After much playing around with adjusting the center frquency of my 500
and 250 Hz xtal filters, I finally came up with a procedure that works.
After performing this procedure, switching between UCW and LCW when the
signal is zeroed (his tone matches the spot tone), he remains tuned dead
center. Here's the procedure:
1) Set the pitch of your desired listening tone by holding the SPOT
button while you adjust the Multi conrol. When it's where you want it,
release the SPOT button. (The sidetone pitch automatically will be the
same at the spot pitch).
2) Go to the FILTERS menu and enable your narrow CW filter (both, if you
have both).
3) While still in the FILTERS menu, set the "Xtal Filter" selection to
"Auto".
3) Exit the FILTERS menu and set the MODE to either LCW or UCW.
4) To adjust your 500 Hz (or INRAD 400 Hz) filter, set the BW control to
370 Hz(this is where the roofing filter switches from the
factory-supplied 1000 Hz xtal filter to your optional 500 (or 400) Hz
filter. Ensure that PBT is set to zero.
5) Tune in a CW signal on the main receiver (better yet, a steady carrier
if one is available) with the MODE set to UCW. Tune the VFO so that the
pitch of the signal's tone matches the SPOT tone.
6) Go to the FILTER menu and adjust "500 Hz C.F. Adj" until the signal
sounds the loudest possible in the headphones. If the signal is strong
enoungh and steady, the S-meter may be used for this adjustment.
7) Exit the FILTERS menu and switch the MODE to LCW. Do not move the
VFO. The signal should be heard at the same pitch you tuned it in at
during step 5).
8) If the signal sounds weaker than it did on UCW, go to the FILTERS menu
and readjust "500 Hz C.F Adj" in the direction where the signal becomes
louder (don't go too far).
9) When the Center Frequency adjustment is set correctly the strength of
the signal in the headphones will be the same in either UCW or LCW modes
(always ensure that the VFO is tuned so that the signal's pitch equals
the SPOT pitch). If necessary, adjust "500 Hz C.F. Adj" until this
desired result is achieved (an adjustment of only +/-10 Hz makes a
noticeable difference).
10) If you have the optional 250 Hz xtal filter installed, set the BW to
190 Hz (the 250 Hz filter "kicks in" at 190 Hz) and repeat steps 5)
through 9), but adjust the "250 Hz C.F. Adj" adjustment instead.
11) When the adjustments are complete, I recommend that you press and
hold USER1 to store your work in case yoiu need to recall it (or at
least write down the C.F. offsets for future reference).
When you finish this procedure, your optional CW filter Center Frequency
adjustments are set correctly and you can switch between UCW and LCW at
any narrow BW setting while the CW signal is zero beat (it's pitch equals
the SPOT pitch) and there will be no change in its pitch or volume.
Even though I have the 250 Hz C.F adjustment set for max loudness, my 250
Hz filter has considerably more attenuation than my 500 Hz filter. When
I narrow the BW to automatically engage the 500 Hz filter (at 370 Hz)
there is no decrease in perceived loudness on either UCW or LCW, however
when I decrease the BW to 190 Hz (where the 250 Hz filter engages), there
is very noticeable decrease in loudness in either CW mode.
For any of you Orion owners that have had problems adjusting your
optional CW filter offests, I hope this helps.
73, de Earl, K6SE
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