Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old September 23rd 07, 05:41 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 146
Default Beverage Antenna, Noise pickup

I was reading in ON4UNs book, a section about Beverage antennas and decided to
do some checking on mine, which is celebrating its ten year anniversary this
month.
Mine is 575 feet long, 6 feet high, with sloping ends, oriented NE.
Termination is 500 ohms into a ground rod. Feedpoint also has a single ground
rod to which is attached a potted matching transformer I got at a hamfest and
supposedly designed for this purpose. Feedline is 150 ft of RG8X which is not
grounded at the antenna but just lays on the ground in the woods. Now, this
is my first and only Beverage and there are times when I am literally amazed
at what it can do. It pulled the 3B7 out of the noise and made him armchair
copy on 80 meters when he was simply not there through the noise on the 80 m
dipole. Now I see why some times there were no stations calling him, and how
I was able to get through. I play with it on the BC band to test if it is
really directional. I use my 80 meter dipole as a reference. For example
during the day, here in NJ WBZ in Boston is nearly inaudible on the dipole but
Q5 on the Beverage. The opposite is true for KDKA in Pittsburgh, so I know it
is directional, just don't know if it could work better.

In the book they talk about how it is best if the transformer has an isolated
winding for the 50 ohm input, rather than a bifilar wound one in which there
is dc continuity between all windings. I checked mine and it does have such
continuity. So I may be replacing it with a homebrew one shortly, maybe after
I get some comments from users of this newsgroup.

Also the article warned of the effect of common mode currents on the shield of
the coax degrading the pattern of the antenna so I did a test to see if mine
was infected. It involves simply disconnecting the feedline and shorting the
end, then checking to see if there are signals to be heard. On mine I did not
hear any signals on any ham band, so went to the BC band where I heard a
couple signals. One is a broadcaster about ten miles from here. It was
audible although the S meter didn't budge. Switched to an 80 meter dipole and
it was 20 over 9. So it appears to me that my feedline is quite good, and not
picking up much common mode currents, but that is as far as I have gone. I
haven't installed any choke nor grounded the feedline out in the vicinity of
the Beverage yet. Any opinion, if I would see any difference by putting ina
common mode choke there or replacing the transformer?

Rick K2XT
  #2   Report Post  
Old September 23rd 07, 06:42 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default Beverage Antenna, Noise pickup

On Sun, 23 Sep 2007 16:41:08 GMT, (Rick) wrote:

Any opinion, if I would see any difference by putting ina
common mode choke there or replacing the transformer?


Hi Rick,

None whatever. Your tests proved your coax was being effectively
choked by the proximity of earth. However, this may change with
weather and you should repeat your tests throughout the year as the
seasons shift. Further, you may gain from the historical data I
provide below.

Another test: simply listen to the coax shield (move its connection
to the antenna input and leave the center conductor open). Make sure
to provide a good ground for your rig (in fact, you should NEVER
ground your rig through a coax if your rig has any other path to
ground). If your coax is grounded at the antenna site, you should
isolate this connection (absolutely nothing connected at the far end).

Sorry for the parentheticals, but ALL grounds should be connected
TOGETHER independently of your feedline. This may mean another 725
feet of wire (not always observed, but it is code). However, having
said this, it does not follow that you will actually observe any
improvement. It could also kill the Beverage action (due to the field
being retarded by the earth which gives rise to a sloping, traveling
wave).

As no one is probably very well instructed on Beverages (which may
include ON4UN because his readers never cite any actual historical
data), you may well do to go to the source:
Harold H. Beverage & Anti-static tuned antennas with Chester W. Rice.
''The Barrage Receiver
Using a 10 mile long wire on the ground, they eliminated static
originating in the Caribbean that masked European signals. The wire
described ran in the opposite direction of their antenna pointing
(just as yours) into central Europe.

These tests were performed nearby you (albeit 80 years ago) by RCA. If
you live in proximity to a good engineering library, I can supply many
inventors' names you would do well to research.

73's
Richard Clark, KB7QHC
  #3   Report Post  
Old September 24th 07, 08:29 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 757
Default Beverage Antenna, Noise pickup

On Sep 23, 11:41 am, (Rick) wrote:
I was reading in ON4UNs book, a section about Beverage antennas and decided to
do some checking on mine, which is celebrating its ten year anniversary this
month.


I've been thinking about putting one or two of those up this winter.
I do a lot of BC band listening along with 160m, so should be
interesting. Trying to decide what directions I want to go though..
I think Europe is probably one direction I'll go for sure, but can't
decide about the west.. I'm kind of leaning placing one basically
towards Asia, but haven't really decided yet..
I've never used them before, so it will be something new to
play with.
I'm also kicking around the idea of a new small loop to use up
there that will be quite large. I want it rotatable just like the
ones I use here at home. Will use heavy PVC I imagine.
My largest small loop here so far is a diamond 44 inches a side.
It's indoors next to me on a rotating stand. Stands almost
8 ft tall on the stand, and almost touches the ceiling.
Uses 5 turns.. Tunes 500kc-2300kc using various variable cap
configs.. Longwave if I tack on extra fixed caps.
I'm thinking about an even bigger one to use outdoors.
Maybe double the size of the present one, or even bigger.
I will use it for BC band more than anything, but will probably
rig it to cover 160m at the top of it's range if possible.
I like the loops when daytime BC listening. Very deep nulls.
Some mention using a shielded loop to aid balance, but
I've never needed to here. My conventional solenoid loops
can make a fairly strong unwanted station or noise totally
vanish in most cases in the daytime, when most is received
via ground wave. I want to try the beverages to see if I can
do a bit better at night when the skywave kicks in.
Also maybe be able to hear a bit of weak DX on 160m for
a change.
MK



  #4   Report Post  
Old September 24th 07, 10:35 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 233
Default Beverage Antenna, Noise pickup

On Mon, 24 Sep 2007 00:29:54 -0700, wrote:

On Sep 23, 11:41 am, (Rick) wrote:
I was reading in ON4UNs book, a section about Beverage antennas and decided to
do some checking on mine, which is celebrating its ten year anniversary this
month.


snip

This comment isn't re noise with the Beverage, but I believe it might be found interesting to those interested
in Beverage antennas. Below is a quote from an article I published a few months ago in QST.

The Beverage Antenna in WW2
by W2DU

As a monitoring officer with the Radio Intelligence Division (RID) of the FCC in Hawaii during WW2 I was
privy to some interesting situations. Our State Department was of course aware of the operations occurring in
the Pacific Theater. The people there were also aware of the propaganda being spewed by the Japanese
short-wave broadcasters. But State was curious concerning what the Japanese living on the homeland were being
told-were they being told the truth, or the same propaganda as told on the short-wave broadcasts, or a totally
different story. State asked the RID to determine whether we could obtain such information.
We cruised the AM broadcast band and found several nighttime signals from Japanese mainland stations, but
most were too weak to copy. However, JOAK, Tokyo, on 640 KHz was S9, but there was a problem in copying it.
KFI, Los Angeles, was also on 640 KHz with an S9 signal-copying intelligence from JOAK was impossible. How can
we eliminate, or reduce KFI's signal level. A Beverage Wave antenna, perhaps?
We then proceeded to the northern portion of Oahu and constructed a Beverage one-half mile long, five
feet above ground, aimed at Tokyo, and terminated with a 1000-ohm pot resistor to ground at the Tokyo end. We
discovered that by varying the pot resistance we could null the KFI signal to almost zero. The resistance
terminating the Beverage that produced the null was around 600 ohms. Because the matching resistive
termination rendered the Beverage a traveling-wave antenna with no standing wave, the signal from JOAK was
terminated by the input of our receiver, while the signal from KFI was dissipated in the matched resistance at
the Tokyo end of the Beverage-no KFI signal reflected toward the receiver. Voila-JOAK was perfectly readable
for recording!
We sent the first recording to Washington, and State was delighted-requesting that we continue recording
JOAK continuously. Consequently, our recordings were flown daily to Washington from Hickam Field in Honolulu.
We were left in the dark concerning the information on the recordings, and how it affected the War effort,
because State didn't share it with us. But it must have been pretty good, because State was on our case every
day to make sure we sent them the recordings.

Walt, W2DU


  #5   Report Post  
Old September 24th 07, 10:45 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 757
Default Beverage Antenna, Noise pickup

On Sep 24, 4:35 pm, Walter Maxwell wrote:
On Mon, 24 Sep 2007 00:29:54 -0700, wrote:
On Sep 23, 11:41 am, (Rick) wrote:
I was reading in ON4UNs book, a section about Beverage antennas and decided to
do some checking on mine, which is celebrating its ten year anniversary this
month.


snip

This comment isn't re noise with the Beverage, but I believe it might be found interesting to those interested
in Beverage antennas. Below is a quote from an article I published a few months ago in QST.

The Beverage Antenna in WW2
by W2DU

As a monitoring officer with the Radio Intelligence Division (RID) of the FCC in Hawaii during WW2 I was
privy to some interesting situations. Our State Department was of course aware of the operations occurring in
the Pacific Theater. The people there were also aware of the propaganda being spewed by the Japanese
short-wave broadcasters. But State was curious concerning what the Japanese living on the homeland were being
told-were they being told the truth, or the same propaganda as told on the short-wave broadcasts, or a totally
different story. State asked the RID to determine whether we could obtain such information.
We cruised the AM broadcast band and found several nighttime signals from Japanese mainland stations, but
most were too weak to copy. However, JOAK, Tokyo, on 640 KHz was S9, but there was a problem in copying it.
KFI, Los Angeles, was also on 640 KHz with an S9 signal-copying intelligence from JOAK was impossible. How can
we eliminate, or reduce KFI's signal level. A Beverage Wave antenna, perhaps?
We then proceeded to the northern portion of Oahu and constructed a Beverage one-half mile long, five
feet above ground, aimed at Tokyo, and terminated with a 1000-ohm pot resistor to ground at the Tokyo end. We
discovered that by varying the pot resistance we could null the KFI signal to almost zero. The resistance
terminating the Beverage that produced the null was around 600 ohms. Because the matching resistive
termination rendered the Beverage a traveling-wave antenna with no standing wave, the signal from JOAK was
terminated by the input of our receiver, while the signal from KFI was dissipated in the matched resistance at
the Tokyo end of the Beverage-no KFI signal reflected toward the receiver. Voila-JOAK was perfectly readable
for recording!
We sent the first recording to Washington, and State was delighted-requesting that we continue recording
JOAK continuously. Consequently, our recordings were flown daily to Washington from Hickam Field in Honolulu.
We were left in the dark concerning the information on the recordings, and how it affected the War effort,
because State didn't share it with us. But it must have been pretty good, because State was on our case every
day to make sure we sent them the recordings.

Walt, W2DU


Thanks for the add Walt. Gives me the idea to try a pot instead of a
fixed resister,
so I can tweak it for best results.
MK



  #6   Report Post  
Old September 24th 07, 11:22 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default Beverage Antenna, Noise pickup

On Mon, 24 Sep 2007 17:35:58 -0400, Walter Maxwell
wrote:

The resistance
terminating the Beverage that produced the null was around 600 ohms. Because the matching resistive
termination rendered the Beverage a traveling-wave antenna with no standing wave, the signal from JOAK was
terminated by the input of our receiver, while the signal from KFI was dissipated in the matched resistance at
the Tokyo end of the Beverage-no KFI signal reflected toward the receiver.


Hi Walt,

A wonderful example of applied electronics revealing theoretical
issues (e.g. the Z of the Transmission Line built as an antenna).

73's
Richard Clark, KB7QHC
  #7   Report Post  
Old September 25th 07, 12:09 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jun 2006
Posts: 1,374
Default Beverage Antenna, Noise pickup

NEC-2 and NEC-2 based programs like EZNEC do a good job of modeling
Beverage antennas. (The EZNEC demo isn't adequate for this.) The only
trick is making the ground connection. In NEC-2 use Sommerfeld ground;
in EZNEC it's called Real, High Accuracy ground. At each end of the
antenna, create a semi-circle of radials, a few inches above the ground.
For wire length, a free-space quarter wavelength is more than adequate
-- the only requirement is that the effective resistance should be
considerably less than the termination resistance. The semi-circles
should be facing away from the antenna, so none of the wires extend
under the antenna wire. Ground "connections" are made to the center of
the semi-circle. This of course assumes that there are reasonably
effective ground connections at both ends of the real antenna.

Roy Lewallen, W7EL
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Beverage Antenna in WW2 - QCWA092205.txt Walter Maxwell Antenna 11 September 27th 05 01:56 PM
Second try with Beverage Antenna in WW2 Walter Maxwell Antenna 7 September 23rd 05 03:34 PM
FS: Beverage Antenna Handbook [email protected] Swap 0 July 31st 05 02:26 AM
Beverage Antenna Used in WW2 Walter Maxwell Antenna 11 August 30th 04 06:23 AM
Beverage Antenna Used in WW2 (0/1) Walter Maxwell Antenna 0 August 24th 04 01:25 PM


All times are GMT +1. The time now is 05:52 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017