[Orion] [TenTec] wanted: TT filters

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

N7XM wrote:
>I already found a 1.8 khz filter
>Now for the 500 hz  or 250 hz

        Josh, for you and any others outfitting a new Orion,
here is what I have in mine after having tried the Ten-Tec
217 (500 Hz), 218 (1800 Hz), 219 (250 Hz), Inrad 759 (400 Hz)
and Inrad 762 (aka #352 kit).

1800 Hz position:  TT 218 (Inrad 761 would be fine also)
1000 Hz position:  Inrad 762 (600 Hz)
500 Hz position:  Nothing (my 1000 Hz is stored there but disabled)
250 Hz position:  Nothing

This setup does the following:

1.  It solves the IMD degradation issue in the 500 & 250 slots.
This was first discovered by ARRL last December in their Expanded
Test Report and has been verified by many others.  More info here:
http://users.vnet.net/btippett/inrad_.htm

2.  The 1800 Hz filters (either TT 218 or Inrad 761) are wonderful
in SSB contests or low band SSB pileups but you must set PBT = 150
or higher to make SSB bandwidths down to DSP = 1600 intelligible.

3.  For some unexplained reason, the 1800 Hz filter's actual bandwidth
on CW is around 1400 Hz.  This makes it a very nice complement to the
Inrad 762 for casual CW tuning when narrower bandwidth is not needed.

4.  You must also be aware of the roofing filter set points.  This
is a problem with the 1800 Hz since it is not currently activated
until DSP = 1400 or less, making it unusable on SSB unless you
lock Filter Menu to the 1800 position.  The next firmware upgrade
will address this issue but it still pays to understand where roofing
filters are activated in Filter Auto if you select that.

        Most of this has been discussed extensively on this reflector,
but I seem to be getting a lot of individual questions from new
Orion owners so am repeating this for any who have not followed the
history.

                                                        73,  Bill  W4ZV

P.S.  If not a contester or low band DX'er, there is probably NO need
for any additional filters beyond what is standard with Orion. 
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