New  Equipment
Used Equipment
Our Office
What We Do
Rate Card
Web Links

Radio Broadcast Technical Consulting and Sales

Customer of M. W. Persons

KOZY AM  1320 KHZ/5 KW
KMFY FM  96.9 MHz/100 KW/479 Ft.
Grand Rapids, MN
Their telephone number is 218-999-5669

Here is the KOZY-KMFY studio building on the south side of Grand Rapids, MN.  Known as Cozy-Comfy Radio, it is a very friendly locally-programmed facility with a local owner and not a part of a larger radio empire.  The Web site is http://kozyradio.com

Grand Rapids, MN, is the birthplace of Judy Garland, who played Dorothy in the 1939 Movie "The Wizard of Oz" Her most memorable song was, "Over the Rainbow." 

The telephone number for KOZY-AM, and KMFY-FM Radio is 218-999-5669.  

Jim Lamke is the Owner/Manager and a great team leader. 

Letters from far-away listeners

January 2012:  Your intrepid engineer Mark Persons built a box in his shop that has two variable inductors.  It is part of a T network to adjust night common point resistance to 50 ohms and reactance to zero ohms on the night phasor system at KOZY-AM. 

About 32" wide x 38" deep, x 18" tall, the box frame is made of 1 inch aluminum angle stock that was miter cut in the corners at 45 degrees so it would fit together.  Flat-head screws were counter sunk into the frame so there are no protrusions.  Then 1/8" aluminum sheet was bolted on.  That sheet metal was cut in sections to allow easy disassembly for maintenance and modification.


KOZY-AM south tower on January 23, 2014.

The moon was in the southwest shining at sunrise. 


Meanwhile in the transmitter building, contract engineer Jim Offerdahl was busy disassembling an RF contactor from the top of the three-tower phasor cabinet.

Note that 5 KW of RF was exposed.  This was "normal" years ago, but not in today's world.

Yes, the "Danger High Voltage" sign meant something.

(l-r) Joe and Jim Offerdahl lifted the new box in place on top of the phasor cabinet.

It fit like a glove and was then bolted down.

Jim and Joe ran new copper strap to the bottom of the phasor cabinet for connection to a new Nautel XR-6 Transmitter.

Brazing with silver solder often takes two people. 

Joe is seen here connecting wires to the power transformer in the bottom of the new transmitter.

Gotta make sure they are in the right place and tight.

Jim was busy with transmitter logic wiring.

The RF contactor is now INSIDE the new metal enclosure with 7/8" transmission lines from the former main transmitter on the right and the new Nautel transmitter on the left. 

There is also a "Jacob's ladder" arc gap to protect the Delta sample transformer and transmitters from lightning damage.  It is the gold anodized V shaped device on the right wall.  When an arc starts, it is naturally drawn upward until it extinguishes.

Jim was busy in front of the Nautel transmitter doing control and audio wiring.

Not difficult, just have to put it in the right places.

The finished setup.  Left to right are a Collins 20V3 1 KW transmitter, a Harris MW-5 Transmitter, the Harris phasor from 40 years ago, an equipment rack, and then the new Nautel XR6 Transmitter. 

Note there is a one-turn loop in the transmission line at the top of the Nautel transmitter.  That helps keep lightning out.  There are also two toroid core "donuts" just above the transmitter for the same purpose.  You can't be too careful when it comes to lightning protection.

The stories go on and on.  Stop in again sometime.  I'll leave the soldering iron on for you. 
Mark W. Persons   Ham WMH


     Return to Home Page

page last edited 12/23/2015