> I beg your indulgence for one last silly question. Is it possible to
> install a 500hz filter in the 8.83Mhz i.f. but a "2 7 0 hz" filter in
> the 455Khz i.f. ? I am wondering what this would do. Surely someone
> has tried it. Would it be a disaster, or would it function like a
> 270hz filter with wider skirts in the next i.f?
Mike,
Much like the situation with only a single narrow filter, the VBT
won't work properly. Remember that the VBT works essentially by
electronically moving the two filter passbands back and forth, using
the high edge of one and the low edge of the other for total
bandwidth. By having different filter widths at each IF, you hardly
ever get to the edge of the wider passband, thus effectively having
only one (narrow) filter in place, and not being able to get the
total passband any narrower than it.
I found that the 500 Hz filters with occasional narrowing with the
VBT was all I needed. Also, although I am not a big time CW
contester, I believe the consensus I have heard from those who are
is that 250/270 Hz filters are just too narrow for contesting. The
sentiment is that the passband is too narrow to effectively search
it for answers while CQing, and similarly, the passband is too
narrow to allow reasonable tuning speed while S&Ping.
I don't believe IRC has a home page, but whatever you do, see if you
can get a compilation of all the mods that were published. One of
them allows you to cut down the tuning speed of the VFO 230 by quite
a bit, and make CW tuning easier.
Regarding the transverter mod we discussed earlier, some
modifications of the transverter are necessary to get bias from the
'830 over to it, and I think I remember you have to reverse the
keying. Having done the mod, I came to the conclusion that, while the
transverter was very effective, particularly with all the great
signal handling capabilities of the '830, it really wasn't worth the
bother, and that a dedicated VHF all-mode radio was a better
investment.
73, Rod N4SI
The DXer formerly known as N9AKE
(c) 5 November, 1996
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