.  A simple dipole will often outperform such a long wire antenna for
general use because it doesn't have as many nulls in the pattern.

Now I happen to have an antenna up that might fit the description you are looking for:  it is end
fed against ground (a combination of radials and a ground rod, the best I can do in that particular
flower bed.)  I use it on 160m and 75m, and it will tune up on all bands with a tuner.  (I haven't
tried making contacts above 20m, but there is no reason that it shouldn't work.  That is simply
a 185' wire that runs up from the ground to the top of a mast at about 30', then out across the
house and barn, turns a 30 degree angle at the top of my tower, with the far end tied off to a
grape arbor.

I have a very short lead-in to a tuner inside the shack, but an autotuner (or remotely switched
matching network) right at the base would work better.  My tuner isn't rated for 6m, and I don't
have any gear that operates there, either, but with a manual tuner I can use it on all HF bands.
That is, with an adequate tuner I can adjust it for a low SWR and get it to radiate power.  Does
enough of that power go in useful directions?  It certainly does on the lower bands, but I haven't
operated enough above 20m to find out.

I also have a 130' end-fed wire running from the barn to a walnut tree for when I operate from
out there.  In that case I feed it at the second story window, rather than at ground level.
It is much more prone to "RF in the shack" problems due to the lack of a good ground - the
first symptom is usually that my keyer continues running after I let go of the paddles.  Adding
quarter wave wires to the tuner chassis helps (as does adding extra wires to the radio itself -
they are separated by about 15'.)  With some fiddling I can get it to work with a simple tuner,
but again the pattern will have a lot of lobes and nulls on the higher bands.

The only time I've gotten good results with an end-fed wire with the feedpoint above ground
level was when I was in an apartment with aluminum window frames, and they were all bonded
together throughout the building.  That gave me a good enough ground system that I didn't
have problems with stray RF.  I've used end-fed wires many other times, with more quirky results.

If all you can manage is an end-fed wire, then you probably can get it to work with a simple
home-brew tuner.  By picking up a suitable variable capacitor at a ham fest (or from a neighbor's
junkbox) and winding a coil of wire on a piece of plastic pipe, you can get on the air with little
cost.  It does help, however, to have a knowledgeable ham to help you deal with the quirks that
are bound to come up.

Meanwhile, don't trust the claims of any commercial antenna that thinks you can get any sort of
good performance over 160m to 6m unless you understand the principle of operation.  Most such
devices will have mediocre performance at one or both ends of the spectrum, and may be
questionable in the rest of the range as well.  The basic trade-off between making it long enough
to be efficient on 160m while having a useful pattern on 6m requires you to understand the
relative importance of those bands in your operating preferences, and what sorts of distances and
directions are of most interest to you.  Some commercial antennas appear to think that, as long
as the SWR with a tuner isn't too bad, they can claim that the antenna "works" on a particular
band, even if only 1% to 10% of your power is actually radiated and some of that goes in
directions that are not useful for communications.
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KF7OCD
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Posts: 24




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« Reply #3 on: July 10, 2011, 11:56:54 PM »

Great advice from BOTH of you, thanks! I have two antenna ports on my radio (only using one right now) and I am thinking of running a two antenna system. One for the lower bands and one for the higher ones, both antennas will be multi-band antennas. Antenna one will be for 160 and 80 the other for 40 and 20. New question, will that configuration work well or better then an one antenna fits all approach? And if so what end fed design will work the best? I wish there was an antenna expert who you could pay $20 an hour to consult with and that person could help you start to finish with your antenna issues (consult, design and build custom antennas for each persons unique situation. If such a person existed he or she would make a TON of money.

THANKS AGAIN!!!!

-George KF7OCD
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WA4FNG
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Posts: 162




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« Reply #4 on: July 11, 2011, 02:20:56 AM »

George,
You can build any type of wire antenna you want. That's the great thing about this hobby. It's not about "hiring" someone to do it for you -- it's about learning to do it yourself. I just can't get my mind around having a ham ticket and buying or paying someone to build me a 40m dipole. Start simple -- build a 40m dipole. Good band to get started, someone to talk to most any time of the day. Read, read and read. Get the ARRL Antenna book, etc. My preference for a multiband wire antenna is a 40m or 80m doublet (dipole) fed with 450 ohm line and use a tuner. Many prefer to build it as a large loop. Just Google "loop skywire" for info. I use them all, as well as single band dipoles for the bands I'm interested in. I have at least 2 antennas I can use for each band and select the one that is best at the time. Good luck, have fun! Build an antenna...
73,
Milt
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N3WAK
Member

Posts: 281




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« Reply #5 on: July 11, 2011, 04:02:23 AM »

George--You have a bunch of excellent suggestions in the responses to your question. 

Look, if you're just starting out, don't bite off more than you can chew.  Build a 40 meter inverted vee and just use that for three months.  One band.  You'll have a ball and learn a lot  I agree with the posters that an end-fed wire is not what you want to begin with, unless you know how to deal with the idiosyncracies of end fed wires. 

You can use #14 wire from Lowe's or Home Depot, or something equivalent from Radio Shack or the gazillions of ham radio stores that sell on the internet.  You can use RG-8X coax for all of the HF frequencies, from 80-10 meters, if you're running 250 watts or less with a reasonable SWR (3:1 or better).  (Perhaps a bit of higher power too, but I would have to check the power handling capability of RG-8X on line or in one of my books.)  You can get it with coax connectors already installed.  Limit your run of coax to 100' or less--less is better.  Get insulators for the end of each leg.  If you can make or buy a balun, great.  If you can't, don't worry about it.  Remember, this is your first HF antenna--a basic one is just fine.   

Cut each leg to 34' and check your SWR.  If your SWR is higher than 3:1 at 7.2 mHz, trim 6" off of each end and measure it again.  You'll be fine. 

Until you learn by doing and by reading stuff, put up a single-band inverted vee.  It really doesn't get more basic than that, and once you develop some experience you can put up a different--although not necessarily better--multiband antenna. 

Good luck.  If you want to email me with questions, my email is tonykurl@aol.com 

73, Tony N3WAK
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W8JI
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« Reply #6 on: July 11, 2011, 04:18:40 AM »

Careful with all the advertising you read about antenna George. Especially all the "feel good" junk like a "kilowatt king 1500 watt longwire". Obviously a bit of PT Barnum in there. :-)
Since your QTH lends itself to a longwire, read this:

http://www.w8ji.com/long_wire_antenna.htm

73 Tom
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W4VR
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« Reply #7 on: July 12, 2011, 08:31:44 AM »

End-fed antennas are fraught with problems....I've tried them in situations where it was impossible to center-feed them...I even had one that was 300 feet long and up about 60 feet out an apartment window.  If you can get yourself a hunk of wire, buy some ladder line and center feed your long wire, or in the least off-center feed it.
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N4JTE
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Posts: 1160




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« Reply #8 on: July 12, 2011, 02:40:45 PM »

George, reading between the lines it seems a future qth will require something like an enfed for lack of trees etc, however if you think it will be a stealth type antenna you are mistaken because for that type of antenna, to get anything above 50% efficency, you will need a substantial ground counterpoise as long as the antenna which will not be easy if your concern is due to some restrictions.
Best of luck,
Bob
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N4JTE
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« Reply #9 on: July 12, 2011, 02:47:06 PM »

One more comment; there is no "Great End fed 6 to160 antenna." It does not exist at least commercially. Actually you will hard pressed to find any truly efficent single wire antenna that can be "great" on all those bands and the endfed is way down the list even on that playing field of compromised antennas.
Bob
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KB1GMX
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Posts: 830




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« Reply #10 on: July 13, 2011, 02:26:05 PM »

N4JE: One more comment; there is no "Great End fed 6 to160 antenna." It does not exist at least commercially. Actually you will hard pressed to find any truly efficent single wire antenna that can be "great" on all those bands and the endfed is way down the list even on that playing field of compromised antennas.

Your nailed it.

First there are too many antennas that claim 6M. often as not he pattern is way to fractured
and more likely off the end then anything.  Also 6M is a band that most of the time a good
antennas (read as BEAM) are needed and maybe a few weeks a year you can get by with a
wet noodle for domestic Es when every one else is working countries.

The Ultimax is a basic idea of compromise antenna.  It's a 9 or 12:1 balun and a non-resonant
wire and must be grounded or counterpoised or you have RF in the shack.  It's in the same league
as the 43ft vertical fed with an unun.  It's useful and can be effective but it's not magic or panacea
and in most cases neither are "all band without tuner".

Counterpoise or radials are generally easy to hide (may take effort to install).

End feeding a random wire is not the same as End fed Half wave.     That said its very different
from a half wave end fed as that is a resonant antenna, it still needs something to work against
but the currents (impedances) are in a different realm.  Both can be build and generally fairly cheap.
if the random wire is worked against a decent ground (and some radials) it's a useful workhorse
if matched to the radio with a simple tuner.

For a trivial amount of work you can build a lot of antennas.  For the lower bands an inverted L
fed at the base (at the ground stake and radial attach point) is good for the low bands.  once you get
to 20M (33ft dipole) then it's possible to use basic dipoles for simplicity and effective result. 
At 10M a wire dipole is about 16.5FT long.  At 6M its a mere 113".

I find it interesting that people insist on one antenna for all when at the high end of HF they are small
and easily hid.  So instead of one poor antenna why not three or four? 

As to free plans, check the Internet, likely after doing that the problem will be which one.
Then there are the ARRL Radio Amateur Handbooks (even older copies) and their antenna
books.



Allison




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W6CD
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« Reply #11 on: July 17, 2011, 10:57:39 AM »

Thoughts and comments on this?  Note the link for installation and wire length info.
http://www.balundesigns.com/servlet/the-100/9-cln-1-9-dsh-1-unun/Detail

I am thinking of something like this to go on my RV when camping.  I have a 28' fiberglass mast on the rear of the motorhome - so the wire would run up the mast then extend downward at an angle to the front of the motorhome.  Chassis and a few radials.

This for when I have restrictions that I must stay pretty much within the foorprint of the RV and/or when there are no trees (desert camping).
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WB6BYU
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Posts: 13578




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« Reply #12 on: July 17, 2011, 02:33:35 PM »

That's an interesting table, especially in what it leaves unsaid.  How are they feeding the wire if it
runs horizontally?  Against free space?  Against a vertical ground plane?

For example, the table shows that a 124' wire would have a SWR of 1.3 : 1 on 160m relative to
the 450 ohm impedance of the balun.  (Or that is what it appears to claim, at any rate.)  I ran a
quick EZNEC model of a 124' vertical wire fed against ground, and the lowest SWR between 1.75
and 22 MHz was 3.32 : 1 at 19.5 MHz.  True, the only bands where the SWR was over 10 : 1
were 160m and 60m, so the coax losses might not be too bad if using a tuner in the shack.
The impedance at resonance 160m was about 36 ohms, and it is difficult to imagine how one
could step that down by a factor of 9 to around 4 ohms and have a low SWR on 50 ohm coax.

But a 124' vertical actually isn't a very good antenna, at least not for the bands above 7 MHz,
as the angle of radiation is too high.  (Not to mention the problems most hams would have
installing such a wire.)  What happens if we make the same wire into an inverted L, 24' high
and 100' long?  That is much more like what we would install in practice.

In that case the SWR is OVER 10 : 1 below 8.5 MHz, around 3 : 1 on 20m, and remains below
5 : 1 from there through 10m, so it may work over the higher bands with a good built-in
auto-tuner.


So I wouldn't trust the stated SWR readings in that table without a much clearer description
of the conditions under which they were measured, because they certainly aren't consistent
with established antenna theory or models.
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W6CD
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« Reply #13 on: July 17, 2011, 04:48:48 PM »

Below the table was the following additional info:

Typical SWR relative to wire lengths. SWR will vary based on typography, wire orientation and use of ground or counterpoise. For best results, use the longest wire length shown on the table that will fit your installation constraints.

Installing your wire as an Inverted L will change the feed point impedance and tuning of the wire thereby limiting bands available. Rows in color are best overall lengths to use for complete HF spectrum coverage.

Try installing the unun three different ways. One with the negative terminal grounded, another with a counterpoise wire of 15-30 feet minimum and the third with no connection at all. In this last configuration the coax shield will act as the counterpoise but you should have 30+ feet of feedline to try this option.
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W8JI
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« Reply #14 on: July 17, 2011, 05:04:32 PM »

An end fed can be a very efficient antenna, if the counterpoise is good and you use a good tuner.



As for the magical 9:1 unun fed things....

If the SWR is as low as claimed, something has significant loss.

Try installing the unun three different ways. One with the negative terminal grounded, another with a counterpoise wire of 15-30 feet minimum and the third with no connection at all. In this last configuration the coax shield will act as the counterpoise but you should have 30+ feet of feedline to try this option.[/i]

.....so what they really want you to do is find the lossiest ground you can. :-)

By the way...here the corrected text about the coax shield:

Quote
.....and the third with no connection at all. In this last configuration the coax shield and everything connected to it, including your radios, house wiring, and even your microphone and headset will act as a radiating counterpoise but you should have 30+ feet of feedline to try this option
 :-)



« Last Edit: July 17, 2011, 05:08:13 PM by W8JI » Logged
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