On Sun, 2006-04-30 at 11:47 -0600, Peter Hoon wrote:
> Fellows,
>
> Four questions at the end.
>
> Have just bought an Omni VI Plus manufactured in mid-1998 with optional 1.8
> kHz SSB filters in the 6.3 and 9 MHz IF strips. (I think I am all set up
> for SSB). I believe this radio has all post 1997 factory mods.
>
> My hearing is 12 db down at about 500 Hz, but as much as 45 db down at the
> 880 Hz CW note in the Omni VI plus. At 1500 Hz, am as much as 70 dB down.
> Have constant ringing tinnitus at high frequency due to irreversible damage
> in the cochlea.
>
> Several years ago, perhaps 1998, there was available a special CW filter
> (I'm not sure whether at 250 or 500 Hz bandwidth) possibly sold under the
> auspices of N4PY to lower the CW note in the Omni rigs.
>
> 1) Any chance a list member has one for sale? Any chance list members know
> where I might get one at this late date?
>
> 2) Would also like recommendations/advice regarding exactly what filters I
> should buy to get most noise reduction and best performance from the Omni
> VI+ on CW. For example, should I buy 250 or 500 Hz filters for both the 6.3
> and 9 MHz IFs? Is the 600 Hz roofing filter available from Inrad
> recommended?
>
> http://www.qth.com/inrad/kits.htm#tentec
>
> Is it possible I would actually be happier with 500 Hz filters in the 6.3
> and 9 MHz IFs, since one op said they work a little better with the pass
> band tuning on the Omni VI+ than the 250 Hz filters do?
>
> 3) If I were able to find the special N4PY "lowered tone" CW filter, what
> other set of CW filters should I buy that are compatible with it?
>
> 4) In addition to crystal filters, should I invest in the Timewave
> DSP-599zx especially for SSB summertime noise reduction? (As you probably
> know, for hearing disabled, getting rid of as much background noise as
> possible is a priority for both CW and SSB.)
>
> http://www.timewave.com/dsp599zx.html
>
> Generally, my major interest is CW, but I've got to have good SSB
> performance (in the midst of summer QRN) for possible fire emergency work
> with the Red Cross this summer.
>
> Thanks for ideas and recommendations from any and all.
>
> 73s,
>
>
> Peter
> VE1CHS (Formerly WA0BAV)
> Nederland, Colorado
Using the narrow filter in the 6.3 MHz IF and the passband tuning can
get you a low pitch CW receive note. It will probably take some
transmitter XIT to get the transmitter frequency to match. You'd not
want the narrow 9 MHz filter, but the SSB filter in the "roofing"
position. In some Tentecs the CW transmit uses a SSB carrier crystal
shifted at key down, most likely that shift is adjustable to get your
transmit carrier to match your preferred LF receive pitch.
--
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer
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