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Author Topic: End Fed antenna question  (Read 1007 times)

KF7ZFC

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End Fed antenna question
« on: September 29, 2020, 01:55:55 PM »

I know that the ultimate answer to my question will be to build the antenna and see how it works. But if there is a low chance of it working better than what I have, at 80 years old I would rather not spend the energy doing it.

I am hearing very few stations. I had a conversation with Yaesu and it appears that the FT450D is working fine. It's DNR appears to be working well.

I have a MFJ 1025 Noise Canceler. I will be building a stealth outside antenna for it.

The home is in a new HOA development with very few trees. It is my daughter's and son-in law's house with a separate apartment for my wife and I. I say this so you can see I have limitations in what I can do.

I currently have an 1/2 wave inverted L antenna for 20m. It is about 10 feet high and about 8 feet from the house and the horizonal section is hidden in a string of outdoor lights.  The end of the lights is connected to the home. The home, in Chandler AZ, is the typical Arizona stucco house which has "screening" to which the stucco is applied. The house next me is about 12 feet from my antenna.

An extensive radial system is at the base of the vertical section. About 70 radials about 11 feet long. Their length is due to limitations of where I am on the property.

I have room to run an end fed about 60 feet long but at only a height of 10 feet or so. I have a FT450D which as a 3:1 capable antenna tuner and a MFJ 939K antenna tuner.

Will there be any improvement in using an end fed antenna at such a low height?

To repeat my opening line: I know that the ultimate answer to my question will be to build the antenna and see how it works. But if there is a low chance of it working, at 80 years old I would rather not do it.
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N7EKU

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Re: End Fed antenna question
« Reply #1 on: September 29, 2020, 02:33:20 PM »

Hi,

Are you aiming for an antenna for the 20m band?  If so, I think you could do better with a small change to your current one.  With a good radial field like you have, for a 20m antenna you only want it 1/4 wave long, so 5m long.

As it is now, you have an inverted L for the 40m band -- OK if that is what you want.  Trying to tune it on 20m would give you a lot of losses because it would have a very high input impedance, thus very high SWR at the feedpoint.

I think in the late evening/night/early morning, your current antenna should find many 40m state-side stations and some DX too.

For better reception, if you can get 60' in the air I would aim for a dipole.  This should work even better for state-side contacts, and should tune up fine on both 40m and 15m.

73,


Mark

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Mark -- N7EKU/VE3

KF7ZFC

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Re: End Fed antenna question
« Reply #2 on: September 29, 2020, 02:43:03 PM »

Mark

Thanks. It is cut for 1/4 wave (my error) 20m antenna. SWR is about 1.2:1 from 14.225 to 14.350

There are no tall trees and the HOA would not allow any antenna that is visible. My ten foot antenna support looks like it supports my outdoor light strip and has fake ivy leaves on it.

The reason I am asking about and End Fed is most are multi-band with a tuner

73
Steve
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W1VT

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Re: End Fed antenna question
« Reply #3 on: September 29, 2020, 02:48:19 PM »

https://www.azleg.gov/ars/33/01808.htm
Arizona has a flag law.
B. The association shall adopt reasonable rules and regulations regarding the placement and manner of display of the American flag, the military flag, the POW/MIA flag, the Arizona state flag or an Arizona Indian nations flag.  The association rules may regulate the location and size of flagpoles, may limit the member to displaying no more than two flags at once and may limit the height of the flagpole to no more than the height of the rooftop of the member's home but shall not prohibit the installation of a flagpole in the front yard or backyard of the member's property.

Installing a flagpole in the front yard or backyard and using it ans an antenna usually results in improved reception by creating space between noisy household electrical and electronic devices and the antenna.

Zak W1VT
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KF7ZFC

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Re: End Fed antenna question
« Reply #4 on: September 29, 2020, 02:53:11 PM »

Zak

Back yard has a large pool and hot tub. No room for antenna or radials there

73
Steve
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N7EKU

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Re: End Fed antenna question
« Reply #5 on: September 29, 2020, 04:18:13 PM »

Ah I see,

If you don't mind purchasing, the MyAntennas brand gets good reviews and seems to tune up easily on all the designed for bands.  It's also is set up for use without a radial field which can keep things simpler.

Low height is not great, but better than nothing.  Plus it will get you more bands.  In addition, "more wire in the air" is always good to shoot for!

73,


Mark
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Mark -- N7EKU/VE3

W4FID

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Re: End Fed antenna question
« Reply #6 on: September 30, 2020, 04:24:38 AM »

I have an end fed Ultimax DXtream antenna in my attic. They make them in various lengths from 24 feet to about 130 feet. You choose when you order. Mine is the 33 foot one that's 14 feet high and as I said inside the attic hung about 6" below the ridge pole. Fed with 55 feet of coax snaked along the baseboard of 2 rooms of the house and up a corner into the attic. NOT much of an antenna by "textbook" standards. But it works very well. I check into SSB nets easily running 100 watts and work lots of DX on FT8 running 20 to 50 watts. Some on 80/75 and 60. Lots on 40 and 30 and 20. 17 and 6 are good when they are open. So the 10 feet high you can do will work. They are very well made and not too expensive so pick whatever length that's good for your yard and go for it.
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KF7ZFC

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Re: End Fed antenna question
« Reply #7 on: September 30, 2020, 06:48:07 AM »

Thanks John I will check them out

73
Steve
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KL7CW

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Re: End Fed antenna question
« Reply #8 on: September 30, 2020, 12:03:25 PM »

I am only 79 years old, but my wife and I often visit AZ and CA and usually I take my 1.5 watt CW QRP rig.  Results from our relatives houses, which are similar to your situation, are sometimes marginally OK, but 80 % of the time when we visit CA, AZ, OR, Norway, the UK, etc. I never even bother trying to operate from the house.  I simply walk to a nearby park, hiking trail, or whatever with my battery powered rig and have a blast often making dozens of nice CW QSO's in several hours.  It's easy in Europe or the NE part of the US, but even from the Phoenix area sometimes is successful on 40, 30, or 20 meters.  Noise level is near zero once you are a few hundred meters from civilization. Propagation is not nearly as favorable as it was a decade or more ago, but still not hopeless near the bottom of the cycle.  SSB will be more difficult with low power than CW or digital, but some folks have had some success with 5 to 15 wats and compromise portable antennas. I would do some listening tests before spending big dollars. As Zak suggested, get your antenna away from houses as much as possible.  Even going from 1 foot to 8 feet away may make a significant difference in RX noise.  On a nice day you could even take your rig outside and hook a temporary antenna right to the antenna terminal for RX noise tests.  If you can find a place where you can receive OK, then you can think about the TX problem.  With two houses so close to and probably absorbing much of your TX energy, it does not look promising, but strange and unexpected things do happen.  First of all a 10 foot vertical with a remote ATU right at the base of the vertical, even with your radial system, should tune and radiate OK on 20, and better on 15, 17, 12, and 10 meters.  If you could make the vertical part a few feet higher 20, 17, and 15 meter performance should improve.  I am concerned about your present set up.  The horizontal 6 feet is right next to the light string which goes into the house.  There is a high probability that noise pick up from inside the house, rather or not the string is plugged in, is coupled to your antenna.  Why not stop the active light string a few feet before it reaches the end of your wire, then just use a fake not hooked up light string in parallel with your 6 foot wire.  Now you have a 16 foot radiator which with a remote ATU which should at least tune up and radiate well on 14 MHz and higher, and may even tune up on 30 and 40 meters, just read the ATU info and it should tell you what the minimum length of wire is recommended for each band.  If you can get a total length of about 26 feet (10 vertical feet and 16 horizontal) I have found it works well on 20, 30, and 40 meters, (at least out in a park away from buildings).  Remote ATU's have some loss, but many hams find them very useful for at least being able to match many non resonate wires.  I am not recommending you jump into buying a remote ATU until you do some more investigation.  I am sure that for many more years when we visit our kids and grandkids in many states and countries, we will continue to walk to a park and my wife will read, knit, or work crosswords while I operate QRP CW.  It is a bit tough in AZ in the summer, but still possible for a few hours in the morning, and even northern Norway and here in Alaska in the winter, is still possible some days for a few hours with lots of winter clothing.  Due to poor propagation, I finally retired my 1.5 watt QRP rig for an Elecraft KX-2 which puts out up to 10 watts.  If you have not tried CW, a 5 watt rig works at least as good as a 100 watt SSB rig.            Rick   KL7CW
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KF7ZFC

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Re: End Fed antenna question
« Reply #9 on: September 30, 2020, 01:28:15 PM »

Rick

Thanks for all that info.

I have a auto antenna tuner in my house. The 1/4 wave inverted L has low SWR (1.2:1) without the tuner.

A 16 foot vertical will have the HOA police at the door quickly. The walls separating the houses is only 6 feet high

The suggestion by W4FID to use an end fed antenna is easy to accomplish. It will also give me 53 feet of wire in the air rather about 18 feet.

I disconnected the light string:  At 1 PM 40m noise was S5 and went down to S3. Noise on 20m was S3 and went down to O

Thanks for the suggestion. I thought the switch would disconnect it enough. If I put a switch that disconnects even the ground would that work or would that be dangerous with a storm with lighting?

I will have the noise canceler antenna up by this weekend to help reduce residual noise and noise in the evenings.

Thanks for suggestions
Steve
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KL7CW

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Re: End Fed antenna question
« Reply #10 on: September 30, 2020, 03:28:30 PM »

Steve,  Glad I could help. When you said you disconnected the light string, I assume you just unplugged it.  If this is the case it helped, but still the string was coupled to your antenna, so noise was still probably still reaching your antenna via the capacity between the light string and the antenna, and who knows how much power is lost by the unplugged light string stealing some of your TX RF power.  The far end sections of any type of antenna are very subject to significant loss by even being feet away from the ground, trees, or wires, so we always try to especially keep the far end as clear as possible from any object, and at least a few feet as a minimum.  Not sure about electrical code, but as a minimum why not just unplug the string.  If at all possible, I would just end the light string a few feet before your antenna, and if necessary just put up a section of dummy lights to hide your wire, and it would just look like part of the lights are burned out.  Lightning is a real concern, and I doubt that switching both AC leads, vs only the  positive one makes a difference.  Your antenna is low, so lightning risk is not high for a direct strike, but even nearby strikes (even a block or more away) can still zap electronics, so the safest path for now is to disconnect your coax, preferably outside the house until you are ready to operate.  Recently I repaired a transceiver belonging to a friend in AZ who forgot to disconnect the coax from his low antenna during the lightning season.  He stated there was regional lightning but nothing real close.  He was lucky, only zapped a few diodes and the repair was free.  If you can make your antenna RX ok, probably half of your problem has been solved, however I will not promise you all will be OK for the TX portion of your antenna.  On occasion I have had situations where the probability of success seemed remote, but were successful, and at other times what looked like an ideal set up failed to even generate a few contacts.  If you can make an antenna work at all on 75/80 meters, it will radiate much of it's power nearly straight up.  During the day, especially in the non summer months, even with our low sunspot number, this band often will support local and regional QSO's on 75 SSB out to say a hundred miles easily with 100 watts, and often even with my QRP SSB rig.  At this point in the sunspot cycle, often these NVIS contacts do not work in the evening hours, but hopefully in 3 or 4 years, even in the evenings 75 meter SSB signals should often be just fine in the evening all the way from local to several or even many hundreds of miles with a low antenna.  Good Luck  KL7CW
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W4MKH

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Re: End Fed antenna question
« Reply #11 on: November 17, 2020, 07:04:20 AM »

Not sure of the size of the yard or if DX is really important to you or not.

But have you considered an 80m NVIS wire antenna? The antenna should tune on all the higher bands and it would have no problems with staying under the 6" wall height so the neighbors and HOA won't notice it. It would allow you to talk out a few hundred miles and sometimes pick up some DX when all the atmospheric conditions line up.
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WB6BYU

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Re: End Fed antenna question
« Reply #12 on: November 17, 2020, 07:52:37 AM »

A few thoughts...

1) the light string may introduce some losses if
it is closely coupled to the wire, especially the
older types with incandescent bulbs (resistors).
(Not that the LED types are necessarily any better.)
But that may be unavoidable if you want the
string to remain functional.

2) the stucco will act as a reflector on 20m, so
consider which side of the house the antenna
is mounted on and whether the house will block
radiation in desired directions.  If the antenna
is on the SW side I’d expect you to hear a lot
fewer signals than on the NE side.

3) you can try running a wire along the top of
your fence (especially if it is wood) as a quick
way to check reception on such a wire, even if
it doesn’t have the same matching network.

4)  the noise pickup antenna for a noise canceler
should be positioned to pick up maximum noise
and minimum desired signal
.  If your major
source of noise is inside the house, that would be
a better location for the noise antenna.
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