Fw: Re: Fw: Re: [Antennas] Rotary Joints for Ladder Line
Sandy and Kees Talen
[email protected]
2002年4月28日 20:06:57 -0500
Thanks Clete,
As luck would have it, I have an old 1948 handbook. Really interesting
how smart we were back then at making whatever we needed. There
is even discussion on how you can use parts off automobiles such as
rearends to make rotors.
Anyway, there are two open wire feeds of rotatable beams discussed
(most of the towers are wooden). One uses two slip rings and
various contact arrangements ....but it does say that contact resistance
and intermittant contacts can be a problem.
The second is a link coupled winding with tuning capacitor ...one part
on the rotating tower/mast and the second on the fixed part of the
tower. It does say that rigidity of the coils is important and they
should
be made from copper tubing and any unwanted movement between
them (when stationary) must be minimized.
73s Kees K5BCQ
--------- Forwarded message ----------
From: Cletus W Whitaker <[email protected]>
To: Sandy and Kees Talen <[email protected]>
Cc: [email protected]
Date: 2002年4月28日 20:23:45 -0400
Subject: Re: Fw: Re: [Antennas] Rotary Joints for Ladder Line
Message-ID: <[email protected]>
References: <[email protected]>
de WB2CPN South Central Pennsylvania USA 2002年04月28日
It was the ARRL Handbook of 1947 or 1948 that showed how to make the
loop coupling between the rotary beam and a balanced line. 200 Ohm
heavy duty twin lead for commercial receiver facilities was in use at
the time. The two loops were approximately 14" in diameter, made of
copper tubing, and spaced approximately 1/2" from each other. I never
did believe it would work, but a couple of guys in our shop put one on
the rotary beam we had. I don't remember what happened, but it came
from the ARRL Handbook. 73 Clete
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