Nope. The cover is not much of an issue. Inrad encloses their filters, thus
they are a little higher. The filters are in the top section of the Orion,
thus have very little risk of wiggling loose. The cover, however does keep
the TT filters firmly in their sockets, until you install the Inrad. But I
really don't think its an issue.
I think Bill's original idea was to get a little tighter roofing filter than
the 1kc filter, and then not use the 500 and 250 Hz filters, primarily
because of the degradation of IMD performance from those filters amplifiers.
Mind you, I've only had the 600hz filter a day, and used it for several
hours in this weekend's WAE contest, and it sure is impressive. Since you
only select one filter at a time, the reduced IMD performance only occurs
when you select the two most narrow filters, and then you only select them
when your trying to dig out a very weak CW signal, so they do not degrade
rcvr performance unless you actually select them. For this contest, I
manually went back and forth from the 1kc to the 600Hz filter, but mainly
stuck with the 600Hz. It, along with the DSP filtering worked quite well for
me so far.
Heck, it's available, why not try it for youself and see what works best for
you?
Tom - W4BQF
----- Original Message -----
From: "Toby Pennington" <toby423@earthlink.net>
To: <tentec@contesting.com>
Sent: Saturday, August 14, 2004 1:49 PM
Subject: Re: [TenTec] Inrad 762
> Tommy, I thought the whole idea of the 600hz filter was to get better IMD
> from 750hz on down to 100 hz, so I wonder about you keeping the two other
> filters enabled. Have you tried just the 600hz with the 500 and 250 hz
> filters disengaged. If so, what have you noticed. First I have heard
about
> the filter cover not being able to be tightened all the way down. Hope
this
> is not much of an issue. Toby W4CAK
>
> ----- Original Message -----
> From: "Tommy" <aldermant@alltel.net>
> To: <tentec@contesting.com>
> Sent: Saturday, August 14, 2004 1:15 PM
> Subject: Re: [TenTec] Inrad 762
>
>
> > Tody,
> >
> > I concur with Bill's writting's. I didn't have the 1.8kc filter in my
> Orion,
> > so I moved the 1kc filter into the 1.8kc slot, put the 600hz filter into
> the
> > 1kc slot, and left the 500hz and 250hz filters installed and enabled.
> Really
> > sounds quite impressive, especially in this CW contest going on this
> > weekend.
> >
> > The Inrad filter is almost a half an inch taller than the TT filters,
but
> I
> > did put the cover back over the filters, but just did not tighten it
down
> > fully. If I was going to keep my Orion, I would modify the filter cover.
> >
> > Tom - W4BQF
> >
> > ----- Original Message -----
> > From: "Bill Tippett" <btippett@alum.mit.edu>
> > To: <tentec@contesting.com>
> > Sent: Saturday, August 14, 2004 11:10 AM
> > Subject: [TenTec] Inrad 762
> >
> >
> > > Hi Toby,
> > >
> > > W4CAK wrote:
> > > >Has anyone tried putting the New Inrad #762 in the 500hz slot of the
> > > Orion. Since the 1khz filter does an excellent job down to 380 hz,
> would
> > > this not be a better use of the 762?
> > >
> > > That won't work very well for several reasons:
> > >
> > > 1. The 500 slot always has the second amplifier engaged...thus it
> > > should still be introducing IMD products.
> > >
> > > 2. The 4-pole Inrad 762 has less insertion loss than standard 8-pole
> > > 500 Hz filters, aggravating the fact that the 500 position already has
> > > too much gain, even for the standard 500 Hz filters. TT used a
> > > fixed 12 dB gain amplifier for both the 500/250 slots. That is a
> > > good match for the 250's high insertion loss but too much for a 500.
> > >
> > > 3. The center frequency of the 762 is 9.001500 but Orion thinks
> > > the 500 position has a 9.000750 Hz center frequency. Thus the
> > > filter will not be correctly centered, although you can partially
> > > compensate for this by using both C.F. Adjust and PBT. I think
> > > it can be made to work for UCW but not LCW (could be the other way
> > > around in the case you propose). If you compensate using PBT,
> > > signals will disappear any time you switch to a different roofing
> > > filter.
> > >
> > > I went through the same thinking when first looking into this
> > > filter issue, but I tried installing the 500 Hz filter into the
> > > 1000 Hz position. That doesn't work well either for similar reasons.
> > >
> > > Just plug your 762 into the 1000 Hz slot and everything works
> > fine.
> > > If your 1800 slot is empty, put your 1000 there. If you already have
> > > an 1800, simply set your 1000 aside...you'll never miss it for reasons
> > > I've explained many times (1800 & 1000 being equivalent IMD fighters
> > > down to 2 kHz spacings where the 762 will take over and is far
> > > superior to either).
> > >
> > > 73, Bill W4ZV
> > >
> > >
> > >
> > > _______________________________________________
> > > TenTec mailing list
> > > TenTec@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/tentec
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|