Thread: ? for the group
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Old December 2nd 04, 08:08 PM
Dave
 
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"Michael Lawson" wrote in message
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"Dave" wrote in message
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"Dale Parfitt" wrote in message
news:25Krd.8148$1z5.1438@trnddc06...

"



Thanks for the quick response, Mike!

65 feet of coax between the radio (DX-402/ATS-505) and the

antenna
(200 feet
of 300 ohm twin-lead hidden along the ridge on the roof of the
house.) And
I don't think I would call it "severely" degraded, only

slightly so.
Only a
little less than the old "temporary" antenna (60 feet of four

strand
copper
wire thrown over the house.) Also, the new antenna is oriented
primarily E/W
while the "temporary" antenna was oriented primarily N/S, if

that
matters.

The orientation does matter if you're not using a vertical,
but the first thing that popped into my mind was overloading
the ATS-505 with 200 feet of antenna wire. The longest
I've ever run into my old DX-440/ATS-803A was about
40-50 feet, and while I never overloaded it, I've never
tried anything close to 200 feet into it.


But yeah, the E/W orientation will work well for stations
that are north or south of you (like tropical band stuff),
but not so good for hearing things east or west of you
(like from Europe or Africa or -depending on where
you're at- relays like Sackville).

Unless the antenna is a approx. 1/2 wavelength up or higher ( at

tropical
band= 150' or so) the end nulls fill in making even horizontal

antennas
near
omni.

Guess my question is, how are you connecting the twin lead- if

simply
connecting it to the balun, you have little more than a 300 Ohm

transmission
line, not an antenna.
In fact, if the baluns were perfectly balanced, and the twin lead

clear of
metallic objects ( which would unbalance it) you would

theoretically get
zero signal.
Dale W4OP



Hey Dale, thanks for jumping in.

Well, get the calculator out. The two freqs of interest to me are

9335 KHz
and 11710 KHz, so I am going to work with something between those

two
numbers (10 MHz). If I am correct, 10 Mhz has a wavelength of 30

meters,
which works out to about 98 feet. And I am working with 200 feet.

(Maybe I
should call this a long-wire antenna?) Question for you: what is an

end
null?

And yes, I simply connected the 300-ohm to the baluns to the coax,

to
another balun, and then a third that plugs into my external antenna

socket.
And I a definetly getting a signal. Whatcha think?


Are you using the 300 ohm balanced as a twin lead folded
dipole or as an equivalent of a longwire?? If you're using it
as a longwire and have hooked up a 300/75 balun to it,
Dale's right and it's effectively a long transmission line.

I'm with Ace on this, I don't understand the 2nd and 3rd baluns.

--Mike L.


I am using it as a longwire. What is a "transmission line" and how does it
differ from a recieving antenna?

The second and third baluns are to allow me to plug it into my external
antenna connector. The first (attached to he coax) makes it possible to
carry the received signal to the second (with the mini-plug on it.) I am
using this with a small portable radio.

Dave