Roofing Filter for Omni 6 Plus

Omni 6 Plus and Inrad Roofing filter installation/performance

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Audio spectrum output - no filters

(Click on each image to see larger view.)

 

Audio spectrum output - Roofing Filter ON

Audio spectrum output

Roofing Filter and 500hz IF filter ON

Photo 1

 

Photo 2

 

Photo 3

 

Photo 4

Ten Tec's Omni 6 Plus, in my opinion, is among the best full QSK CW radios available to the amateur radio user. The addition of the Inrad roofing filter significantly improves the radio's ability to handle strong, close by signals.

This page will show Spectragram plots of the Omni's audio output both with and without the roofing filter. While these pictures are showing the audio spectrum, the roofing filter is limiting the bandwidth that the IF stages  must process.

           CREDITS

These modifications to the Inrad filter instructions were developed by Dave - K1FK, who generously shared them with me. This modification allows you to use the front panel PROC button to turn the roofing filter ON/OFF. NOTE: The SSB processor can not be used with this modification!

A picture is worth a thousand words!

The bottom four pictures are an installation in my own Omni 6 Plus radio, following K1FK instructions. These four pictures are looking at the bottom of the Omni 6 Plus.

 

Photo 1 shows the physical installation of the Inrad roofing filter.

 

Photo 2 shows the wiring to J3, switch positions for S1, and no connections to J4.

 

 

Photo 3 shows the routing of a single wire, from J3 on the filter board, to LOWER POT board in the Omni 6 Plus.

 

 

 

 

Photo 4 shows the connection to the LOWER POT board and where to solder the switch wire.

 

For a copy of K1FK instruction, email me at w4bqf@arrl.net , include your email address and I will send it to you.

NOTE: In the bottom two spectrum plots, I incorrectly labeled the filter as # 764. The correct Inrad model # is 765.