[Boatanchors] Re: [ForSale-Swap] Beam help needed

[rayfri]

It appears this is the Classic 33.   I found this information on the 
Mosely website which confirms the wire inside and the reason for it...
This sounds like a very good antenna.   It's in great condition.  Will 
just have to polish it up a little and reassemble.    May keep my 4 
element HyGain up though and sell this one....    Will let the group know...
Ray  WA7ITZ

The Classic System

In order to give hams a new choice in beam matching systems and an 
antenna featuring maximum gain with increased bandwidth, we devised the 
matching method used on our Classic antennas - Balanced Capacitive 
Matching (Patented) - a method which takes advantage of the principle 
that antenna resistance at the center driving point increases s the 
antenna length increases.  Figure No. 1 shows the radiator element of a 
three-element beam at resonance having an impedance at the driving point 
(ZA) of about 30 + J0 ohms.  If the element is made longer, ZA can be 
raised to about 50 +J50 ohms (Figure No. 2).  Since the reactance is 
inductive, it can be cancelled with a series capacitor of 50 ohms 
reactance, leaving 50 ohms feed point resistance (Figure No. 3).  Series 
capacitors used on the Classic antennas are made by inserting a suitable 
length of heavily insulated wire into each half of the element tube at 
the center.  The wires are terminated in a plastic tube enclosure with a 
type 'N' or type 'SO-239' connector for connection of the coaxial 
cable.  To isolate the outer coax conductor from ground, the coax line 
is coiled for a few turns near the antenna end.  This is designed to 
prevent the very unlikely effect of "Feed Line Radiation."



Merv Schweigert wrote:

> Ray,  probably what they called the Classic 33, or CL-33
> I used to have the 20 meter mono band version
> that was a 3 element with the "coax" inside, actually was just 
> insulated wire or the center part of
> the coax in the originals.   Mine worked extremely well
> and had a low SWR.   Always thought it was a neat
> weather proof matching system..
> 73 Merv K9FD/KH6
>
> rayfri wrote:
>
>> ______________________________________________________________
>>
>> Need the help of the group.
>> Today I took down a 30 foot tower and a triband beam at a ham widow's 
>> home.
>> The beam I thought was a Mosely TA-33 ... it has the cylindrical 
>> traps like a TA-33.   However, looking at the TA-33 manual
>> on BAMA, I'm not so sure now.
>> On the driven element, when I disassembled the sections, there was an 
>> unterminated length of coax on each side of the coax connection.
>> It was just inside the elements ... almost like the antenna was being 
>> capacitive fed.
>> The center connections for the coax on the driven element are not 
>> like the TA-33 manual either...    There is a so-239 at the center on 
>> a black cylindrical insulater that the driven element halves are 
>> fastened into. So I'm not sure it is a TA-33 ... unless it is a newer 
>> model of TA-33..
>>
>> Anyone have any ideas?
>> Ray   WA7ITZ
>>
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>
>