[TenTec] INRAD 600Hz Orion filter arrived
Bill Tippett
btippett at alum.mit.edu
Wed Aug 11 21:43:18 EDT 2004
N5TW:
>Since W4ZV raised good questions about
putting the 1.8KHz filter in the 2.4KHz slot, I decided to leave the 1.8KHz
filter where it was. Pretty easy to turn that on in SSB contests and have
the flexibility of using the DSP filter in less demanding times.
Tom, as I said you really give up nothing doing that since the
1.8 kHz has identical IMD performance to the 1.0 kHz at signal spacings
down to 2 kHz. Below that, you want the 600 Hz over either the 1.0 or
1.8. Plus you have the 1.8 kHz there when you need it for SSB. If I
thought there was a market for my 1.0 kHz I would probably sell it. I
doubt there is so I'll just keep it around to reinstall for whenever I'm
ready to sell my Orion.
On another note, if any of you have Spectrogram, it is very
interesting
to see the effect of PBT on shifting the center of the roofing filter. You
must set DSP = 6000 to view this since the DSP will mask the roofing filter if
it is set nearly the same as the roofing filter bandwidth. I had not realized
how effective this might be in helping the roofing filter do an even better job
if you have particularly bad interference to one side. If my ISP ever fixes a
problem they have which is preventing me from updating my webpage, I may post
a few screen shots to illustrate the effect.
73, Bill W4ZV
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