John K4NP wrote in part:
I had read the info on the insertion loss and increased IMD when using the 250 Hz roofing filter. As a result, I decided to go with the INRAD 600 Hz filter in the 1 KHz slot.
Last week, I picked up a model 219 filter at a fair price. My results have been quite favorable.
John: The problem is with the 500 Hz slot, thus the work-around with the InRad 600. The 250 Hz slot does not, to my knowledge, have the IMD problem and has no additional gain stage as does the 500 slot. The InRad 600 works so well tho that I find no discernible improvement using the 250 Hz roofing filter even during very crowded contest conditions. Thats why my 250 is turned off in menu. I would suspect your results would be "normal" on the Orion.
Thats the reason many of us went to the InRad 600. It works fine and allows
one to hear a bit more around the edges when running in a contest. When
running 250 Hz is too narrow to ever hear the callers who don't know how to
zero beat, or think they have a better chance calling 200 Hz off center. 73
bob de w9ge
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