[Boatanchors] Cardwell 54

[Robert Nickels]

On 4/29/2021 4:50 PM, Richard Knoppow wrote:
> A lot of smaller businesses just vanished, perhaps true of Pierson. 

True but it's a tangled web.  From the N7RK website:  "California was 
home to a number of manufacturers of communications receivers in the 
1930's. Names such as Gillfillan Brothers, Patterson, Sargent and the 
Breting Radio Manufacturing Company in Los Angeles, California were some 
of the better known companies. Emmitt Patterson started the Patterson 
Electric in 1919. The chief engineer was Ray Gudie who also designed the 
Breting receivers. Ray Gudie left Patterson during the design of the 
PR-12, Karl Pierson joined the company in 1934 and was instrumental in 
the design of the PR-15 and PR-16 receivers. Patterson built receivers 
from 1935-1940. The Patterson receivers were high end receivers with 
high tube counts, chrome chassis', crystal filters and many other 
features not available on Hallicrafters and National radios of the same 
vintage. All the Patterson chassis' were manufactured in the Gillfillan 
plants. Patterson went out of business in 1939."

Karl E. Pierson and Mr.DeLaplane formed Pierson-DeLane (shortening the 
latter's name) in 1937. In 1939 they started concentrating on two-way 
radio equipment, e.g. police radio. The Company was wound up in 1943 
after taking over manufacturing of the PR-15.   More here: 
http://www.radiodx.com/articles/technical/equipment-reviews/paterson/

All of which is to set the stage for Karl Pierson's new post-war venture 
to manufacture a high-end communications receiver, the KP-81.   That did 
happen - I know of three including my own, which is still awaiting 
re-assembly.   The definitive work on the KP-81 has been written by my 
buddy John Vendeley K9WT, who is an excellent engineer and who has more 
patience and admiration for Karl Pierson's design skills than I do.    
It is a case where the electrical design was very advanced, the 
mechanical design is robust and very attractive -  but the lack of 
consideration for maintenance and documentation is a critical weakness.

The receiver is modular, which is great as far as it goes, which 
unfortunately does not include the RF front-end.   All the front-end 
components are invisible and inaccessible, trapped inside a two-piece 
metal enclosure that requires unsoldering of 16 hardwired connections, 
then prying apart the two halves which are connected via component leads 
and stiff solid wire interconnects.    Then the aged resistors and 
capacitors can be replaced and the process reversed, which is the stage 
mine is at.   The cast coil drawer is extremely well built but also very 
heavy and fits into the chassis with very little room to spare, so great 
care and gymnastics are required to avoid damaging the contact clips in 
the process.   I've replaced the 20 or so caps in an SP-600 and felt 
that was bad at the time, but the KP-81 takes it to a whole new level.

The receiver was shipped with a schematic that had reference 
designations but no values, nor was a bill of materials provided that 
correlated those designators with actual values.   Pierson evidently 
felt that component values might change over time and it wasn't 
important to inform customers of what they were.    He also drew the 
schematic with the tubes rotated 90 degrees and without pin numbers 
which just makes it that much more fun to read. John, with help from  
Rodger WQ9E have filled in those blanks but working on a KP-81 requires 
a lot patience - aided by a healthy vocabulary!

Everything you ever wanted to know about the design and restoration of 
the KP-81 can be found in John's document, here:

http://jptronics.org/pierson%20kp-81/index.html

73, Bob W9RAN