Karl's Link Radio page
This page is all about modifying radio equipment for a better way to pass signals for long-distance links and other uses,
starting with the COR/Audio board. If any of the drawings are not clear a better copy is available for a modest cost of handling.
My COR board project:
COR/Audio board Ver. 5.3 with a browser
COR/Audio board Ver. 6.5 as a pdf file
COR/Audio board Ver. 6.5 Notes on parts placement
COR/Audio board Ver. 6.5 Schematic
COR/Audio board Ver. 6.5 Layout
Motorola Mitrek area - Lot's of information
Most of these documents are in PDF for easy viewing with any O/S. Also, some of them are large in size:
Mitrek conversion to Repeater or link in PDF
Frequency options in PDF
Details on the antenna ports in PDF
Spec sheet on RG-405 coax Beldon part number of 1671A
Preselector repair in PDF
Operation manual in PDF
Motorola Micor area - Lot's of information (including Spectra-Tac)
Micor transmitter for repeater service in PDF
Transmitter supplement for above in PDF
Micor receiver conversation in PDF
Spectra-Tac supplement (goes with above document)in PDF
Spectra-Tac PL Module (goes with above document) in PDF
Micor squelch theory discussion in PDF
COR board version 5.4 for Micor Spectra-Tac downlink in PDF
MX-350 Portable radio for UHF links
Maxar radio Just a few notes
GE for repeater operation in PDF
Audio Standards Flat or conventional audio and level standards
Microphone discussion by Tomi Engdahl
Direct F.M. a Midland 13-509, or most any transmitter
Midland 13-509 Full story on F.M. and repeater conversions for 1 1/4 meters
Wilson 1 1/4 meter radio For the model T2202SM HT.
Johnson PPL6060 UHF radio notes Improving transmitter frequency stability
Fan assembly to cool a transmitter Used in some SRG 20 repeater equipment
LDG eletronics voter Documentation by Karl Shoemaker
A note about the documents; recently they are starting to be converted to PDF for a couple reasons; this solves the issue with html pages (with images) being displayed on various browsers (with other variables) and generally is smaller in file size. This is especially true for a MS-Word document (with images) compared to the size of the same document in PDF. PDFs are easy to download to your PC for later viewing.
Note: Many of these projects are in the R-n-D stage, therefore, are subject to change and improvement without notice.
They are intended to get the experienced builder in the right direction and not necessarily for the beginner.
Tip: Some are PDF's therefore, to save time you can right click on the link and "save as" to your PC for local (and faster) viewing.