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Author Topic: End feed non resonant inverted L wire with 9:1 unun configuration  (Read 386 times)

GEORGEMINK

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I live in a restrictive HOA neighborhood and been putting my antennas in the attic. I recently put up a Moonraker GP80 which is basically an end fed 19' vertical with a unun in the back yard. I have it set up where I can take it down when needed attached to my privacy fence at 5'. I painted it with flat paint and it really isn't all that noticeable. So far no complaints from the neighbors and no nasty letters.

With all that said I'm thinking I could probably get away with a long wire in my back yard in place of the vertical. Maybe even have two 20' poles on opposite sides of my fenced in back yard mounted on the fence like I have the vertical giving me about 25' in height. I could manage about 60' between the two poles.

I'm thinking about an inverted L configuration with the unun at the base of the pole giving me about 85' of wire.
I have 90' of coax run out of the house to the antenna location to act as a counterpoise.

I could also do a sloper and only have the one pole, or with the two poles have the far end hang down the 25' giving me 110' of wire length.

I know a dipole would work better but then I'd have the coax hanging down in the middle of the yard and I think it would
be more conspicuous as well.

Just curious how you would set up the antenna in the same situation?     
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WB6BYU

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #1 on: December 21, 2022, 07:11:56 AM »

Probably the most important question is,
what bands and distances are you most
interested in working?

Every antenna involves a set of trade-offs,
and each ham will have a different set of
operating preferences with respect to bands,
modes, time of day, and what stations they
are most interested in working.  All of those
need to be factored into choosing an antenna
that will work satisfactorily for your interests.

If your interest is chatting with locals, on
80m, then one of the longer wires will certainly
work better.  For working DX on 20m, the
vertical by itself may be better (although
improving the ground system will help).
On 10m, the longer wires will be noticeably
directional (with maximum radiation more
off the ends rather than broadside to the
wire), so if you are interested in a specific
direction then you will want to make sure the
wire is oriented accordingly.

Generally I’d probably choose the ~85’ wire
as a reasonable starting point, using two
supports rather than a sloper configuration.
But that choice is based on my personal
operating preferences, not yours.

I’d also try to improve the ground system
by adding radials, and consider putting a
tuner at the wire feedpoint, even if it meant
having to walk out to the antenna to switch
bands, rather than using the unun with a
tuner in the shack.  But, again, as a QRP
operator I’ve always wanted reasonable
efficiency from my antennas:  running
100 watts you likely will radiate more
power with just about any antenna than
I do with 5 watts to an optimized antenna.
That’s another example of how personal
operating preferences make a difference
in antenna selection.


Edited to add:

Looking at the description of the antenna,
I notice the manufacturer says the SWR is
1.5 : 1 on 80m, but it requires a wide-range
external tuner.  That might be a clue that
the technical specifications should be taken
a pinch of a large bag of salt.
« Last Edit: December 21, 2022, 07:16:50 AM by WB6BYU »
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GEORGEMINK

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #2 on: December 21, 2022, 08:02:46 AM »

You are right I should have mentioned, I'm interested in covering as many bands as possible.
I'll talk with anyone including local, but would like to do some DX as well.
Would really like to do 80-10m full coverage. I've never even heard anything on 6 meters so don't know if I have any interest in that.
I have 2 meter J pole in the attic that does 70cm too. I already have 36' end fed in the attic but it's very noisy. 

I have a couple of antenna tuners a FMJ 939 for use with my Yaesu FT991,
I have a Xiegu G90 that has a tuner built in, and I just purchased
a LDG AT-1000PROII to use with my Drake TR7 and hopefully an Amp down the road.

I'm only in listen mode right now, planning on taking my general exam after the 1st of the year.
I was licensed years ago as a kid in in 1975, and got my general license when I was 12 in 1977.
Excited to get back on the air.
« Last Edit: December 21, 2022, 08:06:26 AM by GEORGEMINK »
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N6TTV

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #3 on: December 21, 2022, 09:35:56 AM »

I have used a 9:1 unun with non-resonant wires of 41 ft, 55 ft, and 83 ft depending on the site and have had good results running 5 and 10 watts. My K-2 and KX-3 have wide range tuners and I usually use a short counterpoise laying on the ground. Carl, N6TTV.
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GEORGEMINK

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #4 on: December 21, 2022, 09:56:00 AM »

I have used a 9:1 unun with non-resonant wires of 41 ft, 55 ft, and 83 ft depending on the site and have had good results running 5 and 10 watts. My K-2 and KX-3 have wide range tuners and I usually use a short counterpoise laying on the ground. Carl, N6TTV.

Thank you Carl, I've been watching Youtube videos like Coastal waves and wires and he has great luck with end feds. He is actually why I purchased the Moonraker GP80 that is what he uses at his QTH with good results.

What configuration do you typically use a sloper or straight?
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N6TTV

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #5 on: December 21, 2022, 12:38:28 PM »

The configuration usually depends on what supports are available where I set up. I guess I'm partial to straight, sort of inverted L. Last time out I used inverted U, threw it right over a tree. Also I would think the combination of your vertical with a more or less horizontal wire and a way to switch back and forth would be great. Good luck, Carl, N6TTV.
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GEORGEMINK

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #6 on: December 21, 2022, 01:19:55 PM »

Also I would think the combination of your vertical with a more or less horizontal wire and a way to switch back and forth would be great. Good luck, Carl, N6TTV.

That is what I'm doing now, I've got the 36' end fed in my attic which is run North to South mostly horizontal and switch back and forth to the vertical to compare signals. Never can tell which is going to pull in the week signal better.
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GEORGEMINK

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #7 on: February 25, 2023, 04:47:18 PM »

Update: So I ran a 107' inverted L using a 22' fiberglass pole from MFJ at 25' but was uncomfortable with the wire height at the low end. Much improved reception (which I anticipated) over the 35' end fed in my attic. Never got any letters from the HOA and none of the neighbors said anything so last weekend I put up a second 22' support on the other side of my privacy fence and ran a 124.5' wire in an inverted U configuration. WOW what a difference on the lower bands. I purchased a VNA 4H analyzer but have yet to tune the length since it's been raining on my days off. Still studying for my General License so have nothing to report on performance or QSO's.

The day before yesterday I had a knock on the door, I was on the phone working so by the time I got to the door they had left. I thought it was probably a salesman since that's usually all we get knocking. Turns out it was my neighbor behind me, he saw me in the yard and came out his back door as asked "Is that an HF antenna?" I thought my luck had taken a turn for the worst. Turns out he was the one that had knocked on my door. But to my surprise he is a ham too! All of his antennas are in his attic so I never knew. He also informed me that my section of the neighborhood is NOT part of the HOA and how lucky I was to be able to put up an external antenna.

So not only do I feel confident that I'll be able to keep the antenna up but I have a new Ham friend! Didn't catch his call sign but he invited me to check out his Icom 7300 setup which I'll take him up on. Just thought it was a interesting story that I wanted to share.

73's       
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ONAIR

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #8 on: February 25, 2023, 05:03:13 PM »

Can you use a rain gutter?  I have had luck using rain gutters with a 9 to 1 unun in the past.
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GEORGEMINK

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Re: End feed non resonant inverted L wire with 9:1 unun configuration
« Reply #9 on: February 25, 2023, 05:11:42 PM »

Can you use a rain gutter?  I have had luck using rain gutters with a 9 to 1 unun in the past.

I don't have a long run of gutters on my home. Only a short run over the doorways. I posted the question about using my aluminum trip that wraps around the eves as an antenna but got mixed responses so I nixed the idea.
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