Hi, Toby: listening to a QSO on 14.024.86 just now and there's very little drop
down when the 500 Hz filter kicks in. Or the 250, for that matter. But I have
a question for you.
Have you set and optimized the C.F. (center frequency) adjustment? The drill is
to tune in a middlin' strong CW signal, dial down the bandwidth until the 500
or 250 Hz filters kick in and then set the filter offset for max signal. While
I suspect every filters center frequency is a bit off the nominal frequency,
my 500 Hz filter is set to -160 and the 250 is set for -220 Hz.
I found a steady S5 signal, turned the BW down to 100 Hz, then set the 250 Hz
filter offset. Start by noting the frequency where the signal starts getting
louder, over shoot the CF adjustment by 200 Hz or so, then dial back down to
where it just starts getting louder again. Split the difference and your
filters should be centered in the passband. Then I repeated the drill at about
300 Hz for the 500 Hz filter.
For just the 500 Hz filter dial down to maybe 250 and then go through the CF
adjustment. It makes a lot of difference for me.
73 Pete Allen AC5E
r
--
Never squat with your spurs on
-------------- Original message --------------
> I have noticed that on 20 mtrs with all the roofing filters turned on to
> AUTO,
> that there is considerable attenuation of receiver audio when the bandiwdth
> hits
> the 370 HZ level. Of course I am down in the cw portion of the band. It
> doesn't
> seem to bother loud signals but does indeed surpress weak signal reception
> when
> the bandwidth is anywhere between 370 HZ down to 200HZ. At 190 Hz the audio
> comes back up because then the 250 HZ filter kicks in. I can turn the 500 HZ
> filter off and the audio is normal strength level. Does anyone else notice
> this
> or does this sound like a bad 500HZ roofing filter? One other thing, I don't
> seem to notice it on the low bands, but 20 mtrs and above it is most
> noticeable.
> I noticed in the QST review of the Orion the reviewer noted a somewhat
> similar
> observation with the 500 HZ filter. Toby W4CAK
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