TopBand: Summary of responses to Utility of a non-terminated Beverage
lew@teleport.com
lew@teleport.com
Fri, 22 Nov 1996 04:02:42 -0800 (PST)
To the TopBand reflector:
I received a wealth of responses to the recent question I posed about
utilizing a non-terminated Beverage. Below in random order is a summary of
the more cogent responses. Thank you for the interest!
Lew Sayre W7EW/N7AVK lew@teleport.com
P.O.Box 3110 Fax 503-391-2258
Salem, Oregon 97302 160M thru 1296MHz
The Original Question:
I understand that terminating a Beverage makes it unidirectional. Has
anyone utilized a non-terminated Beverage in order to use it for 2
directions? The test case would be a 580',single wire with sloping ends at
6' height oriented shortpath (30deg.-EU) / longpath (210deg.-VK\ZL) as
referenced from the West coast. Would anyone expect this set-up to
function good enough that the effort expended:gain realized ratio would be
worth it? Tnx.....73 and I remain, Lew
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Hi Lew,
I use unterminated beverages here and they do work in both directions,
however they perform better in the direction they are pointed. I have
tried them terminated and my ground is so bad that it didn't seem to make
any difference. They do seem to have more front to back if they are on
the ground. 73, AL K7CA
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Yes and You bet! You won't have gain, though--just good F/B--Turn up the RX
RF. Once it is up, rig it with a quarter watt resistor (about 470 ohm)
between two clip leads and experiment. Clip to ground stake at night or AM
depending on which way it faces. Remove at other times. Try it, you'll
like it.
73, Charles - N5UL - New Mexico
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>It works great for me, Lew...
73 Steve AA4V
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Lew, a bi-directional beverage defeats the pupose. The idea is to be
uni-directional and get that f/b rejection. Why not try inserting the
termination at either end like K1VR did in his 73 magazine article.
73 Craig
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Lew: Yes, it would be worth it. -- Fred K1VR
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Lew, Hello!
I used 2 bi-directional beverages here for about a year or so, until
the guys started clearing the woods about 750' down in the swamp from
my place one day................The next day I noticed a B I G jumble
of wire from the remains of my SE/NW beverage. (sigh)
At least it was still one peice of wire.
Luckily my main 1000'-er is still up favoring NE/SW
(no cutting in that direction). I find I can still here to the SE a
bit on it, but not near as good as my dedicated SE/NW one.
Anyway, the remaining one is unterminated. All looped through trees
down into a swampy type area @ about 12-15' above the ground.
Not in a perfectly straight line either because of gaps in the trees.
Geuss you take what you can get when it's a stealth antenna NOT on
your own property, hi!
It's no.#12awg insulated stranded wire. I did not impedance match it as
the gain of the thing was very good, and I didn't feel it neccessary.
No ground rods at either end. I just fed it with a short 50' chunk
of rg58 cable! On an s9 signal from EU, the beverage is usually about
s5 or so, and a bit quieter. I say only a bit, as I think maybe 15'
is a bit high, and what w/o the impedance matching, and all, I may
have "too-much" gain if that is possible. It really kicks butt down
on the LF bands. VLF, AM broadcast etc. Much better than my inverted
L, hi!
My inverted L is more horizontal and slanted than vertical so it is
not real noisey to start with.
GL and CU on TOP!
-MIKE
Michael & Coreen Smith (AA Antennas & Wynder Photography)
http://members.tripod.com/~ve9aa/index.html
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Lew, I've tried my 700' +/- beverage terminated and (mostly inadvertently)
unterminated. I must say it shows very little improvement to the SW when
unterminated, and the SW gain appears to be offset by degradation in the
performance to the NE (the direction it's intended to operate). I'm adding
a second wire with a push-pull transformer box to make it truly
bi-directional. I hope that works better.
73, Steve K4WA
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Hello Lew. Run two Beverages, one terminated and one open, on the same
supports (separate feedlines).
73,
Bill AA6TT
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>Hi Lew, my beverage is and East/West 580 foot with sloping ends
unterminated. It works great on both
europe and the pacific for me anyway. Pete N4KW
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This is the configuration I use all the time. Non-terminated E-W.
73 Jim K9JF
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From: Bill Tippett <btippett@CTC.Net>
K4WA wrote:
>Lew, I've tried my 700' +/- beverage terminated and (mostly inadvertently)
>unterminated. I must say it shows very little improvement to the SW when
>unterminated, and the SW gain appears to be offset by degradation in the
>performance to the NE (the direction it's intended to operate). I'm adding
>a second wire with a push-pull transformer box to make it truly
>bi-directional. I hope that works better.
Steve, I observed exactly what you described when I've tried unterminating
Beverages. W8JI made some interesting measurements on signal attenuation
in 500 foot Beverages and found the signals to be severely attenuated by
the time they went that far. For the signal off the back of a 700 foot
Beverage to be reflected back to the input it travels 1400 feet! This might
explain why unterminated Beverages don't seem to work very well for signals
off their backside. Tom might have some comments on this.
73, Bill W4ZV
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Lew - suggest you check out the two-wire, switchable version of the
Beverage. I believe it's covered in the ON4UN book. If not, let me know
and I'll go look it up. One uses a phasing box to select which direction
is desired.
73, Ward N0AX
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Just a note to let you know that I am using a NE/SW
unterminated
600 ft beverage,starting the 3rd year, with
excellent results. I take it
down every spring because of hay cutting in the
field and can't wait
to get it back up each fall. It was well worth the
effort here, actually
a very easy project, it is directional, don't hear
much off the sides ,
but it sure makes a difference on 160 and even 80.
I usually have
to put mine back up 2 or 3 times each season,the
deer knock it down!
73 GL de
Lloyd Westbrook W4LSW
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Yes it works fine in both directions. If you are using it at sunrise or
sunset the back lobe does no harm as there is no propagation.
73
Bob Eldridge VE7BS,
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For the past two years I've had 5 terminated Beverages and one terminated
one. This year I'll have 6 terminated Beverages (hopefully I'll finish
installation of the final two tomorrow). I left the one unterminated
because of having problems running it long enough in one direction
without crossing a road. However, the unterminated one always had a
significantly higher noise level and rarely was used since it seldom was
better for receive. The same results occurred with 550' or 825' long
Beverages (different years) [both about 1 meter above ground level, with
very good ground conductivity here].
This year the coax will be longer (away from the road) and the
Beverage will be terminated...
73, Bill K0HA
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Lots of people use them that way, including my buddy AJ6T, to avoid the
switching and/or the far-end ground for the terminator. But my view is
that--having gone to the trouble to put it up--why throw away 3 dB of
S/N improvement, when S/N improvement was the object of the exercise?
Garry Shapiro, NI6T
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Hi Lew...I've used both terminated and unterminated, and while the
unterminated is better than whatever is in third place, the benefits of the
terminated make it by far the antenna of choice. The terminated,
unidirectional beverage offers the f/b that is needed to null out noise and
other signals from the rear.
On most of mine, I use a single wire with coax going to both ends of the
antenna. A relay box at each feedpoint connects the coax to that end when
voltage is applied (piggybacked on the feedline with a capacitor and RFC for
isolation). The other end is terminated through the NC position of its relay.
So one wire serves as a unidirectional beverage in two, opposite directions,
with the addition of just one extra run of coax.
There are also ways to reverse direction with a 2-wire beverage, using a
transformer at the far end. I have not tried, but ON4UN describes it in his
book.
73/Jon AA1K
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Lew my experience with beverages showed that an unterminated beverage was
still directional towards the end, it still had a F/B ratio and was not
at all usable in the direction towards the feedpoint. It behaved more
like a lousy unidirectional beverage than a bi-directional one.
73, Bob NW6N
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I have basically the same antenna as you - but 450ft long - ICE matching box
at west end and runs 450 ft to the east with the east end at 8ft (not
sloping). The antenna receives well from Europe and picked up ZS4TX last
night - 160M Conditions down here on the Mississippi Gulf Coast Stink most of
the time -- My Beverage hears Europe very well on 80M. Most signals on 160
from EU and AF are at or below the ambient noise -- YUK!
An unterminated Beverage has a 3db loss off the back according to the ARRL
Antenna Book. - I hear much better to the West with my sloper --
GL and 73 - Bill
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I am pleased with mine which is 600 ft, SE/NW. It is not as quiet (expected)
as the terminated one, which looks to the NE, but is a definite asset under
most conditions. When a cold front is nearby (NW) or has just passed by
(SE), it is not much good, but the terminated one is NG after a front passes
also.
For further comments, see ARRL Compendium 4. There is an article by N4KG on
unterminated Beverages.
INK N4OO (N. Fla).
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>in 500 foot Beverages and found the signals to be severely attenuated by
the time they went that far. .....
> why unterminated Beverages don't seem to work very well for signals
>off their backside.
This is paradoxical, because:
One job of the terminating resistor is to dissipate the signal from the
rear. If there is little signal to dissipate......?
The operation of two-wire Beverages depends on the reflection from the far
end. I swear they work.
Reflection transformers have nothing to do if there is little signal left to
reflect.
If loss is that high why do we need a hefty terminating resistor for a
travelling wave transmitting antenna?
My experience is that when looking into the darkness path off the far end of
a 250 or 500 ft Beverage it makes no difference whether I terminate or not.
But looking into the darkness path off the back removes the signal. So
removing the termination does not hurt the signal from the front, and
putting in on 'activates' the rear.
BUT:
This is with Beverages not longer than 500 ft (Harold Beverage said that is
the optimum length). If the Beverage were very long (several wavelengths)
you would not need a terminating resistor at all and it would not receive
much off the back end (just like the long wire antennas we used to use on
VHF - many many wavelengths.)
There may be lengths that inhibit rear end signal when the far end of the
'transmission line' is open.
Bob Eldridge VE7BS,
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