[Motorola] PT-300 origins

[CubexCo at aol.com]

In a message dated 3/27/2006 4:01:07 AM Eastern Standard Time, 
motorola-request at mailman.qth.net writes:
Hello to all.

Has anyone documented the conversion steps to bring down any
of the the VHF PT Motorola radios (lunchbox radios) to 2 meters?  I seem
to remember a thread on this and someone saying that the receiver was
identical or nearly such to one of the HT 200 or 220 radios?

Any help would be appreciated.

Ron - AA6D
==================================
The PT-300 series of Motorola products of the 60's used the HT-200 receiver 
and transmitter as core circuits.  In the response thread from you inquiry one 
refering to HT-220 core is not correct as it predates the HT-220 by several 
years, and further the architecture of the PT does not lend itself to accepting 
HT 220 circuits.  
For all practical purposes the HT-200DEN circuits will be applicable to the 
PT-300.  There are early and late models,the former based on the HT 200 DCN 
(germanium devices) and the later models HT200DEN models with silicon devices and 
a stacked log component layout.  

The tuning range on most of the coils is pretty broad, and can be further 
altered with different core materials (not sure how to find them today however).  
Adding a few pico-farads can pad those down that do not tune the desired 
range.

The other circuit descriptions following in the responses did accurately 
describe the circuits used in various models.  The MP-500 models was essentially a 
special model, designed to meet a unique railroad order. 

The PT series products were designed on my watch as engineering manager at 
Augusta Blvd.  

Regards,
Norman W4QN