[Central-Electronics] Central-Electronics Digest, Vol 67, Issue 5
NICKTUSA at aol.com
NICKTUSA at aol.com
Mon Nov 9 18:01:29 EST 2009
Correction folks. Wes Schum started Central Electronics without Joe
Batchelor in 1948 after he was released from active military duty. His first
series of products had to do with language lab and hearing aid equipment for
the profoundly deaf. These were marketed by the J. Warren Company. The
10A, and the 10B had been released and development of the 20A was essentially
completed when Joe and Wes met by chance at a Chicago-land hamfest in 1954.
Joe, like many others, had leveraged the vast depths of WW-II surplus to
make sideband rigs available in the very early 1950's. His rig was built
using the BC-696 as a transmitter foundation, but with an on-frequency
75-meter phasing generator. Wes, however, developed his CE exciters, using a 9MHz
heterodyne scheme as an all-band manufactured product expressly for radio
amateurs. Other than the BC458 pressed into vfo service (as he could buy a
palletload of them for twenty bucks) the CE exciter line was a pure ham
radio product.
The CE 10A was first advertised in QST magazine in September 1952, however,
the little set was available to Chicago area hams for some time prior to
this country-wide marketing move. Wes was aggressively spreading the word
about single-sideband at area hamfests well before he could afford hist
first QST ad.
Joe's initial contribution to Wes's Central Electronics. in 1954-1955, was
the design of broadband couplers of the 600L amplifier....although his
association with Wes was initially forged by their joint collaboration on a
revolutionary no-tune transmitter concept each shared: the 100V. The
amplifier was built to give folks a first taste of no-tune technology. Joe had to
relocate to Chicago from Walnut Grove, GA as his initial broadband coupler
design was not readily reproducible for manufacturing. How the couplers
became such was through the intense labors of Wes and Tom Clemens W9OKA
(SK). Wes understood the sensitivities of manufacturing processes whereas Joe
continued to search for perfection in an imperfect world. Yet, it was
Joe's genius that yielded the innovations that set CE apart and fortunately
garnered the interest of Zenith and Karl Hassel.
So, if ever there was a "Odd Couple" pairing in amateur radio's history it
has to be Wes and Joe's association during the 100V's development. You
could not have paired two entirely opposite personalities onto such a complex
and technically demanding project, intentionally, without a lot of sparks
and fire. Somehow, they made it work. I have the schematic of Joe's W4EGK
75-Meter SSB Exciter/Transmitter and will be happy to post if it is of
interest as well as a picture of Wes and the first 100Vs coming off final
test.
73 Nick, K5EF
In a message dated 11/9/2009 12:04:55 P.M. Central Standard Time,
central-electronics-request at mailman.qth.net writes:
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Today's Topics:
1. Re: 10B Mod (Jim Candela)
2. Re: 10B Mod (k7fm)
----------------------------------------------------------------------
Message: 1
Date: Sun, 8 Nov 2009 12:44:42 -0600
From: "Jim Candela" <jcandela at prodigy.net>
Subject: Re: [Central-Electronics] 10B Mod
To: <telmore1964 at yahoo.com>, <central-electronics at mailman.qth.net>
Message-ID: <164E563ACBB541BA9AD5B9BF38C22909 at DesktopVista>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Tom,
I believe that Tony Vitale's "Cheap and easy SSB" transmitter used a
12AU7 where the 10a, 10b, 20a used a 6U8. Maybe the very early 10's used
the
12AU7. I have a copy of the schematic of the w2ewl special, but not handy.
While looking for it, I uncovered a bunch of other stuff. Maybe the group
will find this stuff interesting. See below,
Jim
WD5JKO
http://www.ac6v.com/73.htm
Tony Vitale W2EWL who lived in Denille NJ wrote an article in CQ in the
early1950's entitled "Cheap and Easy Sideband". It was a 9 Mhz USB
phasing
generator tweaked for optimum suppression on LSB and an ARC-5 used as a 5
Mhz VFO. It summed the 9 Mhz USB signal and 5 Mhz VFO to work on 20
meters.
Sum mixing does not invert the USB signal. It used difference mixing to
work on 75 Meters, causing the USB signal to be inverted to LSB. At this
time commercial SSB rigs were virtually non existent. Shortly after this
article was published, Wes Schaum & Joe Batchelor formed Central
Electronics
and utilized a similar design to make the 10A, 10B, & 20A. The few hams
using "Ducktalk" had only the capability of USB on 20 meters and LSB on 75
meters. Thus the convention was set. When other rigs like the 10A, 10B,
&
20A came along, they followed the precedent that had been set by the
"Cheap
and Easy Sideband" article by Tony Vitale. I met Tony in 1975 when I
worked
for Cessna. Tony retired in the late '70's and died in the mid 80's.
http://www.qsl.net/k5bcq/Lorne/w2ewlside.jpg
http://www.qsl.net/k5bcq/Lorne/w2ewlfront.jpg
here is another one built:
http://www.ohio.net/~ka8wtk/458/458.htm
Some more history:
Single sideband This is not to suggest that no amateurs were developing
the
art in the SSB field, still a controversial area.
Tony Vitale WZEWL, made many a convert with his cheap and Easy S.S.B.''
('March 1956) an ingenious phasing-type exciter built in and around a
surplus BC-458 transmitter.
Murray Crosby, WZXSY, described his ''product detector'' in May, l 956 and
made it impossible for anyone during the following years to peddle a
sideband receiver that didn't have something labeled a ''product detector."
In September 1957 Howard Wright, MQPNB, one of the early sidewinders
described the "Third Method of S.S.B. Generation" a system primarily of
academic interest.
In 1960 the 7360 beam-deflection balanced-modulator be was introduced and
in
the same year Joe Galeski WWIMP described his three-tube complete filter
sideband transmitter which certainly must have set some kind of a record
for
minimums.
By 1960 the pattern of linear-amplifier design was firmly established;
tetrodes operation ABl for high-sensitivity applications, or grounded-grid
Class B triodes when 30 to 100 watts of drive was available.
Historical articles from the
1964 issues of QST. Submitted by Jim Linn, WB8RRR
----- Original Message -----
From: "Thomas Elmore" <telmore1964 at yahoo.com>
To: <central-electronics at mailman.qth.net>
Sent: Saturday, November 07, 2009 3:50 PM
Subject: [Central-Electronics] 10B Mod
> Does anyone know if there was a mod to change the 6U8 tube in the 10B
out
> to a 12AU7? Mine is set up that way and it almost looks factory?
>
>
>
>
> Thanks
> -Tom
>
>
>
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------------------------------
Message: 2
Date: Sun, 8 Nov 2009 11:57:13 -0800
From: "k7fm" <k7fm at teleport.com>
Subject: Re: [Central-Electronics] 10B Mod
To: "Jim Candela" <jcandela at prodigy.net>, <telmore1964 at yahoo.com>,
<central-electronics at mailman.qth.net>
Message-ID: <E890F41240C045468E37A9FBAF423571 at COLIN>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I think the early CE exciters used a 12AU7 for the 9 mc (it was still mc
in
those days) oscillator. That was replaced by a 6U8, and stability of the
crystal oscillator was improved. There was an article in CQ on
stabilizing
the early 12AU7 crystal oscillator.
73, Colin K7FM
------------------------------
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