[W2CRA] CRA: 375 Upgrade

[William Powell]

All,

The 375 upgrades will take part in 3 phases.

Phase 0 provides the opportunity to go to a single-site configuration.  This is necessary in case we loose the current
control site prior to the completion of Phase 2.  It will also be part of Phase 2; the local (Cherryville) receiver.
In order to complete Phase 0 we will need to configure and program a CDM 750 147.975 receiver, connect it to the 147.975
port on the Cherryville receive antenna system and test with the 147.375 transmitter to:
	1.  Determine if there is desense,
	2.  If desense is in evidence determine if it is the result of fundamental overload or transmitter noise.
	3.  Determine the appropriate solution to desense.
Then we will develop the required interface to the current transmitter and integrate with a basic controller.

Phase 1 will update the remote packages with the new remote receiver and link transmit radios.  The new packages will
operate in the same mode as the current remote packages.
With Phase 1 we discontinue field servicing and move to a complete package replacement policy;  When we have a remote
package problem we replace that package with a spare and return the defective package for troubleshooting and repair.

Phase 2 moves the control site to Cherryville.  Phase 2 adds ID and PL to the UHF links.  Currently do NOT ID the links
which is a FCC requirement.  If we simply put ID on the links the IDs will pass thru to the 375 transmitter.  So . . .
We will add PL to the UHF links for normal (voice) operation and turn off PL during the remote ID causing the link
receiver to NOT pass the ID audio.
Phase 2 requires the construction and wiring of the control receiver rack and upgrades to the remote packages.  Once the
link receive rack is completed and installed we can move the control site (Phase 1.5).
As part of Phase 2 we will upgrade the spare remote packages to add a controller, ID and PL. replacing each remote in
turn.

Currently the tech team has almost all the equipment and parts we need for Phase 0 and 1, lacking only 6 of the 8
required 3U 19" rack shelves.

Parts acquisition for Phase 2 is ongoing pending several engineering decisions.
 - George (AC2NX) is working on the design of a filter to remove PL from the link audio,
 - Remote controllers need to be acquired, assembled and programmed,
 - PL encoders may have to be sourced and wired,
 - All of the above will need to be stuffed into an appropriate enclosure and wired.

More as it happens,
Bill - WB1GOT

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