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