[TenTec] Orion - second week impressions and comparisons

[Bill Tippett <btippett@alum.mit.edu>]

Hi John,

N0KHQ wrote:
>I'm mess'in around with filters right now. I ordered an Inrad # 754 / 2.8
which will go in the Orion 2.4 slot, the 2.4 will be moved to the 1.8 slot and
the 1.8 will be moved to the 1.0 slot, the 1.0 will be moved to the 500 
slot and
finally the 500 will be put  up for safe keeping.

        I realize you don't operate CW, but putting the 1.0 in the 500
slot is not a good idea for the following reasons:

1.  All of the filters designed for the 1000 and up slots use an
IF center frequency 750 Hz higher than the 500/250 slots.  This can
cause problems with alignment of UCW, LCW, PBT, etc.  That's not a
big issue if you never operate CW, but something to think about.
BTW, if you really like the low bands, I predict you will eventually
migrate to CW.

2.  The insertion loss of the 1000 is probably ~4 dB less than the
500, which is already overcompensated by about 5-6 dB.  This means
you will probably see a ~10 dB gain bump as you switch from the 1.8
filter to the 1.0, which will also probably degrade IMD.

        If I were you, I would set aside your 2.4, put the 1.8 in the
1.8 slot and leave the 1.0 where it is.  I doubt you would ever
miss having the 2.4 since there is such a slight difference in
bandwidth with the 2.8, and you have the 1.8 for really tough QRM.

                                                73,  Bill  W4ZV





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