Grant,
I guess we don't have a complete meeting of the minds. It seems that all
new equipment designs are using the conversion to a very high IF frequency,
allowing continuous tuning. Ten-Tec chose in the Orion and previous
transceivers to use a much lower IF which allows them a much tighter band
width with in the crystal filters.
Look at diagram 81910.pdf in the Orion I diagrams. The 500Hz and 250Hz
follow the other filters. If I remember correctly, when the signal comes
through the filter circuit, the 1000 Hz filter is active ahead of the 500
and 250. In the Orion II, the 600 and 300 are in the same bank as all of
the other filters.
It looks like my choice of words was not correct for the Orion I. The 500
and 250 would still be roofing filters. With the extra amplifier for the
500 and 250, hopefully addition noise is not introduced.
John
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Grant Youngman
Sent: Monday, May 29, 2006 3:16 PM
To: 'Discussion of Ten-Tec Equipment'
Subject: Re: [TenTec] FT-2000 Webpage
> In the Orion I, the very tight filter is after the roofing
> filter. An amplifier state is switched in to make up for the losses.
>
> The Orion II has all filters as roofing filters.
Huh? What does that mean? Are yo implying that all of the iflters in the
Orion aren't roofing filters (there is no Orion I)? Funny how well those
"old design techniques" work ...
Grant/NQ5T
_______________________________________________
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
|