Beach QTH antenna tests

[WA1GFZ]

1. first test a 200 foot inverted L facing West. 65 feet vertical. Worked well but high noise.

2. lazy Vee, a VEE on its side open end to the West. Imagine a discone with a radius slice out of it.Heard Bob W2ZM holding ZL court Sunday morning on 75 and 40 m SSB. Seems to work well. I didn't have a tuner but remembered I had a couple cores from W3JN in the back seat pocket and wound a BB transformer to interface balanced antenna. Feed at 65 feet top of the hill. one element to the west at 60 feet and the other at 8 feet. Seems to work well but locals down. If I connect one side as an inverted L locals come up. Bob was hearing ZLs a bit over S9 and I was hearing them about 30 dB above a microvolt. An antenna tuner would have matched Bob's RX performance.
3. dipole with drooping ends. feed Line too heavy so feed at only about 45 feet. Did not bother to test.
TO DO:
A. KB3AHE antenna twice as long?
B. The wire should be pretty brown the next trip south and people next door will have some time to look at it. Get up BAs to ask if I can use their tree. That would give me a sloping VEE to the SW 125 feet on a leg with about 100 degree angle. Still a bit of shine in the wire today. Salt air do your thing.

Interesting the Western union splice on my primary older than me seems quiet. There is another one down the street on the secondary that powers a couple houses. I imagine that wire runs hot around supper time. Both are green as Lady Liberty.
 

[The Slab Bacon]

I would be very curious how a "double length" antenna like mine would work. But if I had 120' to play with, I'd just put up a simple flat top fed with ladda line.

                                                The Slab Bacon

[WA1GFZ]

Frank,
I was about to try it when I found the #8 ladder line was too much weight on the center of the antenna pulling it down to about 45 feet.
I then went back to end feed so the line was supported at 65 to 70 feet at the top of the hill. The next door neighbors were not home so I pulled the wire across the back of their lot. Sure enough the big oak in the corner is the perfect tree to hold up the Vee. When the wire gets brown I will ask. They are very nice people. They set me up with the contractors I used. They are about the last people on the planet I would want to make unhappy.......The perfect people to have next door watching things.
You were putting in a good signal I think it was Saturday night.
I hope to get the V2-CDC down there soon with a flash box. fc

[W8EJO]

I'm curious about the 200 inverted L. I'm contemplating this very antenna since I took down my 380' doublet.

You said you got high noise. Is your QTH a high noise environment?

I have no noise issues where I live & could probably go 80' vertical x 120 horz. (40% vertical x 60% horz.).

Then I read where ON4UN says the ratio of vertical to horizontal is important for DX work.
 ON4UN quote in his book "...the longer the vertical part of the (inverted L)
antenna, the better the low-angle radiation characteristics of the
antenna..."  (For 160), a 60' high 1/4 wave inverted-L is about 46% vertical while a 60' high 3/8 wave inverted-L is only 30% vertical, so it (the 3/8 wave) really works much more like a low dipole than a vertical. 

Im going to feed it at the top corner with open wire & attempt to use it on 40, 80 & 160. After I read ON4UNs comments Im thinking I may be better off with a 3/8 wave (on 160), 80 x 100 inverted L. That would get me to nearly 45% vertical.


Terry
W8EJO



 

[WA1GFZ]

Terry,
It appeared as background noise. Signals were also stronger on top of the noise. I'm in a neighborhood next to a state park. Town is a few miles away. I may also put up an inverted L or feed the Vee as a L.
This would just be a switch in the shack later. That is why I tried the L first. The lazy Vee has problems with local signals so I just used the top half as a inverted l and locals come up. So bottom line the L does appear to do well with high angle signals. Nothing was matched. I just had a 6 dB pad on the RX and direct connected the L and used a BB transformer on the Vee.
I've used inverted Ls before and they work quite well if you have a good ground. Another cool looking antenna is the center fed inverted L.
Check Cebik site. The enter fed inverted L gave me the idea for the lazy Vee. The cool thing is it is balanced and does not need a ground system. My ground system is pretty good. I have 500 feet of #8 in the ground some terminated in water. A salt marsh is across the street in the park. gfz

[W8EJO]

Another cool looking antenna is the center fed inverted L.
Check Cebik site. The enter fed inverted L gave me the idea for the lazy Vee. The cool thing is it is balanced and does not need a ground system.  gfz

My QTH is ideal for the center fed inverted L so I will give it a whirl. Besides, the idea of laying down many, many radials wears me out.

I'll get the vert. section as high as possible (I have an 80' tree next to the house). Ill make the horz section 100' to start (total of about 3/8 WL on 160) & see what it does on my bands of interest.

Terry
W8EJO

[WA1GFZ]

http://www.cebik.com/radio.html


check this out. A center fed inverted L is a T another good antenna.
I will have plenty of room for an inverted L if my neighbor lets me use his tree. I like a balanced antenna system so like the idea of the center fed inverted L.  160 meter dipole at 60 feed is all high angle so the L will be good for the long haul.

[WU2D]

My main TX antenna is a 220 ft east-west Inverted L with about 50 ft vertical. I feed it thru my bulkhead with a big insulator. I have a single counterpoise under it that stretches out  250 feet which is buried a few inches. I have a single ground rod at the bulkhead.

During the winter I put 10 ground radials out for 80M and 40M (66 ft and 33 ft) in a fan under the antenna.  I roll these up in the summer.

With a HB motorized tuner in the bulkhead, this antenna works very well on 160 and quite well 80 and 40 and pretty well on 20. It will load on the other bands but works like a longwire favoring the west.

Is it as good as a high dipole fed with ladder line - absolutely not; but is is a flexible antenna.

On RX it is noisy. Probabaly worse than a dipole. So I use a short beverage which makes a great RX antenna without too much directivity. 

Mike

[Steve - WB3HUZ]

The 3/8 wavelength antenna is nice in that it will work well on 160 and also as a self-resonant 3/4 wavelength antenna on 80/75 meters.

If you want good local coverage for AM rag chewing on 160 meters (out to about 300 miles), it's hard to beat a dipole. A 3/8 wavelength Inverted-L, with more horizontal than vertical will likely give local coverage close to a dipole and probably work better at distances beyond 300 miles. It won't work as well at the longer distances as a 1/4 wavelength L or a 3/8 wavelength L that is mostly vertical.

The dipole/T approach is the most versatile in that you get good local coverage when configured as a dipole and great DX coverage when configured as a T. A fairly simple switching arrangement and two preset tuners would allow for quick change-over and signal comparisons. I had this set-up (minus the quick switching) at a previous location. The T arrangement was vastly superior at distances beyond about 400 miles. On one 500-600 mile path it was the difference between no copy (on the dipole) and Q5 (one the T). But the T configuration killed very close in signals due to the null in the pattern at 90 degrees. Beyond 50-100 miles, the T still worked OK, but not as good as the dipole.

Any unbalanced antenna (L, T, etc,) will need ground radials to be fully effective.

I'm curious about the 200 inverted L. I'm contemplating this very antenna since I took down my 380' doublet.

You said you got high noise. Is your QTH a high noise environment?

I have no noise issues where I live & could probably go 80' vertical x 120 horz. (40% vertical x 60% horz.).

Then I read where ON4UN says the ratio of vertical to horizontal is important for DX work.
 ON4UN quote in his book "...the longer the vertical part of the (inverted L)
antenna, the better the low-angle radiation characteristics of the
antenna..."  (For 160), a 60' high 1/4 wave inverted-L is about 46% vertical while a 60' high 3/8 wave inverted-L is only 30% vertical, so it (the 3/8 wave) really works much more like a low dipole than a vertical. 

Im going to feed it at the top corner with open wire & attempt to use it on 40, 80 & 160. After I read ON4UNs comments Im thinking I may be better off with a 3/8 wave (on 160), 80 x 100 inverted L. That would get me to nearly 45% vertical.


Terry
W8EJO



 

[WA1GFZ]

I like the idea of starting with a balanced antenna and just by swapping tuners change to a low angle radiator. I wonder if my next door neighbor will enjoy the mode change with his phone lead coming into his house 30 feet away from the feed line. The good thing is the feed line comes down right over my two service ground rods bonded to the ground system. On top of that right next to one of the master bedroom windows with the breaker panel just below. I'll try for a spot in the bedroom till I make XYL crazy then drop into the basement. I'll try to be a good boy for now and not take too much space upstairs. But this disease spreads fast......

 

[W8EJO]

I just finished reviewing all of W4RNL's modeling work on the inverted L. It is very impressive.  He has at least 4 excellent papers on the subject including a lot of modeling work on the center-fed versions  both 1/2 wl & 3/8wl.

His data indicates that radials under a center-fed 1/2 WL or 3/8WL are as useless as tits on a boar with differences in gain between no GP & 20 radials of about .17dBi.

His plot patterns also indicate that the center-fed L is better than the "T" for close in work & nearly as good as the T for DX work. [See the second plot pattern down here: http://www.cebik.com/wire/ltv.html]

He's done all the modeling work to convince me that the 3/8 WL inverted L cut for 160 (dimensions of about 90 x 90) would be a great all around low band (160, 80 & 40) antenna.

Now I have to figure how to get the wire over the two big trees. I've used the bow & arrow technique & the spinning rod technique at lower heights (50 - 60 feet) with great success. I don't think the spinning rod will go that high.

[flintstone mop]

Well GFZed,
If your neighbor doesn't have a radio receiver for a telephone, he'll never know you are there. Sounds like the work I put into an "L" might have been a waste of time. Seems like for distance work or CW a vertical is the answer. The SSB contest at the end of Feb. proves how rough it is to try to hear anything over the noise and the distance, even on a "quiet" night, 160M. I worked Bill KD0HG in Colorado one fine night on 3860 and it was nice to get beyond the 500 mile limit, but the copy was far from "armchair". This was the RST we both experienced.
fred

[WA1GFZ]

I use a 75 pound hunting bow with the spool of fishing line on the ground. The larger diameter spool feeds line off easier. I can easily clear 100 feet.
Yup the center fed l is an interesting antenna. Many years ago the old Signal corps friend W1JF (SK) who spent many hours helping me do CW suggested it to me.
I have used the lazy V before...not the greatest antenna but works.

[Steve - WB3HUZ]

I just finished reviewing all of W4RNL's modeling work on the inverted L. It is very impressive.  He has at least 4 excellent papers on the subject including a lot of modeling work on the center-fed versions  both 1/2 wl & 3/8wl.

Sounds like this is just a dipole, in which case is is not fed against ground. In this case, yes radials are of much use. But if it's fed against ground, there no way to get around the ground diplacement currents and the associated loss without radials.

[WA1GFZ]

Old W1JF said just picture it as a ground plane up side down

[WU2D]

Frank,

Are you trying to say that it is a ground plane fed at the top (voltage fed)?\

Mike WU2D

[WA1GFZ]

He told me to connect the shield to the horizontal wire and the center conductor to the vertical lead. Cebik uses open wire line. I've never tried it though.

[W8EJO]

I used a bow to go over the tall trees this morning. First shot both ends, no problem. I feel like  William Tell.

The tree at the end of the horizontal run is about 80' high & the tree supporting the vetical section is about 90' high so the horz. section angles down but just slightly. The vert. section touches the ground so Ill have to lop a few feet off, maybe 5-6' & maybe do a bottom cap hat if 160 is a problem.

I'm feeding it at the bend in the L with ladder line.

If conditions are decent tonight I'll give it a test run.

[KB2WIG]

        "  I used a bow to go over the tall trees "

Some prefer the bow, some the swinging choke... I like the pipe wrench as its got a hole in the end to tie things to, and the mass to fly through the branches.... ..   klc

[WA1GFZ]

Very cool Terry that would be similar to the configuration I would use.
It might be short for 160 but good for 75. Cebik suggests at least 3/8 wave.
BTW my first shot bounced off my new 50 year roof so the thought of a pipe wrench makes me feel sick. I use a 2 inch long 3/8 bolt....I think it is a small bloch chevy intake bolt. I tape it to the end of the arrow. Compound bow at 75 pounds does the motivation.  gfz

[W8EJO]

I used a kid's Bear recurve bow. For the arrow, I unscrewed the arrowhead & screwed on a single bolt - just enough weight so it would tip downward pretty fast when it reached it's apex. I used a limp 12 lb. test monofilament fishing line. It was actually very easy.

I made a few 40 meter SSB QSO's last night with very good reults but need to work on 75 & 160 matching.

I use a 2 inch long 3/8 bolt. Compound bow at 75 pounds does the motivation.  gfz

[KB2WIG]

 "  BTW my first shot bounced off my new 50 year roof so the thought of a pipe wrench makes me feel sick.  "

?Use a cresent wrench???    klc