147.285 MHz


London, OH

Photographs at the W. Jefferson and Plain City Receive Sites

Operation Site Map

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Plain City's Receiver
This is the inside of the receiver chassis at Plain City.  The receiver is in the lower right, and the new microprocessor based controller with DTMF and CTCSS decoders is to its left.
The chassis at W. Jefferson looks virtually the same.

Not shown - the UHF link transmitter is mounted in its own chassis on top of this chassis.
Inside view of the link transmitter
This is the inside view of the UHF link transmitter chassis. It is mounted on top of the receive chassis.  The complete assembly is shown in the next photo.
Complete receive site at Plain City
Here is the complete receive site package at Plain City.  The receiver and transmitter chassis are on the top, and the 12V/13AH gel-cell battery and trickle charger are on the lower shelf.
West Jefferson site
This is the installation of the West Jefferson site.  It is located outdoors in an unheated storage shed at the base of the tower.  The Hamtronics receiver and transmitter use the optional TCXO (Temperature Compensated Crystal Oscillator) so the frequency doesn't drift even with extreme temperature changes.  On the right side of the photo is a 12V/13AH gel-cell battery for backup power.  A new power supply  that doubles as a float charge has been added since this photo was taken.
W Jeff site
The outdoor storage shed at the West Jefferson site.
COR Board
This is the microprocessor-based controller board used in the West Jefferson and Plain City receiver sites.  It is the only non-Hamtronics component of the systems used at these sites.  The originally-used Hamtronics COR board had too long delays and poor frequency response.

The receivers were modified to use discriminator audio, and the transmitters were fed directly into the VCO (through a 4 KHz splatter filter) to obtain flat frequency response and linearity.
W Jeff Antennas
The antennas at the West Jefferson site.  A very old Hustler G6-144 was rebuilt and side mounted at about the 25 foot level.  The UHF link antenna above it is a Cushcraft A449-6s.
Installing the antenna
Installing the antennas with the convenience of a rented bucket truck. (W. Jefferson)
Antennas The antennas are being serviced by Don Kovalchik (W8DPK) and Don Brewer (WD8BHK).  The 2-meter antenna, a Hustler G3-144, is installed at the 40 foot level, and the UHF link antenna, a Cushcraft A449-6s, is just below the neck of the tower.  (Plain City)
Antennas at Plain City Another view of the antennas on the firehouse's tower.  (Plain City)
Firehouse The Pleasant Valley Joint Fire District Firehouse in Plain City.  Our antennas are on the tower on the right side of the building.  Our club's HF station is also setup here. A 80-meter off-center fed dipole is attached just below the 2-meter antenna on the tower.

Copyright ©  2006, 2009 All rights reserved
   Donald Kovalchik

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This page last updated January 5, 2009