End fed antenna

Status
Not open for further replies.

n4yek

Member
Joined
Apr 20, 2004
Messages
2,479
Location
Newport, Tennessee
Hi all,
I am thinking of putting up an end fed antenna. I have never used one of these antennas, always used a windom. Due to space, i need something a little smaller and was thinking about this antenna.
I am looking for comments from users that have used one and any pointers.
Do i need to install a counter-poise wire or just a ground round attached to the ground lug on the un-un box?
Thanks for all your input.
Danny
 

prcguy

Member
Joined
Jun 30, 2006
Messages
8,104
Location
So Cal - Richardson, TX - Tewksbury, MA
How much space do you have? I've played with many of the end feds on the market and have learned the end feds that are resonant half waves and multiples of a half wave fed with a very high ratio transformer of about 64:1 to match the 3K ohm plus impedance works about the same as a full size half wave dipole of the same size. The difference is you feed it on the end, which is much easier to deal with and its resonant on most harmonic bands, unlike a center fed dipole.

You can make your own 64:1 transformer for a few $$ or LNR Precision makes the PAR End Fed or MyAntennas probably makes the best multiband end feds on the market. I'm a big fan of Danny Horvat and his creations from MyAntennas.

Then there is the random length non resonant end fed using a 9:1 transformer and various lengths of wire from 27ft to 53ft to 117ft and so on. These are advertised as 80 through 6m or even 160 through 6m and in my opinion are to be avoided. In comparison to the tuned resonant half wave end fed the 9:1 types are a few steps above a dummy load. Plus they must work against the braid of the coax as the other half of the antenna and your coax usually becomes hot with RF.

Some of the 9:1 types are sold under the name of ERCHI, QSO King, Ultimax, and variants from Chameleon and Alpha Antenna. Put any of these side by side with a resonant half wave end fed and you will be shocked at the difference in performance, especially on the lower bands like 80 and 40m.

I've had countless "antenna interventions" with friends using the 9:1 type end feds, wondering why they aren't making any contacts and I'll loan them a resonant half wave end fed and its usually a night and day type of improvement. You don't need a counterpoise on a resonant half wave end fed or a ground connection, except for grounding your feedline to meet NEC or for lightning protection.

A resonant half wave end fed is not necessarily a space saving antenna, it needs to be a half wavelength long on the lowest band you want to use, but it can be shortened some by using a trap or loading coil. For example, an 80-10m version is about 133ft long but you can use a 40m trap about 63ft down the wire from the transformer and now the 80-10m version will be about 110ft long and you can custom tune the 80m portion for the CW or phone portion of the band.

If you have less space you can make a 40-10m version which is about 63 ft long or a 20-10m version about 32ft long. If you interested in making one I can post links to the transformer instructions or you can check these mfrs: EFHW-Multi Band Archives - MyAntennas.com

Par EndFedZ® Antennas | LNR Precision Inc

https://www.hyendcompany.nl/

A couple of nice things about MyAntennas is he makes them up to the 2kW level and will sell you just the transformer if you want to use your own wire.
prcguy


Hi all,
I am thinking of putting up an end fed antenna. I have never used one of these antennas, always used a windom. Due to space, i need something a little smaller and was thinking about this antenna.
I am looking for comments from users that have used one and any pointers.
Do i need to install a counter-poise wire or just a ground round attached to the ground lug on the un-un box?
Thanks for all your input.
Danny
 
Last edited:

TheSpaceMann

Member
Joined
Apr 3, 2014
Messages
1,302
End feds can work quite well! I've used an Ultimax 100 with only 24 feet of wire, with surprisingly good results. Longer wire lengths will perform even better, and they can be bent at 90 degree angles if necessary!
 

K7MEM

Member
Joined
Dec 16, 2013
Messages
341
Location
1158 W. Valley Circle, Ash Fork, AZ 86320-482
An End-Fed can be resonant 1/2 wavelength, or multiples. But they can also be resonant 1/4 wavelengths, or multiples. They can also be a random length between 30' to 150'. The difference being the feed impedance. The resonant 1/2 wavelength wires tend to have a feed impedance in the range of 3,500 Ohms and requires a 64:1 Balun/UnUn. Whereas the resonant 1/4 wavelength wires tend to have much lower feed impedance (450 Ohms) and only requires a 9:1 Balun/UnUn. On some bands you might only need a 4:1 Balun/UnUn. Whether you use a Balun or a UnUn, depends on how you are feeding it.

My End-Fed is a variation on a true End-Fed, which brings the feed point into the shack. But bringing the feed point into the shack can cause RF radiation issues. When I operated that way, my RF would get into every speaker and telephone in the shack.

Currently, I have a 92' End-Fed. I use about 20' of RG8x to the feed point at ground level, which has a 9:1 UnUn and is tied to a ground rod. A ground radial might be better, but I haven't gotten around to adding one. The 92' wire travels up to the main support, about 25', and then horizontally for the rest of the run. With a tuner, I can adjust the feed impedance for a 1:1 SWR from 80 to 10 Meters.

An End-Fed antenna has been use for many, many years. Over this span of time, End-Fed users have come up with a group of Magic Numbers. The Magic Numbers are lengths that seem to work very well for them. But for everyone else, YMMV. Below is a small list of some of the Magic Numbers that I have collected.

Magic Numbers for End-Fed with 9:1 UnUn - 40m through 10m

17', 36', 44', 49', 53', 59', 72', 88', 98', 102'

Magic Numbers for End-Fed with 4:1 and 9:1 UnUns - 160m through 10m

58', 71', 84', 107', 119', 148'

Magic Numbers for End-Fed with 9:1 UnUn - 160m through 10m

53', 59', 72', 88.5', 98.5', 124.5', 135', 146'

There are others, like 36', 44', 49', which uses a 9:1 UnUn for 40m through 10m. These lengths are included in the first list, but came from a different source. But I don't remember the source.

So depending on what your band requirements, you can use a variety of lengths that will fit your available space.

Martin - K7MEM
 

k8krh

Member
Joined
Dec 12, 2009
Messages
371
I have 2 ultimax 100, and extended the length to 46 or 48 feet, per the guy who makes them for ham use. It works good 10-40, for me, 80 OK but not the best, but I use it on digital and cw so no problem. Just unwrap throw up in a tree or pole , hook coax to it , to transceiver and go to town.
DOCTOR/795
 

popnokick

Member
Joined
Mar 21, 2004
Messages
1,904
Location
Northeast PA
The March 2016 issue of QST has a detailed review of the MyAntennas; End-Fed Half-Wave Antenna for 80-10 Meters.
 

prcguy

Member
Joined
Jun 30, 2006
Messages
8,104
Location
So Cal - Richardson, TX - Tewksbury, MA
That's a great antenna and unless you test a resonant EFHW in a side by side A/B comparison with a 9:1 type, you'll never know how bad the 9:1 types are.

K7MWM mentioned he has a lot of RF in his shack from having the feedpoint in the shack. In my experience the RF in the shack is not necessarily from having the feedpoint there, its probably from the 9:1 balun type antenna forcing a lot of RF current onto his coax and into his ground system and getting into everything.

You can have the feedpoint of a resonant EFHW in the shack and not have any problems, they don't put any appreciable RF on the coax. So far I've run 600-700W range in a fiberglass travel trailer using an 80m EFHW antenna with the transformer (the feed point) a few feet from my radio and mic with no hint of trouble.

On the other hand, years ago I tried a few different antennas off the top of my 35ft home tower. One was an SGC auto tuner grounded to the tower with about 100ft of wire over the house and another was a 9:1 type balun feeding one of the "magic" lengths of wire close to 100ft and both of these antennas wreaked my phone, TV, stereo, door bell, wiped out my DSL Internet, you name it. This was using 100W 80 through 10m.

At first I thought it was the radiating antenna wire running the length of my house and about 20ft above it. Playing with the antenna analysis program EZNEC, I modeled these end fed antennas including the complicated tower and elevated cabled trays from the tower to an antenna patching area and all the cables that attach to the tower system. In the analysis I found the grounded tower, cable trays and literally everything attached to it had as much RF current on it as the radiating antenna wire, even though I had 1:1 choke baluns in the coax run.

Shortly after that I put up a somewhat balanced antenna, first a G5RV then its cousin, the ZS6BKW at the exact same height and over the exact same area that the other end fed antennas ran. At full legal limit 1,500W I had no RF into anything, the phone was clean, the stereo was quiet, it was a night and day difference compared to antennas like the 9:1 types that force an equal amount of current into the coax or tower system.

I have also tried a resonant EFHW over the house as a temporary setup and not only did it work great, it also had no RF into anything in the house, at least at the 100W level. I have a new MyAntennas 2kW rated transformer and plan on replacing my current wire antenna with an 80 through 10m EFHW and I don't expect any RFI problems and I also expect really good performance.
prcguy

The March 2016 issue of QST has a detailed review of the MyAntennas; End-Fed Half-Wave Antenna for 80-10 Meters.
 

TheSpaceMann

Member
Joined
Apr 3, 2014
Messages
1,302
I have 2 ultimax 100, and extended the length to 46 or 48 feet, per the guy who makes them for ham use. It works good 10-40, for me, 80 OK but not the best, but I use it on digital and cw so no problem. Just unwrap throw up in a tree or pole , hook coax to it , to transceiver and go to town.
DOCTOR/795
If you use that Ultimax 100 antenna with 66 feet of wire, you'll have much better results on 80 meters!
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
65,126
Location
Virginia
I am a particular fan of terminated antennas- the folded dipoles- and in this case, a terminated long wire. These antennas offer a simple, effective method of putting up an antenna that requires no tuning, no tuners-they can be any length ( there are some minimums depending on how low the desired frequency is) plus they are good in noisy environments. I have used them in situations around the world; string them up from temporary to permanently in more weird configurations and exotic locations than I can recall- and they have invariably worked well.

.
Sounds too ideal, No?… well, there are detractors, like an automatic 3 Db loss thru the terminating resistor. There are some other quirks to them, but I think the plus’s outweigh the negatives.
.
Barker & Williamson (B&W) makes commercial versions, for industry, government and the military- though with little effort most hams can duplicate their designs easily.
.
How do they work?… As I said, I use them for work all the time- especially in the 2-8 Mhz range.
……..Anecdotally ?…Ham-wise, my first Trans Atlantic 60 meter contact was over a 60-some foot terminated long wire, 10-25 feet high, from Washington DC. Q5 S5-7 signals into the UK during the first days "Sixty" was opened in the US-- and this was using 50 Watts.
.
I’d strongly suggest looking into them as a choice.
.
……………………..CF
 

Attachments

prcguy

Member
Joined
Jun 30, 2006
Messages
8,104
Location
So Cal - Richardson, TX - Tewksbury, MA
The B&W AC-110 series is nice for military or Govt use where you may have to operate over any frequency in the HF band, however hams can do between an S unit and several S units better with a simple multiband G5RV, ZS6BKW resonant end fed, etc at the same height.

I have a B&W AC-110 that I used once and was not very happy with its performance compared to the other antennas I was testing at the time. Another problem is B&W is now charging $995.00 for the terminated long wire AC-110 series, or $1,695.00 for the cammo version, which is beyond ridiculous. You could make one with someone else's balun and a home made resistor pack for probably under $100.

I have a trip planned to the CA desert later this month where I'll be testing and tuning a bunch of antennas and I might take the B&W out again for a ride. If it performs like the last time I'll probably dump it on our favorite auction site.
prcguy

I am a particular fan of terminated antennas- the folded dipoles- and in this case, a terminated long wire. These antennas offer a simple, effective method of putting up an antenna that requires no tuning, no tuners-they can be any length ( there are some minimums depending on how low the desired frequency is) plus they are good in noisy environments. I have used them in situations around the world; string them up from temporary to permanently in more weird configurations and exotic locations than I can recall- and they have invariably worked well.

.
Sounds too ideal, No?… well, there are detractors, like an automatic 3 Db loss thru the terminating resistor. There are some other quirks to them, but I think the plus’s outweigh the negatives.
.
Barker & Williamson (B&W) makes commercial versions, for industry, government and the military- though with little effort most hams can duplicate their designs easily.
.
How do they work?… As I said, I use them for work all the time- especially in the 2-8 Mhz range.
……..Anecdotally ?…Ham-wise, my first Trans Atlantic 60 meter contact was over a 60-some foot terminated long wire, 10-25 feet high, from Washington DC. Q5 S5-7 signals into the UK during the first days "Sixty" was opened in the US-- and this was using 50 Watts.
.
I’d strongly suggest looking into them as a choice.
.
……………………..CF
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
65,126
Location
Virginia
I agree, the terminated antennas fall well short of the resonate ones. I like them because they are very tolerant of the ‘idiot factor’ (and I do not exempt myself from that austere group :) )) They are compromise antennas that have their niche- though amateurs with any antenna savvy can do better.
.
I like them because we do our HF point-to-point. The paths are known, and the losses and limitations are all factor’d into which frequency band, power levels, etc., are chosen. Hams have a much broader latitude of variables- which makers the hobby all the more interesting. That “interesting” portion of the equation is what I strive hard to avoid when setting up a station in the wilderness… I’ll save that for back home and my hobby. For what the Terminate’s do, they do well for us, and I think they have their (limit'd) niche in ham radio.
.

I totally agree: the B&W prices are outrageous! When I have submitted cost accountings of projects where we have had to abandon one or two of them on sites, the querulous inquiry’s as to how some simple piece of wire can cost so much….well-- Your tax dollars hard at work…. otherwise I would be home brewing them…..
.
As I said, this is offer’d as an alternative to the conventional antenna wisdom- :)
.
.
…………………………….CF
 
Status
Not open for further replies.
Top