>Speaking of factory alignment, one thing I have noticed is the 500Hz
>filter is about 2 or 3 S-units stronger than the 250Hz filter - I
>carefully adjusted the PBT to zero-beating against the 700Hz sidetone
>and another rig on my desk transmitting into a dummy load. I can be
>dead-on centered for maximum signal strength with the 250Hz filter and
>then select the 500Hz filter and the 500Hz filter produces considerably
>louder audio from the speaker and about 3 S-Units stronger on the S
>meter. Is this typical or do I need to consider filter replacement or
>alignment?
There are gain settings that need to be set to match each filter. If they
aren't right,
you'll find poor level match between the filters.
>I've thought about purchasing some INRAD filters but I am confused as to
>which ones to buy because I do not know how the 9MHz center frequency of
>the filter corresponds to the CW 700hz center frequency - for example,
>INRAD's website lists two 400Hz 9MHz filters, #753, 9000.6 KHz and #759,
>9000.7 KHz. Does this mean the 9000.6 KHz filter is designed to center
>around a 600Hz sidetone and the 9000.7 is for 700Hz (keeping the PBT
>knob at 12:00 o'clock)?
Call the phone number in the morning (west coast time) listed for Inrad and ask
George what filters you should be using. I did that a week ago, and got very
thoughtful and straightforward answers to my questions. He didn't try to sell
me
stuff I didn't need, and offered me good advice. He will know exactly what
filter to
put in what position in each radio depending on your needs.
>I have been considering picking up #754 2.8K 9MHz filter depending on
>any reports I get about the CW click that some Omnis have - given that
>i've made only a half dozen contacts since I got the radio I am a bit
>premature to go off spending money on things I don't need - hi - but i'm
>an avid CW op and anything I can do within reason to improve picking out
>the QRP rigs in VK land is ok by me - hi
I don't see how changing the filter will affect clicks. Clicks are generated by
rise
times in the keying circuit. Others here can respond to that issue better than
I.
Jim Brown K9YC
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